This series fixes the fallback of the top-down mmap: in case of
failure, a bottom-up scheme can be tried as a last resort between
the top-down mmap base and the stack, hoping for a large unused stack
limit.
Lots of architectures and even mm code start this fallback
at TASK_UNMAPPED_BASE, which is useless since the top-down scheme
already failed on the whole address space: instead, simply use
mmap_base.
Along the way, it allows to get rid of of mmap_legacy_base and
mmap_compat_legacy_base from mm_struct.
Note that arm and mips already implement this behaviour.
Alexandre Ghiti (8):
s390: Start fallback of top-down mmap at mm->mmap_base
sh: Start fallback of top-down mmap at mm->mmap_base
sparc: Start fallback of top-down mmap at mm->mmap_base
x86, hugetlbpage: Start fallback of top-down mmap at mm->mmap_base
mm: Start fallback top-down mmap at mm->mmap_base
parisc: Use mmap_base, not mmap_legacy_base, as low_limit for
bottom-up mmap
x86: Use mmap_*base, not mmap_*legacy_base, as low_limit for bottom-up
mmap
mm: Remove mmap_legacy_base and mmap_compat_legacy_code fields from
mm_struct
arch/parisc/kernel/sys_parisc.c | 8 +++-----
arch/s390/mm/mmap.c | 2 +-
arch/sh/mm/mmap.c | 2 +-
arch/sparc/kernel/sys_sparc_64.c | 2 +-
arch/sparc/mm/hugetlbpage.c | 2 +-
arch/x86/include/asm/elf.h | 2 +-
arch/x86/kernel/sys_x86_64.c | 4 ++--
arch/x86/mm/hugetlbpage.c | 7 ++++---
arch/x86/mm/mmap.c | 20 +++++++++-----------
include/linux/mm_types.h | 2 --
mm/debug.c | 4 ++--
mm/mmap.c | 2 +-
12 files changed, 26 insertions(+), 31 deletions(-)
--
2.20.1
In case of mmap failure in top-down mode, there is no need to go through
the whole address space again for the bottom-up fallback: the goal of this
fallback is to find, as a last resort, space between the top-down mmap base
and the stack, which is the only place not covered by the top-down mmap.
Signed-off-by: Alexandre Ghiti <[email protected]>
---
arch/x86/mm/hugetlbpage.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
index fab095362c50..4b90339aef50 100644
--- a/arch/x86/mm/hugetlbpage.c
+++ b/arch/x86/mm/hugetlbpage.c
@@ -106,11 +106,12 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
{
struct hstate *h = hstate_file(file);
struct vm_unmapped_area_info info;
+ unsigned long mmap_base = get_mmap_base(0);
info.flags = VM_UNMAPPED_AREA_TOPDOWN;
info.length = len;
info.low_limit = PAGE_SIZE;
- info.high_limit = get_mmap_base(0);
+ info.high_limit = mmap_base;
/*
* If hint address is above DEFAULT_MAP_WINDOW, look for unmapped area
@@ -132,7 +133,7 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
if (addr & ~PAGE_MASK) {
VM_BUG_ON(addr != -ENOMEM);
info.flags = 0;
- info.low_limit = TASK_UNMAPPED_BASE;
+ info.low_limit = mmap_base;
info.high_limit = TASK_SIZE_LOW;
addr = vm_unmapped_area(&info);
}
--
2.20.1
On 6/20/19 7:03 AM, Alexandre Ghiti wrote:
> This series fixes the fallback of the top-down mmap: in case of
> failure, a bottom-up scheme can be tried as a last resort between
> the top-down mmap base and the stack, hoping for a large unused stack
> limit.
>
> Lots of architectures and even mm code start this fallback
> at TASK_UNMAPPED_BASE, which is useless since the top-down scheme
> already failed on the whole address space: instead, simply use
> mmap_base.
>
> Along the way, it allows to get rid of of mmap_legacy_base and
> mmap_compat_legacy_base from mm_struct.
>
> Note that arm and mips already implement this behaviour.
