This patch series enable reserving crashkernel above 4G in arm64.
There are following issues in arm64 kdump:
1. We use crashkernel=X to reserve crashkernel below 4G, which will fail
when there is no enough low memory.
2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G,
in this case, if swiotlb or DMA buffers are required, crash dump kernel
will boot failure because there is no low memory available for allocation.
To solve these issues, introduce crashkernel=X,low to reserve specified
size low memory.
Crashkernel=X tries to reserve memory for the crash dump kernel under
4G. If crashkernel=Y,low is specified simultaneously, reserve spcified
size low memory for crash kdump kernel devices firstly and then reserve
memory above 4G.
When crashkernel is reserved above 4G in memory, that is, crashkernel=X,low
is specified simultaneously, kernel should reserve specified size low memory
for crash dump kernel devices. So there may be two crash kernel regions, one
is below 4G, the other is above 4G.
In order to distinct from the high region and make no effect to the use of
kexec-tools, rename the low region as "Crash kernel (low)", and add DT property
"linux,low-memory-range" to crash dump kernel's dtb to pass the low region.
Besides, we need to modify kexec-tools:
arm64: kdump: add another DT property to crash dump kernel's dtb(see [1])
The previous changes and discussions can be retrieved from:
Changes since [v7]
- Move x86 CRASH_ALIGN to 2M
Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
- Update Documentation/devicetree/bindings/chosen.txt
Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt suggested by Arnd.
- Add Tested-by from Jhon and pk
Changes since [v6]
- Fix build errors reported by kbuild test robot.
Changes since [v5]
- Move reserve_crashkernel_low() into kernel/crash_core.c.
- Delete crashkernel=X,high.
- Modify crashkernel=X,low.
If crashkernel=X,low is specified simultaneously, reserve spcified size low
memory for crash kdump kernel devices firstly and then reserve memory above 4G.
In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
pass to crash dump kernel by DT property "linux,low-memory-range".
- Update Documentation/admin-guide/kdump/kdump.rst.
Changes since [v4]
- Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.
Changes since [v3]
- Add memblock_cap_memory_ranges back for multiple ranges.
- Fix some compiling warnings.
Changes since [v2]
- Split patch "arm64: kdump: support reserving crashkernel above 4G" as
two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
patch.
Changes since [v1]:
- Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
- Remove memblock_cap_memory_ranges() i added in v1 and implement that
in fdt_enforce_memory_region().
There are at most two crash kernel regions, for two crash kernel regions
case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
and then remove the memory range in the middle.
[1]: http://lists.infradead.org/pipermail/kexec/2020-May/025128.html
[v1]: https://lkml.org/lkml/2019/4/2/1174
[v2]: https://lkml.org/lkml/2019/4/9/86
[v3]: https://lkml.org/lkml/2019/4/9/306
[v4]: https://lkml.org/lkml/2019/4/15/273
[v5]: https://lkml.org/lkml/2019/5/6/1360
[v6]: https://lkml.org/lkml/2019/8/30/142
[v7]: https://lkml.org/lkml/2019/12/23/411
Chen Zhou (5):
x86: kdump: move reserve_crashkernel_low() into crash_core.c
arm64: kdump: reserve crashkenel above 4G for crash dump kernel
arm64: kdump: add memory for devices by DT property, low-memory-range
kdump: update Documentation about crashkernel on arm64
dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump
Documentation/admin-guide/kdump/kdump.rst | 13 ++-
.../admin-guide/kernel-parameters.txt | 12 ++-
Documentation/devicetree/bindings/chosen.txt | 25 ++++++
arch/arm64/kernel/setup.c | 8 +-
arch/arm64/mm/init.c | 61 ++++++++++++-
arch/x86/kernel/setup.c | 66 ++------------
include/linux/crash_core.h | 3 +
include/linux/kexec.h | 2 -
kernel/crash_core.c | 85 +++++++++++++++++++
kernel/kexec_core.c | 17 ----
10 files changed, 208 insertions(+), 84 deletions(-)
--
2.20.1
On 05/21/20 at 05:38pm, Chen Zhou wrote:
> This patch series enable reserving crashkernel above 4G in arm64.
>
> There are following issues in arm64 kdump:
> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail
> when there is no enough low memory.
> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G,
> in this case, if swiotlb or DMA buffers are required, crash dump kernel
> will boot failure because there is no low memory available for allocation.
>
> To solve these issues, introduce crashkernel=X,low to reserve specified
> size low memory.
> Crashkernel=X tries to reserve memory for the crash dump kernel under
> 4G. If crashkernel=Y,low is specified simultaneously, reserve spcified
> size low memory for crash kdump kernel devices firstly and then reserve
> memory above 4G.
>
> When crashkernel is reserved above 4G in memory, that is, crashkernel=X,low
> is specified simultaneously, kernel should reserve specified size low memory
> for crash dump kernel devices. So there may be two crash kernel regions, one
> is below 4G, the other is above 4G.
> In order to distinct from the high region and make no effect to the use of
> kexec-tools, rename the low region as "Crash kernel (low)", and add DT property
> "linux,low-memory-range" to crash dump kernel's dtb to pass the low region.
>
> Besides, we need to modify kexec-tools:
> arm64: kdump: add another DT property to crash dump kernel's dtb(see [1])
>
> The previous changes and discussions can be retrieved from:
>
> Changes since [v7]
> - Move x86 CRASH_ALIGN to 2M
> Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
OK, moving x86 CRASH_ALIGN to 2M is suggested by Dave. Because
CONFIG_PHYSICAL_ALIGN can be selected from 2M to 16M. So 2M seems good.
But, anyway, we should tell the reason why it need be changed in commit
log.
arch/x86/Kconfig:
config PHYSICAL_ALIGN
hex "Alignment value to which kernel should be aligned"
default "0x200000"
range 0x2000 0x1000000 if X86_32
range 0x200000 0x1000000 if X86_64
> - Update Documentation/devicetree/bindings/chosen.txt
> Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt suggested by Arnd.
> - Add Tested-by from Jhon and pk
>
> Changes since [v6]
> - Fix build errors reported by kbuild test robot.
>
> Changes since [v5]
> - Move reserve_crashkernel_low() into kernel/crash_core.c.
> - Delete crashkernel=X,high.
And the crashkernel=X,high being deleted need be told too. Otherwise
people reading the commit have to check why themselves. I didn't follow
the old version, can't see why ,high can't be specified explicitly.
> - Modify crashkernel=X,low.
> If crashkernel=X,low is specified simultaneously, reserve spcified size low
> memory for crash kdump kernel devices firstly and then reserve memory above 4G.
> In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
> pass to crash dump kernel by DT property "linux,low-memory-range".
> - Update Documentation/admin-guide/kdump/kdump.rst.
>
> Changes since [v4]
> - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.
>
> Changes since [v3]
> - Add memblock_cap_memory_ranges back for multiple ranges.
> - Fix some compiling warnings.
>
> Changes since [v2]
> - Split patch "arm64: kdump: support reserving crashkernel above 4G" as
> two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
> patch.
>
> Changes since [v1]:
> - Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
> - Remove memblock_cap_memory_ranges() i added in v1 and implement that
> in fdt_enforce_memory_region().
> There are at most two crash kernel regions, for two crash kernel regions
> case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
> and then remove the memory range in the middle.
>
> [1]: http://lists.infradead.org/pipermail/kexec/2020-May/025128.html
> [v1]: https://lkml.org/lkml/2019/4/2/1174
> [v2]: https://lkml.org/lkml/2019/4/9/86
> [v3]: https://lkml.org/lkml/2019/4/9/306
> [v4]: https://lkml.org/lkml/2019/4/15/273
> [v5]: https://lkml.org/lkml/2019/5/6/1360
> [v6]: https://lkml.org/lkml/2019/8/30/142
> [v7]: https://lkml.org/lkml/2019/12/23/411
>
> Chen Zhou (5):
> x86: kdump: move reserve_crashkernel_low() into crash_core.c
> arm64: kdump: reserve crashkenel above 4G for crash dump kernel
> arm64: kdump: add memory for devices by DT property, low-memory-range
> kdump: update Documentation about crashkernel on arm64
> dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump
>
> Documentation/admin-guide/kdump/kdump.rst | 13 ++-
> .../admin-guide/kernel-parameters.txt | 12 ++-
> Documentation/devicetree/bindings/chosen.txt | 25 ++++++
> arch/arm64/kernel/setup.c | 8 +-
> arch/arm64/mm/init.c | 61 ++++++++++++-
> arch/x86/kernel/setup.c | 66 ++------------
> include/linux/crash_core.h | 3 +
> include/linux/kexec.h | 2 -
> kernel/crash_core.c | 85 +++++++++++++++++++
> kernel/kexec_core.c | 17 ----
> 10 files changed, 208 insertions(+), 84 deletions(-)
>
> --
> 2.20.1
>
>
> _______________________________________________
> kexec mailing list
> [email protected]
> http://lists.infradead.org/mailman/listinfo/kexec
>
Hi Baoquan,
Thanks for your suggestions.
You are right, some details should be made in the commit log.
Thanks,
Chen Zhou
On 2020/5/26 9:42, Baoquan He wrote:
> On 05/21/20 at 05:38pm, Chen Zhou wrote:
>> This patch series enable reserving crashkernel above 4G in arm64.
>>
>> There are following issues in arm64 kdump:
>> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail
>> when there is no enough low memory.
>> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G,
>> in this case, if swiotlb or DMA buffers are required, crash dump kernel
>> will boot failure because there is no low memory available for allocation.
>>
>> To solve these issues, introduce crashkernel=X,low to reserve specified
>> size low memory.
>> Crashkernel=X tries to reserve memory for the crash dump kernel under
>> 4G. If crashkernel=Y,low is specified simultaneously, reserve spcified
>> size low memory for crash kdump kernel devices firstly and then reserve
>> memory above 4G.
>>
>> When crashkernel is reserved above 4G in memory, that is, crashkernel=X,low
>> is specified simultaneously, kernel should reserve specified size low memory
>> for crash dump kernel devices. So there may be two crash kernel regions, one
>> is below 4G, the other is above 4G.
>> In order to distinct from the high region and make no effect to the use of
>> kexec-tools, rename the low region as "Crash kernel (low)", and add DT property
>> "linux,low-memory-range" to crash dump kernel's dtb to pass the low region.
>>
>> Besides, we need to modify kexec-tools:
>> arm64: kdump: add another DT property to crash dump kernel's dtb(see [1])
>>
>> The previous changes and discussions can be retrieved from:
>>
>> Changes since [v7]
>> - Move x86 CRASH_ALIGN to 2M
>> Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
> OK, moving x86 CRASH_ALIGN to 2M is suggested by Dave. Because
> CONFIG_PHYSICAL_ALIGN can be selected from 2M to 16M. So 2M seems good.
> But, anyway, we should tell the reason why it need be changed in commit
> log.
>
>
> arch/x86/Kconfig:
> config PHYSICAL_ALIGN
> hex "Alignment value to which kernel should be aligned"
> default "0x200000"
> range 0x2000 0x1000000 if X86_32
> range 0x200000 0x1000000 if X86_64
>
>> - Update Documentation/devicetree/bindings/chosen.txt
>> Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt suggested by Arnd.
>> - Add Tested-by from Jhon and pk
>>
>> Changes since [v6]
>> - Fix build errors reported by kbuild test robot.
>>
>> Changes since [v5]
>> - Move reserve_crashkernel_low() into kernel/crash_core.c.
>> - Delete crashkernel=X,high.
> And the crashkernel=X,high being deleted need be told too. Otherwise
> people reading the commit have to check why themselves. I didn't follow
> the old version, can't see why ,high can't be specified explicitly.
>
>> - Modify crashkernel=X,low.
>> If crashkernel=X,low is specified simultaneously, reserve spcified size low
>> memory for crash kdump kernel devices firstly and then reserve memory above 4G.
>> In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
>> pass to crash dump kernel by DT property "linux,low-memory-range".
>> - Update Documentation/admin-guide/kdump/kdump.rst.
>>
>> Changes since [v4]
>> - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.
>>
>> Changes since [v3]
>> - Add memblock_cap_memory_ranges back for multiple ranges.
>> - Fix some compiling warnings.
>>
>> Changes since [v2]
>> - Split patch "arm64: kdump: support reserving crashkernel above 4G" as
>> two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
>> patch.
>>
>> Changes since [v1]:
>> - Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
>> - Remove memblock_cap_memory_ranges() i added in v1 and implement that
>> in fdt_enforce_memory_region().
>> There are at most two crash kernel regions, for two crash kernel regions
>> case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
>> and then remove the memory range in the middle.
>>
>> [1]: http://lists.infradead.org/pipermail/kexec/2020-May/025128.html
>> [v1]: https://lkml.org/lkml/2019/4/2/1174
>> [v2]: https://lkml.org/lkml/2019/4/9/86
>> [v3]: https://lkml.org/lkml/2019/4/9/306
>> [v4]: https://lkml.org/lkml/2019/4/15/273
>> [v5]: https://lkml.org/lkml/2019/5/6/1360
>> [v6]: https://lkml.org/lkml/2019/8/30/142
>> [v7]: https://lkml.org/lkml/2019/12/23/411
>>
>> Chen Zhou (5):
>> x86: kdump: move reserve_crashkernel_low() into crash_core.c
>> arm64: kdump: reserve crashkenel above 4G for crash dump kernel
>> arm64: kdump: add memory for devices by DT property, low-memory-range
>> kdump: update Documentation about crashkernel on arm64
>> dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump
>>
>> Documentation/admin-guide/kdump/kdump.rst | 13 ++-
>> .../admin-guide/kernel-parameters.txt | 12 ++-
>> Documentation/devicetree/bindings/chosen.txt | 25 ++++++
>> arch/arm64/kernel/setup.c | 8 +-
>> arch/arm64/mm/init.c | 61 ++++++++++++-
>> arch/x86/kernel/setup.c | 66 ++------------
>> include/linux/crash_core.h | 3 +
>> include/linux/kexec.h | 2 -
>> kernel/crash_core.c | 85 +++++++++++++++++++
>> kernel/kexec_core.c | 17 ----
>> 10 files changed, 208 insertions(+), 84 deletions(-)
>>
>> --
>> 2.20.1
>>
>>
>> _______________________________________________
>> kexec mailing list
>> [email protected]
>> http://lists.infradead.org/mailman/listinfo/kexec
>>
>
> .
>
On 5/25/20 8:42 PM, Baoquan He wrote:
> On 05/21/20 at 05:38pm, Chen Zhou wrote:
>> This patch series enable reserving crashkernel above 4G in arm64.
>>
>> There are following issues in arm64 kdump:
>> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail
>> when there is no enough low memory.
>> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G,
>> in this case, if swiotlb or DMA buffers are required, crash dump kernel
>> will boot failure because there is no low memory available for allocation.
>>
>> To solve these issues, introduce crashkernel=X,low to reserve specified
>> size low memory.
>> Crashkernel=X tries to reserve memory for the crash dump kernel under
>> 4G. If crashkernel=Y,low is specified simultaneously, reserve spcified
>> size low memory for crash kdump kernel devices firstly and then reserve
>> memory above 4G.
>>
>> When crashkernel is reserved above 4G in memory, that is, crashkernel=X,low
>> is specified simultaneously, kernel should reserve specified size low memory
>> for crash dump kernel devices. So there may be two crash kernel regions, one
>> is below 4G, the other is above 4G.
>> In order to distinct from the high region and make no effect to the use of
>> kexec-tools, rename the low region as "Crash kernel (low)", and add DT property
>> "linux,low-memory-range" to crash dump kernel's dtb to pass the low region.
>>
>> Besides, we need to modify kexec-tools:
>> arm64: kdump: add another DT property to crash dump kernel's dtb(see [1])
>>
>> The previous changes and discussions can be retrieved from:
>>
>> Changes since [v7]
>> - Move x86 CRASH_ALIGN to 2M
>> Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
> OK, moving x86 CRASH_ALIGN to 2M is suggested by Dave. Because
> CONFIG_PHYSICAL_ALIGN can be selected from 2M to 16M. So 2M seems good.
> But, anyway, we should tell the reason why it need be changed in commit
> log.
>
>
> arch/x86/Kconfig:
> config PHYSICAL_ALIGN
> hex "Alignment value to which kernel should be aligned"
> default "0x200000"
> range 0x2000 0x1000000 if X86_32
> range 0x200000 0x1000000 if X86_64
>
>> - Update Documentation/devicetree/bindings/chosen.txt
>> Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt suggested by Arnd.
>> - Add Tested-by from Jhon and pk
>>
>> Changes since [v6]
>> - Fix build errors reported by kbuild test robot.
>>
>> Changes since [v5]
>> - Move reserve_crashkernel_low() into kernel/crash_core.c.
>> - Delete crashkernel=X,high.
> And the crashkernel=X,high being deleted need be told too. Otherwise
> people reading the commit have to check why themselves. I didn't follow
> the old version, can't see why ,high can't be specified explicitly.
>
>> - Modify crashkernel=X,low.
>> If crashkernel=X,low is specified simultaneously, reserve spcified size low
>> memory for crash kdump kernel devices firstly and then reserve memory above 4G.
>> In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
>> pass to crash dump kernel by DT property "linux,low-memory-range".
>> - Update Documentation/admin-guide/kdump/kdump.rst.
>>
>> Changes since [v4]
>> - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.
>>
>> Changes since [v3]
>> - Add memblock_cap_memory_ranges back for multiple ranges.
>> - Fix some compiling warnings.
>>
>> Changes since [v2]
>> - Split patch "arm64: kdump: support reserving crashkernel above 4G" as
>> two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
>> patch.
>>
>> Changes since [v1]:
>> - Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
>> - Remove memblock_cap_memory_ranges() i added in v1 and implement that
>> in fdt_enforce_memory_region().
>> There are at most two crash kernel regions, for two crash kernel regions
>> case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
>> and then remove the memory range in the middle.
>>
>> [1]: https://urldefense.com/v3/__http://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJwQs3C4x$
>> [v1]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/2/1174__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJ6e-mIEp$
>> [v2]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/86__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJyUVjUta$
>> [v3]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/306__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJ3CXBRdT$
>> [v4]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/15/273__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJ7SxW1Vj$
>> [v5]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/5/6/1360__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJ2wyJ9tj$
>> [v6]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/8/30/142__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJzvGhWBh$
>> [v7]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/12/23/411__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJ6pAg6tX$
>>
>> Chen Zhou (5):
>> x86: kdump: move reserve_crashkernel_low() into crash_core.c
>> arm64: kdump: reserve crashkenel above 4G for crash dump kernel
>> arm64: kdump: add memory for devices by DT property, low-memory-range
>> kdump: update Documentation about crashkernel on arm64
>> dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump
>>
>> Documentation/admin-guide/kdump/kdump.rst | 13 ++-
>> .../admin-guide/kernel-parameters.txt | 12 ++-
>> Documentation/devicetree/bindings/chosen.txt | 25 ++++++
>> arch/arm64/kernel/setup.c | 8 +-
>> arch/arm64/mm/init.c | 61 ++++++++++++-
>> arch/x86/kernel/setup.c | 66 ++------------
>> include/linux/crash_core.h | 3 +
>> include/linux/kexec.h | 2 -
>> kernel/crash_core.c | 85 +++++++++++++++++++
>> kernel/kexec_core.c | 17 ----
>> 10 files changed, 208 insertions(+), 84 deletions(-)
>>
>> --
>> 2.20.1
>>
>>
>> _______________________________________________
>> kexec mailing list
>> [email protected]
>> https://urldefense.com/v3/__http://lists.infradead.org/mailman/listinfo/kexec__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJwwX8HSl$
>>
Hi,
This proposal to improve vmcore creation on Arm has been going on for
almost a year now.
Who is the final maintainer that needs to approve and except these ?
What are the lingering issues that are remaining so we get these
accepted into a upstream commit ?
Thank you.
John.
[+James Morse]
On Thu, May 28, 2020 at 05:20:34PM -0500, John Donnelly wrote:
> On 5/25/20 8:42 PM, Baoquan He wrote:
> > On 05/21/20 at 05:38pm, Chen Zhou wrote:
> > > This patch series enable reserving crashkernel above 4G in arm64.
[...]
> > > Chen Zhou (5):
> > > x86: kdump: move reserve_crashkernel_low() into crash_core.c
> > > arm64: kdump: reserve crashkenel above 4G for crash dump kernel
> > > arm64: kdump: add memory for devices by DT property, low-memory-range
> > > kdump: update Documentation about crashkernel on arm64
> > > dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump
> > >
> > > Documentation/admin-guide/kdump/kdump.rst | 13 ++-
> > > .../admin-guide/kernel-parameters.txt | 12 ++-
> > > Documentation/devicetree/bindings/chosen.txt | 25 ++++++
> > > arch/arm64/kernel/setup.c | 8 +-
> > > arch/arm64/mm/init.c | 61 ++++++++++++-
> > > arch/x86/kernel/setup.c | 66 ++------------
> > > include/linux/crash_core.h | 3 +
> > > include/linux/kexec.h | 2 -
> > > kernel/crash_core.c | 85 +++++++++++++++++++
> > > kernel/kexec_core.c | 17 ----
> > > 10 files changed, 208 insertions(+), 84 deletions(-)
> > >
> This proposal to improve vmcore creation on Arm? has been going on for
> almost a year now.
>
> Who is the? final maintainer that needs to approve and except these ?
>
> What are the lingering issues that are remaining so we get these accepted
> into a upstream commit ?
The arm64 bits need an Ack from James Morse, but he's not on CC despite
offering feedback on earlier versions.
Will
Hi Chen,
On Thu, May 21, 2020 at 3:05 PM Chen Zhou <[email protected]> wrote:
>
> This patch series enable reserving crashkernel above 4G in arm64.
>
> There are following issues in arm64 kdump:
> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail
> when there is no enough low memory.
> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G,
> in this case, if swiotlb or DMA buffers are required, crash dump kernel
> will boot failure because there is no low memory available for allocation.
>
> To solve these issues, introduce crashkernel=X,low to reserve specified
> size low memory.
> Crashkernel=X tries to reserve memory for the crash dump kernel under
> 4G. If crashkernel=Y,low is specified simultaneously, reserve spcified
> size low memory for crash kdump kernel devices firstly and then reserve
> memory above 4G.
>
> When crashkernel is reserved above 4G in memory, that is, crashkernel=X,low
> is specified simultaneously, kernel should reserve specified size low memory
> for crash dump kernel devices. So there may be two crash kernel regions, one
> is below 4G, the other is above 4G.
> In order to distinct from the high region and make no effect to the use of
> kexec-tools, rename the low region as "Crash kernel (low)", and add DT property
> "linux,low-memory-range" to crash dump kernel's dtb to pass the low region.
>
> Besides, we need to modify kexec-tools:
> arm64: kdump: add another DT property to crash dump kernel's dtb(see [1])
>
> The previous changes and discussions can be retrieved from:
>
> Changes since [v7]
> - Move x86 CRASH_ALIGN to 2M
> Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
> - Update Documentation/devicetree/bindings/chosen.txt
> Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt suggested by Arnd.
> - Add Tested-by from Jhon and pk
>
> Changes since [v6]
> - Fix build errors reported by kbuild test robot.
>
> Changes since [v5]
> - Move reserve_crashkernel_low() into kernel/crash_core.c.
> - Delete crashkernel=X,high.
> - Modify crashkernel=X,low.
> If crashkernel=X,low is specified simultaneously, reserve spcified size low
> memory for crash kdump kernel devices firstly and then reserve memory above 4G.
> In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
> pass to crash dump kernel by DT property "linux,low-memory-range".
> - Update Documentation/admin-guide/kdump/kdump.rst.
>
> Changes since [v4]
> - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.
>
> Changes since [v3]
> - Add memblock_cap_memory_ranges back for multiple ranges.
> - Fix some compiling warnings.
>
> Changes since [v2]
> - Split patch "arm64: kdump: support reserving crashkernel above 4G" as
> two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
> patch.
>
> Changes since [v1]:
> - Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
> - Remove memblock_cap_memory_ranges() i added in v1 and implement that
> in fdt_enforce_memory_region().
> There are at most two crash kernel regions, for two crash kernel regions
> case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
> and then remove the memory range in the middle.
>
> [1]: http://lists.infradead.org/pipermail/kexec/2020-May/025128.html
> [v1]: https://lkml.org/lkml/2019/4/2/1174
> [v2]: https://lkml.org/lkml/2019/4/9/86
> [v3]: https://lkml.org/lkml/2019/4/9/306
> [v4]: https://lkml.org/lkml/2019/4/15/273
> [v5]: https://lkml.org/lkml/2019/5/6/1360
> [v6]: https://lkml.org/lkml/2019/8/30/142
> [v7]: https://lkml.org/lkml/2019/12/23/411
>
> Chen Zhou (5):
> x86: kdump: move reserve_crashkernel_low() into crash_core.c
> arm64: kdump: reserve crashkenel above 4G for crash dump kernel
> arm64: kdump: add memory for devices by DT property, low-memory-range
> kdump: update Documentation about crashkernel on arm64
> dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump
>
We are getting "warn_alloc" [1] warning during boot of kdump kernel
with bootargs as [2] of primary kernel.
This error observed on ThunderX2 ARM64 platform.
It is observed with latest upstream tag (v5.7-rc3) with this patch set
and https://lists.infradead.org/pipermail/kexec/2020-May/025128.html
Also **without** this patch-set
"https://www.spinics.net/lists/arm-kernel/msg806882.html"
This issue comes whenever crashkernel memory is reserved after 0xc000_0000.
More details discussed earlier in
https://www.spinics.net/lists/arm-kernel/msg806882.html without any
solution
This patch-set is expected to solve similar kind of issue.
i.e. low memory is only targeted for DMA, swiotlb; So above mentioned
observation should be considered/fixed. .
--pk
[1]
[ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
[ 30.367696] NET: Registered protocol family 16
[ 30.369973] swapper/0: page allocation failure: order:6,
mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
[ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc3+ #121
[ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS
TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
[ 30.369984] Call trace:
[ 30.369989] dump_backtrace+0x0/0x1f8
[ 30.369991] show_stack+0x20/0x30
[ 30.369997] dump_stack+0xc0/0x10c
[ 30.370001] warn_alloc+0x10c/0x178
[ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0xb50
[ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
[ 30.370008] alloc_page_interleave+0x24/0x98
[ 30.370011] alloc_pages_current+0xe4/0x108
[ 30.370017] dma_atomic_pool_init+0x44/0x1a4
[ 30.370020] do_one_initcall+0x54/0x228
[ 30.370027] kernel_init_freeable+0x228/0x2cc
[ 30.370031] kernel_init+0x1c/0x110
[ 30.370034] ret_from_fork+0x10/0x18
[ 30.370036] Mem-Info:
[ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0
[ 30.370064] active_file:0 inactive_file:0 isolated_file:0
[ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0
[ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438
[ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
[ 30.370064] free:1537719 free_pcp:219 free_cma:0
[ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
unstable:0kB all_unreclaimable? no
[ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
unstable:0kB all_unreclaimable? no
[ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB
reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
present:128kB managed:0kB mlocked:0kB kernel_stack:0kB pagetables:0kB
bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[ 30.370084] lowmem_reserve[]: 0 250 6063 6063
[ 30.370090] Node 0 DMA32 free:256000kB min:408kB low:664kB
high:920kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
present:269700kB managed:256000kB mlocked:0kB kernel_stack:0kB
pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[ 30.370094] lowmem_reserve[]: 0 0 5813 5813
[ 30.370100] Node 0 Normal free:5894876kB min:9552kB low:15504kB
high:21456kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
present:8388608kB managed:5953112kB mlocked:0kB kernel_stack:21672kB
pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB free_cma:0kB
[ 30.370104] lowmem_reserve[]: 0 0 0 0
[ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
[ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) = 256000kB
[ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB (UE) 3*32kB
(UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME) 3*1024kB (ME)
3*2048kB (UME) 1436*4096kB (M) = 5893600kB
[ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
hugepages_surp=0 hugepages_size=1048576kB
[ 30.370130] 0 total pagecache pages
[ 30.370132] 0 pages in swap cache
[ 30.370134] Swap cache stats: add 0, delete 0, find 0/0
[ 30.370135] Free swap = 0kB
[ 30.370136] Total swap = 0kB
[ 30.370137] 2164609 pages RAM
[ 30.370139] 0 pages HighMem/MovableOnly
[ 30.370140] 612331 pages reserved
[ 30.370141] 0 pages hwpoisoned
[ 30.370143] DMA: failed to allocate 256 KiB pool for atomic
coherent allocation
[2]
root@localhost$ dmesg | grep crash
[ 0.000000] Reserving 250MB of low memory at 3724MB for crashkernel
(System low RAM: 2029MB)
[ 0.000000] crashkernel reserved: 0x0000000e00000000 -
0x0000001000000000 (8192 MB)
[ 0.000000] Kernel command line:
BOOT_IMAGE=(hd11,gpt2)/vmlinuz-5.7.0-rc3+
root=UUID=e5c34f86-6727-4668-81f9-f41433555df6 ro crashkernel=250M,low
crashkernel=8G nowatchdog console=ttyAMA0 default_hugepagesz=1G
hugepagesz=1G hugepages=2
[ 44.019393] crashkernel=8G
Hi,
On 6/1/20 7:02 AM, Prabhakar Kushwaha wrote:
> Hi Chen,
>
> On Thu, May 21, 2020 at 3:05 PM Chen Zhou <[email protected]> wrote:
>> This patch series enable reserving crashkernel above 4G in arm64.
>>
>> There are following issues in arm64 kdump:
>> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail
>> when there is no enough low memory.
>> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G,
>> in this case, if swiotlb or DMA buffers are required, crash dump kernel
>> will boot failure because there is no low memory available for allocation.
>>
>> To solve these issues, introduce crashkernel=X,low to reserve specified
>> size low memory.
>> Crashkernel=X tries to reserve memory for the crash dump kernel under
>> 4G. If crashkernel=Y,low is specified simultaneously, reserve spcified
>> size low memory for crash kdump kernel devices firstly and then reserve
>> memory above 4G.
>>
>> When crashkernel is reserved above 4G in memory, that is, crashkernel=X,low
>> is specified simultaneously, kernel should reserve specified size low memory
>> for crash dump kernel devices. So there may be two crash kernel regions, one
>> is below 4G, the other is above 4G.
