From: Paul Walmsley <paul.walmsley@sifive.com>
To: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Albert Ou <aou@eecs.berkeley.edu>,
Kees Cook <keescook@chromium.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Palmer Dabbelt <palmer@sifive.com>,
Will Deacon <will.deacon@arm.com>,
Russell King <linux@armlinux.org.uk>,
Ralf Baechle <ralf@linux-mips.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Luis Chamberlain <mcgrof@kernel.org>,
Paul Burton <paul.burton@mips.com>,
James Hogan <jhogan@kernel.org>,
linux-fsdevel@vger.kernel.org, linux-riscv@lists.infradead.org,
linux-mips@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
linux-arm-kernel@lists.infradead.org,
Alexander Viro <viro@zeniv.linux.org.uk>
Subject: Re: [PATCH v5 14/14] riscv: Make mmap allocation top-down by default
Date: Wed, 31 Jul 2019 15:40:35 -0700 (PDT) [thread overview]
Message-ID: <alpine.DEB.2.21.9999.1907311538460.22372@viisi.sifive.com> (raw)
In-Reply-To: <20190730055113.23635-15-alex@ghiti.fr>
On Tue, 30 Jul 2019, Alexandre Ghiti wrote:
> In order to avoid wasting user address space by using bottom-up mmap
> allocation scheme, prefer top-down scheme when possible.
>
> Before:
> root@qemuriscv64:~# cat /proc/self/maps
> 00010000-00016000 r-xp 00000000 fe:00 6389 /bin/cat.coreutils
> 00016000-00017000 r--p 00005000 fe:00 6389 /bin/cat.coreutils
> 00017000-00018000 rw-p 00006000 fe:00 6389 /bin/cat.coreutils
> 00018000-00039000 rw-p 00000000 00:00 0 [heap]
> 1555556000-155556d000 r-xp 00000000 fe:00 7193 /lib/ld-2.28.so
> 155556d000-155556e000 r--p 00016000 fe:00 7193 /lib/ld-2.28.so
> 155556e000-155556f000 rw-p 00017000 fe:00 7193 /lib/ld-2.28.so
> 155556f000-1555570000 rw-p 00000000 00:00 0
> 1555570000-1555572000 r-xp 00000000 00:00 0 [vdso]
> 1555574000-1555576000 rw-p 00000000 00:00 0
> 1555576000-1555674000 r-xp 00000000 fe:00 7187 /lib/libc-2.28.so
> 1555674000-1555678000 r--p 000fd000 fe:00 7187 /lib/libc-2.28.so
> 1555678000-155567a000 rw-p 00101000 fe:00 7187 /lib/libc-2.28.so
> 155567a000-15556a0000 rw-p 00000000 00:00 0
> 3fffb90000-3fffbb1000 rw-p 00000000 00:00 0 [stack]
>
> After:
> root@qemuriscv64:~# cat /proc/self/maps
> 00010000-00016000 r-xp 00000000 fe:00 6389 /bin/cat.coreutils
> 00016000-00017000 r--p 00005000 fe:00 6389 /bin/cat.coreutils
> 00017000-00018000 rw-p 00006000 fe:00 6389 /bin/cat.coreutils
> 2de81000-2dea2000 rw-p 00000000 00:00 0 [heap]
> 3ff7eb6000-3ff7ed8000 rw-p 00000000 00:00 0
> 3ff7ed8000-3ff7fd6000 r-xp 00000000 fe:00 7187 /lib/libc-2.28.so
> 3ff7fd6000-3ff7fda000 r--p 000fd000 fe:00 7187 /lib/libc-2.28.so
> 3ff7fda000-3ff7fdc000 rw-p 00101000 fe:00 7187 /lib/libc-2.28.so
> 3ff7fdc000-3ff7fe2000 rw-p 00000000 00:00 0
> 3ff7fe4000-3ff7fe6000 r-xp 00000000 00:00 0 [vdso]
> 3ff7fe6000-3ff7ffd000 r-xp 00000000 fe:00 7193 /lib/ld-2.28.so
> 3ff7ffd000-3ff7ffe000 r--p 00016000 fe:00 7193 /lib/ld-2.28.so
> 3ff7ffe000-3ff7fff000 rw-p 00017000 fe:00 7193 /lib/ld-2.28.so
> 3ff7fff000-3ff8000000 rw-p 00000000 00:00 0
> 3fff888000-3fff8a9000 rw-p 00000000 00:00 0 [stack]
>
> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Acked-by: Paul Walmsley <paul.walmsley@sifive.com> # for arch/riscv
As Alex notes, this patch depends on "[PATCH] riscv: kbuild: add virtual
memory system selection":
https://lore.kernel.org/linux-riscv/alpine.DEB.2.21.9999.1907301218560.3486@viisi.sifive.com/T/#t
which will likely go up during v5.3-rc.
- Paul
prev parent reply other threads:[~2019-07-31 22:40 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-30 5:50 [PATCH v5 00/14] Provide generic top-down mmap layout functions Alexandre Ghiti
2019-07-30 5:51 ` [PATCH v5 01/14] mm, fs: Move randomize_stack_top from fs to mm Alexandre Ghiti
2019-07-30 5:51 ` [PATCH v5 02/14] arm64: Make use of is_compat_task instead of hardcoding this test Alexandre Ghiti
2019-07-30 5:51 ` [PATCH v5 03/14] arm64: Consider stack randomization for mmap base only when necessary Alexandre Ghiti
2019-07-30 5:51 ` [PATCH v5 04/14] arm64, mm: Move generic mmap layout functions to mm Alexandre Ghiti
2019-07-30 5:51 ` [PATCH v5 05/14] arm64, mm: Make randomization selected by generic topdown mmap layout Alexandre Ghiti
2019-07-30 5:51 ` [PATCH v5 07/14] arm: Use STACK_TOP when computing mmap base address Alexandre Ghiti
2019-07-30 5:51 ` [PATCH v5 08/14] arm: Use generic mmap top-down layout and brk randomization Alexandre Ghiti
2019-07-30 5:51 ` [PATCH v5 10/14] mips: Use STACK_TOP when computing mmap base address Alexandre Ghiti
2019-07-30 5:51 ` [PATCH v5 11/14] mips: Adjust brk randomization offset to fit generic version Alexandre Ghiti
2019-07-30 5:51 ` [PATCH v5 12/14] mips: Replace arch specific way to determine 32bit task with " Alexandre Ghiti
2019-07-30 5:51 ` [PATCH v5 13/14] mips: Use generic mmap top-down layout and brk randomization Alexandre Ghiti
2019-07-30 5:51 ` [PATCH v5 14/14] riscv: Make mmap allocation top-down by default Alexandre Ghiti
2019-07-31 6:05 ` Alex Ghiti
2019-07-31 17:33 ` Guenter Roeck
2019-07-31 22:40 ` Paul Walmsley [this message]
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