>
> Alexandre Ghiti (8):
> s390: Start fallback of top-down mmap at mm->mmap_base
> sh: Start fallback of top-down mmap at mm->mmap_base
> sparc: Start fallback of top-down mmap at mm->mmap_base
> x86, hugetlbpage: Start fallback of top-down mmap at mm->mmap_base
> mm: Start fallback top-down mmap at mm->mmap_base
> parisc: Use mmap_base, not mmap_legacy_base, as low_limit for
> bottom-up mmap
> x86: Use mmap_*base, not mmap_*legacy_base, as low_limit for bottom-up
> mmap
> mm: Remove mmap_legacy_base and mmap_compat_legacy_code fields from
> mm_struct
>
> arch/parisc/kernel/sys_parisc.c | 8 +++-----
> arch/s390/mm/mmap.c | 2 +-
> arch/sh/mm/mmap.c | 2 +-
> arch/sparc/kernel/sys_sparc_64.c | 2 +-
> arch/sparc/mm/hugetlbpage.c | 2 +-
> arch/x86/include/asm/elf.h | 2 +-
> arch/x86/kernel/sys_x86_64.c | 4 ++--
> arch/x86/mm/hugetlbpage.c | 7 ++++---
> arch/x86/mm/mmap.c | 20 +++++++++-----------
> include/linux/mm_types.h | 2 --
> mm/debug.c | 4 ++--
> mm/mmap.c | 2 +-
> 12 files changed, 26 insertions(+), 31 deletions(-)
>
Hi everyone,
This is just a preparatory series for the merging of x86 mmap top-down
functions with
the generic ones (those should get into v5.3), if you could take some
time to take a look,
that would be great :)
Thanks,
Alex
On 6/20/19 7:03 AM, Alexandre Ghiti wrote:
> This series fixes the fallback of the top-down mmap: in case of
> failure, a bottom-up scheme can be tried as a last resort between
> the top-down mmap base and the stack, hoping for a large unused stack
> limit.
>
> Lots of architectures and even mm code start this fallback
> at TASK_UNMAPPED_BASE, which is useless since the top-down scheme
> already failed on the whole address space: instead, simply use
> mmap_base.
>
> Along the way, it allows to get rid of of mmap_legacy_base and
> mmap_compat_legacy_base from mm_struct.
>
> Note that arm and mips already implement this behaviour.
>
> Alexandre Ghiti (8):
> s390: Start fallback of top-down mmap at mm->mmap_base
> sh: Start fallback of top-down mmap at mm->mmap_base
> sparc: Start fallback of top-down mmap at mm->mmap_base
> x86, hugetlbpage: Start fallback of top-down mmap at mm->mmap_base
> mm: Start fallback top-down mmap at mm->mmap_base
> parisc: Use mmap_base, not mmap_legacy_base, as low_limit for
> bottom-up mmap
> x86: Use mmap_*base, not mmap_*legacy_base, as low_limit for bottom-up
> mmap
> mm: Remove mmap_legacy_base and mmap_compat_legacy_code fields from
> mm_struct
>
> arch/parisc/kernel/sys_parisc.c | 8 +++-----
> arch/s390/mm/mmap.c | 2 +-
> arch/sh/mm/mmap.c | 2 +-
> arch/sparc/kernel/sys_sparc_64.c | 2 +-
> arch/sparc/mm/hugetlbpage.c | 2 +-
> arch/x86/include/asm/elf.h | 2 +-
> arch/x86/kernel/sys_x86_64.c | 4 ++--
> arch/x86/mm/hugetlbpage.c | 7 ++++---
> arch/x86/mm/mmap.c | 20 +++++++++-----------
> include/linux/mm_types.h | 2 --
> mm/debug.c | 4 ++--
> mm/mmap.c | 2 +-
> 12 files changed, 26 insertions(+), 31 deletions(-)
>
Hi everyone,
Any thoughts about that series ? As said before, this is just a
preparatory patchset in order to
merge x86 mmap top down code with the generic version.
Thanks for taking a look,
Alex
On 26.08.19 09:34, Alexandre Ghiti wrote:
> On 6/20/19 7:03 AM, Alexandre Ghiti wrote:
>> This series fixes the fallback of the top-down mmap: in case of
>> failure, a bottom-up scheme can be tried as a last resort between
>> the top-down mmap base and the stack, hoping for a large unused stack
>> limit.
>>
>> Lots of architectures and even mm code start this fallback
>> at TASK_UNMAPPED_BASE, which is useless since the top-down scheme
>> already failed on the whole address space: instead, simply use
>> mmap_base.
>>
>> Along the way, it allows to get rid of of mmap_legacy_base and
>> mmap_compat_legacy_base from mm_struct.
>>
>> Note that arm and mips already implement this behaviour.