>> In order to distinct from the high region and make no effect to the use of
>> kexec-tools, rename the low region as "Crash kernel (low)", and add DT property
>> "linux,low-memory-range" to crash dump kernel's dtb to pass the low region.
>>
>> Besides, we need to modify kexec-tools:
>> arm64: kdump: add another DT property to crash dump kernel's dtb(see [1])
>>
>> The previous changes and discussions can be retrieved from:
>>
>> Changes since [v7]
>> - Move x86 CRASH_ALIGN to 2M
>> Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
>> - Update Documentation/devicetree/bindings/chosen.txt
>> Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt suggested by Arnd.
>> - Add Tested-by from Jhon and pk
>>
>> Changes since [v6]
>> - Fix build errors reported by kbuild test robot.
>>
>> Changes since [v5]
>> - Move reserve_crashkernel_low() into kernel/crash_core.c.
>> - Delete crashkernel=X,high.
>> - Modify crashkernel=X,low.
>> If crashkernel=X,low is specified simultaneously, reserve spcified size low
>> memory for crash kdump kernel devices firstly and then reserve memory above 4G.
>> In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
>> pass to crash dump kernel by DT property "linux,low-memory-range".
>> - Update Documentation/admin-guide/kdump/kdump.rst.
>>
>> Changes since [v4]
>> - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.
>>
>> Changes since [v3]
>> - Add memblock_cap_memory_ranges back for multiple ranges.
>> - Fix some compiling warnings.
>>
>> Changes since [v2]
>> - Split patch "arm64: kdump: support reserving crashkernel above 4G" as
>> two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
>> patch.
>>
>> Changes since [v1]:
>> - Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
>> - Remove memblock_cap_memory_ranges() i added in v1 and implement that
>> in fdt_enforce_memory_region().
>> There are at most two crash kernel regions, for two crash kernel regions
>> case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
>> and then remove the memory range in the middle.
>>
>> [1]: https://urldefense.com/v3/__http://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbvpn1uM1$
>> [v1]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/2/1174__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbt0xN9PE$
>> [v2]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/86__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbub7yUQH$
>> [v3]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/306__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbnc4zPPV$
>> [v4]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/15/273__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbvsAsZLu$
>> [v5]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/5/6/1360__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbl24n-79$
>> [v6]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/8/30/142__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbs7r8G2a$
>> [v7]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/12/23/411__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiFUH90G$
>>
>> Chen Zhou (5):
>> x86: kdump: move reserve_crashkernel_low() into crash_core.c
>> arm64: kdump: reserve crashkenel above 4G for crash dump kernel
>> arm64: kdump: add memory for devices by DT property, low-memory-range
>> kdump: update Documentation about crashkernel on arm64
>> dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump
>>
> We are getting "warn_alloc" [1] warning during boot of kdump kernel
> with bootargs as [2] of primary kernel.
> This error observed on ThunderX2 ARM64 platform.
>
> It is observed with latest upstream tag (v5.7-rc3) with this patch set
> and https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiIAAlzu$
> Also **without** this patch-set
> "https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$"
>
> This issue comes whenever crashkernel memory is reserved after 0xc000_0000.
> More details discussed earlier in
> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$ without any
> solution
>
> This patch-set is expected to solve similar kind of issue.
> i.e. low memory is only targeted for DMA, swiotlb; So above mentioned
> observation should be considered/fixed. .
>
> --pk
>
> [1]
> [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
> [ 30.367696] NET: Registered protocol family 16
> [ 30.369973] swapper/0: page allocation failure: order:6,
> mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
> [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc3+ #121
> [ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS
> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
> [ 30.369984] Call trace:
> [ 30.369989] dump_backtrace+0x0/0x1f8
> [ 30.369991] show_stack+0x20/0x30
> [ 30.369997] dump_stack+0xc0/0x10c
> [ 30.370001] warn_alloc+0x10c/0x178
> [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0xb50
> [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
> [ 30.370008] alloc_page_interleave+0x24/0x98
> [ 30.370011] alloc_pages_current+0xe4/0x108
> [ 30.370017] dma_atomic_pool_init+0x44/0x1a4
> [ 30.370020] do_one_initcall+0x54/0x228
> [ 30.370027] kernel_init_freeable+0x228/0x2cc
> [ 30.370031] kernel_init+0x1c/0x110
> [ 30.370034] ret_from_fork+0x10/0x18
> [ 30.370036] Mem-Info:
> [ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0
> [ 30.370064] active_file:0 inactive_file:0 isolated_file:0
> [ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0
> [ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438
> [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
> [ 30.370064] free:1537719 free_pcp:219 free_cma:0
> [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
> unstable:0kB all_unreclaimable? no
> [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
> unstable:0kB all_unreclaimable? no
> [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB
> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
> present:128kB managed:0kB mlocked:0kB kernel_stack:0kB pagetables:0kB
> bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> [ 30.370084] lowmem_reserve[]: 0 250 6063 6063
> [ 30.370090] Node 0 DMA32 free:256000kB min:408kB low:664kB
> high:920kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
> present:269700kB managed:256000kB mlocked:0kB kernel_stack:0kB
> pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> [ 30.370094] lowmem_reserve[]: 0 0 5813 5813
> [ 30.370100] Node 0 Normal free:5894876kB min:9552kB low:15504kB
> high:21456kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
> present:8388608kB managed:5953112kB mlocked:0kB kernel_stack:21672kB
> pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB free_cma:0kB
> [ 30.370104] lowmem_reserve[]: 0 0 0 0
> [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
> 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
> [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
> 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) = 256000kB
> [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB (UE) 3*32kB
> (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME) 3*1024kB (ME)
> 3*2048kB (UME) 1436*4096kB (M) = 5893600kB
> [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
> hugepages_surp=0 hugepages_size=1048576kB
> [ 30.370130] 0 total pagecache pages
> [ 30.370132] 0 pages in swap cache
> [ 30.370134] Swap cache stats: add 0, delete 0, find 0/0
> [ 30.370135] Free swap = 0kB
> [ 30.370136] Total swap = 0kB
> [ 30.370137] 2164609 pages RAM
> [ 30.370139] 0 pages HighMem/MovableOnly
> [ 30.370140] 612331 pages reserved
> [ 30.370141] 0 pages hwpoisoned
> [ 30.370143] DMA: failed to allocate 256 KiB pool for atomic
> coherent allocation
During my testing I saw the same error and Chen's solution corrected it .
Hi John,
On Tue, Jun 2, 2020 at 1:01 AM John Donnelly <[email protected]> wrote:
>
> Hi,
>
>
> On 6/1/20 7:02 AM, Prabhakar Kushwaha wrote:
> > Hi Chen,
> >
> > On Thu, May 21, 2020 at 3:05 PM Chen Zhou <[email protected]> wrote:
> >> This patch series enable reserving crashkernel above 4G in arm64.
> >>
> >> There are following issues in arm64 kdump:
> >> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail
> >> when there is no enough low memory.
> >> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G,
> >> in this case, if swiotlb or DMA buffers are required, crash dump kernel
> >> will boot failure because there is no low memory available for allocation.
> >>
> >> To solve these issues, introduce crashkernel=X,low to reserve specified
> >> size low memory.
> >> Crashkernel=X tries to reserve memory for the crash dump kernel under
> >> 4G. If crashkernel=Y,low is specified simultaneously, reserve spcified
> >> size low memory for crash kdump kernel devices firstly and then reserve
> >> memory above 4G.
> >>
> >> When crashkernel is reserved above 4G in memory, that is, crashkernel=X,low
> >> is specified simultaneously, kernel should reserve specified size low memory
> >> for crash dump kernel devices. So there may be two crash kernel regions, one
> >> is below 4G, the other is above 4G.
> >> In order to distinct from the high region and make no effect to the use of
> >> kexec-tools, rename the low region as "Crash kernel (low)", and add DT property
> >> "linux,low-memory-range" to crash dump kernel's dtb to pass the low region.
> >>
> >> Besides, we need to modify kexec-tools:
> >> arm64: kdump: add another DT property to crash dump kernel's dtb(see [1])
> >>
> >> The previous changes and discussions can be retrieved from:
> >>
> >> Changes since [v7]
> >> - Move x86 CRASH_ALIGN to 2M
> >> Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
> >> - Update Documentation/devicetree/bindings/chosen.txt
> >> Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt suggested by Arnd.
> >> - Add Tested-by from Jhon and pk
> >>
> >> Changes since [v6]
> >> - Fix build errors reported by kbuild test robot.
> >>
> >> Changes since [v5]
> >> - Move reserve_crashkernel_low() into kernel/crash_core.c.
> >> - Delete crashkernel=X,high.
> >> - Modify crashkernel=X,low.
> >> If crashkernel=X,low is specified simultaneously, reserve spcified size low
> >> memory for crash kdump kernel devices firstly and then reserve memory above 4G.
> >> In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
> >> pass to crash dump kernel by DT property "linux,low-memory-range".
> >> - Update Documentation/admin-guide/kdump/kdump.rst.
> >>
> >> Changes since [v4]
> >> - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.
> >>
> >> Changes since [v3]
> >> - Add memblock_cap_memory_ranges back for multiple ranges.
> >> - Fix some compiling warnings.
> >>
> >> Changes since [v2]
> >> - Split patch "arm64: kdump: support reserving crashkernel above 4G" as
> >> two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
> >> patch.
> >>
> >> Changes since [v1]:
> >> - Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
> >> - Remove memblock_cap_memory_ranges() i added in v1 and implement that
> >> in fdt_enforce_memory_region().
> >> There are at most two crash kernel regions, for two crash kernel regions
> >> case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
> >> and then remove the memory range in the middle.
> >>
> >> [1]: https://urldefense.com/v3/__http://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbvpn1uM1$
> >> [v1]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/2/1174__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbt0xN9PE$
> >> [v2]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/86__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbub7yUQH$
> >> [v3]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/306__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbnc4zPPV$
> >> [v4]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/15/273__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbvsAsZLu$
> >> [v5]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/5/6/1360__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbl24n-79$
> >> [v6]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/8/30/142__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbs7r8G2a$
> >> [v7]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/12/23/411__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiFUH90G$
> >>
> >> Chen Zhou (5):
> >> x86: kdump: move reserve_crashkernel_low() into crash_core.c
> >> arm64: kdump: reserve crashkenel above 4G for crash dump kernel
> >> arm64: kdump: add memory for devices by DT property, low-memory-range
> >> kdump: update Documentation about crashkernel on arm64
> >> dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump
> >>
> > We are getting "warn_alloc" [1] warning during boot of kdump kernel
> > with bootargs as [2] of primary kernel.
> > This error observed on ThunderX2 ARM64 platform.
> >
> > It is observed with latest upstream tag (v5.7-rc3) with this patch set
> > and https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiIAAlzu$
> > Also **without** this patch-set
> > "https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$"
> >
> > This issue comes whenever crashkernel memory is reserved after 0xc000_0000.
> > More details discussed earlier in
> > https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$ without any
> > solution
> >
> > This patch-set is expected to solve similar kind of issue.
> > i.e. low memory is only targeted for DMA, swiotlb; So above mentioned
> > observation should be considered/fixed. .
> >
> > --pk
> >
> > [1]
> > [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
> > TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
> > [ 30.367696] NET: Registered protocol family 16
> > [ 30.369973] swapper/0: page allocation failure: order:6,
> > mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
> > [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc3+ #121
> > [ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS
> > TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
> > [ 30.369984] Call trace:
> > [ 30.369989] dump_backtrace+0x0/0x1f8
> > [ 30.369991] show_stack+0x20/0x30
> > [ 30.369997] dump_stack+0xc0/0x10c
> > [ 30.370001] warn_alloc+0x10c/0x178
> > [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0xb50
> > [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
> > [ 30.370008] alloc_page_interleave+0x24/0x98
> > [ 30.370011] alloc_pages_current+0xe4/0x108
> > [ 30.370017] dma_atomic_pool_init+0x44/0x1a4
> > [ 30.370020] do_one_initcall+0x54/0x228
> > [ 30.370027] kernel_init_freeable+0x228/0x2cc
> > [ 30.370031] kernel_init+0x1c/0x110
> > [ 30.370034] ret_from_fork+0x10/0x18
> > [ 30.370036] Mem-Info:
> > [ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0
> > [ 30.370064] active_file:0 inactive_file:0 isolated_file:0
> > [ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0
> > [ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438
> > [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
> > [ 30.370064] free:1537719 free_pcp:219 free_cma:0
> > [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
> > active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
> > isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
> > shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
> > unstable:0kB all_unreclaimable? no
> > [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
> > active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
> > isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
> > shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
> > unstable:0kB all_unreclaimable? no
> > [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB
> > reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> > active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
> > present:128kB managed:0kB mlocked:0kB kernel_stack:0kB pagetables:0kB
> > bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> > [ 30.370084] lowmem_reserve[]: 0 250 6063 6063
> > [ 30.370090] Node 0 DMA32 free:256000kB min:408kB low:664kB
> > high:920kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> > active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
> > present:269700kB managed:256000kB mlocked:0kB kernel_stack:0kB
> > pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> > [ 30.370094] lowmem_reserve[]: 0 0 5813 5813
> > [ 30.370100] Node 0 Normal free:5894876kB min:9552kB low:15504kB
> > high:21456kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> > active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
> > present:8388608kB managed:5953112kB mlocked:0kB kernel_stack:21672kB
> > pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB free_cma:0kB
> > [ 30.370104] lowmem_reserve[]: 0 0 0 0
> > [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
> > 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
> > [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
> > 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) = 256000kB
> > [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB (UE) 3*32kB
> > (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME) 3*1024kB (ME)
> > 3*2048kB (UME) 1436*4096kB (M) = 5893600kB
> > [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
> > hugepages_surp=0 hugepages_size=1048576kB
> > [ 30.370130] 0 total pagecache pages
> > [ 30.370132] 0 pages in swap cache
> > [ 30.370134] Swap cache stats: add 0, delete 0, find 0/0
> > [ 30.370135] Free swap = 0kB
> > [ 30.370136] Total swap = 0kB
> > [ 30.370137] 2164609 pages RAM
> > [ 30.370139] 0 pages HighMem/MovableOnly
> > [ 30.370140] 612331 pages reserved
> > [ 30.370141] 0 pages hwpoisoned
> > [ 30.370143] DMA: failed to allocate 256 KiB pool for atomic
> > coherent allocation
>
>
> During my testing I saw the same error and Chen's solution corrected it .
Which combination you are using on your side? I am using Prabhakar's
suggested environment and can reproduce the issue
with or without Chen's crashkernel support above 4G patchset.
I am also using a ThunderX2 platform with latest makedumpfile code and
kexec-tools (with the suggested patch
<https://lists.infradead.org/pipermail/kexec/2020-May/025128.html>).
Thanks,
Bhupesh
Hi . See below !
> On Jun 1, 2020, at 4:02 PM, Bhupesh Sharma <[email protected]> wrote:
>
> Hi John,
>
> On Tue, Jun 2, 2020 at 1:01 AM John Donnelly <[email protected]> wrote:
>>
>> Hi,
>>
>>
>> On 6/1/20 7:02 AM, Prabhakar Kushwaha wrote:
>>> Hi Chen,
>>>
>>> On Thu, May 21, 2020 at 3:05 PM Chen Zhou <[email protected]> wrote:
>>>> This patch series enable reserving crashkernel above 4G in arm64.
>>>>
>>>> There are following issues in arm64 kdump:
>>>> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail
>>>> when there is no enough low memory.
>>>> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G,
>>>> in this case, if swiotlb or DMA buffers are required, crash dump kernel
>>>> will boot failure because there is no low memory available for allocation.
>>>>
>>>> To solve these issues, introduce crashkernel=X,low to reserve specified
>>>> size low memory.
>>>> Crashkernel=X tries to reserve memory for the crash dump kernel under
>>>> 4G. If crashkernel=Y,low is specified simultaneously, reserve spcified
>>>> size low memory for crash kdump kernel devices firstly and then reserve
>>>> memory above 4G.
>>>>
>>>> When crashkernel is reserved above 4G in memory, that is, crashkernel=X,low
>>>> is specified simultaneously, kernel should reserve specified size low memory
>>>> for crash dump kernel devices. So there may be two crash kernel regions, one
>>>> is below 4G, the other is above 4G.
>>>> In order to distinct from the high region and make no effect to the use of
>>>> kexec-tools, rename the low region as "Crash kernel (low)", and add DT property
>>>> "linux,low-memory-range" to crash dump kernel's dtb to pass the low region.
>>>>
>>>> Besides, we need to modify kexec-tools:
>>>> arm64: kdump: add another DT property to crash dump kernel's dtb(see [1])
>>>>
>>>> The previous changes and discussions can be retrieved from:
>>>>
>>>> Changes since [v7]
>>>> - Move x86 CRASH_ALIGN to 2M
>>>> Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
>>>> - Update Documentation/devicetree/bindings/chosen.txt
>>>> Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt suggested by Arnd.
>>>> - Add Tested-by from Jhon and pk
>>>>
>>>> Changes since [v6]
>>>> - Fix build errors reported by kbuild test robot.
>>>>
>>>> Changes since [v5]
>>>> - Move reserve_crashkernel_low() into kernel/crash_core.c.
>>>> - Delete crashkernel=X,high.
>>>> - Modify crashkernel=X,low.
>>>> If crashkernel=X,low is specified simultaneously, reserve spcified size low
>>>> memory for crash kdump kernel devices firstly and then reserve memory above 4G.
>>>> In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
>>>> pass to crash dump kernel by DT property "linux,low-memory-range".
>>>> - Update Documentation/admin-guide/kdump/kdump.rst.
>>>>
>>>> Changes since [v4]
>>>> - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.
>>>>
>>>> Changes since [v3]
>>>> - Add memblock_cap_memory_ranges back for multiple ranges.
>>>> - Fix some compiling warnings.
>>>>
>>>> Changes since [v2]
>>>> - Split patch "arm64: kdump: support reserving crashkernel above 4G" as
>>>> two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
>>>> patch.
>>>>
>>>> Changes since [v1]:
>>>> - Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
>>>> - Remove memblock_cap_memory_ranges() i added in v1 and implement that
>>>> in fdt_enforce_memory_region().
>>>> There are at most two crash kernel regions, for two crash kernel regions
>>>> case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
>>>> and then remove the memory range in the middle.
>>>>
>>>> [1]: https://urldefense.com/v3/__http://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbvpn1uM1$
>>>> [v1]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/2/1174__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbt0xN9PE$
>>>> [v2]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/86__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbub7yUQH$
>>>> [v3]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/306__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbnc4zPPV$
>>>> [v4]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/15/273__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbvsAsZLu$
>>>> [v5]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/5/6/1360__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbl24n-79$
>>>> [v6]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/8/30/142__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbs7r8G2a$
>>>> [v7]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/12/23/411__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiFUH90G$
>>>>
>>>> Chen Zhou (5):
>>>> x86: kdump: move reserve_crashkernel_low() into crash_core.c
>>>> arm64: kdump: reserve crashkenel above 4G for crash dump kernel
>>>> arm64: kdump: add memory for devices by DT property, low-memory-range
>>>> kdump: update Documentation about crashkernel on arm64
>>>> dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump
>>>>
>>> We are getting "warn_alloc" [1] warning during boot of kdump kernel
>>> with bootargs as [2] of primary kernel.
>>> This error observed on ThunderX2 ARM64 platform.
>>>
>>> It is observed with latest upstream tag (v5.7-rc3) with this patch set
>>> and https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiIAAlzu$
>>> Also **without** this patch-set
>>> "https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$"
>>>
>>> This issue comes whenever crashkernel memory is reserved after 0xc000_0000.
>>> More details discussed earlier in
>>> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$ without any
>>> solution
>>>
>>> This patch-set is expected to solve similar kind of issue.
>>> i.e. low memory is only targeted for DMA, swiotlb; So above mentioned
>>> observation should be considered/fixed. .
>>>
>>> --pk
>>>
>>> [1]
>>> [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>> [ 30.367696] NET: Registered protocol family 16
>>> [ 30.369973] swapper/0: page allocation failure: order:6,
>>> mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
>>> [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc3+ #121
>>> [ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS
>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>> [ 30.369984] Call trace:
>>> [ 30.369989] dump_backtrace+0x0/0x1f8
>>> [ 30.369991] show_stack+0x20/0x30
>>> [ 30.369997] dump_stack+0xc0/0x10c
>>> [ 30.370001] warn_alloc+0x10c/0x178
>>> [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0xb50
>>> [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
>>> [ 30.370008] alloc_page_interleave+0x24/0x98
>>> [ 30.370011] alloc_pages_current+0xe4/0x108
>>> [ 30.370017] dma_atomic_pool_init+0x44/0x1a4
>>> [ 30.370020] do_one_initcall+0x54/0x228
>>> [ 30.370027] kernel_init_freeable+0x228/0x2cc
>>> [ 30.370031] kernel_init+0x1c/0x110
>>> [ 30.370034] ret_from_fork+0x10/0x18
>>> [ 30.370036] Mem-Info:
>>> [ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0
>>> [ 30.370064] active_file:0 inactive_file:0 isolated_file:0
>>> [ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0
>>> [ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438
>>> [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
>>> [ 30.370064] free:1537719 free_pcp:219 free_cma:0
>>> [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
>>> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
>>> unstable:0kB all_unreclaimable? no
>>> [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
>>> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
>>> unstable:0kB all_unreclaimable? no
>>> [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB
>>> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
>>> present:128kB managed:0kB mlocked:0kB kernel_stack:0kB pagetables:0kB
>>> bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>>> [ 30.370084] lowmem_reserve[]: 0 250 6063 6063
>>> [ 30.370090] Node 0 DMA32 free:256000kB min:408kB low:664kB
>>> high:920kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
>>> present:269700kB managed:256000kB mlocked:0kB kernel_stack:0kB
>>> pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>>> [ 30.370094] lowmem_reserve[]: 0 0 5813 5813
>>> [ 30.370100] Node 0 Normal free:5894876kB min:9552kB low:15504kB
>>> high:21456kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
>>> present:8388608kB managed:5953112kB mlocked:0kB kernel_stack:21672kB
>>> pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB free_cma:0kB
>>> [ 30.370104] lowmem_reserve[]: 0 0 0 0
>>> [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
>>> 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
>>> [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
>>> 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) = 256000kB
>>> [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB (UE) 3*32kB
>>> (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME) 3*1024kB (ME)
>>> 3*2048kB (UME) 1436*4096kB (M) = 5893600kB
>>> [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
>>> hugepages_surp=0 hugepages_size=1048576kB
>>> [ 30.370130] 0 total pagecache pages
>>> [ 30.370132] 0 pages in swap cache
>>> [ 30.370134] Swap cache stats: add 0, delete 0, find 0/0
>>> [ 30.370135] Free swap = 0kB
>>> [ 30.370136] Total swap = 0kB
>>> [ 30.370137] 2164609 pages RAM
>>> [ 30.370139] 0 pages HighMem/MovableOnly
>>> [ 30.370140] 612331 pages reserved
>>> [ 30.370141] 0 pages hwpoisoned
>>> [ 30.370143] DMA: failed to allocate 256 KiB pool for atomic
>>> coherent allocation
>>
>>
>> During my testing I saw the same error and Chen's solution corrected it .
>
> Which combination you are using on your side? I am using Prabhakar's
> suggested environment and can reproduce the issue
> with or without Chen's crashkernel support above 4G patchset.
>
> I am also using a ThunderX2 platform with latest makedumpfile code and
> kexec-tools (with the suggested patch
> <https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!J6lUig58-Gw6TKZnEEYzEeSU36T-1SqlB1kImU00xtX_lss5Tx-JbUmLE9TJC3foXBLg$ >).
>
> Thanks,
> Bhupesh
I did this activity 5 months ago and I have moved on to other activities. My DMA failures were related to PCI devices that could not be enumerated because low-DMA space was not available when crashkernel was moved above 4G; I don’t recall the exact platform.
For this failure ,
>>> DMA: failed to allocate 256 KiB pool for atomic
>>> coherent allocation
Is due to :
3618082c
("arm64 use both ZONE_DMA and ZONE_DMA32")
With the introduction of ZONE_DMA to support the Raspberry DMA
region below 1G, the crashkernel is placed in the upper 4G
ZONE_DMA_32 region. Since the crashkernel does not have access
to the ZONE_DMA region, it prints out call trace during bootup.
It is due to having this CONFIG item ON :
CONFIG_ZONE_DMA=y
Turning off ZONE_DMA fixes a issue and Raspberry PI 4 will
use the device tree to specify memory below 1G.
I would like to see Chen’s feature added , perhaps as EXPERIMENTAL, so we can get some configuration testing done on it. It corrects having a DMA zone in low memory while crash-kernel is above 4GB. This has been going on for a year now.
Thank you,
John.
( Note .. I am not on the all the kernel-dlist emails so this won’t be seen by everyone , - someone may have to bounce it )
On Tue, Jun 2, 2020 at 3:29 AM John Donnelly <[email protected]> wrote:
>
> Hi . See below !
>
> > On Jun 1, 2020, at 4:02 PM, Bhupesh Sharma <[email protected]> wrote:
> >
> > Hi John,
> >
> > On Tue, Jun 2, 2020 at 1:01 AM John Donnelly <[email protected]> wrote:
> >>
> >> Hi,
> >>
> >>
> >> On 6/1/20 7:02 AM, Prabhakar Kushwaha wrote:
> >>> Hi Chen,
> >>>
> >>> On Thu, May 21, 2020 at 3:05 PM Chen Zhou <[email protected]> wrote:
> >>>> This patch series enable reserving crashkernel above 4G in arm64.
> >>>>
> >>>> There are following issues in arm64 kdump:
> >>>> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail
> >>>> when there is no enough low memory.
> >>>> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G,
> >>>> in this case, if swiotlb or DMA buffers are required, crash dump kernel
> >>>> will boot failure because there is no low memory available for allocation.
> >>>>
> >>>> To solve these issues, introduce crashkernel=X,low to reserve specified
> >>>> size low memory.
> >>>> Crashkernel=X tries to reserve memory for the crash dump kernel under
> >>>> 4G. If crashkernel=Y,low is specified simultaneously, reserve spcified
> >>>> size low memory for crash kdump kernel devices firstly and then reserve
> >>>> memory above 4G.
> >>>>
> >>>> When crashkernel is reserved above 4G in memory, that is, crashkernel=X,low
> >>>> is specified simultaneously, kernel should reserve specified size low memory
> >>>> for crash dump kernel devices. So there may be two crash kernel regions, one
> >>>> is below 4G, the other is above 4G.
> >>>> In order to distinct from the high region and make no effect to the use of
> >>>> kexec-tools, rename the low region as "Crash kernel (low)", and add DT property
> >>>> "linux,low-memory-range" to crash dump kernel's dtb to pass the low region.
> >>>>
> >>>> Besides, we need to modify kexec-tools:
> >>>> arm64: kdump: add another DT property to crash dump kernel's dtb(see [1])
> >>>>
> >>>> The previous changes and discussions can be retrieved from:
> >>>>
> >>>> Changes since [v7]
> >>>> - Move x86 CRASH_ALIGN to 2M
> >>>> Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
> >>>> - Update Documentation/devicetree/bindings/chosen.txt
> >>>> Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt suggested by Arnd.
> >>>> - Add Tested-by from Jhon and pk
> >>>>
> >>>> Changes since [v6]
> >>>> - Fix build errors reported by kbuild test robot.
> >>>>
> >>>> Changes since [v5]
> >>>> - Move reserve_crashkernel_low() into kernel/crash_core.c.
> >>>> - Delete crashkernel=X,high.
> >>>> - Modify crashkernel=X,low.
> >>>> If crashkernel=X,low is specified simultaneously, reserve spcified size low
> >>>> memory for crash kdump kernel devices firstly and then reserve memory above 4G.
> >>>> In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
> >>>> pass to crash dump kernel by DT property "linux,low-memory-range".
> >>>> - Update Documentation/admin-guide/kdump/kdump.rst.
> >>>>
> >>>> Changes since [v4]
> >>>> - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.
> >>>>
> >>>> Changes since [v3]
> >>>> - Add memblock_cap_memory_ranges back for multiple ranges.
> >>>> - Fix some compiling warnings.
> >>>>
> >>>> Changes since [v2]
> >>>> - Split patch "arm64: kdump: support reserving crashkernel above 4G" as
> >>>> two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
> >>>> patch.
> >>>>
> >>>> Changes since [v1]:
> >>>> - Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
> >>>> - Remove memblock_cap_memory_ranges() i added in v1 and implement that
> >>>> in fdt_enforce_memory_region().
> >>>> There are at most two crash kernel regions, for two crash kernel regions
> >>>> case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
> >>>> and then remove the memory range in the middle.
> >>>>
> >>>> [1]: https://urldefense.com/v3/__http://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbvpn1uM1$
> >>>> [v1]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/2/1174__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbt0xN9PE$
> >>>> [v2]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/86__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbub7yUQH$
> >>>> [v3]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/306__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbnc4zPPV$
> >>>> [v4]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/15/273__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbvsAsZLu$
> >>>> [v5]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/5/6/1360__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbl24n-79$
> >>>> [v6]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/8/30/142__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbs7r8G2a$
> >>>> [v7]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/12/23/411__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiFUH90G$
> >>>>
> >>>> Chen Zhou (5):
> >>>> x86: kdump: move reserve_crashkernel_low() into crash_core.c
> >>>> arm64: kdump: reserve crashkenel above 4G for crash dump kernel
> >>>> arm64: kdump: add memory for devices by DT property, low-memory-range
> >>>> kdump: update Documentation about crashkernel on arm64
> >>>> dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump
> >>>>
> >>> We are getting "warn_alloc" [1] warning during boot of kdump kernel
> >>> with bootargs as [2] of primary kernel.
> >>> This error observed on ThunderX2 ARM64 platform.
> >>>
> >>> It is observed with latest upstream tag (v5.7-rc3) with this patch set
> >>> and https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiIAAlzu$
> >>> Also **without** this patch-set
> >>> "https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$"
> >>>
> >>> This issue comes whenever crashkernel memory is reserved after 0xc000_0000.
