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Message-ID: <175168c1-d25f-7a93-e19b-dbb6ae6289e1@ghiti.fr>
Date: Tue, 30 Jul 2019 08:12:20 +0200
From: Alexandre Ghiti <alex@...ti.fr>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: "James E . J . Bottomley" <James.Bottomley@...senPartnership.com>,
Helge Deller <deller@....de>,
Heiko Carstens <heiko.carstens@...ibm.com>,
Vasily Gorbik <gor@...ux.ibm.com>,
Christian Borntraeger <borntraeger@...ibm.com>,
Yoshinori Sato <ysato@...rs.sourceforge.jp>,
Rich Felker <dalias@...c.org>,
"David S . Miller" <davem@...emloft.net>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
"H . Peter Anvin" <hpa@...or.com>, x86@...nel.org,
Dave Hansen <dave.hansen@...ux.intel.com>,
Andy Lutomirski <luto@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
linux-parisc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-s390@...r.kernel.org, linux-sh@...r.kernel.org,
sparclinux@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH RESEND 0/8] Fix mmap base in bottom-up mmap
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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