>>
>> Alexandre Ghiti (8):
>> s390: Start fallback of top-down mmap at mm->mmap_base
>> sh: Start fallback of top-down mmap at mm->mmap_base
>> sparc: Start fallback of top-down mmap at mm->mmap_base
>> x86, hugetlbpage: Start fallback of top-down mmap at mm->mmap_base
>> mm: Start fallback top-down mmap at mm->mmap_base
>> parisc: Use mmap_base, not mmap_legacy_base, as low_limit for
>> bottom-up mmap
>> x86: Use mmap_*base, not mmap_*legacy_base, as low_limit for bottom-up
>> mmap
>> mm: Remove mmap_legacy_base and mmap_compat_legacy_code fields from
>> mm_struct
>>
>> arch/parisc/kernel/sys_parisc.c | 8 +++-----
>> arch/s390/mm/mmap.c | 2 +-
>> arch/sh/mm/mmap.c | 2 +-
>> arch/sparc/kernel/sys_sparc_64.c | 2 +-
>> arch/sparc/mm/hugetlbpage.c | 2 +-
>> arch/x86/include/asm/elf.h | 2 +-
>> arch/x86/kernel/sys_x86_64.c | 4 ++--
>> arch/x86/mm/hugetlbpage.c | 7 ++++---
>> arch/x86/mm/mmap.c | 20 +++++++++-----------
>> include/linux/mm_types.h | 2 --
>> mm/debug.c | 4 ++--
>> mm/mmap.c | 2 +-
>> 12 files changed, 26 insertions(+), 31 deletions(-)
>>
>
> Any thoughts about that series ? As said before, this is just a preparatory patchset in order to
> merge x86 mmap top down code with the generic version.
I just tested your patch series successfully on the parisc
architeture. You may add:
Tested-by: Helge Deller <[email protected]> # parisc
Thanks!
Helge
On 8/26/19 6:37 PM, Helge Deller wrote:
> On 26.08.19 09:34, Alexandre Ghiti wrote:
>> On 6/20/19 7:03 AM, Alexandre Ghiti wrote:
>>> This series fixes the fallback of the top-down mmap: in case of
>>> failure, a bottom-up scheme can be tried as a last resort between
>>> the top-down mmap base and the stack, hoping for a large unused stack
>>> limit.
>>>
>>> Lots of architectures and even mm code start this fallback
>>> at TASK_UNMAPPED_BASE, which is useless since the top-down scheme
>>> already failed on the whole address space: instead, simply use
>>> mmap_base.
>>>
>>> Along the way, it allows to get rid of of mmap_legacy_base and
>>> mmap_compat_legacy_base from mm_struct.
>>>
>>> Note that arm and mips already implement this behaviour.
>>>
>>> Alexandre Ghiti (8):
>>> s390: Start fallback of top-down mmap at mm->mmap_base
>>> sh: Start fallback of top-down mmap at mm->mmap_base
>>> sparc: Start fallback of top-down mmap at mm->mmap_base
>>> x86, hugetlbpage: Start fallback of top-down mmap at mm->mmap_base
>>> mm: Start fallback top-down mmap at mm->mmap_base
>>> parisc: Use mmap_base, not mmap_legacy_base, as low_limit for
>>> bottom-up mmap
>>> x86: Use mmap_*base, not mmap_*legacy_base, as low_limit for
>>> bottom-up
>>> mmap
>>> mm: Remove mmap_legacy_base and mmap_compat_legacy_code fields from
>>> mm_struct
>>>
>>> arch/parisc/kernel/sys_parisc.c | 8 +++-----
>>> arch/s390/mm/mmap.c | 2 +-
>>> arch/sh/mm/mmap.c | 2 +-
>>> arch/sparc/kernel/sys_sparc_64.c | 2 +-
>>> arch/sparc/mm/hugetlbpage.c | 2 +-
>>> arch/x86/include/asm/elf.h | 2 +-
>>> arch/x86/kernel/sys_x86_64.c | 4 ++--
>>> arch/x86/mm/hugetlbpage.c | 7 ++++---
>>> arch/x86/mm/mmap.c | 20 +++++++++-----------
>>> include/linux/mm_types.h | 2 --
>>> mm/debug.c | 4 ++--
>>> mm/mmap.c | 2 +-
>>> 12 files changed, 26 insertions(+), 31 deletions(-)
>>>
>>
>> Any thoughts about that series ? As said before, this is just a
>> preparatory patchset in order to
>> merge x86 mmap top down code with the generic version.
>
> I just tested your patch series successfully on the parisc
> architeture. You may add:
>
> Tested-by: Helge Deller <[email protected]> # parisc
Thanks again Helge !
Alex
>
> Thanks!
> Helge