> >>> More details discussed earlier in
> >>> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$ without any
> >>> solution
> >>>
> >>> This patch-set is expected to solve similar kind of issue.
> >>> i.e. low memory is only targeted for DMA, swiotlb; So above mentioned
> >>> observation should be considered/fixed. .
> >>>
> >>> --pk
> >>>
> >>> [1]
> >>> [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
> >>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
> >>> [ 30.367696] NET: Registered protocol family 16
> >>> [ 30.369973] swapper/0: page allocation failure: order:6,
> >>> mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
> >>> [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc3+ #121
> >>> [ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS
> >>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
> >>> [ 30.369984] Call trace:
> >>> [ 30.369989] dump_backtrace+0x0/0x1f8
> >>> [ 30.369991] show_stack+0x20/0x30
> >>> [ 30.369997] dump_stack+0xc0/0x10c
> >>> [ 30.370001] warn_alloc+0x10c/0x178
> >>> [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0xb50
> >>> [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
> >>> [ 30.370008] alloc_page_interleave+0x24/0x98
> >>> [ 30.370011] alloc_pages_current+0xe4/0x108
> >>> [ 30.370017] dma_atomic_pool_init+0x44/0x1a4
> >>> [ 30.370020] do_one_initcall+0x54/0x228
> >>> [ 30.370027] kernel_init_freeable+0x228/0x2cc
> >>> [ 30.370031] kernel_init+0x1c/0x110
> >>> [ 30.370034] ret_from_fork+0x10/0x18
> >>> [ 30.370036] Mem-Info:
> >>> [ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0
> >>> [ 30.370064] active_file:0 inactive_file:0 isolated_file:0
> >>> [ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0
> >>> [ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438
> >>> [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
> >>> [ 30.370064] free:1537719 free_pcp:219 free_cma:0
> >>> [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
> >>> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
> >>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
> >>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
> >>> unstable:0kB all_unreclaimable? no
> >>> [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
> >>> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
> >>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
> >>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
> >>> unstable:0kB all_unreclaimable? no
> >>> [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB
> >>> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> >>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
> >>> present:128kB managed:0kB mlocked:0kB kernel_stack:0kB pagetables:0kB
> >>> bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> >>> [ 30.370084] lowmem_reserve[]: 0 250 6063 6063
> >>> [ 30.370090] Node 0 DMA32 free:256000kB min:408kB low:664kB
> >>> high:920kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> >>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
> >>> present:269700kB managed:256000kB mlocked:0kB kernel_stack:0kB
> >>> pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> >>> [ 30.370094] lowmem_reserve[]: 0 0 5813 5813
> >>> [ 30.370100] Node 0 Normal free:5894876kB min:9552kB low:15504kB
> >>> high:21456kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> >>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
> >>> present:8388608kB managed:5953112kB mlocked:0kB kernel_stack:21672kB
> >>> pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB free_cma:0kB
> >>> [ 30.370104] lowmem_reserve[]: 0 0 0 0
> >>> [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
> >>> 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
> >>> [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
> >>> 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) = 256000kB
> >>> [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB (UE) 3*32kB
> >>> (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME) 3*1024kB (ME)
> >>> 3*2048kB (UME) 1436*4096kB (M) = 5893600kB
> >>> [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
> >>> hugepages_surp=0 hugepages_size=1048576kB
> >>> [ 30.370130] 0 total pagecache pages
> >>> [ 30.370132] 0 pages in swap cache
> >>> [ 30.370134] Swap cache stats: add 0, delete 0, find 0/0
> >>> [ 30.370135] Free swap = 0kB
> >>> [ 30.370136] Total swap = 0kB
> >>> [ 30.370137] 2164609 pages RAM
> >>> [ 30.370139] 0 pages HighMem/MovableOnly
> >>> [ 30.370140] 612331 pages reserved
> >>> [ 30.370141] 0 pages hwpoisoned
> >>> [ 30.370143] DMA: failed to allocate 256 KiB pool for atomic
> >>> coherent allocation
> >>
> >>
> >> During my testing I saw the same error and Chen's solution corrected it .
> >
> > Which combination you are using on your side? I am using Prabhakar's
> > suggested environment and can reproduce the issue
> > with or without Chen's crashkernel support above 4G patchset.
> >
> > I am also using a ThunderX2 platform with latest makedumpfile code and
> > kexec-tools (with the suggested patch
> > <https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!J6lUig58-Gw6TKZnEEYzEeSU36T-1SqlB1kImU00xtX_lss5Tx-JbUmLE9TJC3foXBLg$ >).
> >
> > Thanks,
> > Bhupesh
>
>
> I did this activity 5 months ago and I have moved on to other activities. My DMA failures were related to PCI devices that could not be enumerated because low-DMA space was not available when crashkernel was moved above 4G; I don’t recall the exact platform.
>
>
>
> For this failure ,
>
> >>> DMA: failed to allocate 256 KiB pool for atomic
> >>> coherent allocation
>
>
> Is due to :
>
>
> 3618082c
> ("arm64 use both ZONE_DMA and ZONE_DMA32")
>
> With the introduction of ZONE_DMA to support the Raspberry DMA
> region below 1G, the crashkernel is placed in the upper 4G
> ZONE_DMA_32 region. Since the crashkernel does not have access
> to the ZONE_DMA region, it prints out call trace during bootup.
>
> It is due to having this CONFIG item ON :
>
>
> CONFIG_ZONE_DMA=y
>
> Turning off ZONE_DMA fixes a issue and Raspberry PI 4 will
> use the device tree to specify memory below 1G.
>
>
Disabling ZONE_DMA is temporary solution. We may need proper solution
> I would like to see Chen’s feature added , perhaps as EXPERIMENTAL, so we can get some configuration testing done on it. It corrects having a DMA zone in low memory while crash-kernel is above 4GB. This has been going on for a year now.
I will also like this patch to be added in Linux as early as possible.
Issue mentioned by me happens with or without this patch.
This patch-set can consider fixing because it uses low memory for DMA
& swiotlb only.
We can consider restricting crashkernel within the required range like below
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 7f9e5a6dc48c..bd67b90d35bd 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -354,7 +354,7 @@ int __init reserve_crashkernel_low(void)
return 0;
}
- low_base = memblock_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
+ low_base = memblock_find_in_range(0, 0xc0000000, low_size, CRASH_ALIGN);
if (!low_base) {
pr_err("Cannot reserve %ldMB crashkernel low memory,
please try smaller size.\n",
(unsigned long)(low_size >> 20));
Similar change can be considered for scenario "without" this patch.
But it will decrease memory availability for crashkernel.
Hence increase the failure probability of crashkernel reservation.
--pk
> On Jun 2, 2020, at 12:38 AM, Prabhakar Kushwaha <[email protected]> wrote:
>
> On Tue, Jun 2, 2020 at 3:29 AM John Donnelly <[email protected]> wrote:
>>
>> Hi . See below !
>>
>>> On Jun 1, 2020, at 4:02 PM, Bhupesh Sharma <[email protected]> wrote:
>>>
>>> Hi John,
>>>
>>> On Tue, Jun 2, 2020 at 1:01 AM John Donnelly <[email protected]> wrote:
>>>>
>>>> Hi,
>>>>
>>>>
>>>> On 6/1/20 7:02 AM, Prabhakar Kushwaha wrote:
>>>>> Hi Chen,
>>>>>
>>>>> On Thu, May 21, 2020 at 3:05 PM Chen Zhou <[email protected]> wrote:
>>>>>> This patch series enable reserving crashkernel above 4G in arm64.
>>>>>>
>>>>>> There are following issues in arm64 kdump:
>>>>>> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail
>>>>>> when there is no enough low memory.
>>>>>> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G,
>>>>>> in this case, if swiotlb or DMA buffers are required, crash dump kernel
>>>>>> will boot failure because there is no low memory available for allocation.
>>>>>>
>>>>>> To solve these issues, introduce crashkernel=X,low to reserve specified
>>>>>> size low memory.
>>>>>> Crashkernel=X tries to reserve memory for the crash dump kernel under
>>>>>> 4G. If crashkernel=Y,low is specified simultaneously, reserve spcified
>>>>>> size low memory for crash kdump kernel devices firstly and then reserve
>>>>>> memory above 4G.
>>>>>>
>>>>>> When crashkernel is reserved above 4G in memory, that is, crashkernel=X,low
>>>>>> is specified simultaneously, kernel should reserve specified size low memory
>>>>>> for crash dump kernel devices. So there may be two crash kernel regions, one
>>>>>> is below 4G, the other is above 4G.
>>>>>> In order to distinct from the high region and make no effect to the use of
>>>>>> kexec-tools, rename the low region as "Crash kernel (low)", and add DT property
>>>>>> "linux,low-memory-range" to crash dump kernel's dtb to pass the low region.
>>>>>>
>>>>>> Besides, we need to modify kexec-tools:
>>>>>> arm64: kdump: add another DT property to crash dump kernel's dtb(see [1])
>>>>>>
>>>>>> The previous changes and discussions can be retrieved from:
>>>>>>
>>>>>> Changes since [v7]
>>>>>> - Move x86 CRASH_ALIGN to 2M
>>>>>> Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
>>>>>> - Update Documentation/devicetree/bindings/chosen.txt
>>>>>> Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt suggested by Arnd.
>>>>>> - Add Tested-by from Jhon and pk
>>>>>>
>>>>>> Changes since [v6]
>>>>>> - Fix build errors reported by kbuild test robot.
>>>>>>
>>>>>> Changes since [v5]
>>>>>> - Move reserve_crashkernel_low() into kernel/crash_core.c.
>>>>>> - Delete crashkernel=X,high.
>>>>>> - Modify crashkernel=X,low.
>>>>>> If crashkernel=X,low is specified simultaneously, reserve spcified size low
>>>>>> memory for crash kdump kernel devices firstly and then reserve memory above 4G.
>>>>>> In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
>>>>>> pass to crash dump kernel by DT property "linux,low-memory-range".
>>>>>> - Update Documentation/admin-guide/kdump/kdump.rst.
>>>>>>
>>>>>> Changes since [v4]
>>>>>> - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.
>>>>>>
>>>>>> Changes since [v3]
>>>>>> - Add memblock_cap_memory_ranges back for multiple ranges.
>>>>>> - Fix some compiling warnings.
>>>>>>
>>>>>> Changes since [v2]
>>>>>> - Split patch "arm64: kdump: support reserving crashkernel above 4G" as
>>>>>> two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
>>>>>> patch.
>>>>>>
>>>>>> Changes since [v1]:
>>>>>> - Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
>>>>>> - Remove memblock_cap_memory_ranges() i added in v1 and implement that
>>>>>> in fdt_enforce_memory_region().
>>>>>> There are at most two crash kernel regions, for two crash kernel regions
>>>>>> case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
>>>>>> and then remove the memory range in the middle.
>>>>>>
>>>>>> [1]: https://urldefense.com/v3/__http://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbvpn1uM1$
>>>>>> [v1]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/2/1174__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbt0xN9PE$
>>>>>> [v2]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/86__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbub7yUQH$
>>>>>> [v3]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/306__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbnc4zPPV$
>>>>>> [v4]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/15/273__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbvsAsZLu$
>>>>>> [v5]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/5/6/1360__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbl24n-79$
>>>>>> [v6]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/8/30/142__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbs7r8G2a$
>>>>>> [v7]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/12/23/411__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiFUH90G$
>>>>>>
>>>>>> Chen Zhou (5):
>>>>>> x86: kdump: move reserve_crashkernel_low() into crash_core.c
>>>>>> arm64: kdump: reserve crashkenel above 4G for crash dump kernel
>>>>>> arm64: kdump: add memory for devices by DT property, low-memory-range
>>>>>> kdump: update Documentation about crashkernel on arm64
>>>>>> dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump
>>>>>>
>>>>> We are getting "warn_alloc" [1] warning during boot of kdump kernel
>>>>> with bootargs as [2] of primary kernel.
>>>>> This error observed on ThunderX2 ARM64 platform.
>>>>>
>>>>> It is observed with latest upstream tag (v5.7-rc3) with this patch set
>>>>> and https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiIAAlzu$
>>>>> Also **without** this patch-set
>>>>> "https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$"
>>>>>
>>>>> This issue comes whenever crashkernel memory is reserved after 0xc000_0000.
>>>>> More details discussed earlier in
>>>>> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$ without any
>>>>> solution
>>>>>
>>>>> This patch-set is expected to solve similar kind of issue.
>>>>> i.e. low memory is only targeted for DMA, swiotlb; So above mentioned
>>>>> observation should be considered/fixed. .
>>>>>
>>>>> --pk
>>>>>
>>>>> [1]
>>>>> [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>>>> [ 30.367696] NET: Registered protocol family 16
>>>>> [ 30.369973] swapper/0: page allocation failure: order:6,
>>>>> mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
>>>>> [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc3+ #121
>>>>> [ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS
>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>>>> [ 30.369984] Call trace:
>>>>> [ 30.369989] dump_backtrace+0x0/0x1f8
>>>>> [ 30.369991] show_stack+0x20/0x30
>>>>> [ 30.369997] dump_stack+0xc0/0x10c
>>>>> [ 30.370001] warn_alloc+0x10c/0x178
>>>>> [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0xb50
>>>>> [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
>>>>> [ 30.370008] alloc_page_interleave+0x24/0x98
>>>>> [ 30.370011] alloc_pages_current+0xe4/0x108
>>>>> [ 30.370017] dma_atomic_pool_init+0x44/0x1a4
>>>>> [ 30.370020] do_one_initcall+0x54/0x228
>>>>> [ 30.370027] kernel_init_freeable+0x228/0x2cc
>>>>> [ 30.370031] kernel_init+0x1c/0x110
>>>>> [ 30.370034] ret_from_fork+0x10/0x18
>>>>> [ 30.370036] Mem-Info:
>>>>> [ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0
>>>>> [ 30.370064] active_file:0 inactive_file:0 isolated_file:0
>>>>> [ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0
>>>>> [ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438
>>>>> [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
>>>>> [ 30.370064] free:1537719 free_pcp:219 free_cma:0
>>>>> [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
>>>>> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
>>>>> unstable:0kB all_unreclaimable? no
>>>>> [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
>>>>> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
>>>>> unstable:0kB all_unreclaimable? no
>>>>> [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB
>>>>> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
>>>>> present:128kB managed:0kB mlocked:0kB kernel_stack:0kB pagetables:0kB
>>>>> bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>>>>> [ 30.370084] lowmem_reserve[]: 0 250 6063 6063
>>>>> [ 30.370090] Node 0 DMA32 free:256000kB min:408kB low:664kB
>>>>> high:920kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
>>>>> present:269700kB managed:256000kB mlocked:0kB kernel_stack:0kB
>>>>> pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>>>>> [ 30.370094] lowmem_reserve[]: 0 0 5813 5813
>>>>> [ 30.370100] Node 0 Normal free:5894876kB min:9552kB low:15504kB
>>>>> high:21456kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
>>>>> present:8388608kB managed:5953112kB mlocked:0kB kernel_stack:21672kB
>>>>> pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB free_cma:0kB
>>>>> [ 30.370104] lowmem_reserve[]: 0 0 0 0
>>>>> [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
>>>>> 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
>>>>> [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
>>>>> 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) = 256000kB
>>>>> [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB (UE) 3*32kB
>>>>> (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME) 3*1024kB (ME)
>>>>> 3*2048kB (UME) 1436*4096kB (M) = 5893600kB
>>>>> [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
>>>>> hugepages_surp=0 hugepages_size=1048576kB
>>>>> [ 30.370130] 0 total pagecache pages
>>>>> [ 30.370132] 0 pages in swap cache
>>>>> [ 30.370134] Swap cache stats: add 0, delete 0, find 0/0
>>>>> [ 30.370135] Free swap = 0kB
>>>>> [ 30.370136] Total swap = 0kB
>>>>> [ 30.370137] 2164609 pages RAM
>>>>> [ 30.370139] 0 pages HighMem/MovableOnly
>>>>> [ 30.370140] 612331 pages reserved
>>>>> [ 30.370141] 0 pages hwpoisoned
>>>>> [ 30.370143] DMA: failed to allocate 256 KiB pool for atomic
>>>>> coherent allocation
>>>>
>>>>
>>>> During my testing I saw the same error and Chen's solution corrected it .
>>>
>>> Which combination you are using on your side? I am using Prabhakar's
>>> suggested environment and can reproduce the issue
>>> with or without Chen's crashkernel support above 4G patchset.
>>>
>>> I am also using a ThunderX2 platform with latest makedumpfile code and
>>> kexec-tools (with the suggested patch
>>> <https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!J6lUig58-Gw6TKZnEEYzEeSU36T-1SqlB1kImU00xtX_lss5Tx-JbUmLE9TJC3foXBLg$ >).
>>>
>>> Thanks,
>>> Bhupesh
>>
>>
>> I did this activity 5 months ago and I have moved on to other activities. My DMA failures were related to PCI devices that could not be enumerated because low-DMA space was not available when crashkernel was moved above 4G; I don’t recall the exact platform.
>>
>>
>>
>> For this failure ,
>>
>>>>> DMA: failed to allocate 256 KiB pool for atomic
>>>>> coherent allocation
>>
>>
>> Is due to :
>>
>>
>> 3618082c
>> ("arm64 use both ZONE_DMA and ZONE_DMA32")
>>
>> With the introduction of ZONE_DMA to support the Raspberry DMA
>> region below 1G, the crashkernel is placed in the upper 4G
>> ZONE_DMA_32 region. Since the crashkernel does not have access
>> to the ZONE_DMA region, it prints out call trace during bootup.
>>
>> It is due to having this CONFIG item ON :
>>
>>
>> CONFIG_ZONE_DMA=y
>>
>> Turning off ZONE_DMA fixes a issue and Raspberry PI 4 will
>> use the device tree to specify memory below 1G.
>>
>>
>
> Disabling ZONE_DMA is temporary solution. We may need proper solution
Perhaps the Raspberry platform configuration dependencies need separated from “server class” Arm equipment ? Or auto-configured on boot ? Consult an expert ;-)
>
>> I would like to see Chen’s feature added , perhaps as EXPERIMENTAL, so we can get some configuration testing done on it. It corrects having a DMA zone in low memory while crash-kernel is above 4GB. This has been going on for a year now.
>
> I will also like this patch to be added in Linux as early as possible.
>
> Issue mentioned by me happens with or without this patch.
>
> This patch-set can consider fixing because it uses low memory for DMA
> & swiotlb only.
> We can consider restricting crashkernel within the required range like below
>
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 7f9e5a6dc48c..bd67b90d35bd 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -354,7 +354,7 @@ int __init reserve_crashkernel_low(void)
> return 0;
> }
>
> - low_base = memblock_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
> + low_base = memblock_find_in_range(0,0xc0000000, low_size, CRASH_ALIGN);
> if (!low_base) {
> pr_err("Cannot reserve %ldMB crashkernel low memory,
> please try smaller size.\n",
> (unsigned long)(low_size >> 20));
>
>
I suspect 0xc0000000 would need to be a CONFIG item and not hard-coded.
> Similar change can be considered for scenario "without" this patch.
> But it will decrease memory availability for crashkernel.
> Hence increase the failure probability of crashkernel reservation.
>
> --pk
Hi Chen,
On Tue, Jun 2, 2020 at 8:12 PM John Donnelly <[email protected]> wrote:
>
>
>
> > On Jun 2, 2020, at 12:38 AM, Prabhakar Kushwaha <[email protected]> wrote:
> >
> > On Tue, Jun 2, 2020 at 3:29 AM John Donnelly <[email protected]> wrote:
> >>
> >> Hi . See below !
> >>
> >>> On Jun 1, 2020, at 4:02 PM, Bhupesh Sharma <[email protected]> wrote:
> >>>
> >>> Hi John,
> >>>
> >>> On Tue, Jun 2, 2020 at 1:01 AM John Donnelly <[email protected]> wrote:
> >>>>
> >>>> Hi,
> >>>>
> >>>>
> >>>> On 6/1/20 7:02 AM, Prabhakar Kushwaha wrote:
> >>>>> Hi Chen,
> >>>>>
> >>>>> On Thu, May 21, 2020 at 3:05 PM Chen Zhou <[email protected]> wrote:
> >>>>>> This patch series enable reserving crashkernel above 4G in arm64.
> >>>>>>
> >>>>>> There are following issues in arm64 kdump:
> >>>>>> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail
> >>>>>> when there is no enough low memory.
> >>>>>> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G,
> >>>>>> in this case, if swiotlb or DMA buffers are required, crash dump kernel
> >>>>>> will boot failure because there is no low memory available for allocation.
> >>>>>>
> >>>>>> To solve these issues, introduce crashkernel=X,low to reserve specified
> >>>>>> size low memory.
> >>>>>> Crashkernel=X tries to reserve memory for the crash dump kernel under
> >>>>>> 4G. If crashkernel=Y,low is specified simultaneously, reserve spcified
> >>>>>> size low memory for crash kdump kernel devices firstly and then reserve
> >>>>>> memory above 4G.
> >>>>>>
> >>>>>> When crashkernel is reserved above 4G in memory, that is, crashkernel=X,low
> >>>>>> is specified simultaneously, kernel should reserve specified size low memory
> >>>>>> for crash dump kernel devices. So there may be two crash kernel regions, one
> >>>>>> is below 4G, the other is above 4G.
> >>>>>> In order to distinct from the high region and make no effect to the use of
> >>>>>> kexec-tools, rename the low region as "Crash kernel (low)", and add DT property
> >>>>>> "linux,low-memory-range" to crash dump kernel's dtb to pass the low region.
> >>>>>>
> >>>>>> Besides, we need to modify kexec-tools:
> >>>>>> arm64: kdump: add another DT property to crash dump kernel's dtb(see [1])
> >>>>>>
> >>>>>> The previous changes and discussions can be retrieved from:
> >>>>>>
> >>>>>> Changes since [v7]
> >>>>>> - Move x86 CRASH_ALIGN to 2M
> >>>>>> Suggested by Dave and do some test, move x86 CRASH_ALIGN to 2M.
> >>>>>> - Update Documentation/devicetree/bindings/chosen.txt
> >>>>>> Add corresponding documentation to Documentation/devicetree/bindings/chosen.txt suggested by Arnd.
> >>>>>> - Add Tested-by from Jhon and pk
> >>>>>>
> >>>>>> Changes since [v6]
> >>>>>> - Fix build errors reported by kbuild test robot.
> >>>>>>
> >>>>>> Changes since [v5]
> >>>>>> - Move reserve_crashkernel_low() into kernel/crash_core.c.
> >>>>>> - Delete crashkernel=X,high.
> >>>>>> - Modify crashkernel=X,low.
> >>>>>> If crashkernel=X,low is specified simultaneously, reserve spcified size low
> >>>>>> memory for crash kdump kernel devices firstly and then reserve memory above 4G.
> >>>>>> In addition, rename crashk_low_res as "Crash kernel (low)" for arm64, and then
> >>>>>> pass to crash dump kernel by DT property "linux,low-memory-range".
> >>>>>> - Update Documentation/admin-guide/kdump/kdump.rst.
> >>>>>>
> >>>>>> Changes since [v4]
> >>>>>> - Reimplement memblock_cap_memory_ranges for multiple ranges by Mike.
> >>>>>>
> >>>>>> Changes since [v3]
> >>>>>> - Add memblock_cap_memory_ranges back for multiple ranges.
> >>>>>> - Fix some compiling warnings.
> >>>>>>
> >>>>>> Changes since [v2]
> >>>>>> - Split patch "arm64: kdump: support reserving crashkernel above 4G" as
> >>>>>> two. Put "move reserve_crashkernel_low() into kexec_core.c" in a separate
> >>>>>> patch.
> >>>>>>
> >>>>>> Changes since [v1]:
> >>>>>> - Move common reserve_crashkernel_low() code into kernel/kexec_core.c.
> >>>>>> - Remove memblock_cap_memory_ranges() i added in v1 and implement that
> >>>>>> in fdt_enforce_memory_region().
> >>>>>> There are at most two crash kernel regions, for two crash kernel regions
> >>>>>> case, we cap the memory range [min(regs[*].start), max(regs[*].end)]
> >>>>>> and then remove the memory range in the middle.
> >>>>>>
> >>>>>> [1]: https://urldefense.com/v3/__http://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbvpn1uM1$
> >>>>>> [v1]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/2/1174__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbt0xN9PE$
> >>>>>> [v2]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/86__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbub7yUQH$
> >>>>>> [v3]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/306__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbnc4zPPV$
> >>>>>> [v4]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/15/273__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbvsAsZLu$
> >>>>>> [v5]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/5/6/1360__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbl24n-79$
> >>>>>> [v6]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/8/30/142__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbs7r8G2a$
> >>>>>> [v7]: https://urldefense.com/v3/__https://lkml.org/lkml/2019/12/23/411__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiFUH90G$
> >>>>>>
> >>>>>> Chen Zhou (5):
> >>>>>> x86: kdump: move reserve_crashkernel_low() into crash_core.c
> >>>>>> arm64: kdump: reserve crashkenel above 4G for crash dump kernel
> >>>>>> arm64: kdump: add memory for devices by DT property, low-memory-range
> >>>>>> kdump: update Documentation about crashkernel on arm64
> >>>>>> dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump
> >>>>>>
> >>>>> We are getting "warn_alloc" [1] warning during boot of kdump kernel
> >>>>> with bootargs as [2] of primary kernel.
> >>>>> This error observed on ThunderX2 ARM64 platform.
> >>>>>
> >>>>> It is observed with latest upstream tag (v5.7-rc3) with this patch set
> >>>>> and https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiIAAlzu$
> >>>>> Also **without** this patch-set
> >>>>> "https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$"
> >>>>>
> >>>>> This issue comes whenever crashkernel memory is reserved after 0xc000_0000.
> >>>>> More details discussed earlier in
> >>>>> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$ without any
> >>>>> solution
> >>>>>
> >>>>> This patch-set is expected to solve similar kind of issue.
> >>>>> i.e. low memory is only targeted for DMA, swiotlb; So above mentioned
> >>>>> observation should be considered/fixed. .
> >>>>>
> >>>>> --pk
> >>>>>
> >>>>> [1]
> >>>>> [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
> >>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
> >>>>> [ 30.367696] NET: Registered protocol family 16
> >>>>> [ 30.369973] swapper/0: page allocation failure: order:6,
> >>>>> mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
> >>>>> [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc3+ #121
> >>>>> [ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS
> >>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
> >>>>> [ 30.369984] Call trace:
> >>>>> [ 30.369989] dump_backtrace+0x0/0x1f8
> >>>>> [ 30.369991] show_stack+0x20/0x30
> >>>>> [ 30.369997] dump_stack+0xc0/0x10c
> >>>>> [ 30.370001] warn_alloc+0x10c/0x178
> >>>>> [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0xb50
> >>>>> [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
> >>>>> [ 30.370008] alloc_page_interleave+0x24/0x98
> >>>>> [ 30.370011] alloc_pages_current+0xe4/0x108
> >>>>> [ 30.370017] dma_atomic_pool_init+0x44/0x1a4
> >>>>> [ 30.370020] do_one_initcall+0x54/0x228
> >>>>> [ 30.370027] kernel_init_freeable+0x228/0x2cc
> >>>>> [ 30.370031] kernel_init+0x1c/0x110
> >>>>> [ 30.370034] ret_from_fork+0x10/0x18
> >>>>> [ 30.370036] Mem-Info:
> >>>>> [ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0
> >>>>> [ 30.370064] active_file:0 inactive_file:0 isolated_file:0
> >>>>> [ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0
> >>>>> [ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438
> >>>>> [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
> >>>>> [ 30.370064] free:1537719 free_pcp:219 free_cma:0
> >>>>> [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
> >>>>> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
> >>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
> >>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
> >>>>> unstable:0kB all_unreclaimable? no
> >>>>> [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
> >>>>> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
> >>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
> >>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
> >>>>> unstable:0kB all_unreclaimable? no
> >>>>> [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB
> >>>>> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> >>>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
> >>>>> present:128kB managed:0kB mlocked:0kB kernel_stack:0kB pagetables:0kB
> >>>>> bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> >>>>> [ 30.370084] lowmem_reserve[]: 0 250 6063 6063
> >>>>> [ 30.370090] Node 0 DMA32 free:256000kB min:408kB low:664kB
> >>>>> high:920kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> >>>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
> >>>>> present:269700kB managed:256000kB mlocked:0kB kernel_stack:0kB
> >>>>> pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> >>>>> [ 30.370094] lowmem_reserve[]: 0 0 5813 5813
> >>>>> [ 30.370100] Node 0 Normal free:5894876kB min:9552kB low:15504kB
> >>>>> high:21456kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> >>>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
> >>>>> present:8388608kB managed:5953112kB mlocked:0kB kernel_stack:21672kB
> >>>>> pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB free_cma:0kB
> >>>>> [ 30.370104] lowmem_reserve[]: 0 0 0 0
> >>>>> [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
> >>>>> 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
> >>>>> [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
> >>>>> 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) = 256000kB
> >>>>> [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB (UE) 3*32kB
> >>>>> (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME) 3*1024kB (ME)
> >>>>> 3*2048kB (UME) 1436*4096kB (M) = 5893600kB
> >>>>> [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
> >>>>> hugepages_surp=0 hugepages_size=1048576kB
> >>>>> [ 30.370130] 0 total pagecache pages
> >>>>> [ 30.370132] 0 pages in swap cache
> >>>>> [ 30.370134] Swap cache stats: add 0, delete 0, find 0/0
> >>>>> [ 30.370135] Free swap = 0kB
> >>>>> [ 30.370136] Total swap = 0kB
> >>>>> [ 30.370137] 2164609 pages RAM
> >>>>> [ 30.370139] 0 pages HighMem/MovableOnly
> >>>>> [ 30.370140] 612331 pages reserved
> >>>>> [ 30.370141] 0 pages hwpoisoned
> >>>>> [ 30.370143] DMA: failed to allocate 256 KiB pool for atomic
> >>>>> coherent allocation
> >>>>
> >>>>
> >>>> During my testing I saw the same error and Chen's solution corrected it .
> >>>
> >>> Which combination you are using on your side? I am using Prabhakar's
> >>> suggested environment and can reproduce the issue
> >>> with or without Chen's crashkernel support above 4G patchset.
