From: Mike Rapoport <[email protected]>
The existing description of mem= does not cover all the cases and
differences between how architectures treat it.
Extend the description to match the code.
Signed-off-by: Mike Rapoport <[email protected]>
---
This is in a way a followup for the discussion of mem= usage on MIPS:
https://lore.kernel.org/all/[email protected]
.../admin-guide/kernel-parameters.txt | 20 +++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index f5a27f067db9..f3597841a031 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2834,6 +2834,15 @@
2 when the kernel is not able to see the whole system memory;
3 memory that lies after 'mem=' boundary is excluded from
the hypervisor, then assigned to KVM guests.
+ 4 to limit the memory available for kdump kernel.
+
+ [ARC,MICROBLAZE] - the limit applies only to low memory,
+ high memory is not affected.
+
+ [ARM64] - only limits memory covered by the linear
+ mapping. The NOMAP regions are not affected.
+
+ [HEXAGON] - must be use to set the memory size, there is
[X86] Work as limiting max address. Use together
with memmap= to avoid physical address space collisions.
@@ -2844,6 +2853,17 @@
in above case 3, memory may need be hot added after boot
if system memory of hypervisor is not sufficient.
+ mem=nn[KMG]@ss[KMG]
+ [ARM,MIPS] - override the memory layout reported by
+ firmware.
+ Define a memory region of size nn[KMG] starting at
+ ss[KMG].
+ Multiple different regions can be specified with
+ multiple mem= parameters on the command line.
+
+ mem=nn[KMG] [HEXAGON] Set the memory size.
+ Must be specified, otherwise memory size will be 0.
+
mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
memory.
--
2.34.1
Hi Mike,
On 3/9/22 04:24, Mike Rapoport wrote:
> From: Mike Rapoport <[email protected]>
>
> The existing description of mem= does not cover all the cases and
> differences between how architectures treat it.
>
> Extend the description to match the code.
>
> Signed-off-by: Mike Rapoport <[email protected]>
> ---
>
> This is in a way a followup for the discussion of mem= usage on MIPS:
>
> https://lore.kernel.org/all/[email protected]
>
> .../admin-guide/kernel-parameters.txt | 20 +++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index f5a27f067db9..f3597841a031 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -2834,6 +2834,15 @@
> 2 when the kernel is not able to see the whole system memory;
> 3 memory that lies after 'mem=' boundary is excluded from
> the hypervisor, then assigned to KVM guests.
> + 4 to limit the memory available for kdump kernel.
> +
> + [ARC,MICROBLAZE] - the limit applies only to low memory,
> + high memory is not affected.
> +
> + [ARM64] - only limits memory covered by the linear
> + mapping. The NOMAP regions are not affected.
> +
> + [HEXAGON] - must be use to set the memory size, there is
Above line seems to be missing something?
Otherwise looks good AFAIK.
>
> [X86] Work as limiting max address. Use together
> with memmap= to avoid physical address space collisions.
> @@ -2844,6 +2853,17 @@
> in above case 3, memory may need be hot added after boot
> if system memory of hypervisor is not sufficient.
>
> + mem=nn[KMG]@ss[KMG]
> + [ARM,MIPS] - override the memory layout reported by
> + firmware.
> + Define a memory region of size nn[KMG] starting at
> + ss[KMG].
> + Multiple different regions can be specified with
> + multiple mem= parameters on the command line.
> +
> + mem=nn[KMG] [HEXAGON] Set the memory size.
> + Must be specified, otherwise memory size will be 0.
> +
> mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
> memory.
>
--
~Randy
On 3/9/22 3:24 PM, Mike Rapoport wrote:
> From: Mike Rapoport <[email protected]>
>
> The existing description of mem= does not cover all the cases and
> differences between how architectures treat it.
>
> Extend the description to match the code.
>
> Signed-off-by: Mike Rapoport <[email protected]>
> ---
>
> This is in a way a followup for the discussion of mem= usage on MIPS:
>
> https://lore.kernel.org/all/[email protected]
>
> .../admin-guide/kernel-parameters.txt | 20 +++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index f5a27f067db9..f3597841a031 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -2834,6 +2834,15 @@
> 2 when the kernel is not able to see the whole system memory;
> 3 memory that lies after 'mem=' boundary is excluded from
> the hypervisor, then assigned to KVM guests.
> + 4 to limit the memory available for kdump kernel.
> +
> + [ARC,MICROBLAZE] - the limit applies only to low memory,
> + high memory is not affected.
> +
> + [ARM64] - only limits memory covered by the linear
> + mapping. The NOMAP regions are not affected.
> +
> + [HEXAGON] - must be use
Used?
> to set the memory size, there is
What? :-)
[...]
MBR, Sergey
On Wed, Mar 09, 2022 at 08:05:05AM -0800, Randy Dunlap wrote:
> Hi Mike,
>
> On 3/9/22 04:24, Mike Rapoport wrote:
> > From: Mike Rapoport <[email protected]>
> >
> > The existing description of mem= does not cover all the cases and
> > differences between how architectures treat it.
> >
> > Extend the description to match the code.
> >
> > Signed-off-by: Mike Rapoport <[email protected]>
> > ---
> >
> > This is in a way a followup for the discussion of mem= usage on MIPS:
> >
> > https://lore.kernel.org/all/[email protected]
> >
> > .../admin-guide/kernel-parameters.txt | 20 +++++++++++++++++++
> > 1 file changed, 20 insertions(+)
> >
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index f5a27f067db9..f3597841a031 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -2834,6 +2834,15 @@
> > 2 when the kernel is not able to see the whole system memory;
> > 3 memory that lies after 'mem=' boundary is excluded from
> > the hypervisor, then assigned to KVM guests.
> > + 4 to limit the memory available for kdump kernel.
> > +
> > + [ARC,MICROBLAZE] - the limit applies only to low memory,
> > + high memory is not affected.
> > +
> > + [ARM64] - only limits memory covered by the linear
> > + mapping. The NOMAP regions are not affected.
> > +
> > + [HEXAGON] - must be use to set the memory size, there is
>
> Above line seems to be missing something?
Yes :)
> Otherwise looks good AFAIK.
>
> >
> > [X86] Work as limiting max address. Use together
> > with memmap= to avoid physical address space collisions.
> > @@ -2844,6 +2853,17 @@
> > in above case 3, memory may need be hot added after boot
> > if system memory of hypervisor is not sufficient.
> >
> > + mem=nn[KMG]@ss[KMG]
> > + [ARM,MIPS] - override the memory layout reported by
> > + firmware.
> > + Define a memory region of size nn[KMG] starting at
> > + ss[KMG].
> > + Multiple different regions can be specified with
> > + multiple mem= parameters on the command line.
> > +
> > + mem=nn[KMG] [HEXAGON] Set the memory size.
> > + Must be specified, otherwise memory size will be 0.
> > +
> > mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
> > memory.
> >
>
> --
> ~Randy
--
Sincerely yours,
Mike.