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SubjectRe: [PATCH RESEND 0/8] Fix mmap base in bottom-up mmap
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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

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