> >>>
> >>> I am also using a ThunderX2 platform with latest makedumpfile code and
> >>> kexec-tools (with the suggested patch
> >>> <https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!J6lUig58-Gw6TKZnEEYzEeSU36T-1SqlB1kImU00xtX_lss5Tx-JbUmLE9TJC3foXBLg$ >).
> >>>
> >>> Thanks,
> >>> Bhupesh
> >>
> >>
> >> I did this activity 5 months ago and I have moved on to other activities. My DMA failures were related to PCI devices that could not be enumerated because low-DMA space was not available when crashkernel was moved above 4G; I don’t recall the exact platform.
> >>
> >>
> >>
> >> For this failure ,
> >>
> >>>>> DMA: failed to allocate 256 KiB pool for atomic
> >>>>> coherent allocation
> >>
> >>
> >> Is due to :
> >>
> >>
> >> 3618082c
> >> ("arm64 use both ZONE_DMA and ZONE_DMA32")
> >>
> >> With the introduction of ZONE_DMA to support the Raspberry DMA
> >> region below 1G, the crashkernel is placed in the upper 4G
> >> ZONE_DMA_32 region. Since the crashkernel does not have access
> >> to the ZONE_DMA region, it prints out call trace during bootup.
> >>
> >> It is due to having this CONFIG item ON :
> >>
> >>
> >> CONFIG_ZONE_DMA=y
> >>
> >> Turning off ZONE_DMA fixes a issue and Raspberry PI 4 will
> >> use the device tree to specify memory below 1G.
> >>
> >>
> >
> > Disabling ZONE_DMA is temporary solution. We may need proper solution
>
>
> Perhaps the Raspberry platform configuration dependencies need separated from “server class” Arm equipment ? Or auto-configured on boot ? Consult an expert ;-)
>
>
>
> >
> >> I would like to see Chen’s feature added , perhaps as EXPERIMENTAL, so we can get some configuration testing done on it. It corrects having a DMA zone in low memory while crash-kernel is above 4GB. This has been going on for a year now.
> >
> > I will also like this patch to be added in Linux as early as possible.
> >
> > Issue mentioned by me happens with or without this patch.
> >
> > This patch-set can consider fixing because it uses low memory for DMA
> > & swiotlb only.
> > We can consider restricting crashkernel within the required range like below
> >
> > diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> > index 7f9e5a6dc48c..bd67b90d35bd 100644
> > --- a/kernel/crash_core.c
> > +++ b/kernel/crash_core.c
> > @@ -354,7 +354,7 @@ int __init reserve_crashkernel_low(void)
> > return 0;
> > }
> >
> > - low_base = memblock_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
> > + low_base = memblock_find_in_range(0,0xc0000000, low_size, CRASH_ALIGN);
> > if (!low_base) {
> > pr_err("Cannot reserve %ldMB crashkernel low memory,
> > please try smaller size.\n",
> > (unsigned long)(low_size >> 20));
> >
> >
>
> I suspect 0xc0000000 would need to be a CONFIG item and not hard-coded.
>
if you consider this as valid change, can you please incorporate as
part of your patch-set.
--pk.
Hi,
On 2020/6/3 19:47, Prabhakar Kushwaha wrote:
> Hi Chen,
>
> On Tue, Jun 2, 2020 at 8:12 PM John Donnelly <[email protected]> wrote:
>>
>>
>>> On Jun 2, 2020, at 12:38 AM, Prabhakar Kushwaha <[email protected]> wrote:
>>>
>>> On Tue, Jun 2, 2020 at 3:29 AM John Donnelly <[email protected]> wrote:
>>>> Hi . See below !
>>>>
>>>>> On Jun 1, 2020, at 4:02 PM, Bhupesh Sharma <[email protected]> wrote:
>>>>>
>>>>> Hi John,
>>>>>
>>>>> On Tue, Jun 2, 2020 at 1:01 AM John Donnelly <[email protected]> wrote:
>>>>>> Hi,
>>>>>>
>>>>>>
>>>>>> On 6/1/20 7:02 AM, Prabhakar Kushwaha wrote:
>>>>>>> Hi Chen,
>>>>>>>
>>>>>>> On Thu, May 21, 2020 at 3:05 PM Chen Zhou <[email protected]> wrote:
>>>>>>>> This patch series enable reserving crashkernel above 4G in arm64.
>>>>>>>>
>>>>>>>> There are following issues in arm64 kdump:
>>>>>>>> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail
>>>>>>>> when there is no enough low memory.
>>>>>>>> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G,
>>>>>>>> in this case, if swiotlb or DMA buffers are required, crash dump kernel
>>>>>>>> will boot failure because there is no low memory available for allocation.
>>>>>>>>
>>>>>>> We are getting "warn_alloc" [1] warning during boot of kdump kernel
>>>>>>> with bootargs as [2] of primary kernel.
>>>>>>> This error observed on ThunderX2 ARM64 platform.
>>>>>>>
>>>>>>> It is observed with latest upstream tag (v5.7-rc3) with this patch set
>>>>>>> and https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiIAAlzu$
>>>>>>> Also **without** this patch-set
>>>>>>> "https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$"
>>>>>>>
>>>>>>> This issue comes whenever crashkernel memory is reserved after 0xc000_0000.
>>>>>>> More details discussed earlier in
>>>>>>> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$ without any
>>>>>>> solution
>>>>>>>
>>>>>>> This patch-set is expected to solve similar kind of issue.
>>>>>>> i.e. low memory is only targeted for DMA, swiotlb; So above mentioned
>>>>>>> observation should be considered/fixed. .
>>>>>>>
>>>>>>> --pk
>>>>>>>
>>>>>>> [1]
>>>>>>> [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
>>>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>>>>>> [ 30.367696] NET: Registered protocol family 16
>>>>>>> [ 30.369973] swapper/0: page allocation failure: order:6,
>>>>>>> mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
>>>>>>> [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc3+ #121
>>>>>>> [ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS
>>>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>>>>>> [ 30.369984] Call trace:
>>>>>>> [ 30.369989] dump_backtrace+0x0/0x1f8
>>>>>>> [ 30.369991] show_stack+0x20/0x30
>>>>>>> [ 30.369997] dump_stack+0xc0/0x10c
>>>>>>> [ 30.370001] warn_alloc+0x10c/0x178
>>>>>>> [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0xb50
>>>>>>> [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
>>>>>>> [ 30.370008] alloc_page_interleave+0x24/0x98
>>>>>>> [ 30.370011] alloc_pages_current+0xe4/0x108
>>>>>>> [ 30.370017] dma_atomic_pool_init+0x44/0x1a4
>>>>>>> [ 30.370020] do_one_initcall+0x54/0x228
>>>>>>> [ 30.370027] kernel_init_freeable+0x228/0x2cc
>>>>>>> [ 30.370031] kernel_init+0x1c/0x110
>>>>>>> [ 30.370034] ret_from_fork+0x10/0x18
>>>>>>> [ 30.370036] Mem-Info:
>>>>>>> [ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0
>>>>>>> [ 30.370064] active_file:0 inactive_file:0 isolated_file:0
>>>>>>> [ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0
>>>>>>> [ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438
>>>>>>> [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
>>>>>>> [ 30.370064] free:1537719 free_pcp:219 free_cma:0
>>>>>>> [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
>>>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
>>>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
>>>>>>> unstable:0kB all_unreclaimable? no
>>>>>>> [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
>>>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
>>>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
>>>>>>> unstable:0kB all_unreclaimable? no
>>>>>>> [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB
>>>>>>> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
>>>>>>> present:128kB managed:0kB mlocked:0kB kernel_stack:0kB pagetables:0kB
>>>>>>> bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>>>>>>> [ 30.370084] lowmem_reserve[]: 0 250 6063 6063
>>>>>>> [ 30.370090] Node 0 DMA32 free:256000kB min:408kB low:664kB
>>>>>>> high:920kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
>>>>>>> present:269700kB managed:256000kB mlocked:0kB kernel_stack:0kB
>>>>>>> pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>>>>>>> [ 30.370094] lowmem_reserve[]: 0 0 5813 5813
>>>>>>> [ 30.370100] Node 0 Normal free:5894876kB min:9552kB low:15504kB
>>>>>>> high:21456kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
>>>>>>> present:8388608kB managed:5953112kB mlocked:0kB kernel_stack:21672kB
>>>>>>> pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB free_cma:0kB
>>>>>>> [ 30.370104] lowmem_reserve[]: 0 0 0 0
>>>>>>> [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
>>>>>>> 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
>>>>>>> [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
>>>>>>> 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) = 256000kB
>>>>>>> [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB (UE) 3*32kB
>>>>>>> (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME) 3*1024kB (ME)
>>>>>>> 3*2048kB (UME) 1436*4096kB (M) = 5893600kB
>>>>>>> [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
>>>>>>> hugepages_surp=0 hugepages_size=1048576kB
>>>>>>> [ 30.370130] 0 total pagecache pages
>>>>>>> [ 30.370132] 0 pages in swap cache
>>>>>>> [ 30.370134] Swap cache stats: add 0, delete 0, find 0/0
>>>>>>> [ 30.370135] Free swap = 0kB
>>>>>>> [ 30.370136] Total swap = 0kB
>>>>>>> [ 30.370137] 2164609 pages RAM
>>>>>>> [ 30.370139] 0 pages HighMem/MovableOnly
>>>>>>> [ 30.370140] 612331 pages reserved
>>>>>>> [ 30.370141] 0 pages hwpoisoned
>>>>>>> [ 30.370143] DMA: failed to allocate 256 KiB pool for atomic
>>>>>>> coherent allocation
>>>>>>
>>>>>> During my testing I saw the same error and Chen's solution corrected it .
>>>>> Which combination you are using on your side? I am using Prabhakar's
>>>>> suggested environment and can reproduce the issue
>>>>> with or without Chen's crashkernel support above 4G patchset.
>>>>>
>>>>> I am also using a ThunderX2 platform with latest makedumpfile code and
>>>>> kexec-tools (with the suggested patch
>>>>> <https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!J6lUig58-Gw6TKZnEEYzEeSU36T-1SqlB1kImU00xtX_lss5Tx-JbUmLE9TJC3foXBLg$ >).
>>>>>
>>>>> Thanks,
>>>>> Bhupesh
>>>>
>>>> I did this activity 5 months ago and I have moved on to other activities. My DMA failures were related to PCI devices that could not be enumerated because low-DMA space was not available when crashkernel was moved above 4G; I don’t recall the exact platform.
>>>>
>>>>
>>>>
>>>> For this failure ,
>>>>
>>>>>>> DMA: failed to allocate 256 KiB pool for atomic
>>>>>>> coherent allocation
>>>>
>>>> Is due to :
>>>>
>>>>
>>>> 3618082c
>>>> ("arm64 use both ZONE_DMA and ZONE_DMA32")
>>>>
>>>> With the introduction of ZONE_DMA to support the Raspberry DMA
>>>> region below 1G, the crashkernel is placed in the upper 4G
>>>> ZONE_DMA_32 region. Since the crashkernel does not have access
>>>> to the ZONE_DMA region, it prints out call trace during bootup.
>>>>
>>>> It is due to having this CONFIG item ON :
>>>>
>>>>
>>>> CONFIG_ZONE_DMA=y
>>>>
>>>> Turning off ZONE_DMA fixes a issue and Raspberry PI 4 will
>>>> use the device tree to specify memory below 1G.
>>>>
>>>>
>>> Disabling ZONE_DMA is temporary solution. We may need proper solution
>>
>> Perhaps the Raspberry platform configuration dependencies need separated from “server class” Arm equipment ? Or auto-configured on boot ? Consult an expert ;-)
>>
>>
>>
>>>> I would like to see Chen’s feature added , perhaps as EXPERIMENTAL, so we can get some configuration testing done on it. It corrects having a DMA zone in low memory while crash-kernel is above 4GB. This has been going on for a year now.
>>> I will also like this patch to be added in Linux as early as possible.
>>>
>>> Issue mentioned by me happens with or without this patch.
>>>
>>> This patch-set can consider fixing because it uses low memory for DMA
>>> & swiotlb only.
>>> We can consider restricting crashkernel within the required range like below
>>>
>>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
>>> index 7f9e5a6dc48c..bd67b90d35bd 100644
>>> --- a/kernel/crash_core.c
>>> +++ b/kernel/crash_core.c
>>> @@ -354,7 +354,7 @@ int __init reserve_crashkernel_low(void)
>>> return 0;
>>> }
>>>
>>> - low_base = memblock_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
>>> + low_base = memblock_find_in_range(0,0xc0000000, low_size, CRASH_ALIGN);
>>> if (!low_base) {
>>> pr_err("Cannot reserve %ldMB crashkernel low memory,
>>> please try smaller size.\n",
>>> (unsigned long)(low_size >> 20));
>>>
>>>
>> I suspect 0xc0000000 would need to be a CONFIG item and not hard-coded.
>>
> if you consider this as valid change, can you please incorporate as
> part of your patch-set.
After commit 1a8e1cef7 ("arm64: use both ZONE_DMA and ZONE_DMA32")，the 0-4G memory is splited
to DMA [mem 0x0000000000000000-0x000000003fffffff] and DMA32 [mem 0x0000000040000000-0x00000000ffffffff] on arm64.
From the above discussion, on your platform, the low crashkernel fall in DMA32 region, but your environment needs to access DMA
region, so there is the call trace.
I have a question, why do you choose 0xc0000000 here?
Besides, this is common code, we also need to consider about x86.
Thanks,
Chen Zhou
>
> --pk.
>
> .
>
> On Jun 3, 2020, at 8:20 AM, chenzhou <[email protected]> wrote:
>
> Hi,
>
>
> On 2020/6/3 19:47, Prabhakar Kushwaha wrote:
>> Hi Chen,
>>
>> On Tue, Jun 2, 2020 at 8:12 PM John Donnelly <[email protected]> wrote:
>>>
>>>
>>>> On Jun 2, 2020, at 12:38 AM, Prabhakar Kushwaha <[email protected]> wrote:
>>>>
>>>> On Tue, Jun 2, 2020 at 3:29 AM John Donnelly <[email protected]> wrote:
>>>>> Hi . See below !
>>>>>
>>>>>> On Jun 1, 2020, at 4:02 PM, Bhupesh Sharma <[email protected]> wrote:
>>>>>>
>>>>>> Hi John,
>>>>>>
>>>>>> On Tue, Jun 2, 2020 at 1:01 AM John Donnelly <[email protected]> wrote:
>>>>>>> Hi,
>>>>>>>
>>>>>>>
>>>>>>> On 6/1/20 7:02 AM, Prabhakar Kushwaha wrote:
>>>>>>>> Hi Chen,
>>>>>>>>
>>>>>>>> On Thu, May 21, 2020 at 3:05 PM Chen Zhou <[email protected]> wrote:
>>>>>>>>> This patch series enable reserving crashkernel above 4G in arm64.
>>>>>>>>>
>>>>>>>>> There are following issues in arm64 kdump:
>>>>>>>>> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail
>>>>>>>>> when there is no enough low memory.
>>>>>>>>> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G,
>>>>>>>>> in this case, if swiotlb or DMA buffers are required, crash dump kernel
>>>>>>>>> will boot failure because there is no low memory available for allocation.
>>>>>>>>>
>>>>>>>> We are getting "warn_alloc" [1] warning during boot of kdump kernel
>>>>>>>> with bootargs as [2] of primary kernel.
>>>>>>>> This error observed on ThunderX2 ARM64 platform.
>>>>>>>>
>>>>>>>> It is observed with latest upstream tag (v5.7-rc3) with this patch set
>>>>>>>> and https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiIAAlzu$
>>>>>>>> Also **without** this patch-set
>>>>>>>> "https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$"
>>>>>>>>
>>>>>>>> This issue comes whenever crashkernel memory is reserved after 0xc000_0000.
>>>>>>>> More details discussed earlier in
>>>>>>>> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$ without any
>>>>>>>> solution
>>>>>>>>
>>>>>>>> This patch-set is expected to solve similar kind of issue.
>>>>>>>> i.e. low memory is only targeted for DMA, swiotlb; So above mentioned
>>>>>>>> observation should be considered/fixed. .
>>>>>>>>
>>>>>>>> --pk
>>>>>>>>
>>>>>>>> [1]
>>>>>>>> [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
>>>>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>>>>>>> [ 30.367696] NET: Registered protocol family 16
>>>>>>>> [ 30.369973] swapper/0: page allocation failure: order:6,
>>>>>>>> mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
>>>>>>>> [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc3+ #121
>>>>>>>> [ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS
>>>>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>>>>>>> [ 30.369984] Call trace:
>>>>>>>> [ 30.369989] dump_backtrace+0x0/0x1f8
>>>>>>>> [ 30.369991] show_stack+0x20/0x30
>>>>>>>> [ 30.369997] dump_stack+0xc0/0x10c
>>>>>>>> [ 30.370001] warn_alloc+0x10c/0x178
>>>>>>>> [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0xb50
>>>>>>>> [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
>>>>>>>> [ 30.370008] alloc_page_interleave+0x24/0x98
>>>>>>>> [ 30.370011] alloc_pages_current+0xe4/0x108
>>>>>>>> [ 30.370017] dma_atomic_pool_init+0x44/0x1a4
>>>>>>>> [ 30.370020] do_one_initcall+0x54/0x228
>>>>>>>> [ 30.370027] kernel_init_freeable+0x228/0x2cc
>>>>>>>> [ 30.370031] kernel_init+0x1c/0x110
>>>>>>>> [ 30.370034] ret_from_fork+0x10/0x18
>>>>>>>> [ 30.370036] Mem-Info:
>>>>>>>> [ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0
>>>>>>>> [ 30.370064] active_file:0 inactive_file:0 isolated_file:0
>>>>>>>> [ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0
>>>>>>>> [ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438
>>>>>>>> [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
>>>>>>>> [ 30.370064] free:1537719 free_pcp:219 free_cma:0
>>>>>>>> [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
>>>>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
>>>>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
>>>>>>>> unstable:0kB all_unreclaimable? no
>>>>>>>> [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
>>>>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
>>>>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
>>>>>>>> unstable:0kB all_unreclaimable? no
>>>>>>>> [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB
>>>>>>>> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
>>>>>>>> present:128kB managed:0kB mlocked:0kB kernel_stack:0kB pagetables:0kB
>>>>>>>> bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>>>>>>>> [ 30.370084] lowmem_reserve[]: 0 250 6063 6063
>>>>>>>> [ 30.370090] Node 0 DMA32 free:256000kB min:408kB low:664kB
>>>>>>>> high:920kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
>>>>>>>> present:269700kB managed:256000kB mlocked:0kB kernel_stack:0kB
>>>>>>>> pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>>>>>>>> [ 30.370094] lowmem_reserve[]: 0 0 5813 5813
>>>>>>>> [ 30.370100] Node 0 Normal free:5894876kB min:9552kB low:15504kB
>>>>>>>> high:21456kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
>>>>>>>> present:8388608kB managed:5953112kB mlocked:0kB kernel_stack:21672kB
>>>>>>>> pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB free_cma:0kB
>>>>>>>> [ 30.370104] lowmem_reserve[]: 0 0 0 0
>>>>>>>> [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
>>>>>>>> 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
>>>>>>>> [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
>>>>>>>> 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) = 256000kB
>>>>>>>> [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB (UE) 3*32kB
>>>>>>>> (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME) 3*1024kB (ME)
>>>>>>>> 3*2048kB (UME) 1436*4096kB (M) = 5893600kB
>>>>>>>> [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
>>>>>>>> hugepages_surp=0 hugepages_size=1048576kB
>>>>>>>> [ 30.370130] 0 total pagecache pages
>>>>>>>> [ 30.370132] 0 pages in swap cache
>>>>>>>> [ 30.370134] Swap cache stats: add 0, delete 0, find 0/0
>>>>>>>> [ 30.370135] Free swap = 0kB
>>>>>>>> [ 30.370136] Total swap = 0kB
>>>>>>>> [ 30.370137] 2164609 pages RAM
>>>>>>>> [ 30.370139] 0 pages HighMem/MovableOnly
>>>>>>>> [ 30.370140] 612331 pages reserved
>>>>>>>> [ 30.370141] 0 pages hwpoisoned
>>>>>>>> [ 30.370143] DMA: failed to allocate 256 KiB pool for atomic
>>>>>>>> coherent allocation
>>>>>>>
>>>>>>> During my testing I saw the same error and Chen's solution corrected it .
>>>>>> Which combination you are using on your side? I am using Prabhakar's
>>>>>> suggested environment and can reproduce the issue
>>>>>> with or without Chen's crashkernel support above 4G patchset.
>>>>>>
>>>>>> I am also using a ThunderX2 platform with latest makedumpfile code and
>>>>>> kexec-tools (with the suggested patch
>>>>>> <https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!J6lUig58-Gw6TKZnEEYzEeSU36T-1SqlB1kImU00xtX_lss5Tx-JbUmLE9TJC3foXBLg$ >).
>>>>>>
>>>>>> Thanks,
>>>>>> Bhupesh
>>>>>
>>>>> I did this activity 5 months ago and I have moved on to other activities. My DMA failures were related to PCI devices that could not be enumerated because low-DMA space was not available when crashkernel was moved above 4G; I don’t recall the exact platform.
>>>>>
>>>>>
>>>>>
>>>>> For this failure ,
>>>>>
>>>>>>>> DMA: failed to allocate 256 KiB pool for atomic
>>>>>>>> coherent allocation
>>>>>
>>>>> Is due to :
>>>>>
>>>>>
>>>>> 3618082c
>>>>> ("arm64 use both ZONE_DMA and ZONE_DMA32")
>>>>>
>>>>> With the introduction of ZONE_DMA to support the Raspberry DMA
>>>>> region below 1G, the crashkernel is placed in the upper 4G
>>>>> ZONE_DMA_32 region. Since the crashkernel does not have access
>>>>> to the ZONE_DMA region, it prints out call trace during bootup.
>>>>>
>>>>> It is due to having this CONFIG item ON :
>>>>>
>>>>>
>>>>> CONFIG_ZONE_DMA=y
>>>>>
>>>>> Turning off ZONE_DMA fixes a issue and Raspberry PI 4 will
>>>>> use the device tree to specify memory below 1G.
>>>>>
>>>>>
>>>> Disabling ZONE_DMA is temporary solution. We may need proper solution
>>>
>>> Perhaps the Raspberry platform configuration dependencies need separated from “server class” Arm equipment ? Or auto-configured on boot ? Consult an expert ;-)
>>>
>>>
>>>
>>>>> I would like to see Chen’s feature added , perhaps as EXPERIMENTAL, so we can get some configuration testing done on it. It corrects having a DMA zone in low memory while crash-kernel is above 4GB. This has been going on for a year now.
>>>> I will also like this patch to be added in Linux as early as possible.
>>>>
>>>> Issue mentioned by me happens with or without this patch.
>>>>
>>>> This patch-set can consider fixing because it uses low memory for DMA
>>>> & swiotlb only.
>>>> We can consider restricting crashkernel within the required range like below
>>>>
>>>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
>>>> index 7f9e5a6dc48c..bd67b90d35bd 100644
>>>> --- a/kernel/crash_core.c
>>>> +++ b/kernel/crash_core.c
>>>> @@ -354,7 +354,7 @@ int __init reserve_crashkernel_low(void)
>>>> return 0;
>>>> }
>>>>
>>>> - low_base = memblock_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
>>>> + low_base = memblock_find_in_range(0,0xc0000000, low_size, CRASH_ALIGN);
>>>> if (!low_base) {
>>>> pr_err("Cannot reserve %ldMB crashkernel low memory,
>>>> please try smaller size.\n",
>>>> (unsigned long)(low_size >> 20));
>>>>
>>>>
>>> I suspect 0xc0000000 would need to be a CONFIG item and not hard-coded.
>>>
>> if you consider this as valid change, can you please incorporate as
>> part of your patch-set.
>
> After commit 1a8e1cef7 ("arm64: use both ZONE_DMA and ZONE_DMA32")，the 0-4G memory is splited
> to DMA [mem 0x0000000000000000-0x000000003fffffff] and DMA32 [mem 0x0000000040000000-0x00000000ffffffff] on arm64.
>
> From the above discussion, on your platform, the low crashkernel fall in DMA32 region, but your environment needs to access DMA
> region, so there is the call trace.
>
> I have a question, why do you choose 0xc0000000 here?
>
> Besides, this is common code, we also need to consider about x86.
>
+ [email protected]
Exactly . This is why it needs to be a CONFIG option for Raspberry .., or device tree option.
We could revert 1a8e1cef7 since it broke Arm kdump too.
>
> Thanks,
> Chen Zhou
>
Hi All,
On Wed, Jun 3, 2020 at 9:03 PM John Donnelly <[email protected]> wrote:
>
>
>
> > On Jun 3, 2020, at 8:20 AM, chenzhou <[email protected]> wrote:
> >
> > Hi,
> >
> >
> > On 2020/6/3 19:47, Prabhakar Kushwaha wrote:
> >> Hi Chen,
> >>
> >> On Tue, Jun 2, 2020 at 8:12 PM John Donnelly <[email protected]> wrote:
> >>>
> >>>
> >>>> On Jun 2, 2020, at 12:38 AM, Prabhakar Kushwaha <[email protected]> wrote:
> >>>>
> >>>> On Tue, Jun 2, 2020 at 3:29 AM John Donnelly <[email protected]> wrote:
> >>>>> Hi . See below !
> >>>>>
> >>>>>> On Jun 1, 2020, at 4:02 PM, Bhupesh Sharma <[email protected]> wrote:
> >>>>>>
> >>>>>> Hi John,
> >>>>>>
> >>>>>> On Tue, Jun 2, 2020 at 1:01 AM John Donnelly <[email protected]> wrote:
> >>>>>>> Hi,
> >>>>>>>
> >>>>>>>
> >>>>>>> On 6/1/20 7:02 AM, Prabhakar Kushwaha wrote:
> >>>>>>>> Hi Chen,
> >>>>>>>>
> >>>>>>>> On Thu, May 21, 2020 at 3:05 PM Chen Zhou <[email protected]> wrote:
> >>>>>>>>> This patch series enable reserving crashkernel above 4G in arm64.
> >>>>>>>>>
> >>>>>>>>> There are following issues in arm64 kdump:
> >>>>>>>>> 1. We use crashkernel=X to reserve crashkernel below 4G, which will fail
> >>>>>>>>> when there is no enough low memory.
> >>>>>>>>> 2. Currently, crashkernel=Y@X can be used to reserve crashkernel above 4G,
> >>>>>>>>> in this case, if swiotlb or DMA buffers are required, crash dump kernel
> >>>>>>>>> will boot failure because there is no low memory available for allocation.
> >>>>>>>>>
> >>>>>>>> We are getting "warn_alloc" [1] warning during boot of kdump kernel
> >>>>>>>> with bootargs as [2] of primary kernel.
> >>>>>>>> This error observed on ThunderX2 ARM64 platform.
> >>>>>>>>
> >>>>>>>> It is observed with latest upstream tag (v5.7-rc3) with this patch set
> >>>>>>>> and https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiIAAlzu$
> >>>>>>>> Also **without** this patch-set
> >>>>>>>> "https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$"
> >>>>>>>>
> >>>>>>>> This issue comes whenever crashkernel memory is reserved after 0xc000_0000.
> >>>>>>>> More details discussed earlier in
> >>>>>>>> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$ without any
> >>>>>>>> solution
> >>>>>>>>
> >>>>>>>> This patch-set is expected to solve similar kind of issue.
> >>>>>>>> i.e. low memory is only targeted for DMA, swiotlb; So above mentioned
> >>>>>>>> observation should be considered/fixed. .
> >>>>>>>>
> >>>>>>>> --pk
> >>>>>>>>
> >>>>>>>> [1]
> >>>>>>>> [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
> >>>>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
> >>>>>>>> [ 30.367696] NET: Registered protocol family 16
> >>>>>>>> [ 30.369973] swapper/0: page allocation failure: order:6,
> >>>>>>>> mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
> >>>>>>>> [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc3+ #121
> >>>>>>>> [ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS
> >>>>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
> >>>>>>>> [ 30.369984] Call trace:
> >>>>>>>> [ 30.369989] dump_backtrace+0x0/0x1f8
> >>>>>>>> [ 30.369991] show_stack+0x20/0x30
> >>>>>>>> [ 30.369997] dump_stack+0xc0/0x10c
> >>>>>>>> [ 30.370001] warn_alloc+0x10c/0x178
> >>>>>>>> [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0xb50
> >>>>>>>> [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
> >>>>>>>> [ 30.370008] alloc_page_interleave+0x24/0x98
> >>>>>>>> [ 30.370011] alloc_pages_current+0xe4/0x108
> >>>>>>>> [ 30.370017] dma_atomic_pool_init+0x44/0x1a4
> >>>>>>>> [ 30.370020] do_one_initcall+0x54/0x228
> >>>>>>>> [ 30.370027] kernel_init_freeable+0x228/0x2cc
> >>>>>>>> [ 30.370031] kernel_init+0x1c/0x110
> >>>>>>>> [ 30.370034] ret_from_fork+0x10/0x18
> >>>>>>>> [ 30.370036] Mem-Info:
> >>>>>>>> [ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0
> >>>>>>>> [ 30.370064] active_file:0 inactive_file:0 isolated_file:0
> >>>>>>>> [ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0
> >>>>>>>> [ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438
> >>>>>>>> [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
> >>>>>>>> [ 30.370064] free:1537719 free_pcp:219 free_cma:0
> >>>>>>>> [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
> >>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
> >>>>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
> >>>>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
> >>>>>>>> unstable:0kB all_unreclaimable? no
> >>>>>>>> [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
> >>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB
> >>>>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB shmem:0kB
> >>>>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB writeback_tmp:0kB
> >>>>>>>> unstable:0kB all_unreclaimable? no
> >>>>>>>> [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB
> >>>>>>>> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> >>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
> >>>>>>>> present:128kB managed:0kB mlocked:0kB kernel_stack:0kB pagetables:0kB
> >>>>>>>> bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> >>>>>>>> [ 30.370084] lowmem_reserve[]: 0 250 6063 6063
> >>>>>>>> [ 30.370090] Node 0 DMA32 free:256000kB min:408kB low:664kB
> >>>>>>>> high:920kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> >>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
> >>>>>>>> present:269700kB managed:256000kB mlocked:0kB kernel_stack:0kB
> >>>>>>>> pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> >>>>>>>> [ 30.370094] lowmem_reserve[]: 0 0 5813 5813
> >>>>>>>> [ 30.370100] Node 0 Normal free:5894876kB min:9552kB low:15504kB
> >>>>>>>> high:21456kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> >>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB
> >>>>>>>> present:8388608kB managed:5953112kB mlocked:0kB kernel_stack:21672kB
> >>>>>>>> pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB free_cma:0kB
> >>>>>>>> [ 30.370104] lowmem_reserve[]: 0 0 0 0
> >>>>>>>> [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
> >>>>>>>> 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
> >>>>>>>> [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB
> >>>>>>>> 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) = 256000kB
> >>>>>>>> [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB (UE) 3*32kB
> >>>>>>>> (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME) 3*1024kB (ME)
> >>>>>>>> 3*2048kB (UME) 1436*4096kB (M) = 5893600kB
> >>>>>>>> [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
> >>>>>>>> hugepages_surp=0 hugepages_size=1048576kB
> >>>>>>>> [ 30.370130] 0 total pagecache pages
> >>>>>>>> [ 30.370132] 0 pages in swap cache
> >>>>>>>> [ 30.370134] Swap cache stats: add 0, delete 0, find 0/0
> >>>>>>>> [ 30.370135] Free swap = 0kB
> >>>>>>>> [ 30.370136] Total swap = 0kB
> >>>>>>>> [ 30.370137] 2164609 pages RAM
> >>>>>>>> [ 30.370139] 0 pages HighMem/MovableOnly
> >>>>>>>> [ 30.370140] 612331 pages reserved
> >>>>>>>> [ 30.370141] 0 pages hwpoisoned
> >>>>>>>> [ 30.370143] DMA: failed to allocate 256 KiB pool for atomic
> >>>>>>>> coherent allocation
> >>>>>>>
> >>>>>>> During my testing I saw the same error and Chen's solution corrected it .
> >>>>>> Which combination you are using on your side? I am using Prabhakar's
> >>>>>> suggested environment and can reproduce the issue
> >>>>>> with or without Chen's crashkernel support above 4G patchset.
> >>>>>>
> >>>>>> I am also using a ThunderX2 platform with latest makedumpfile code and
> >>>>>> kexec-tools (with the suggested patch
> >>>>>> <https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!J6lUig58-Gw6TKZnEEYzEeSU36T-1SqlB1kImU00xtX_lss5Tx-JbUmLE9TJC3foXBLg$ >).
> >>>>>>
> >>>>>> Thanks,
> >>>>>> Bhupesh
> >>>>>
> >>>>> I did this activity 5 months ago and I have moved on to other activities. My DMA failures were related to PCI devices that could not be enumerated because low-DMA space was not available when crashkernel was moved above 4G; I don’t recall the exact platform.
> >>>>>
> >>>>>
> >>>>>
> >>>>> For this failure ,
> >>>>>
> >>>>>>>> DMA: failed to allocate 256 KiB pool for atomic
> >>>>>>>> coherent allocation
> >>>>>
> >>>>> Is due to :
> >>>>>
> >>>>>
> >>>>> 3618082c
> >>>>> ("arm64 use both ZONE_DMA and ZONE_DMA32")
> >>>>>
> >>>>> With the introduction of ZONE_DMA to support the Raspberry DMA
> >>>>> region below 1G, the crashkernel is placed in the upper 4G
> >>>>> ZONE_DMA_32 region. Since the crashkernel does not have access
> >>>>> to the ZONE_DMA region, it prints out call trace during bootup.
> >>>>>
> >>>>> It is due to having this CONFIG item ON :
> >>>>>
> >>>>>
> >>>>> CONFIG_ZONE_DMA=y
> >>>>>
> >>>>> Turning off ZONE_DMA fixes a issue and Raspberry PI 4 will
> >>>>> use the device tree to specify memory below 1G.
> >>>>>
> >>>>>
> >>>> Disabling ZONE_DMA is temporary solution. We may need proper solution
> >>>
> >>> Perhaps the Raspberry platform configuration dependencies need separated from “server class” Arm equipment ? Or auto-configured on boot ? Consult an expert ;-)
> >>>
> >>>
> >>>
> >>>>> I would like to see Chen’s feature added , perhaps as EXPERIMENTAL, so we can get some configuration testing done on it. It corrects having a DMA zone in low memory while crash-kernel is above 4GB. This has been going on for a year now.
> >>>> I will also like this patch to be added in Linux as early as possible.
> >>>>
> >>>> Issue mentioned by me happens with or without this patch.
> >>>>
> >>>> This patch-set can consider fixing because it uses low memory for DMA
> >>>> & swiotlb only.
> >>>> We can consider restricting crashkernel within the required range like below
> >>>>
> >>>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> >>>> index 7f9e5a6dc48c..bd67b90d35bd 100644
> >>>> --- a/kernel/crash_core.c
> >>>> +++ b/kernel/crash_core.c
> >>>> @@ -354,7 +354,7 @@ int __init reserve_crashkernel_low(void)
> >>>> return 0;
> >>>> }
> >>>>
> >>>> - low_base = memblock_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
> >>>> + low_base = memblock_find_in_range(0,0xc0000000, low_size, CRASH_ALIGN);
> >>>> if (!low_base) {
> >>>> pr_err("Cannot reserve %ldMB crashkernel low memory,
> >>>> please try smaller size.\n",
> >>>> (unsigned long)(low_size >> 20));
> >>>>
> >>>>
> >>> I suspect 0xc0000000 would need to be a CONFIG item and not hard-coded.
> >>>
> >> if you consider this as valid change, can you please incorporate as
> >> part of your patch-set.
> >
> > After commit 1a8e1cef7 ("arm64: use both ZONE_DMA and ZONE_DMA32")，the 0-4G memory is splited
> > to DMA [mem 0x0000000000000000-0x000000003fffffff] and DMA32 [mem 0x0000000040000000-0x00000000ffffffff] on arm64.
> >
> > From the above discussion, on your platform, the low crashkernel fall in DMA32 region, but your environment needs to access DMA
> > region, so there is the call trace.
> >
> > I have a question, why do you choose 0xc0000000 here?
> >
> > Besides, this is common code, we also need to consider about x86.
> >
>
> + [email protected]
>
> Exactly . This is why it needs to be a CONFIG option for Raspberry .., or device tree option.
>
>
> We could revert 1a8e1cef7 since it broke Arm kdump too.
Well, unfortunately the patch for commit 1a8e1cef7603 ("arm64: use
both ZONE_DMA and ZONE_DMA32") was not Cc'ed to the kexec mailing
list, thus we couldn't get many eyes on it for a thorough review from
kexec/kdump p-o-v.
Also we historically never had distinction in common arch code on the
basis of the intended end use-case: embedded, server or automotive, so
I am not sure introducing a Raspberry specific CONFIG option would be
a good idea.
So, rather than reverting the patch, we can look at addressing the
same properly this time - especially from a kdump p-o-v.
This issue has been reported by some Red Hat arm64 partners with
upstream kernel also and as we have noticed in the past as well,
hardcoding the placement of the crashkernel base address (unless the
base address is specified by a crashkernel=X@Y like bootargs) is also
not a portable suggestion.
I am working on a possible fix and will have more updates on the same
in a day-or-two.
Thanks,
Bhupesh
On Thu, Jun 04, 2020 at 01:17:06AM +0530, Bhupesh Sharma wrote:
> On Wed, Jun 3, 2020 at 9:03 PM John Donnelly <[email protected]> wrote:
> > > On Jun 3, 2020, at 8:20 AM, chenzhou <[email protected]> wrote:
> > > On 2020/6/3 19:47, Prabhakar Kushwaha wrote:
> > >>>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> > >>>> index 7f9e5a6dc48c..bd67b90d35bd 100644
> > >>>> --- a/kernel/crash_core.c
> > >>>> +++ b/kernel/crash_core.c
> > >>>> @@ -354,7 +354,7 @@ int __init reserve_crashkernel_low(void)
> > >>>> return 0;
> > >>>> }
> > >>>>
> > >>>> - low_base = memblock_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
> > >>>> + low_base = memblock_find_in_range(0,0xc0000000, low_size, CRASH_ALIGN);
> > >>>> if (!low_base) {
> > >>>> pr_err("Cannot reserve %ldMB crashkernel low memory,
> > >>>> please try smaller size.\n",
> > >>>> (unsigned long)(low_size >> 20));
> > >>>>
> > >>>>
> > >>> I suspect 0xc0000000 would need to be a CONFIG item and not hard-coded.
> > >>>
> > >> if you consider this as valid change, can you please incorporate as
> > >> part of your patch-set.
> > >
> > > After commit 1a8e1cef7 ("arm64: use both ZONE_DMA and
> > > ZONE_DMA32")，the 0-4G memory is splited to DMA [mem
> > > 0x0000000000000000-0x000000003fffffff] and DMA32 [mem
> > > 0x0000000040000000-0x00000000ffffffff] on arm64.
> > >
> > > From the above discussion, on your platform, the low crashkernel fall
> > > in DMA32 region, but your environment needs to access DMA region, so
> > > there is the call trace.
> > >
> > > I have a question, why do you choose 0xc0000000 here?
> > >
> > > Besides, this is common code, we also need to consider about x86.
> > >
> >
> > + [email protected]
> >
> > Exactly . This is why it needs to be a CONFIG option for Raspberry
> > .., or device tree option.
> >
> >
> > We could revert 1a8e1cef7 since it broke Arm kdump too.
>
> Well, unfortunately the patch for commit 1a8e1cef7603 ("arm64: use
> both ZONE_DMA and ZONE_DMA32") was not Cc'ed to the kexec mailing
> list, thus we couldn't get many eyes on it for a thorough review from
> kexec/kdump p-o-v.
>
> Also we historically never had distinction in common arch code on the
> basis of the intended end use-case: embedded, server or automotive, so
> I am not sure introducing a Raspberry specific CONFIG option would be
> a good idea.
Right, we need a fix that works for everybody, since we try hard for a
single Image that works for all platforms.
What I don't really understand is why, with Chen's patches applied, we can't
just keep the crashkernel out of the DMA zones altogether when no base is
specified. I guess I'll just look out for your patch!
Will
On Thu, 2020-06-04 at 01:17 +0530, Bhupesh Sharma wrote:
> Hi All,
>
> On Wed, Jun 3, 2020 at 9:03 PM John Donnelly <[email protected]>
> wrote:
> >
> >
> > > On Jun 3, 2020, at 8:20 AM, chenzhou <[email protected]> wrote:
> > >
> > > Hi,
> > >
> > >
> > > On 2020/6/3 19:47, Prabhakar Kushwaha wrote:
> > > > Hi Chen,
> > > >
> > > > On Tue, Jun 2, 2020 at 8:12 PM John Donnelly <[email protected]
> > > > > wrote:
> > > > >
> > > > > > On Jun 2, 2020, at 12:38 AM, Prabhakar Kushwaha <
> > > > > > [email protected]> wrote:
> > > > > >
> > > > > > On Tue, Jun 2, 2020 at 3:29 AM John Donnelly <
> > > > > > [email protected]> wrote:
> > > > > > > Hi . See below !
> > > > > > >
> > > > > > > > On Jun 1, 2020, at 4:02 PM, Bhupesh Sharma <[email protected]>
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > Hi John,
> > > > > > > >
> > > > > > > > On Tue, Jun 2, 2020 at 1:01 AM John Donnelly <
> > > > > > > > [email protected]> wrote:
> > > > > > > > > Hi,
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > On 6/1/20 7:02 AM, Prabhakar Kushwaha wrote:
> > > > > > > > > > Hi Chen,
> > > > > > > > > >
> > > > > > > > > > On Thu, May 21, 2020 at 3:05 PM Chen Zhou <
> > > > > > > > > > [email protected]> wrote:
> > > > > > > > > > > This patch series enable reserving crashkernel above 4G in
> > > > > > > > > > > arm64.
> > > > > > > > > > >
> > > > > > > > > > > There are following issues in arm64 kdump:
> > > > > > > > > > > 1. We use crashkernel=X to reserve crashkernel below 4G,
> > > > > > > > > > > which will fail
> > > > > > > > > > > when there is no enough low memory.
> > > > > > > > > > > 2. Currently, crashkernel=Y@X can be used to reserve
> > > > > > > > > > > crashkernel above 4G,
> > > > > > > > > > > in this case, if swiotlb or DMA buffers are required,
> > > > > > > > > > > crash dump kernel
> > > > > > > > > > > will boot failure because there is no low memory available
> > > > > > > > > > > for allocation.
> > > > > > > > > > >
> > > > > > > > > > We are getting "warn_alloc" [1] warning during boot of kdump
> > > > > > > > > > kernel
> > > > > > > > > > with bootargs as [2] of primary kernel.
> > > > > > > > > > This error observed on ThunderX2 ARM64 platform.
> > > > > > > > > >
> > > > > > > > > > It is observed with latest upstream tag (v5.7-rc3) with this
> > > > > > > > > > patch set
> > > > > > > > > > and
> > > > > > > > > >
https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiIAAlzu$
> > > > > > > > > > Also **without** this patch-set
> > > > > > > > > > "
> > > > > > > > > >
https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$
> > > > > > > > > > "
> > > > > > > > > >
> > > > > > > > > > This issue comes whenever crashkernel memory is reserved
> > > > > > > > > > after 0xc000_0000.
> > > > > > > > > > More details discussed earlier in
> > > > > > > > > >
https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$
without
> > > > > > > > > > any
> > > > > > > > > > solution
> > > > > > > > > >
> > > > > > > > > > This patch-set is expected to solve similar kind of issue.
> > > > > > > > > > i.e. low memory is only targeted for DMA, swiotlb; So above
> > > > > > > > > > mentioned
> > > > > > > > > > observation should be considered/fixed. .
> > > > > > > > > >
> > > > > > > > > > --pk
> > > > > > > > > >
> > > > > > > > > > [1]
> > > > > > > > > > [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
> > > > > > > > > > TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
> > > > > > > > > > [ 30.367696] NET: Registered protocol family 16
> > > > > > > > > > [ 30.369973] swapper/0: page allocation failure: order:6,
> > > > > > > > > > mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
> > > > > > > > > > [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
> > > > > > > > > > 5.7.0-rc3+ #121
> > > > > > > > > > [ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS
> > > > > > > > > > TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
> > > > > > > > > > [ 30.369984] Call trace:
> > > > > > > > > > [ 30.369989] dump_backtrace+0x0/0x1f8
> > > > > > > > > > [ 30.369991] show_stack+0x20/0x30
> > > > > > > > > > [ 30.369997] dump_stack+0xc0/0x10c
> > > > > > > > > > [ 30.370001] warn_alloc+0x10c/0x178
> > > > > > > > > > [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0
> > > > > > > > > > xb50
> > > > > > > > > > [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
> > > > > > > > > > [ 30.370008] alloc_page_interleave+0x24/0x98
> > > > > > > > > > [ 30.370011] alloc_pages_current+0xe4/0x108
> > > > > > > > > > [ 30.370017] dma_atomic_pool_init+0x44/0x1a4
> > > > > > > > > > [ 30.370020] do_one_initcall+0x54/0x228
> > > > > > > > > > [ 30.370027] kernel_init_freeable+0x228/0x2cc
> > > > > > > > > > [ 30.370031] kernel_init+0x1c/0x110
> > > > > > > > > > [ 30.370034] ret_from_fork+0x10/0x18
> > > > > > > > > > [ 30.370036] Mem-Info:
> > > > > > > > > > [ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0
> > > > > > > > > > [ 30.370064] active_file:0 inactive_file:0
> > > > > > > > > > isolated_file:0
> > > > > > > > > > [ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0
> > > > > > > > > > [ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438
> > > > > > > > > > [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
> > > > > > > > > > [ 30.370064] free:1537719 free_pcp:219 free_cma:0
> > > > > > > > > > [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
> > > > > > > > > > active_file:0kB inactive_file:0kB unevictable:0kB
> > > > > > > > > > isolated(anon):0kB
> > > > > > > > > > isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB
> > > > > > > > > > shmem:0kB
> > > > > > > > > > shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB
> > > > > > > > > > writeback_tmp:0kB
> > > > > > > > > > unstable:0kB all_unreclaimable? no
> > > > > > > > > > [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
> > > > > > > > > > active_file:0kB inactive_file:0kB unevictable:0kB
> > > > > > > > > > isolated(anon):0kB
> > > > > > > > > > isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB
> > > > > > > > > > shmem:0kB
> > > > > > > > > > shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB
> > > > > > > > > > writeback_tmp:0kB
> > > > > > > > > > unstable:0kB all_unreclaimable? no
> > > > > > > > > > [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB
> > > > > > > > > > reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
> > > > > > > > > > active_file:0kB inactive_file:0kB unevictable:0kB
> > > > > > > > > > writepending:0kB
> > > > > > > > > > present:128kB managed:0kB mlocked:0kB kernel_stack:0kB
> > > > > > > > > > pagetables:0kB
> > > > > > > > > > bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> > > > > > > > > > [ 30.370084] lowmem_reserve[]: 0 250 6063 6063
> > > > > > > > > > [ 30.370090] Node 0 DMA32 free:256000kB min:408kB
> > > > > > > > > > low:664kB
> > > > > > > > > > high:920kB reserved_highatomic:0KB active_anon:0kB
> > > > > > > > > > inactive_anon:0kB
> > > > > > > > > > active_file:0kB inactive_file:0kB unevictable:0kB
> > > > > > > > > > writepending:0kB
> > > > > > > > > > present:269700kB managed:256000kB mlocked:0kB
> > > > > > > > > > kernel_stack:0kB
> > > > > > > > > > pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB
> > > > > > > > > > free_cma:0kB
> > > > > > > > > > [ 30.370094] lowmem_reserve[]: 0 0 5813 5813
> > > > > > > > > > [ 30.370100] Node 0 Normal free:5894876kB min:9552kB
> > > > > > > > > > low:15504kB
> > > > > > > > > > high:21456kB reserved_highatomic:0KB active_anon:0kB
> > > > > > > > > > inactive_anon:0kB
> > > > > > > > > > active_file:0kB inactive_file:0kB unevictable:0kB
> > > > > > > > > > writepending:0kB
> > > > > > > > > > present:8388608kB managed:5953112kB mlocked:0kB
> > > > > > > > > > kernel_stack:21672kB
> > > > > > > > > > pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB
> > > > > > > > > > free_cma:0kB
> > > > > > > > > > [ 30.370104] lowmem_reserve[]: 0 0 0 0
> > > > > > > > > > [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB
> > > > > > > > > > 0*128kB
> > > > > > > > > > 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
> > > > > > > > > > [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB
> > > > > > > > > > 0*64kB 0*128kB
> > > > > > > > > > 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) =
> > > > > > > > > > 256000kB
> > > > > > > > > > [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB
> > > > > > > > > > (UE) 3*32kB
> > > > > > > > > > (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME)
> > > > > > > > > > 3*1024kB (ME)
> > > > > > > > > > 3*2048kB (UME) 1436*4096kB (M) = 5893600kB
> > > > > > > > > > [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
> > > > > > > > > > hugepages_surp=0 hugepages_size=1048576kB
> > > > > > > > > > [ 30.370130] 0 total pagecache pages
> > > > > > > > > > [ 30.370132] 0 pages in swap cache
> > > > > > > > > > [ 30.370134] Swap cache stats: add 0, delete 0, find 0/0
> > > > > > > > > > [ 30.370135] Free swap = 0kB
> > > > > > > > > > [ 30.370136] Total swap = 0kB
> > > > > > > > > > [ 30.370137] 2164609 pages RAM
> > > > > > > > > > [ 30.370139] 0 pages HighMem/MovableOnly
> > > > > > > > > > [ 30.370140] 612331 pages reserved
> > > > > > > > > > [ 30.370141] 0 pages hwpoisoned
> > > > > > > > > > [ 30.370143] DMA: failed to allocate 256 KiB pool for
> > > > > > > > > > atomic
> > > > > > > > > > coherent allocation
> > > > > > > > >
> > > > > > > > > During my testing I saw the same error and Chen's solution
> > > > > > > > > corrected it .
> > > > > > > > Which combination you are using on your side? I am using
> > > > > > > > Prabhakar's
> > > > > > > > suggested environment and can reproduce the issue
> > > > > > > > with or without Chen's crashkernel support above 4G patchset.
> > > > > > > >
> > > > > > > > I am also using a ThunderX2 platform with latest makedumpfile
> > > > > > > > code and
> > > > > > > > kexec-tools (with the suggested patch
> > > > > > > > <
> > > > > > > >
https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!J6lUig58-Gw6TKZnEEYzEeSU36T-1SqlB1kImU00xtX_lss5Tx-JbUmLE9TJC3foXBLg$
> > > > > > > > >).
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Bhupesh
> > > > > > >
> > > > > > > I did this activity 5 months ago and I have moved on to other
> > > > > > > activities. My DMA failures were related to PCI devices that could
> > > > > > > not be enumerated because low-DMA space was not available when
> > > > > > > crashkernel was moved above 4G; I don’t recall the exact platform.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > For this failure ,
> > > > > > >
> > > > > > > > > > DMA: failed to allocate 256 KiB pool for atomic
> > > > > > > > > > coherent allocation
> > > > > > >
> > > > > > > Is due to :
> > > > > > >
> > > > > > >
> > > > > > > 3618082c
> > > > > > > ("arm64 use both ZONE_DMA and ZONE_DMA32")
> > > > > > >
> > > > > > > With the introduction of ZONE_DMA to support the Raspberry DMA
> > > > > > > region below 1G, the crashkernel is placed in the upper 4G
> > > > > > > ZONE_DMA_32 region. Since the crashkernel does not have access
> > > > > > > to the ZONE_DMA region, it prints out call trace during bootup.
> > > > > > >
> > > > > > > It is due to having this CONFIG item ON :
> > > > > > >
> > > > > > >
> > > > > > > CONFIG_ZONE_DMA=y
> > > > > > >
> > > > > > > Turning off ZONE_DMA fixes a issue and Raspberry PI 4 will
> > > > > > > use the device tree to specify memory below 1G.
> > > > > > >
> > > > > > >
> > > > > > Disabling ZONE_DMA is temporary solution. We may need proper
> > > > > > solution
> > > > >
> > > > > Perhaps the Raspberry platform configuration dependencies need
> > > > > separated from “server class” Arm equipment ? Or auto-configured on
> > > > > boot ? Consult an expert ;-)
> > > > >
> > > > >
> > > > >
> > > > > > > I would like to see Chen’s feature added , perhaps as
> > > > > > > EXPERIMENTAL, so we can get some configuration testing done on
> > > > > > > it. It corrects having a DMA zone in low memory while crash-
> > > > > > > kernel is above 4GB. This has been going on for a year now.
> > > > > > I will also like this patch to be added in Linux as early as
> > > > > > possible.
> > > > > >
> > > > > > Issue mentioned by me happens with or without this patch.
> > > > > >
> > > > > > This patch-set can consider fixing because it uses low memory for
> > > > > > DMA
> > > > > > & swiotlb only.
> > > > > > We can consider restricting crashkernel within the required range
> > > > > > like below
> > > > > >
> > > > > > diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> > > > > > index 7f9e5a6dc48c..bd67b90d35bd 100644
> > > > > > --- a/kernel/crash_core.c
> > > > > > +++ b/kernel/crash_core.c
> > > > > > @@ -354,7 +354,7 @@ int __init reserve_crashkernel_low(void)
> > > > > > return 0;
> > > > > > }
> > > > > >
> > > > > > - low_base = memblock_find_in_range(0, 1ULL << 32, low_size,
> > > > > > CRASH_ALIGN);
> > > > > > + low_base = memblock_find_in_range(0,0xc0000000, low_size,
> > > > > > CRASH_ALIGN);
> > > > > > if (!low_base) {
> > > > > > pr_err("Cannot reserve %ldMB crashkernel low memory,
> > > > > > please try smaller size.\n",
> > > > > > (unsigned long)(low_size >> 20));
> > > > > >
> > > > > >
> > > > > I suspect 0xc0000000 would need to be a CONFIG item and not
> > > > > hard-coded.
> > > > >
> > > > if you consider this as valid change, can you please incorporate as
> > > > part of your patch-set.
> > >
> > > After commit 1a8e1cef7 ("arm64: use both ZONE_DMA and ZONE_DMA32")，the 0-
> > > 4G memory is splited
> > > to DMA [mem 0x0000000000000000-0x000000003fffffff] and DMA32 [mem
> > > 0x0000000040000000-0x00000000ffffffff] on arm64.
> > >
> > > From the above discussion, on your platform, the low crashkernel fall in
> > > DMA32 region, but your environment needs to access DMA
> > > region, so there is the call trace.
> > >
> > > I have a question, why do you choose 0xc0000000 here?
> > >
> > > Besides, this is common code, we also need to consider about x86.
> > >
> >
> > + [email protected]
Thanks for adding me to the conversation, and sorry for the headaches.
> >
> > Exactly . This is why it needs to be a CONFIG option for Raspberry
> > .., or device tree option.
> >
> >
> > We could revert 1a8e1cef7 since it broke Arm kdump too.
>
> Well, unfortunately the patch for commit 1a8e1cef7603 ("arm64: use
> both ZONE_DMA and ZONE_DMA32") was not Cc'ed to the kexec mailing
> list, thus we couldn't get many eyes on it for a thorough review from
> kexec/kdump p-o-v.
>
> Also we historically never had distinction in common arch code on the
> basis of the intended end use-case: embedded, server or automotive, so
> I am not sure introducing a Raspberry specific CONFIG option would be
> a good idea.
+1
From the distros perspective it's very important to keep a single kernel image.
> So, rather than reverting the patch, we can look at addressing the
> same properly this time - especially from a kdump p-o-v.
> This issue has been reported by some Red Hat arm64 partners with
> upstream kernel also and as we have noticed in the past as well,
> hardcoding the placement of the crashkernel base address (unless the
> base address is specified by a crashkernel=X@Y like bootargs) is also
> not a portable suggestion.
>
> I am working on a possible fix and will have more updates on the same
> in a day-or-two.
Please keep me in the loop, we've also had issues pointing to this reported by
SUSE partners. I can do some testing both on the RPi4 and on big servers that
need huge crashkernel sizes.
Regards,
Nicolas
On 6/4/20 12:01 PM, Nicolas Saenz Julienne wrote:
> On Thu, 2020-06-04 at 01:17 +0530, Bhupesh Sharma wrote:
>> Hi All,
>>
>> On Wed, Jun 3, 2020 at 9:03 PM John Donnelly <[email protected]>
>> wrote:
>>>
>>>> On Jun 3, 2020, at 8:20 AM, chenzhou <[email protected]> wrote:
>>>>
>>>> Hi,
>>>>
>>>>
>>>> On 2020/6/3 19:47, Prabhakar Kushwaha wrote:
>>>>> Hi Chen,
>>>>>
>>>>> On Tue, Jun 2, 2020 at 8:12 PM John Donnelly <[email protected]
>>>>>> wrote:
>>>>>>
>>>>>>> On Jun 2, 2020, at 12:38 AM, Prabhakar Kushwaha <
>>>>>>> [email protected]> wrote:
>>>>>>>
>>>>>>> On Tue, Jun 2, 2020 at 3:29 AM John Donnelly <
>>>>>>> [email protected]> wrote:
>>>>>>>> Hi . See below !
>>>>>>>>
>>>>>>>>> On Jun 1, 2020, at 4:02 PM, Bhupesh Sharma <[email protected]>
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>> Hi John,
>>>>>>>>>
>>>>>>>>> On Tue, Jun 2, 2020 at 1:01 AM John Donnelly <
>>>>>>>>> [email protected]> wrote:
>>>>>>>>>> Hi,
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On 6/1/20 7:02 AM, Prabhakar Kushwaha wrote:
>>>>>>>>>>> Hi Chen,
>>>>>>>>>>>
>>>>>>>>>>> On Thu, May 21, 2020 at 3:05 PM Chen Zhou <
>>>>>>>>>>> [email protected]> wrote:
>>>>>>>>>>>> This patch series enable reserving crashkernel above 4G in
>>>>>>>>>>>> arm64.
>>>>>>>>>>>>
>>>>>>>>>>>> There are following issues in arm64 kdump:
>>>>>>>>>>>> 1. We use crashkernel=X to reserve crashkernel below 4G,
>>>>>>>>>>>> which will fail
>>>>>>>>>>>> when there is no enough low memory.
>>>>>>>>>>>> 2. Currently, crashkernel=Y@X can be used to reserve
>>>>>>>>>>>> crashkernel above 4G,
>>>>>>>>>>>> in this case, if swiotlb or DMA buffers are required,
>>>>>>>>>>>> crash dump kernel
>>>>>>>>>>>> will boot failure because there is no low memory available
>>>>>>>>>>>> for allocation.
>>>>>>>>>>>>
>>>>>>>>>>> We are getting "warn_alloc" [1] warning during boot of kdump
>>>>>>>>>>> kernel
>>>>>>>>>>> with bootargs as [2] of primary kernel.
>>>>>>>>>>> This error observed on ThunderX2 ARM64 platform.
>>>>>>>>>>>
>>>>>>>>>>> It is observed with latest upstream tag (v5.7-rc3) with this
>>>>>>>>>>> patch set
>>>>>>>>>>> and
>>>>>>>>>>>
> https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiIAAlzu$
>>>>>>>>>>> Also **without** this patch-set
>>>>>>>>>>> "
>>>>>>>>>>>
> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$
>>>>>>>>>>> "
>>>>>>>>>>>
>>>>>>>>>>> This issue comes whenever crashkernel memory is reserved
>>>>>>>>>>> after 0xc000_0000.
>>>>>>>>>>> More details discussed earlier in
>>>>>>>>>>>
> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$
> without
>>>>>>>>>>> any
>>>>>>>>>>> solution
>>>>>>>>>>>
>>>>>>>>>>> This patch-set is expected to solve similar kind of issue.
>>>>>>>>>>> i.e. low memory is only targeted for DMA, swiotlb; So above
>>>>>>>>>>> mentioned
>>>>>>>>>>> observation should be considered/fixed. .
>>>>>>>>>>>
>>>>>>>>>>> --pk
>>>>>>>>>>>
>>>>>>>>>>> [1]
>>>>>>>>>>> [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
>>>>>>>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>>>>>>>>>> [ 30.367696] NET: Registered protocol family 16
>>>>>>>>>>> [ 30.369973] swapper/0: page allocation failure: order:6,
>>>>>>>>>>> mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
>>>>>>>>>>> [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
>>>>>>>>>>> 5.7.0-rc3+ #121
>>>>>>>>>>> [ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS
>>>>>>>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>>>>>>>>>> [ 30.369984] Call trace:
>>>>>>>>>>> [ 30.369989] dump_backtrace+0x0/0x1f8
>>>>>>>>>>> [ 30.369991] show_stack+0x20/0x30
>>>>>>>>>>> [ 30.369997] dump_stack+0xc0/0x10c
>>>>>>>>>>> [ 30.370001] warn_alloc+0x10c/0x178
>>>>>>>>>>> [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0
>>>>>>>>>>> xb50
>>>>>>>>>>> [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
>>>>>>>>>>> [ 30.370008] alloc_page_interleave+0x24/0x98
>>>>>>>>>>> [ 30.370011] alloc_pages_current+0xe4/0x108
>>>>>>>>>>> [ 30.370017] dma_atomic_pool_init+0x44/0x1a4
>>>>>>>>>>> [ 30.370020] do_one_initcall+0x54/0x228
>>>>>>>>>>> [ 30.370027] kernel_init_freeable+0x228/0x2cc
>>>>>>>>>>> [ 30.370031] kernel_init+0x1c/0x110
>>>>>>>>>>> [ 30.370034] ret_from_fork+0x10/0x18
>>>>>>>>>>> [ 30.370036] Mem-Info:
>>>>>>>>>>> [ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0
>>>>>>>>>>> [ 30.370064] active_file:0 inactive_file:0
>>>>>>>>>>> isolated_file:0
>>>>>>>>>>> [ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0
>>>>>>>>>>> [ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438
>>>>>>>>>>> [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
>>>>>>>>>>> [ 30.370064] free:1537719 free_pcp:219 free_cma:0
>>>>>>>>>>> [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>> isolated(anon):0kB
>>>>>>>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB
>>>>>>>>>>> shmem:0kB
>>>>>>>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB
>>>>>>>>>>> writeback_tmp:0kB
>>>>>>>>>>> unstable:0kB all_unreclaimable? no
>>>>>>>>>>> [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>> isolated(anon):0kB
>>>>>>>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB
>>>>>>>>>>> shmem:0kB
>>>>>>>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB
>>>>>>>>>>> writeback_tmp:0kB
>>>>>>>>>>> unstable:0kB all_unreclaimable? no
>>>>>>>>>>> [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB
>>>>>>>>>>> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>> writepending:0kB
>>>>>>>>>>> present:128kB managed:0kB mlocked:0kB kernel_stack:0kB
>>>>>>>>>>> pagetables:0kB
>>>>>>>>>>> bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>>>>>>>>>>> [ 30.370084] lowmem_reserve[]: 0 250 6063 6063
>>>>>>>>>>> [ 30.370090] Node 0 DMA32 free:256000kB min:408kB
>>>>>>>>>>> low:664kB
>>>>>>>>>>> high:920kB reserved_highatomic:0KB active_anon:0kB
>>>>>>>>>>> inactive_anon:0kB
>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>> writepending:0kB
>>>>>>>>>>> present:269700kB managed:256000kB mlocked:0kB
>>>>>>>>>>> kernel_stack:0kB
>>>>>>>>>>> pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB
>>>>>>>>>>> free_cma:0kB
>>>>>>>>>>> [ 30.370094] lowmem_reserve[]: 0 0 5813 5813
>>>>>>>>>>> [ 30.370100] Node 0 Normal free:5894876kB min:9552kB
>>>>>>>>>>> low:15504kB
>>>>>>>>>>> high:21456kB reserved_highatomic:0KB active_anon:0kB
>>>>>>>>>>> inactive_anon:0kB
>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>> writepending:0kB
>>>>>>>>>>> present:8388608kB managed:5953112kB mlocked:0kB
>>>>>>>>>>> kernel_stack:21672kB
>>>>>>>>>>> pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB
>>>>>>>>>>> free_cma:0kB
>>>>>>>>>>> [ 30.370104] lowmem_reserve[]: 0 0 0 0
>>>>>>>>>>> [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB
>>>>>>>>>>> 0*128kB
>>>>>>>>>>> 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
>>>>>>>>>>> [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB
>>>>>>>>>>> 0*64kB 0*128kB
>>>>>>>>>>> 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) =
>>>>>>>>>>> 256000kB
>>>>>>>>>>> [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB
>>>>>>>>>>> (UE) 3*32kB
>>>>>>>>>>> (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME)
>>>>>>>>>>> 3*1024kB (ME)
>>>>>>>>>>> 3*2048kB (UME) 1436*4096kB (M) = 5893600kB
>>>>>>>>>>> [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
>>>>>>>>>>> hugepages_surp=0 hugepages_size=1048576kB
>>>>>>>>>>> [ 30.370130] 0 total pagecache pages
>>>>>>>>>>> [ 30.370132] 0 pages in swap cache
>>>>>>>>>>> [ 30.370134] Swap cache stats: add 0, delete 0, find 0/0
>>>>>>>>>>> [ 30.370135] Free swap = 0kB
>>>>>>>>>>> [ 30.370136] Total swap = 0kB
>>>>>>>>>>> [ 30.370137] 2164609 pages RAM
>>>>>>>>>>> [ 30.370139] 0 pages HighMem/MovableOnly
>>>>>>>>>>> [ 30.370140] 612331 pages reserved
>>>>>>>>>>> [ 30.370141] 0 pages hwpoisoned
>>>>>>>>>>> [ 30.370143] DMA: failed to allocate 256 KiB pool for
>>>>>>>>>>> atomic
>>>>>>>>>>> coherent allocation
>>>>>>>>>> During my testing I saw the same error and Chen's solution
>>>>>>>>>> corrected it .
>>>>>>>>> Which combination you are using on your side? I am using
>>>>>>>>> Prabhakar's
>>>>>>>>> suggested environment and can reproduce the issue
>>>>>>>>> with or without Chen's crashkernel support above 4G patchset.
>>>>>>>>>
>>>>>>>>> I am also using a ThunderX2 platform with latest makedumpfile
>>>>>>>>> code and
>>>>>>>>> kexec-tools (with the suggested patch
>>>>>>>>> <
>>>>>>>>>
> https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!J6lUig58-Gw6TKZnEEYzEeSU36T-1SqlB1kImU00xtX_lss5Tx-JbUmLE9TJC3foXBLg$
>>>>>>>>>> ).
>>>>>>>>> Thanks,
>>>>>>>>> Bhupesh
>>>>>>>> I did this activity 5 months ago and I have moved on to other
>>>>>>>> activities. My DMA failures were related to PCI devices that could
>>>>>>>> not be enumerated because low-DMA space was not available when
>>>>>>>> crashkernel was moved above 4G; I don’t recall the exact platform.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> For this failure ,
>>>>>>>>
>>>>>>>>>>> DMA: failed to allocate 256 KiB pool for atomic
>>>>>>>>>>> coherent allocation
>>>>>>>> Is due to :
>>>>>>>>
>>>>>>>>
>>>>>>>> 3618082c
>>>>>>>> ("arm64 use both ZONE_DMA and ZONE_DMA32")
>>>>>>>>
>>>>>>>> With the introduction of ZONE_DMA to support the Raspberry DMA
>>>>>>>> region below 1G, the crashkernel is placed in the upper 4G
>>>>>>>> ZONE_DMA_32 region. Since the crashkernel does not have access
>>>>>>>> to the ZONE_DMA region, it prints out call trace during bootup.
>>>>>>>>
>>>>>>>> It is due to having this CONFIG item ON :
>>>>>>>>
>>>>>>>>
>>>>>>>> CONFIG_ZONE_DMA=y
>>>>>>>>
>>>>>>>> Turning off ZONE_DMA fixes a issue and Raspberry PI 4 will
>>>>>>>> use the device tree to specify memory below 1G.
>>>>>>>>
>>>>>>>>
>>>>>>> Disabling ZONE_DMA is temporary solution. We may need proper
>>>>>>> solution
>>>>>> Perhaps the Raspberry platform configuration dependencies need
>>>>>> separated from “server class” Arm equipment ? Or auto-configured on
>>>>>> boot ? Consult an expert ;-)
>>>>>>
>>>>>>
>>>>>>
>>>>>>>> I would like to see Chen’s feature added , perhaps as
>>>>>>>> EXPERIMENTAL, so we can get some configuration testing done on
>>>>>>>> it. It corrects having a DMA zone in low memory while crash-
>>>>>>>> kernel is above 4GB. This has been going on for a year now.
>>>>>>> I will also like this patch to be added in Linux as early as
>>>>>>> possible.
>>>>>>>
>>>>>>> Issue mentioned by me happens with or without this patch.
>>>>>>>
>>>>>>> This patch-set can consider fixing because it uses low memory for
>>>>>>> DMA
>>>>>>> & swiotlb only.
>>>>>>> We can consider restricting crashkernel within the required range
>>>>>>> like below
>>>>>>>
>>>>>>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
>>>>>>> index 7f9e5a6dc48c..bd67b90d35bd 100644
>>>>>>> --- a/kernel/crash_core.c
>>>>>>> +++ b/kernel/crash_core.c
>>>>>>> @@ -354,7 +354,7 @@ int __init reserve_crashkernel_low(void)
>>>>>>> return 0;
>>>>>>> }
>>>>>>>
>>>>>>> - low_base = memblock_find_in_range(0, 1ULL << 32, low_size,
>>>>>>> CRASH_ALIGN);
>>>>>>> + low_base = memblock_find_in_range(0,0xc0000000, low_size,
>>>>>>> CRASH_ALIGN);
>>>>>>> if (!low_base) {
>>>>>>> pr_err("Cannot reserve %ldMB crashkernel low memory,
>>>>>>> please try smaller size.\n",
>>>>>>> (unsigned long)(low_size >> 20));
>>>>>>>
>>>>>>>
>>>>>> I suspect 0xc0000000 would need to be a CONFIG item and not
>>>>>> hard-coded.
>>>>>>
>>>>> if you consider this as valid change, can you please incorporate as
>>>>> part of your patch-set.
>>>> After commit 1a8e1cef7 ("arm64: use both ZONE_DMA and ZONE_DMA32")，the 0-
>>>> 4G memory is splited
>>>> to DMA [mem 0x0000000000000000-0x000000003fffffff] and DMA32 [mem
>>>> 0x0000000040000000-0x00000000ffffffff] on arm64.
>>>>
>>>> From the above discussion, on your platform, the low crashkernel fall in
>>>> DMA32 region, but your environment needs to access DMA
>>>> region, so there is the call trace.
>>>>
>>>> I have a question, why do you choose 0xc0000000 here?
>>>>
>>>> Besides, this is common code, we also need to consider about x86.
>>>>
>>> + [email protected]
> Thanks for adding me to the conversation, and sorry for the headaches.
>
>>> Exactly . This is why it needs to be a CONFIG option for Raspberry
>>> .., or device tree option.
>>>
>>>
>>> We could revert 1a8e1cef7 since it broke Arm kdump too.
>> Well, unfortunately the patch for commit 1a8e1cef7603 ("arm64: use
>> both ZONE_DMA and ZONE_DMA32") was not Cc'ed to the kexec mailing
>> list, thus we couldn't get many eyes on it for a thorough review from
>> kexec/kdump p-o-v.
>>
>> Also we historically never had distinction in common arch code on the
>> basis of the intended end use-case: embedded, server or automotive, so
>> I am not sure introducing a Raspberry specific CONFIG option would be
>> a good idea.
> +1
>
> From the distros perspective it's very important to keep a single kernel image.
>
>> So, rather than reverting the patch, we can look at addressing the
>> same properly this time - especially from a kdump p-o-v.
>> This issue has been reported by some Red Hat arm64 partners with
>> upstream kernel also and as we have noticed in the past as well,
>> hardcoding the placement of the crashkernel base address (unless the
>> base address is specified by a crashkernel=X@Y like bootargs) is also
>> not a portable suggestion.
>>
>> I am working on a possible fix and will have more updates on the same
>> in a day-or-two.
> Please keep me in the loop, we've also had issues pointing to this reported by
> SUSE partners. I can do some testing both on the RPi4 and on big servers that
> need huge crashkernel sizes.
>
> Regards,
> Nicolas
>
Hi Nicolas,
You want want to review this topic with the various email threads . It
has been a long journey.
[1]:https://urldefense.com/v3/__http://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJwQs3C4x$
[v1]:https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/2/1174__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJ6e-mIEp$
[v2]:https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/86__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJyUVjUta$
[v3]:https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/9/306__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJ3CXBRdT$
[v4]:https://urldefense.com/v3/__https://lkml.org/lkml/2019/4/15/273__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJ7SxW1Vj$
[v5]:https://urldefense.com/v3/__https://lkml.org/lkml/2019/5/6/1360__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJ2wyJ9tj$
[v6]:https://urldefense.com/v3/__https://lkml.org/lkml/2019/8/30/142__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJzvGhWBh$
[v7]:https://urldefense.com/v3/__https://lkml.org/lkml/2019/12/23/411__;!!GqivPVa7Brio!NHQIQVbVz5bR1SSP7U7SwT3uHb6OnycPGa6nM0oLTaQdZT4pjRsjrMjn5GqOJ6pAg6tX$
Chen Zhou (5):
x86: kdump: move reserve_crashkernel_low() into crash_core.c
arm64: kdump: reserve crashkenel above 4G for crash dump kernel
arm64: kdump: add memory for devices by DT property, low-memory-range
kdump: update Documentation about crashkernel on arm64
dt-bindings: chosen: Document linux,low-memory-range for arm64 kdump
Documentation/admin-guide/kdump/kdump.rst | 13 ++-
.../admin-guide/kernel-parameters.txt | 12 ++-
Documentation/devicetree/bindings/chosen.txt | 25 ++++++
arch/arm64/kernel/setup.c | 8 +-
arch/arm64/mm/init.c | 61 ++++++++++++-
arch/x86/kernel/setup.c | 66 ++------------
include/linux/crash_core.h | 3 +
include/linux/kexec.h | 2 -
kernel/crash_core.c | 85 +++++++++++++++++++
kernel/kexec_core.c | 17 ----
10 files changed, 208 insertions(+), 84 deletions(-)
--
2.20.1
On Thu, 2020-06-04 at 21:26 -0500, John Donnelly wrote:
> On 6/4/20 12:01 PM, Nicolas Saenz Julienne wrote:
> > On Thu, 2020-06-04 at 01:17 +0530, Bhupesh Sharma wrote:
> > > Hi All,
> > >
> > > On Wed, Jun 3, 2020 at 9:03 PM John Donnelly <[email protected]>
> > > wrote:
> > > > > On Jun 3, 2020, at 8:20 AM, chenzhou <[email protected]> wrote:
> > > > >
> > > > > Hi,
> > > > >
> > > > >
> > > > > On 2020/6/3 19:47, Prabhakar Kushwaha wrote:
> > > > > > Hi Chen,
> > > > > >
> > > > > > On Tue, Jun 2, 2020 at 8:12 PM John Donnelly <
> > > > > > [email protected]
> > > > > > > wrote:
> > > > > > >
> > > > > > > > On Jun 2, 2020, at 12:38 AM, Prabhakar Kushwaha <
> > > > > > > > [email protected]> wrote:
> > > > > > > >
> > > > > > > > On Tue, Jun 2, 2020 at 3:29 AM John Donnelly <
> > > > > > > > [email protected]> wrote:
> > > > > > > > > Hi . See below !
> > > > > > > > >
> > > > > > > > > > On Jun 1, 2020, at 4:02 PM, Bhupesh Sharma <
> > > > > > > > > > [email protected]>
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > Hi John,
> > > > > > > > > >
> > > > > > > > > > On Tue, Jun 2, 2020 at 1:01 AM John Donnelly <
> > > > > > > > > > [email protected]> wrote:
> > > > > > > > > > > Hi,
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > On 6/1/20 7:02 AM, Prabhakar Kushwaha wrote:
> > > > > > > > > > > > Hi Chen,
> > > > > > > > > > > >
> > > > > > > > > > > > On Thu, May 21, 2020 at 3:05 PM Chen Zhou <
> > > > > > > > > > > > [email protected]> wrote:
> > > > > > > > > > > > > This patch series enable reserving crashkernel above
> > > > > > > > > > > > > 4G in
> > > > > > > > > > > > > arm64.
> > > > > > > > > > > > >
> > > > > > > > > > > > > There are following issues in arm64 kdump:
> > > > > > > > > > > > > 1. We use crashkernel=X to reserve crashkernel below
> > > > > > > > > > > > > 4G,
> > > > > > > > > > > > > which will fail
> > > > > > > > > > > > > when there is no enough low memory.
> > > > > > > > > > > > > 2. Currently, crashkernel=Y@X can be used to reserve
> > > > > > > > > > > > > crashkernel above 4G,
> > > > > > > > > > > > > in this case, if swiotlb or DMA buffers are required,
> > > > > > > > > > > > > crash dump kernel
> > > > > > > > > > > > > will boot failure because there is no low memory
> > > > > > > > > > > > > available
> > > > > > > > > > > > > for allocation.
> > > > > > > > > > > > >
> > > > > > > > > > > > We are getting "warn_alloc" [1] warning during boot of
> > > > > > > > > > > > kdump
> > > > > > > > > > > > kernel
> > > > > > > > > > > > with bootargs as [2] of primary kernel.
> > > > > > > > > > > > This error observed on ThunderX2 ARM64 platform.
> > > > > > > > > > > >
> > > > > > > > > > > > It is observed with latest upstream tag (v5.7-rc3) with
> > > > > > > > > > > > this
> > > > > > > > > > > > patch set
> > > > > > > > > > > > and
> > > > > > > > > > > >
> >
https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiIAAlzu$
> > > > > > > > > > > > Also **without** this patch-set
> > > > > > > > > > > > "
> > > > > > > > > > > >
> >
https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$
> > > > > > > > > > > > "
> > > > > > > > > > > >
> > > > > > > > > > > > This issue comes whenever crashkernel memory is reserved
> > > > > > > > > > > > after 0xc000_0000.
> > > > > > > > > > > > More details discussed earlier in
> > > > > > > > > > > >
> >
https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$
> > without
> > > > > > > > > > > > any
> > > > > > > > > > > > solution
> > > > > > > > > > > >
> > > > > > > > > > > > This patch-set is expected to solve similar kind of
> > > > > > > > > > > > issue.
> > > > > > > > > > > > i.e. low memory is only targeted for DMA, swiotlb; So
> > > > > > > > > > > > above
> > > > > > > > > > > > mentioned
> > > > > > > > > > > > observation should be considered/fixed. .
> > > > > > > > > > > >
> > > > > > > > > > > > --pk
> > > > > > > > > > > >
> > > > > > > > > > > > [1]
> > > > > > > > > > > > [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
> > > > > > > > > > > > TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
> > > > > > > > > > > > [ 30.367696] NET: Registered protocol family 16
> > > > > > > > > > > > [ 30.369973] swapper/0: page allocation failure:
> > > > > > > > > > > > order:6,
> > > > > > > > > > > > mode:0x1(GFP_DMA),
> > > > > > > > > > > > nodemask=(null),cpuset=/,mems_allowed=0
> > > > > > > > > > > > [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
> > > > > > > > > > > > 5.7.0-rc3+ #121
> > > > > > > > > > > > [ 30.369981] Hardware name: Cavium Inc. Saber/Saber,
> > > > > > > > > > > > BIOS
> > > > > > > > > > > > TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
> > > > > > > > > > > > [ 30.369984] Call trace:
> > > > > > > > > > > > [ 30.369989] dump_backtrace+0x0/0x1f8
> > > > > > > > > > > > [ 30.369991] show_stack+0x20/0x30
> > > > > > > > > > > > [ 30.369997] dump_stack+0xc0/0x10c
> > > > > > > > > > > > [ 30.370001] warn_alloc+0x10c/0x178
> > > > > > > > > > > > [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb
> > > > > > > > > > > > 10/0
> > > > > > > > > > > > xb50
> > > > > > > > > > > > [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
> > > > > > > > > > > > [ 30.370008] alloc_page_interleave+0x24/0x98
> > > > > > > > > > > > [ 30.370011] alloc_pages_current+0xe4/0x108
> > > > > > > > > > > > [ 30.370017] dma_atomic_pool_init+0x44/0x1a4
> > > > > > > > > > > > [ 30.370020] do_one_initcall+0x54/0x228
> > > > > > > > > > > > [ 30.370027] kernel_init_freeable+0x228/0x2cc
> > > > > > > > > > > > [ 30.370031] kernel_init+0x1c/0x110
> > > > > > > > > > > > [ 30.370034] ret_from_fork+0x10/0x18
> > > > > > > > > > > > [ 30.370036] Mem-Info:
> > > > > > > > > > > > [ 30.370064] active_anon:0 inactive_anon:0
> > > > > > > > > > > > isolated_anon:0
> > > > > > > > > > > > [ 30.370064] active_file:0 inactive_file:0
> > > > > > > > > > > > isolated_file:0
> > > > > > > > > > > > [ 30.370064] unevictable:0 dirty:0 writeback:0
> > > > > > > > > > > > unstable:0
> > > > > > > > > > > > [ 30.370064] slab_reclaimable:34
> > > > > > > > > > > > slab_unreclaimable:4438
> > > > > > > > > > > > [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
> > > > > > > > > > > > [ 30.370064] free:1537719 free_pcp:219 free_cma:0
> > > > > > > > > > > > [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
> > > > > > > > > > > > active_file:0kB inactive_file:0kB unevictable:0kB
> > > > > > > > > > > > isolated(anon):0kB
> > > > > > > > > > > > isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB
> > > > > > > > > > > > shmem:0kB
> > > > > > > > > > > > shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB
> > > > > > > > > > > > writeback_tmp:0kB
> > > > > > > > > > > > unstable:0kB all_unreclaimable? no
> > > > > > > > > > > > [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
> > > > > > > > > > > > active_file:0kB inactive_file:0kB unevictable:0kB
> > > > > > > > > > > > isolated(anon):0kB
> > > > > > > > > > > > isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB
> > > > > > > > > > > > shmem:0kB
> > > > > > > > > > > > shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB
> > > > > > > > > > > > writeback_tmp:0kB
> > > > > > > > > > > > unstable:0kB all_unreclaimable? no
> > > > > > > > > > > > [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB
> > > > > > > > > > > > high:0kB
> > > > > > > > > > > > reserved_highatomic:0KB active_anon:0kB
> > > > > > > > > > > > inactive_anon:0kB
> > > > > > > > > > > > active_file:0kB inactive_file:0kB unevictable:0kB
> > > > > > > > > > > > writepending:0kB
> > > > > > > > > > > > present:128kB managed:0kB mlocked:0kB kernel_stack:0kB
> > > > > > > > > > > > pagetables:0kB
> > > > > > > > > > > > bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
> > > > > > > > > > > > [ 30.370084] lowmem_reserve[]: 0 250 6063 6063
> > > > > > > > > > > > [ 30.370090] Node 0 DMA32 free:256000kB min:408kB
> > > > > > > > > > > > low:664kB
> > > > > > > > > > > > high:920kB reserved_highatomic:0KB active_anon:0kB
> > > > > > > > > > > > inactive_anon:0kB
> > > > > > > > > > > > active_file:0kB inactive_file:0kB unevictable:0kB
> > > > > > > > > > > > writepending:0kB
> > > > > > > > > > > > present:269700kB managed:256000kB mlocked:0kB
> > > > > > > > > > > > kernel_stack:0kB
> > > > > > > > > > > > pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB
> > > > > > > > > > > > free_cma:0kB
> > > > > > > > > > > > [ 30.370094] lowmem_reserve[]: 0 0 5813 5813
> > > > > > > > > > > > [ 30.370100] Node 0 Normal free:5894876kB min:9552kB
> > > > > > > > > > > > low:15504kB
> > > > > > > > > > > > high:21456kB reserved_highatomic:0KB active_anon:0kB
> > > > > > > > > > > > inactive_anon:0kB
> > > > > > > > > > > > active_file:0kB inactive_file:0kB unevictable:0kB
> > > > > > > > > > > > writepending:0kB
> > > > > > > > > > > > present:8388608kB managed:5953112kB mlocked:0kB
> > > > > > > > > > > > kernel_stack:21672kB
> > > > > > > > > > > > pagetables:56kB bounce:0kB free_pcp:876kB
> > > > > > > > > > > > local_pcp:176kB
> > > > > > > > > > > > free_cma:0kB
> > > > > > > > > > > > [ 30.370104] lowmem_reserve[]: 0 0 0 0
> > > > > > > > > > > > [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB
> > > > > > > > > > > > 0*64kB
> > > > > > > > > > > > 0*128kB
> > > > > > > > > > > > 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
> > > > > > > > > > > > [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB
> > > > > > > > > > > > 0*64kB 0*128kB
> > > > > > > > > > > > 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) =
> > > > > > > > > > > > 256000kB
> > > > > > > > > > > > [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME)
> > > > > > > > > > > > 2*16kB
> > > > > > > > > > > > (UE) 3*32kB
> > > > > > > > > > > > (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME)
> > > > > > > > > > > > 3*1024kB (ME)
> > > > > > > > > > > > 3*2048kB (UME) 1436*4096kB (M) = 5893600kB
> > > > > > > > > > > > [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
> > > > > > > > > > > > hugepages_surp=0 hugepages_size=1048576kB
> > > > > > > > > > > > [ 30.370130] 0 total pagecache pages
> > > > > > > > > > > > [ 30.370132] 0 pages in swap cache
> > > > > > > > > > > > [ 30.370134] Swap cache stats: add 0, delete 0, find
> > > > > > > > > > > > 0/0
> > > > > > > > > > > > [ 30.370135] Free swap = 0kB
> > > > > > > > > > > > [ 30.370136] Total swap = 0kB
> > > > > > > > > > > > [ 30.370137] 2164609 pages RAM
> > > > > > > > > > > > [ 30.370139] 0 pages HighMem/MovableOnly
> > > > > > > > > > > > [ 30.370140] 612331 pages reserved
> > > > > > > > > > > > [ 30.370141] 0 pages hwpoisoned
> > > > > > > > > > > > [ 30.370143] DMA: failed to allocate 256 KiB pool for
> > > > > > > > > > > > atomic
> > > > > > > > > > > > coherent allocation
> > > > > > > > > > > During my testing I saw the same error and
> > > > > > > > > > > Chen's solution
> > > > > > > > > > > corrected it .
> > > > > > > > > > Which combination you are using on your side? I am using
> > > > > > > > > > Prabhakar's
> > > > > > > > > > suggested environment and can reproduce the issue
> > > > > > > > > > with or without Chen's crashkernel support above 4G
> > > > > > > > > > patchset.
> > > > > > > > > >
> > > > > > > > > > I am also using a ThunderX2 platform with latest
> > > > > > > > > > makedumpfile
> > > > > > > > > > code and
> > > > > > > > > > kexec-tools (with the suggested patch
> > > > > > > > > > <
> > > > > > > > > >
> >
https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!J6lUig58-Gw6TKZnEEYzEeSU36T-1SqlB1kImU00xtX_lss5Tx-JbUmLE9TJC3foXBLg$
> > > > > > > > > > > ).
> > > > > > > > > > Thanks,
> > > > > > > > > > Bhupesh
> > > > > > > > > I did this activity 5 months ago and I have moved on to other
> > > > > > > > > activities. My DMA failures were related to PCI devices that
> > > > > > > > > could
> > > > > > > > > not be enumerated because low-DMA space was not available
> > > > > > > > > when
> > > > > > > > > crashkernel was moved above 4G; I don’t recall the exact
> > > > > > > > > platform.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > For this failure ,
> > > > > > > > >
> > > > > > > > > > > > DMA: failed to allocate 256 KiB pool for atomic
> > > > > > > > > > > > coherent allocation
> > > > > > > > > Is due to :
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 3618082c
> > > > > > > > > ("arm64 use both ZONE_DMA and ZONE_DMA32")
> > > > > > > > >
> > > > > > > > > With the introduction of ZONE_DMA to support the Raspberry DMA
> > > > > > > > > region below 1G, the crashkernel is placed in the upper 4G
> > > > > > > > > ZONE_DMA_32 region. Since the crashkernel does not have access
> > > > > > > > > to the ZONE_DMA region, it prints out call trace during
> > > > > > > > > bootup.
> > > > > > > > >
> > > > > > > > > It is due to having this CONFIG item ON :
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > CONFIG_ZONE_DMA=y
> > > > > > > > >
> > > > > > > > > Turning off ZONE_DMA fixes a issue and Raspberry PI 4 will
> > > > > > > > > use the device tree to specify memory below 1G.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > Disabling ZONE_DMA is temporary solution. We may need proper
> > > > > > > > solution
> > > > > > > Perhaps the Raspberry platform configuration dependencies need
> > > > > > > separated from “server class” Arm equipment ? Or auto-
> > > > > > > configured on
> > > > > > > boot ? Consult an expert ;-)
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > > > I would like to see Chen’s feature added , perhaps as
> > > > > > > > > EXPERIMENTAL, so we can get some configuration testing done
> > > > > > > > > on
> > > > > > > > > it. It corrects having a DMA zone in low memory while crash-
> > > > > > > > > kernel is above 4GB. This has been going on for a year now.
> > > > > > > > I will also like this patch to be added in Linux as early as
> > > > > > > > possible.
> > > > > > > >
> > > > > > > > Issue mentioned by me happens with or without this patch.
> > > > > > > >
> > > > > > > > This patch-set can consider fixing because it uses low memory
> > > > > > > > for
> > > > > > > > DMA
> > > > > > > > & swiotlb only.
> > > > > > > > We can consider restricting crashkernel within the required
> > > > > > > > range
> > > > > > > > like below
> > > > > > > >
> > > > > > > > diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> > > > > > > > index 7f9e5a6dc48c..bd67b90d35bd 100644
> > > > > > > > --- a/kernel/crash_core.c
> > > > > > > > +++ b/kernel/crash_core.c
> > > > > > > > @@ -354,7 +354,7 @@ int __init reserve_crashkernel_low(void)
> > > > > > > > return 0;
> > > > > > > > }
> > > > > > > >
> > > > > > > > - low_base = memblock_find_in_range(0, 1ULL << 32,
> > > > > > > > low_size,
> > > > > > > > CRASH_ALIGN);
> > > > > > > > + low_base = memblock_find_in_range(0,0xc0000000,
> > > > > > > > low_size,
> > > > > > > > CRASH_ALIGN);
> > > > > > > > if (!low_base) {
> > > > > > > > pr_err("Cannot reserve %ldMB crashkernel low
> > > > > > > > memory,
> > > > > > > > please try smaller size.\n",
> > > > > > > > (unsigned long)(low_size >> 20));
> > > > > > > >
> > > > > > > >
> > > > > > > I suspect 0xc0000000 would need to be a CONFIG item and not
> > > > > > > hard-coded.
> > > > > > >
> > > > > > if you consider this as valid change, can you please incorporate as
> > > > > > part of your patch-set.
> > > > > After commit 1a8e1cef7 ("arm64: use both ZONE_DMA and ZONE_DMA32")，the
> > > > > 0-
> > > > > 4G memory is splited
> > > > > to DMA [mem 0x0000000000000000-0x000000003fffffff] and DMA32 [mem
> > > > > 0x0000000040000000-0x00000000ffffffff] on arm64.
> > > > >
> > > > > From the above discussion, on your platform, the low crashkernel fall
> > > > > in
> > > > > DMA32 region, but your environment needs to access DMA
> > > > > region, so there is the call trace.
> > > > >
> > > > > I have a question, why do you choose 0xc0000000 here?
> > > > >
> > > > > Besides, this is common code, we also need to consider about x86.
> > > > >
> > > > + [email protected]
> > Thanks for adding me to the conversation, and sorry for the headaches.
> >
> > > > Exactly . This is why it needs to be a CONFIG option for Raspberry
> > > > .., or device tree option.
> > > >
> > > >
> > > > We could revert 1a8e1cef7 since it broke Arm kdump too.
> > > Well, unfortunately the patch for commit 1a8e1cef7603 ("arm64: use
> > > both ZONE_DMA and ZONE_DMA32") was not Cc'ed to the kexec mailing
> > > list, thus we couldn't get many eyes on it for a thorough review from
> > > kexec/kdump p-o-v.
> > >
> > > Also we historically never had distinction in common arch code on the
> > > basis of the intended end use-case: embedded, server or automotive, so
> > > I am not sure introducing a Raspberry specific CONFIG option would be
> > > a good idea.
> > +1
> >
> > From the distros perspective it's very important to keep a single kernel
> > image.
> >
> > > So, rather than reverting the patch, we can look at addressing the
> > > same properly this time - especially from a kdump p-o-v.
> > > This issue has been reported by some Red Hat arm64 partners with
> > > upstream kernel also and as we have noticed in the past as well,
> > > hardcoding the placement of the crashkernel base address (unless the
> > > base address is specified by a crashkernel=X@Y like bootargs) is also
> > > not a portable suggestion.
> > >
> > > I am working on a possible fix and will have more updates on the same
> > > in a day-or-two.
> > Please keep me in the loop, we've also had issues pointing to this reported
> > by
> > SUSE partners. I can do some testing both on the RPi4 and on big servers
> > that
> > need huge crashkernel sizes.
> >
> > Regards,
> > Nicolas
> >
> Hi Nicolas,
>
>
> You want want to review this topic with the various email threads . It
> has been a long journey.
Will do, thanks!
Regards,
Nicolas
On 6/4/20 12:01 PM, Nicolas Saenz Julienne wrote:
> On Thu, 2020-06-04 at 01:17 +0530, Bhupesh Sharma wrote:
>> Hi All,
>>
>> On Wed, Jun 3, 2020 at 9:03 PM John Donnelly <[email protected]>
>> wrote:
>>>
>>>> On Jun 3, 2020, at 8:20 AM, chenzhou <[email protected]> wrote:
>>>>
>>>> Hi,
>>>>
>>>>
>>>> On 2020/6/3 19:47, Prabhakar Kushwaha wrote:
>>>>> Hi Chen,
>>>>>
>>>>> On Tue, Jun 2, 2020 at 8:12 PM John Donnelly <[email protected]
>>>>>> wrote:
>>>>>>
>>>>>>> On Jun 2, 2020, at 12:38 AM, Prabhakar Kushwaha <
>>>>>>> [email protected]> wrote:
>>>>>>>
>>>>>>> On Tue, Jun 2, 2020 at 3:29 AM John Donnelly <
>>>>>>> [email protected]> wrote:
>>>>>>>> Hi . See below !
>>>>>>>>
>>>>>>>>> On Jun 1, 2020, at 4:02 PM, Bhupesh Sharma <[email protected]>
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>> Hi John,
>>>>>>>>>
>>>>>>>>> On Tue, Jun 2, 2020 at 1:01 AM John Donnelly <
>>>>>>>>> [email protected]> wrote:
>>>>>>>>>> Hi,
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On 6/1/20 7:02 AM, Prabhakar Kushwaha wrote:
>>>>>>>>>>> Hi Chen,
>>>>>>>>>>>
>>>>>>>>>>> On Thu, May 21, 2020 at 3:05 PM Chen Zhou <
>>>>>>>>>>> [email protected]> wrote:
>>>>>>>>>>>> This patch series enable reserving crashkernel above 4G in
>>>>>>>>>>>> arm64.
>>>>>>>>>>>>
>>>>>>>>>>>> There are following issues in arm64 kdump:
>>>>>>>>>>>> 1. We use crashkernel=X to reserve crashkernel below 4G,
>>>>>>>>>>>> which will fail
>>>>>>>>>>>> when there is no enough low memory.
>>>>>>>>>>>> 2. Currently, crashkernel=Y@X can be used to reserve
>>>>>>>>>>>> crashkernel above 4G,
>>>>>>>>>>>> in this case, if swiotlb or DMA buffers are required,
>>>>>>>>>>>> crash dump kernel
>>>>>>>>>>>> will boot failure because there is no low memory available
>>>>>>>>>>>> for allocation.
>>>>>>>>>>>>
>>>>>>>>>>> We are getting "warn_alloc" [1] warning during boot of kdump
>>>>>>>>>>> kernel
>>>>>>>>>>> with bootargs as [2] of primary kernel.
>>>>>>>>>>> This error observed on ThunderX2 ARM64 platform.
>>>>>>>>>>>
>>>>>>>>>>> It is observed with latest upstream tag (v5.7-rc3) with this
>>>>>>>>>>> patch set
>>>>>>>>>>> and
>>>>>>>>>>>
> https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiIAAlzu$
>>>>>>>>>>> Also **without** this patch-set
>>>>>>>>>>> "
>>>>>>>>>>>
> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$
>>>>>>>>>>> "
>>>>>>>>>>>
>>>>>>>>>>> This issue comes whenever crashkernel memory is reserved
>>>>>>>>>>> after 0xc000_0000.
>>>>>>>>>>> More details discussed earlier in
>>>>>>>>>>>
> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$
> without
>>>>>>>>>>> any
>>>>>>>>>>> solution
>>>>>>>>>>>
>>>>>>>>>>> This patch-set is expected to solve similar kind of issue.
>>>>>>>>>>> i.e. low memory is only targeted for DMA, swiotlb; So above
>>>>>>>>>>> mentioned
>>>>>>>>>>> observation should be considered/fixed. .
>>>>>>>>>>>
>>>>>>>>>>> --pk
>>>>>>>>>>>
>>>>>>>>>>> [1]
>>>>>>>>>>> [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
>>>>>>>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>>>>>>>>>> [ 30.367696] NET: Registered protocol family 16
>>>>>>>>>>> [ 30.369973] swapper/0: page allocation failure: order:6,
>>>>>>>>>>> mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
>>>>>>>>>>> [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
>>>>>>>>>>> 5.7.0-rc3+ #121
>>>>>>>>>>> [ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS
>>>>>>>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>>>>>>>>>> [ 30.369984] Call trace:
>>>>>>>>>>> [ 30.369989] dump_backtrace+0x0/0x1f8
>>>>>>>>>>> [ 30.369991] show_stack+0x20/0x30
>>>>>>>>>>> [ 30.369997] dump_stack+0xc0/0x10c
>>>>>>>>>>> [ 30.370001] warn_alloc+0x10c/0x178
>>>>>>>>>>> [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0
>>>>>>>>>>> xb50
>>>>>>>>>>> [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
>>>>>>>>>>> [ 30.370008] alloc_page_interleave+0x24/0x98
>>>>>>>>>>> [ 30.370011] alloc_pages_current+0xe4/0x108
>>>>>>>>>>> [ 30.370017] dma_atomic_pool_init+0x44/0x1a4
>>>>>>>>>>> [ 30.370020] do_one_initcall+0x54/0x228
>>>>>>>>>>> [ 30.370027] kernel_init_freeable+0x228/0x2cc
>>>>>>>>>>> [ 30.370031] kernel_init+0x1c/0x110
>>>>>>>>>>> [ 30.370034] ret_from_fork+0x10/0x18
>>>>>>>>>>> [ 30.370036] Mem-Info:
>>>>>>>>>>> [ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0
>>>>>>>>>>> [ 30.370064] active_file:0 inactive_file:0
>>>>>>>>>>> isolated_file:0
>>>>>>>>>>> [ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0
>>>>>>>>>>> [ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438
>>>>>>>>>>> [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
>>>>>>>>>>> [ 30.370064] free:1537719 free_pcp:219 free_cma:0
>>>>>>>>>>> [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>> isolated(anon):0kB
>>>>>>>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB
>>>>>>>>>>> shmem:0kB
>>>>>>>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB
>>>>>>>>>>> writeback_tmp:0kB
>>>>>>>>>>> unstable:0kB all_unreclaimable? no
>>>>>>>>>>> [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>> isolated(anon):0kB
>>>>>>>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB
>>>>>>>>>>> shmem:0kB
>>>>>>>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB
>>>>>>>>>>> writeback_tmp:0kB
>>>>>>>>>>> unstable:0kB all_unreclaimable? no
>>>>>>>>>>> [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB
>>>>>>>>>>> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>> writepending:0kB
>>>>>>>>>>> present:128kB managed:0kB mlocked:0kB kernel_stack:0kB
>>>>>>>>>>> pagetables:0kB
>>>>>>>>>>> bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>>>>>>>>>>> [ 30.370084] lowmem_reserve[]: 0 250 6063 6063
>>>>>>>>>>> [ 30.370090] Node 0 DMA32 free:256000kB min:408kB
>>>>>>>>>>> low:664kB
>>>>>>>>>>> high:920kB reserved_highatomic:0KB active_anon:0kB
>>>>>>>>>>> inactive_anon:0kB
>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>> writepending:0kB
>>>>>>>>>>> present:269700kB managed:256000kB mlocked:0kB
>>>>>>>>>>> kernel_stack:0kB
>>>>>>>>>>> pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB
>>>>>>>>>>> free_cma:0kB
>>>>>>>>>>> [ 30.370094] lowmem_reserve[]: 0 0 5813 5813
>>>>>>>>>>> [ 30.370100] Node 0 Normal free:5894876kB min:9552kB
>>>>>>>>>>> low:15504kB
>>>>>>>>>>> high:21456kB reserved_highatomic:0KB active_anon:0kB
>>>>>>>>>>> inactive_anon:0kB
>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>> writepending:0kB
>>>>>>>>>>> present:8388608kB managed:5953112kB mlocked:0kB
>>>>>>>>>>> kernel_stack:21672kB
>>>>>>>>>>> pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB
>>>>>>>>>>> free_cma:0kB
>>>>>>>>>>> [ 30.370104] lowmem_reserve[]: 0 0 0 0
>>>>>>>>>>> [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB
>>>>>>>>>>> 0*128kB
>>>>>>>>>>> 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
>>>>>>>>>>> [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB
>>>>>>>>>>> 0*64kB 0*128kB
>>>>>>>>>>> 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) =
>>>>>>>>>>> 256000kB
>>>>>>>>>>> [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB
>>>>>>>>>>> (UE) 3*32kB
>>>>>>>>>>> (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME)
>>>>>>>>>>> 3*1024kB (ME)
>>>>>>>>>>> 3*2048kB (UME) 1436*4096kB (M) = 5893600kB
>>>>>>>>>>> [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
>>>>>>>>>>> hugepages_surp=0 hugepages_size=1048576kB
>>>>>>>>>>> [ 30.370130] 0 total pagecache pages
>>>>>>>>>>> [ 30.370132] 0 pages in swap cache
>>>>>>>>>>> [ 30.370134] Swap cache stats: add 0, delete 0, find 0/0
>>>>>>>>>>> [ 30.370135] Free swap = 0kB
>>>>>>>>>>> [ 30.370136] Total swap = 0kB
>>>>>>>>>>> [ 30.370137] 2164609 pages RAM
>>>>>>>>>>> [ 30.370139] 0 pages HighMem/MovableOnly
>>>>>>>>>>> [ 30.370140] 612331 pages reserved
>>>>>>>>>>> [ 30.370141] 0 pages hwpoisoned
>>>>>>>>>>> [ 30.370143] DMA: failed to allocate 256 KiB pool for
>>>>>>>>>>> atomic
>>>>>>>>>>> coherent allocation
>>>>>>>>>> During my testing I saw the same error and Chen's solution
>>>>>>>>>> corrected it .
>>>>>>>>> Which combination you are using on your side? I am using
>>>>>>>>> Prabhakar's
>>>>>>>>> suggested environment and can reproduce the issue
>>>>>>>>> with or without Chen's crashkernel support above 4G patchset.
>>>>>>>>>
>>>>>>>>> I am also using a ThunderX2 platform with latest makedumpfile
>>>>>>>>> code and
>>>>>>>>> kexec-tools (with the suggested patch
>>>>>>>>> <
>>>>>>>>>
> https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!J6lUig58-Gw6TKZnEEYzEeSU36T-1SqlB1kImU00xtX_lss5Tx-JbUmLE9TJC3foXBLg$
>>>>>>>>>> ).
>>>>>>>>> Thanks,
>>>>>>>>> Bhupesh
>>>>>>>> I did this activity 5 months ago and I have moved on to other
>>>>>>>> activities. My DMA failures were related to PCI devices that could
>>>>>>>> not be enumerated because low-DMA space was not available when
>>>>>>>> crashkernel was moved above 4G; I don’t recall the exact platform.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> For this failure ,
>>>>>>>>
>>>>>>>>>>> DMA: failed to allocate 256 KiB pool for atomic
>>>>>>>>>>> coherent allocation
>>>>>>>> Is due to :
>>>>>>>>
>>>>>>>>
>>>>>>>> 3618082c
>>>>>>>> ("arm64 use both ZONE_DMA and ZONE_DMA32")
>>>>>>>>
>>>>>>>> With the introduction of ZONE_DMA to support the Raspberry DMA
>>>>>>>> region below 1G, the crashkernel is placed in the upper 4G
>>>>>>>> ZONE_DMA_32 region. Since the crashkernel does not have access
>>>>>>>> to the ZONE_DMA region, it prints out call trace during bootup.
>>>>>>>>
>>>>>>>> It is due to having this CONFIG item ON :
>>>>>>>>
>>>>>>>>
>>>>>>>> CONFIG_ZONE_DMA=y
>>>>>>>>
>>>>>>>> Turning off ZONE_DMA fixes a issue and Raspberry PI 4 will
>>>>>>>> use the device tree to specify memory below 1G.
>>>>>>>>
>>>>>>>>
>>>>>>> Disabling ZONE_DMA is temporary solution. We may need proper
>>>>>>> solution
>>>>>> Perhaps the Raspberry platform configuration dependencies need
>>>>>> separated from “server class” Arm equipment ? Or auto-configured on
>>>>>> boot ? Consult an expert ;-)
>>>>>>
>>>>>>
>>>>>>
>>>>>>>> I would like to see Chen’s feature added , perhaps as
>>>>>>>> EXPERIMENTAL, so we can get some configuration testing done on
>>>>>>>> it. It corrects having a DMA zone in low memory while crash-
>>>>>>>> kernel is above 4GB. This has been going on for a year now.
>>>>>>> I will also like this patch to be added in Linux as early as
>>>>>>> possible.
>>>>>>>
>>>>>>> Issue mentioned by me happens with or without this patch.
>>>>>>>
>>>>>>> This patch-set can consider fixing because it uses low memory for
>>>>>>> DMA
>>>>>>> & swiotlb only.
>>>>>>> We can consider restricting crashkernel within the required range
>>>>>>> like below
>>>>>>>
>>>>>>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
>>>>>>> index 7f9e5a6dc48c..bd67b90d35bd 100644
>>>>>>> --- a/kernel/crash_core.c
>>>>>>> +++ b/kernel/crash_core.c
>>>>>>> @@ -354,7 +354,7 @@ int __init reserve_crashkernel_low(void)
>>>>>>> return 0;
>>>>>>> }
>>>>>>>
>>>>>>> - low_base = memblock_find_in_range(0, 1ULL << 32, low_size,
>>>>>>> CRASH_ALIGN);
>>>>>>> + low_base = memblock_find_in_range(0,0xc0000000, low_size,
>>>>>>> CRASH_ALIGN);
>>>>>>> if (!low_base) {
>>>>>>> pr_err("Cannot reserve %ldMB crashkernel low memory,
>>>>>>> please try smaller size.\n",
>>>>>>> (unsigned long)(low_size >> 20));
>>>>>>>
>>>>>>>
>>>>>> I suspect 0xc0000000 would need to be a CONFIG item and not
>>>>>> hard-coded.
>>>>>>
>>>>> if you consider this as valid change, can you please incorporate as
>>>>> part of your patch-set.
>>>> After commit 1a8e1cef7 ("arm64: use both ZONE_DMA and ZONE_DMA32")，the 0-
>>>> 4G memory is splited
>>>> to DMA [mem 0x0000000000000000-0x000000003fffffff] and DMA32 [mem
>>>> 0x0000000040000000-0x00000000ffffffff] on arm64.
>>>>
>>>> From the above discussion, on your platform, the low crashkernel fall in
>>>> DMA32 region, but your environment needs to access DMA
>>>> region, so there is the call trace.
>>>>
>>>> I have a question, why do you choose 0xc0000000 here?
>>>>
>>>> Besides, this is common code, we also need to consider about x86.
>>>>
>>> + [email protected]
> Thanks for adding me to the conversation, and sorry for the headaches.
>
>>> Exactly . This is why it needs to be a CONFIG option for Raspberry
>>> .., or device tree option.
>>>
>>>
>>> We could revert 1a8e1cef7 since it broke Arm kdump too.
>> Well, unfortunately the patch for commit 1a8e1cef7603 ("arm64: use
>> both ZONE_DMA and ZONE_DMA32") was not Cc'ed to the kexec mailing
>> list, thus we couldn't get many eyes on it for a thorough review from
>> kexec/kdump p-o-v.
>>
>> Also we historically never had distinction in common arch code on the
>> basis of the intended end use-case: embedded, server or automotive, so
>> I am not sure introducing a Raspberry specific CONFIG option would be
>> a good idea.
> +1
>
> From the distros perspective it's very important to keep a single kernel image.
>
>> So, rather than reverting the patch, we can look at addressing the
>> same properly this time - especially from a kdump p-o-v.
>> This issue has been reported by some Red Hat arm64 partners with
>> upstream kernel also and as we have noticed in the past as well,
>> hardcoding the placement of the crashkernel base address (unless the
>> base address is specified by a crashkernel=X@Y like bootargs) is also
>> not a portable suggestion.
>>
>> I am working on a possible fix and will have more updates on the same
>> in a day-or-two.
> Please keep me in the loop, we've also had issues pointing to this reported by
> SUSE partners. I can do some testing both on the RPi4 and on big servers that
> need huge crashkernel sizes.
>
> Regards,
> Nicolas
>
Hi
Has there been any progress on this ? It appears we are stalled
because Nicolas's and Chen's changes are not compatible . One is needed
for RPi4 and the other for server class equipment.
Thanks,
John
On 2020/6/19 10:32, John Donnelly wrote:
>
> On 6/4/20 12:01 PM, Nicolas Saenz Julienne wrote:
>> On Thu, 2020-06-04 at 01:17 +0530, Bhupesh Sharma wrote:
>>> Hi All,
>>>
>>> On Wed, Jun 3, 2020 at 9:03 PM John Donnelly <[email protected]>
>>> wrote:
>>>>
>>>>> On Jun 3, 2020, at 8:20 AM, chenzhou <[email protected]> wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>>
>>>>> On 2020/6/3 19:47, Prabhakar Kushwaha wrote:
>>>>>> Hi Chen,
>>>>>>
>>>>>> On Tue, Jun 2, 2020 at 8:12 PM John Donnelly <[email protected]
>>>>>>> wrote:
>>>>>>>
>>>>>>>> On Jun 2, 2020, at 12:38 AM, Prabhakar Kushwaha <
>>>>>>>> [email protected]> wrote:
>>>>>>>>
>>>>>>>> On Tue, Jun 2, 2020 at 3:29 AM John Donnelly <
>>>>>>>> [email protected]> wrote:
>>>>>>>>> Hi . See below !
>>>>>>>>>
>>>>>>>>>> On Jun 1, 2020, at 4:02 PM, Bhupesh Sharma <[email protected]>
>>>>>>>>>> wrote:
>>>>>>>>>>
>>>>>>>>>> Hi John,
>>>>>>>>>>
>>>>>>>>>> On Tue, Jun 2, 2020 at 1:01 AM John Donnelly <
>>>>>>>>>> [email protected]> wrote:
>>>>>>>>>>> Hi,
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On 6/1/20 7:02 AM, Prabhakar Kushwaha wrote:
>>>>>>>>>>>> Hi Chen,
>>>>>>>>>>>>
>>>>>>>>>>>> On Thu, May 21, 2020 at 3:05 PM Chen Zhou <
>>>>>>>>>>>> [email protected]> wrote:
>>>>>>>>>>>>> This patch series enable reserving crashkernel above 4G in
>>>>>>>>>>>>> arm64.
>>>>>>>>>>>>>
>>>>>>>>>>>>> There are following issues in arm64 kdump:
>>>>>>>>>>>>> 1. We use crashkernel=X to reserve crashkernel below 4G,
>>>>>>>>>>>>> which will fail
>>>>>>>>>>>>> when there is no enough low memory.
>>>>>>>>>>>>> 2. Currently, crashkernel=Y@X can be used to reserve
>>>>>>>>>>>>> crashkernel above 4G,
>>>>>>>>>>>>> in this case, if swiotlb or DMA buffers are required,
>>>>>>>>>>>>> crash dump kernel
>>>>>>>>>>>>> will boot failure because there is no low memory available
>>>>>>>>>>>>> for allocation.
>>>>>>>>>>>>>
>>>>>>>>>>>> We are getting "warn_alloc" [1] warning during boot of kdump
>>>>>>>>>>>> kernel
>>>>>>>>>>>> with bootargs as [2] of primary kernel.
>>>>>>>>>>>> This error observed on ThunderX2 ARM64 platform.
>>>>>>>>>>>>
>>>>>>>>>>>> It is observed with latest upstream tag (v5.7-rc3) with this
>>>>>>>>>>>> patch set
>>>>>>>>>>>> and
>>>>>>>>>>>>
>> https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiIAAlzu$
>>>>>>>>>>>> Also **without** this patch-set
>>>>>>>>>>>> "
>>>>>>>>>>>>
>> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$
>>>>>>>>>>>> "
>>>>>>>>>>>>
>>>>>>>>>>>> This issue comes whenever crashkernel memory is reserved
>>>>>>>>>>>> after 0xc000_0000.
>>>>>>>>>>>> More details discussed earlier in
>>>>>>>>>>>>
>> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$
>> without
>>>>>>>>>>>> any
>>>>>>>>>>>> solution
>>>>>>>>>>>>
>>>>>>>>>>>> This patch-set is expected to solve similar kind of issue.
>>>>>>>>>>>> i.e. low memory is only targeted for DMA, swiotlb; So above
>>>>>>>>>>>> mentioned
>>>>>>>>>>>> observation should be considered/fixed. .
>>>>>>>>>>>>
>>>>>>>>>>>> --pk
>>>>>>>>>>>>
>>>>>>>>>>>> [1]
>>>>>>>>>>>> [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
>>>>>>>>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>>>>>>>>>>> [ 30.367696] NET: Registered protocol family 16
>>>>>>>>>>>> [ 30.369973] swapper/0: page allocation failure: order:6,
>>>>>>>>>>>> mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
>>>>>>>>>>>> [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
>>>>>>>>>>>> 5.7.0-rc3+ #121
>>>>>>>>>>>> [ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS
>>>>>>>>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>>>>>>>>>>> [ 30.369984] Call trace:
>>>>>>>>>>>> [ 30.369989] dump_backtrace+0x0/0x1f8
>>>>>>>>>>>> [ 30.369991] show_stack+0x20/0x30
>>>>>>>>>>>> [ 30.369997] dump_stack+0xc0/0x10c
>>>>>>>>>>>> [ 30.370001] warn_alloc+0x10c/0x178
>>>>>>>>>>>> [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0
>>>>>>>>>>>> xb50
>>>>>>>>>>>> [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
>>>>>>>>>>>> [ 30.370008] alloc_page_interleave+0x24/0x98
>>>>>>>>>>>> [ 30.370011] alloc_pages_current+0xe4/0x108
>>>>>>>>>>>> [ 30.370017] dma_atomic_pool_init+0x44/0x1a4
>>>>>>>>>>>> [ 30.370020] do_one_initcall+0x54/0x228
>>>>>>>>>>>> [ 30.370027] kernel_init_freeable+0x228/0x2cc
>>>>>>>>>>>> [ 30.370031] kernel_init+0x1c/0x110
>>>>>>>>>>>> [ 30.370034] ret_from_fork+0x10/0x18
>>>>>>>>>>>> [ 30.370036] Mem-Info:
>>>>>>>>>>>> [ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0
>>>>>>>>>>>> [ 30.370064] active_file:0 inactive_file:0
>>>>>>>>>>>> isolated_file:0
>>>>>>>>>>>> [ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0
>>>>>>>>>>>> [ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438
>>>>>>>>>>>> [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
>>>>>>>>>>>> [ 30.370064] free:1537719 free_pcp:219 free_cma:0
>>>>>>>>>>>> [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
>>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>>> isolated(anon):0kB
>>>>>>>>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB
>>>>>>>>>>>> shmem:0kB
>>>>>>>>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB
>>>>>>>>>>>> writeback_tmp:0kB
>>>>>>>>>>>> unstable:0kB all_unreclaimable? no
>>>>>>>>>>>> [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
>>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>>> isolated(anon):0kB
>>>>>>>>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB
>>>>>>>>>>>> shmem:0kB
>>>>>>>>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB
>>>>>>>>>>>> writeback_tmp:0kB
>>>>>>>>>>>> unstable:0kB all_unreclaimable? no
>>>>>>>>>>>> [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB
>>>>>>>>>>>> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>>> writepending:0kB
>>>>>>>>>>>> present:128kB managed:0kB mlocked:0kB kernel_stack:0kB
>>>>>>>>>>>> pagetables:0kB
>>>>>>>>>>>> bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>>>>>>>>>>>> [ 30.370084] lowmem_reserve[]: 0 250 6063 6063
>>>>>>>>>>>> [ 30.370090] Node 0 DMA32 free:256000kB min:408kB
>>>>>>>>>>>> low:664kB
>>>>>>>>>>>> high:920kB reserved_highatomic:0KB active_anon:0kB
>>>>>>>>>>>> inactive_anon:0kB
>>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>>> writepending:0kB
>>>>>>>>>>>> present:269700kB managed:256000kB mlocked:0kB
>>>>>>>>>>>> kernel_stack:0kB
>>>>>>>>>>>> pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB
>>>>>>>>>>>> free_cma:0kB
>>>>>>>>>>>> [ 30.370094] lowmem_reserve[]: 0 0 5813 5813
>>>>>>>>>>>> [ 30.370100] Node 0 Normal free:5894876kB min:9552kB
>>>>>>>>>>>> low:15504kB
>>>>>>>>>>>> high:21456kB reserved_highatomic:0KB active_anon:0kB
>>>>>>>>>>>> inactive_anon:0kB
>>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>>> writepending:0kB
>>>>>>>>>>>> present:8388608kB managed:5953112kB mlocked:0kB
>>>>>>>>>>>> kernel_stack:21672kB
>>>>>>>>>>>> pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB
>>>>>>>>>>>> free_cma:0kB
>>>>>>>>>>>> [ 30.370104] lowmem_reserve[]: 0 0 0 0
>>>>>>>>>>>> [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB
>>>>>>>>>>>> 0*128kB
>>>>>>>>>>>> 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
>>>>>>>>>>>> [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB
>>>>>>>>>>>> 0*64kB 0*128kB
>>>>>>>>>>>> 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) =
>>>>>>>>>>>> 256000kB
>>>>>>>>>>>> [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB
>>>>>>>>>>>> (UE) 3*32kB
>>>>>>>>>>>> (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME)
>>>>>>>>>>>> 3*1024kB (ME)
>>>>>>>>>>>> 3*2048kB (UME) 1436*4096kB (M) = 5893600kB
>>>>>>>>>>>> [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
>>>>>>>>>>>> hugepages_surp=0 hugepages_size=1048576kB
>>>>>>>>>>>> [ 30.370130] 0 total pagecache pages
>>>>>>>>>>>> [ 30.370132] 0 pages in swap cache
>>>>>>>>>>>> [ 30.370134] Swap cache stats: add 0, delete 0, find 0/0
>>>>>>>>>>>> [ 30.370135] Free swap = 0kB
>>>>>>>>>>>> [ 30.370136] Total swap = 0kB
>>>>>>>>>>>> [ 30.370137] 2164609 pages RAM
>>>>>>>>>>>> [ 30.370139] 0 pages HighMem/MovableOnly
>>>>>>>>>>>> [ 30.370140] 612331 pages reserved
>>>>>>>>>>>> [ 30.370141] 0 pages hwpoisoned
>>>>>>>>>>>> [ 30.370143] DMA: failed to allocate 256 KiB pool for
>>>>>>>>>>>> atomic
>>>>>>>>>>>> coherent allocation
>>>>>>>>>>> During my testing I saw the same error and Chen's solution
>>>>>>>>>>> corrected it .
>>>>>>>>>> Which combination you are using on your side? I am using
>>>>>>>>>> Prabhakar's
>>>>>>>>>> suggested environment and can reproduce the issue
>>>>>>>>>> with or without Chen's crashkernel support above 4G patchset.
>>>>>>>>>>
>>>>>>>>>> I am also using a ThunderX2 platform with latest makedumpfile
>>>>>>>>>> code and
>>>>>>>>>> kexec-tools (with the suggested patch
>>>>>>>>>> <
>>>>>>>>>>
>> https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!J6lUig58-Gw6TKZnEEYzEeSU36T-1SqlB1kImU00xtX_lss5Tx-JbUmLE9TJC3foXBLg$
>>>>>>>>>>> ).
>>>>>>>>>> Thanks,
>>>>>>>>>> Bhupesh
>>>>>>>>> I did this activity 5 months ago and I have moved on to other
>>>>>>>>> activities. My DMA failures were related to PCI devices that could
>>>>>>>>> not be enumerated because low-DMA space was not available when
>>>>>>>>> crashkernel was moved above 4G; I don’t recall the exact platform.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> For this failure ,
>>>>>>>>>
>>>>>>>>>>>> DMA: failed to allocate 256 KiB pool for atomic
>>>>>>>>>>>> coherent allocation
>>>>>>>>> Is due to :
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> 3618082c
>>>>>>>>> ("arm64 use both ZONE_DMA and ZONE_DMA32")
>>>>>>>>>
>>>>>>>>> With the introduction of ZONE_DMA to support the Raspberry DMA
>>>>>>>>> region below 1G, the crashkernel is placed in the upper 4G
>>>>>>>>> ZONE_DMA_32 region. Since the crashkernel does not have access
>>>>>>>>> to the ZONE_DMA region, it prints out call trace during bootup.
>>>>>>>>>
>>>>>>>>> It is due to having this CONFIG item ON :
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> CONFIG_ZONE_DMA=y
>>>>>>>>>
>>>>>>>>> Turning off ZONE_DMA fixes a issue and Raspberry PI 4 will
>>>>>>>>> use the device tree to specify memory below 1G.
>>>>>>>>>
>>>>>>>>>
>>>>>>>> Disabling ZONE_DMA is temporary solution. We may need proper
>>>>>>>> solution
>>>>>>> Perhaps the Raspberry platform configuration dependencies need
>>>>>>> separated from “server class” Arm equipment ? Or auto-configured on
>>>>>>> boot ? Consult an expert ;-)
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>>> I would like to see Chen’s feature added , perhaps as
>>>>>>>>> EXPERIMENTAL, so we can get some configuration testing done on
>>>>>>>>> it. It corrects having a DMA zone in low memory while crash-
>>>>>>>>> kernel is above 4GB. This has been going on for a year now.
>>>>>>>> I will also like this patch to be added in Linux as early as
>>>>>>>> possible.
>>>>>>>>
>>>>>>>> Issue mentioned by me happens with or without this patch.
>>>>>>>>
>>>>>>>> This patch-set can consider fixing because it uses low memory for
>>>>>>>> DMA
>>>>>>>> & swiotlb only.
>>>>>>>> We can consider restricting crashkernel within the required range
>>>>>>>> like below
>>>>>>>>
>>>>>>>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
>>>>>>>> index 7f9e5a6dc48c..bd67b90d35bd 100644
>>>>>>>> --- a/kernel/crash_core.c
>>>>>>>> +++ b/kernel/crash_core.c
>>>>>>>> @@ -354,7 +354,7 @@ int __init reserve_crashkernel_low(void)
>>>>>>>> return 0;
>>>>>>>> }
>>>>>>>>
>>>>>>>> - low_base = memblock_find_in_range(0, 1ULL << 32, low_size,
>>>>>>>> CRASH_ALIGN);
>>>>>>>> + low_base = memblock_find_in_range(0,0xc0000000, low_size,
>>>>>>>> CRASH_ALIGN);
>>>>>>>> if (!low_base) {
>>>>>>>> pr_err("Cannot reserve %ldMB crashkernel low memory,
>>>>>>>> please try smaller size.\n",
>>>>>>>> (unsigned long)(low_size >> 20));
>>>>>>>>
>>>>>>>>
>>>>>>> I suspect 0xc0000000 would need to be a CONFIG item and not
>>>>>>> hard-coded.
>>>>>>>
>>>>>> if you consider this as valid change, can you please incorporate as
>>>>>> part of your patch-set.
>>>>> After commit 1a8e1cef7 ("arm64: use both ZONE_DMA and ZONE_DMA32")，the 0-
>>>>> 4G memory is splited
>>>>> to DMA [mem 0x0000000000000000-0x000000003fffffff] and DMA32 [mem
>>>>> 0x0000000040000000-0x00000000ffffffff] on arm64.
>>>>>
>>>>> From the above discussion, on your platform, the low crashkernel fall in
>>>>> DMA32 region, but your environment needs to access DMA
>>>>> region, so there is the call trace.
>>>>>
>>>>> I have a question, why do you choose 0xc0000000 here?
>>>>>
>>>>> Besides, this is common code, we also need to consider about x86.
>>>>>
>>>> + [email protected]
>> Thanks for adding me to the conversation, and sorry for the headaches.
>>
>>>> Exactly . This is why it needs to be a CONFIG option for Raspberry
>>>> .., or device tree option.
>>>>
>>>>
>>>> We could revert 1a8e1cef7 since it broke Arm kdump too.
>>> Well, unfortunately the patch for commit 1a8e1cef7603 ("arm64: use
>>> both ZONE_DMA and ZONE_DMA32") was not Cc'ed to the kexec mailing
>>> list, thus we couldn't get many eyes on it for a thorough review from
>>> kexec/kdump p-o-v.
>>>
>>> Also we historically never had distinction in common arch code on the
>>> basis of the intended end use-case: embedded, server or automotive, so
>>> I am not sure introducing a Raspberry specific CONFIG option would be
>>> a good idea.
>> +1
>>
>> From the distros perspective it's very important to keep a single kernel image.
>>
>>> So, rather than reverting the patch, we can look at addressing the
>>> same properly this time - especially from a kdump p-o-v.
>>> This issue has been reported by some Red Hat arm64 partners with
>>> upstream kernel also and as we have noticed in the past as well,
>>> hardcoding the placement of the crashkernel base address (unless the
>>> base address is specified by a crashkernel=X@Y like bootargs) is also
>>> not a portable suggestion.
>>>
>>> I am working on a possible fix and will have more updates on the same
>>> in a day-or-two.
>> Please keep me in the loop, we've also had issues pointing to this reported by
>> SUSE partners. I can do some testing both on the RPi4 and on big servers that
>> need huge crashkernel sizes.
>>
>> Regards,
>> Nicolas
>>
>
> Hi
>
> Has there been any progress on this ? It appears we are stalled because Nicolas's and Chen's changes are not compatible . One is needed for RPi4 and the other for server class equipment.
>
>
> Thanks,
>
> John
>
>
Hi all,
Thanks for John's reminder.
commit 1a8e1cef7 ("arm64: use both ZONE_DMA and ZONE_DMA32") broken the arm64 kdump,
there is a simple solution similar to pk's to fix this, see below:
In crash dump kernel, if the peripherals need to use ZONE_DMA like the the Raspberry Pi 4, based on
my solution, we adjusted the memory range in memblock_find_in_range.
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index a7580d291c37..eb16c6d54b73 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -320,6 +320,7 @@ int __init reserve_crashkernel_low(void)
unsigned long long base, low_base = 0, low_size = 0;
unsigned long total_low_mem;
int ret;
+ phys_addr_t crash_max = 1ULL << 32;
total_low_mem = memblock_mem_size(1UL << (32 - PAGE_SHIFT));
@@ -352,7 +353,12 @@ int __init reserve_crashkernel_low(void)
return 0;
}
- low_base = memblock_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
+#ifdef CONFIG_ARM64
+ if (IS_ENABLED(CONFIG_ZONE_DMA)) {
+ crash_max = arm64_dma_phys_limit;
+ }
+#endif
+ low_base = memblock_find_in_range(0, crash_max, low_size, CRASH_ALIGN);
if (!low_base) {
pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
(unsigned long)(low_size >> 20));
Thanks,
Chen Zhou
>
> .
>
On 6/19/20 3:21 AM, chenzhou wrote:
> On 2020/6/19 10:32, John Donnelly wrote:
>> On 6/4/20 12:01 PM, Nicolas Saenz Julienne wrote:
>>> On Thu, 2020-06-04 at 01:17 +0530, Bhupesh Sharma wrote:
>>>> Hi All,
>>>>
>>>> On Wed, Jun 3, 2020 at 9:03 PM John Donnelly <[email protected]>
>>>> wrote:
>>>>>> On Jun 3, 2020, at 8:20 AM, chenzhou <[email protected]> wrote:
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>>
>>>>>> On 2020/6/3 19:47, Prabhakar Kushwaha wrote:
>>>>>>> Hi Chen,
>>>>>>>
>>>>>>> On Tue, Jun 2, 2020 at 8:12 PM John Donnelly <[email protected]
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> On Jun 2, 2020, at 12:38 AM, Prabhakar Kushwaha <
>>>>>>>>> [email protected]> wrote:
>>>>>>>>>
>>>>>>>>> On Tue, Jun 2, 2020 at 3:29 AM John Donnelly <
>>>>>>>>> [email protected]> wrote:
>>>>>>>>>> Hi . See below !
>>>>>>>>>>
>>>>>>>>>>> On Jun 1, 2020, at 4:02 PM, Bhupesh Sharma <[email protected]>
>>>>>>>>>>> wrote:
>>>>>>>>>>>
>>>>>>>>>>> Hi John,
>>>>>>>>>>>
>>>>>>>>>>> On Tue, Jun 2, 2020 at 1:01 AM John Donnelly <
>>>>>>>>>>> [email protected]> wrote:
>>>>>>>>>>>> Hi,
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> On 6/1/20 7:02 AM, Prabhakar Kushwaha wrote:
>>>>>>>>>>>>> Hi Chen,
>>>>>>>>>>>>>
>>>>>>>>>>>>> On Thu, May 21, 2020 at 3:05 PM Chen Zhou <
>>>>>>>>>>>>> [email protected]> wrote:
>>>>>>>>>>>>>> This patch series enable reserving crashkernel above 4G in
>>>>>>>>>>>>>> arm64.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> There are following issues in arm64 kdump:
>>>>>>>>>>>>>> 1. We use crashkernel=X to reserve crashkernel below 4G,
>>>>>>>>>>>>>> which will fail
>>>>>>>>>>>>>> when there is no enough low memory.
>>>>>>>>>>>>>> 2. Currently, crashkernel=Y@X can be used to reserve
>>>>>>>>>>>>>> crashkernel above 4G,
>>>>>>>>>>>>>> in this case, if swiotlb or DMA buffers are required,
>>>>>>>>>>>>>> crash dump kernel
>>>>>>>>>>>>>> will boot failure because there is no low memory available
>>>>>>>>>>>>>> for allocation.
>>>>>>>>>>>>>>
>>>>>>>>>>>>> We are getting "warn_alloc" [1] warning during boot of kdump
>>>>>>>>>>>>> kernel
>>>>>>>>>>>>> with bootargs as [2] of primary kernel.
>>>>>>>>>>>>> This error observed on ThunderX2 ARM64 platform.
>>>>>>>>>>>>>
>>>>>>>>>>>>> It is observed with latest upstream tag (v5.7-rc3) with this
>>>>>>>>>>>>> patch set
>>>>>>>>>>>>> and
>>>>>>>>>>>>>
>>> https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbiIAAlzu$
>>>>>>>>>>>>> Also **without** this patch-set
>>>>>>>>>>>>> "
>>>>>>>>>>>>>
>>> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$
>>>>>>>>>>>>> "
>>>>>>>>>>>>>
>>>>>>>>>>>>> This issue comes whenever crashkernel memory is reserved
>>>>>>>>>>>>> after 0xc000_0000.
>>>>>>>>>>>>> More details discussed earlier in
>>>>>>>>>>>>>
>>> https://urldefense.com/v3/__https://www.spinics.net/lists/arm-kernel/msg806882.html__;!!GqivPVa7Brio!LnTSARkCt0V0FozR0KmqooaH5ADtdXvs3mPdP3KRVqALmvSK2VmCkIPIhsaxbjC6ujMA$
>>> without
>>>>>>>>>>>>> any
>>>>>>>>>>>>> solution
>>>>>>>>>>>>>
>>>>>>>>>>>>> This patch-set is expected to solve similar kind of issue.
>>>>>>>>>>>>> i.e. low memory is only targeted for DMA, swiotlb; So above
>>>>>>>>>>>>> mentioned
>>>>>>>>>>>>> observation should be considered/fixed. .
>>>>>>>>>>>>>
>>>>>>>>>>>>> --pk
>>>>>>>>>>>>>
>>>>>>>>>>>>> [1]
>>>>>>>>>>>>> [ 30.366695] DMI: Cavium Inc. Saber/Saber, BIOS
>>>>>>>>>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>>>>>>>>>>>> [ 30.367696] NET: Registered protocol family 16
>>>>>>>>>>>>> [ 30.369973] swapper/0: page allocation failure: order:6,
>>>>>>>>>>>>> mode:0x1(GFP_DMA), nodemask=(null),cpuset=/,mems_allowed=0
>>>>>>>>>>>>> [ 30.369980] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
>>>>>>>>>>>>> 5.7.0-rc3+ #121
>>>>>>>>>>>>> [ 30.369981] Hardware name: Cavium Inc. Saber/Saber, BIOS
>>>>>>>>>>>>> TX2-FW-Release-3.1-build_01-2803-g74253a541a mm/dd/yyyy
>>>>>>>>>>>>> [ 30.369984] Call trace:
>>>>>>>>>>>>> [ 30.369989] dump_backtrace+0x0/0x1f8
>>>>>>>>>>>>> [ 30.369991] show_stack+0x20/0x30
>>>>>>>>>>>>> [ 30.369997] dump_stack+0xc0/0x10c
>>>>>>>>>>>>> [ 30.370001] warn_alloc+0x10c/0x178
>>>>>>>>>>>>> [ 30.370004] __alloc_pages_slowpath.constprop.111+0xb10/0
>>>>>>>>>>>>> xb50
>>>>>>>>>>>>> [ 30.370006] __alloc_pages_nodemask+0x2b4/0x300
>>>>>>>>>>>>> [ 30.370008] alloc_page_interleave+0x24/0x98
>>>>>>>>>>>>> [ 30.370011] alloc_pages_current+0xe4/0x108
>>>>>>>>>>>>> [ 30.370017] dma_atomic_pool_init+0x44/0x1a4
>>>>>>>>>>>>> [ 30.370020] do_one_initcall+0x54/0x228
>>>>>>>>>>>>> [ 30.370027] kernel_init_freeable+0x228/0x2cc
>>>>>>>>>>>>> [ 30.370031] kernel_init+0x1c/0x110
>>>>>>>>>>>>> [ 30.370034] ret_from_fork+0x10/0x18
>>>>>>>>>>>>> [ 30.370036] Mem-Info:
>>>>>>>>>>>>> [ 30.370064] active_anon:0 inactive_anon:0 isolated_anon:0
>>>>>>>>>>>>> [ 30.370064] active_file:0 inactive_file:0
>>>>>>>>>>>>> isolated_file:0
>>>>>>>>>>>>> [ 30.370064] unevictable:0 dirty:0 writeback:0 unstable:0
>>>>>>>>>>>>> [ 30.370064] slab_reclaimable:34 slab_unreclaimable:4438
>>>>>>>>>>>>> [ 30.370064] mapped:0 shmem:0 pagetables:14 bounce:0
>>>>>>>>>>>>> [ 30.370064] free:1537719 free_pcp:219 free_cma:0
>>>>>>>>>>>>> [ 30.370070] Node 0 active_anon:0kB inactive_anon:0kB
>>>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>>>> isolated(anon):0kB
>>>>>>>>>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB
>>>>>>>>>>>>> shmem:0kB
>>>>>>>>>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB
>>>>>>>>>>>>> writeback_tmp:0kB
>>>>>>>>>>>>> unstable:0kB all_unreclaimable? no
>>>>>>>>>>>>> [ 30.370073] Node 1 active_anon:0kB inactive_anon:0kB
>>>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>>>> isolated(anon):0kB
>>>>>>>>>>>>> isolated(file):0kB mapped:0kB dirty:0kB writeback:0kB
>>>>>>>>>>>>> shmem:0kB
>>>>>>>>>>>>> shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 0kB
>>>>>>>>>>>>> writeback_tmp:0kB
>>>>>>>>>>>>> unstable:0kB all_unreclaimable? no
>>>>>>>>>>>>> [ 30.370079] Node 0 DMA free:0kB min:0kB low:0kB high:0kB
>>>>>>>>>>>>> reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB
>>>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>>>> writepending:0kB
>>>>>>>>>>>>> present:128kB managed:0kB mlocked:0kB kernel_stack:0kB
>>>>>>>>>>>>> pagetables:0kB
>>>>>>>>>>>>> bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
>>>>>>>>>>>>> [ 30.370084] lowmem_reserve[]: 0 250 6063 6063
>>>>>>>>>>>>> [ 30.370090] Node 0 DMA32 free:256000kB min:408kB
>>>>>>>>>>>>> low:664kB
>>>>>>>>>>>>> high:920kB reserved_highatomic:0KB active_anon:0kB
>>>>>>>>>>>>> inactive_anon:0kB
>>>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>>>> writepending:0kB
>>>>>>>>>>>>> present:269700kB managed:256000kB mlocked:0kB
>>>>>>>>>>>>> kernel_stack:0kB
>>>>>>>>>>>>> pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB
>>>>>>>>>>>>> free_cma:0kB
>>>>>>>>>>>>> [ 30.370094] lowmem_reserve[]: 0 0 5813 5813
>>>>>>>>>>>>> [ 30.370100] Node 0 Normal free:5894876kB min:9552kB
>>>>>>>>>>>>> low:15504kB
>>>>>>>>>>>>> high:21456kB reserved_highatomic:0KB active_anon:0kB
>>>>>>>>>>>>> inactive_anon:0kB
>>>>>>>>>>>>> active_file:0kB inactive_file:0kB unevictable:0kB
>>>>>>>>>>>>> writepending:0kB
>>>>>>>>>>>>> present:8388608kB managed:5953112kB mlocked:0kB
>>>>>>>>>>>>> kernel_stack:21672kB
>>>>>>>>>>>>> pagetables:56kB bounce:0kB free_pcp:876kB local_pcp:176kB
>>>>>>>>>>>>> free_cma:0kB
>>>>>>>>>>>>> [ 30.370104] lowmem_reserve[]: 0 0 0 0
>>>>>>>>>>>>> [ 30.370107] Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB
>>>>>>>>>>>>> 0*128kB
>>>>>>>>>>>>> 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB
>>>>>>>>>>>>> [ 30.370113] Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB
>>>>>>>>>>>>> 0*64kB 0*128kB
>>>>>>>>>>>>> 0*256kB 0*512kB 0*1024kB 1*2048kB (M) 62*4096kB (M) =
>>>>>>>>>>>>> 256000kB
>>>>>>>>>>>>> [ 30.370119] Node 0 Normal: 2*4kB (M) 3*8kB (ME) 2*16kB
>>>>>>>>>>>>> (UE) 3*32kB
>>>>>>>>>>>>> (UM) 1*64kB (U) 2*128kB (M) 2*256kB (ME) 3*512kB (ME)
>>>>>>>>>>>>> 3*1024kB (ME)
>>>>>>>>>>>>> 3*2048kB (UME) 1436*4096kB (M) = 5893600kB
>>>>>>>>>>>>> [ 30.370129] Node 0 hugepages_total=0 hugepages_free=0
>>>>>>>>>>>>> hugepages_surp=0 hugepages_size=1048576kB
>>>>>>>>>>>>> [ 30.370130] 0 total pagecache pages
>>>>>>>>>>>>> [ 30.370132] 0 pages in swap cache
>>>>>>>>>>>>> [ 30.370134] Swap cache stats: add 0, delete 0, find 0/0
>>>>>>>>>>>>> [ 30.370135] Free swap = 0kB
>>>>>>>>>>>>> [ 30.370136] Total swap = 0kB
>>>>>>>>>>>>> [ 30.370137] 2164609 pages RAM
>>>>>>>>>>>>> [ 30.370139] 0 pages HighMem/MovableOnly
>>>>>>>>>>>>> [ 30.370140] 612331 pages reserved
>>>>>>>>>>>>> [ 30.370141] 0 pages hwpoisoned
>>>>>>>>>>>>> [ 30.370143] DMA: failed to allocate 256 KiB pool for
>>>>>>>>>>>>> atomic
>>>>>>>>>>>>> coherent allocation
>>>>>>>>>>>> During my testing I saw the same error and Chen's solution
>>>>>>>>>>>> corrected it .
>>>>>>>>>>> Which combination you are using on your side? I am using
>>>>>>>>>>> Prabhakar's
>>>>>>>>>>> suggested environment and can reproduce the issue
>>>>>>>>>>> with or without Chen's crashkernel support above 4G patchset.
>>>>>>>>>>>
>>>>>>>>>>> I am also using a ThunderX2 platform with latest makedumpfile
>>>>>>>>>>> code and
>>>>>>>>>>> kexec-tools (with the suggested patch
>>>>>>>>>>> <
>>>>>>>>>>>
>>> https://urldefense.com/v3/__https://lists.infradead.org/pipermail/kexec/2020-May/025128.html__;!!GqivPVa7Brio!J6lUig58-Gw6TKZnEEYzEeSU36T-1SqlB1kImU00xtX_lss5Tx-JbUmLE9TJC3foXBLg$
>>>>>>>>>>>> ).
>>>>>>>>>>> Thanks,
>>>>>>>>>>> Bhupesh
>>>>>>>>>> I did this activity 5 months ago and I have moved on to other
>>>>>>>>>> activities. My DMA failures were related to PCI devices that could
>>>>>>>>>> not be enumerated because low-DMA space was not available when
>>>>>>>>>> crashkernel was moved above 4G; I don’t recall the exact platform.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> For this failure ,
>>>>>>>>>>
>>>>>>>>>>>>> DMA: failed to allocate 256 KiB pool for atomic
>>>>>>>>>>>>> coherent allocation
>>>>>>>>>> Is due to :
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> 3618082c
>>>>>>>>>> ("arm64 use both ZONE_DMA and ZONE_DMA32")
>>>>>>>>>>
>>>>>>>>>> With the introduction of ZONE_DMA to support the Raspberry DMA
>>>>>>>>>> region below 1G, the crashkernel is placed in the upper 4G
>>>>>>>>>> ZONE_DMA_32 region. Since the crashkernel does not have access
>>>>>>>>>> to the ZONE_DMA region, it prints out call trace during bootup.
>>>>>>>>>>
>>>>>>>>>> It is due to having this CONFIG item ON :
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> CONFIG_ZONE_DMA=y
>>>>>>>>>>
>>>>>>>>>> Turning off ZONE_DMA fixes a issue and Raspberry PI 4 will
>>>>>>>>>> use the device tree to specify memory below 1G.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>> Disabling ZONE_DMA is temporary solution. We may need proper
>>>>>>>>> solution
>>>>>>>> Perhaps the Raspberry platform configuration dependencies need
>>>>>>>> separated from “server class” Arm equipment ? Or auto-configured on
>>>>>>>> boot ? Consult an expert ;-)
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>> I would like to see Chen’s feature added , perhaps as
>>>>>>>>>> EXPERIMENTAL, so we can get some configuration testing done on
>>>>>>>>>> it. It corrects having a DMA zone in low memory while crash-
>>>>>>>>>> kernel is above 4GB. This has been going on for a year now.
>>>>>>>>> I will also like this patch to be added in Linux as early as
>>>>>>>>> possible.
>>>>>>>>>
>>>>>>>>> Issue mentioned by me happens with or without this patch.
>>>>>>>>>
>>>>>>>>> This patch-set can consider fixing because it uses low memory for
>>>>>>>>> DMA
>>>>>>>>> & swiotlb only.
>>>>>>>>> We can consider restricting crashkernel within the required range
>>>>>>>>> like below
>>>>>>>>>
>>>>>>>>> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
>>>>>>>>> index 7f9e5a6dc48c..bd67b90d35bd 100644
>>>>>>>>> --- a/kernel/crash_core.c
>>>>>>>>> +++ b/kernel/crash_core.c
>>>>>>>>> @@ -354,7 +354,7 @@ int __init reserve_crashkernel_low(void)
>>>>>>>>> return 0;
>>>>>>>>> }
>>>>>>>>>
>>>>>>>>> - low_base = memblock_find_in_range(0, 1ULL << 32, low_size,
>>>>>>>>> CRASH_ALIGN);
>>>>>>>>> + low_base = memblock_find_in_range(0,0xc0000000, low_size,
>>>>>>>>> CRASH_ALIGN);
>>>>>>>>> if (!low_base) {
>>>>>>>>> pr_err("Cannot reserve %ldMB crashkernel low memory,
>>>>>>>>> please try smaller size.\n",
>>>>>>>>> (unsigned long)(low_size >> 20));
>>>>>>>>>
>>>>>>>>>
>>>>>>>> I suspect 0xc0000000 would need to be a CONFIG item and not
>>>>>>>> hard-coded.
>>>>>>>>
>>>>>>> if you consider this as valid change, can you please incorporate as
>>>>>>> part of your patch-set.
>>>>>> After commit 1a8e1cef7 ("arm64: use both ZONE_DMA and ZONE_DMA32")，the 0-
>>>>>> 4G memory is splited
>>>>>> to DMA [mem 0x0000000000000000-0x000000003fffffff] and DMA32 [mem
>>>>>> 0x0000000040000000-0x00000000ffffffff] on arm64.
>>>>>>
>>>>>> From the above discussion, on your platform, the low crashkernel fall in
>>>>>> DMA32 region, but your environment needs to access DMA
>>>>>> region, so there is the call trace.
>>>>>>
>>>>>> I have a question, why do you choose 0xc0000000 here?
>>>>>>
>>>>>> Besides, this is common code, we also need to consider about x86.
>>>>>>
>>>>> + [email protected]
>>> Thanks for adding me to the conversation, and sorry for the headaches.
>>>
>>>>> Exactly . This is why it needs to be a CONFIG option for Raspberry
>>>>> .., or device tree option.
>>>>>
>>>>>
>>>>> We could revert 1a8e1cef7 since it broke Arm kdump too.
>>>> Well, unfortunately the patch for commit 1a8e1cef7603 ("arm64: use
>>>> both ZONE_DMA and ZONE_DMA32") was not Cc'ed to the kexec mailing
>>>> list, thus we couldn't get many eyes on it for a thorough review from
>>>> kexec/kdump p-o-v.
>>>>
>>>> Also we historically never had distinction in common arch code on the
>>>> basis of the intended end use-case: embedded, server or automotive, so
>>>> I am not sure introducing a Raspberry specific CONFIG option would be
>>>> a good idea.
>>> +1
>>>
>>> From the distros perspective it's very important to keep a single kernel image.
>>>
>>>> So, rather than reverting the patch, we can look at addressing the
>>>> same properly this time - especially from a kdump p-o-v.
>>>> This issue has been reported by some Red Hat arm64 partners with
>>>> upstream kernel also and as we have noticed in the past as well,
>>>> hardcoding the placement of the crashkernel base address (unless the
>>>> base address is specified by a crashkernel=X@Y like bootargs) is also
>>>> not a portable suggestion.
>>>>
>>>> I am working on a possible fix and will have more updates on the same
>>>> in a day-or-two.
>>> Please keep me in the loop, we've also had issues pointing to this reported by
>>> SUSE partners. I can do some testing both on the RPi4 and on big servers that
>>> need huge crashkernel sizes.
>>>
>>> Regards,
>>> Nicolas
>>>
>> Hi
>>
>> Has there been any progress on this ? It appears we are stalled because Nicolas's and Chen's changes are not compatible . One is needed for RPi4 and the other for server class equipment.
>>
>>
>> Thanks,
>>
>> John
>>
>>
> Hi all,
>
> Thanks for John's reminder.
> commit 1a8e1cef7 ("arm64: use both ZONE_DMA and ZONE_DMA32") broken the arm64 kdump,
> there is a simple solution similar to pk's to fix this, see below:
>
> In crash dump kernel, if the peripherals need to use ZONE_DMA like the the Raspberry Pi 4, based on
> my solution, we adjusted the memory range in memblock_find_in_range.
>
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index a7580d291c37..eb16c6d54b73 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -320,6 +320,7 @@ int __init reserve_crashkernel_low(void)
> unsigned long long base, low_base = 0, low_size = 0;
> unsigned long total_low_mem;
> int ret;
> + phys_addr_t crash_max = 1ULL << 32;
>
> total_low_mem = memblock_mem_size(1UL << (32 - PAGE_SHIFT));
>
> @@ -352,7 +353,12 @@ int __init reserve_crashkernel_low(void)
> return 0;
> }
>
> - low_base = memblock_find_in_range(0, 1ULL << 32, low_size, CRASH_ALIGN);
> +#ifdef CONFIG_ARM64
> + if (IS_ENABLED(CONFIG_ZONE_DMA)) {
> + crash_max = arm64_dma_phys_limit;
> + }
> +#endif
> + low_base = memblock_find_in_range(0, crash_max, low_size, CRASH_ALIGN);
> if (!low_base) {
> pr_err("Cannot reserve %ldMB crashkernel low memory, please try smaller size.\n",
> (unsigned long)(low_size >> 20));
>
>
> Thanks,
> Chen Zhou
>
Hi,
I don't have any objections to this proposal.
>> .
>>
>