Re: [PATCH v2] mm: export NR_SHMEM via sysinfo(2) / si_meminfo() interfaces

From: Rik van Riel
Date: Thu Jun 26 2014 - 16:29:14 EST


On 06/26/2014 04:00 PM, Rafael Aquini wrote:
> Historically, we exported shared pages to userspace via sysinfo(2) sharedram
> and /proc/meminfo's "MemShared" fields. With the advent of tmpfs, from kernel
> v2.4 onward, that old way for accounting shared mem was deemed inaccurate and
> we started to export a hard-coded 0 for sysinfo.sharedram. Later on, during
> the 2.6 timeframe, "MemShared" got re-introduced to /proc/meminfo re-branded
> as "Shmem", but we're still reporting sysinfo.sharedmem as that old hard-coded
> zero, which makes the "shared memory" report inconsistent across interfaces.
>
> This patch leverages the addition of explicit accounting for pages used by
> shmem/tmpfs -- "4b02108 mm: oom analysis: add shmem vmstat" -- in order to
> make the users of sysinfo(2) and si_meminfo*() friends aware of that
> vmstat entry and make them report it consistently across the interfaces,
> as well to make sysinfo(2) returned data consistent with our current API
> documentation states.
>
> Signed-off-by: Rafael Aquini <aquini@xxxxxxxxxx>

Acked-by: Rik van Riel <riel@xxxxxxxxxx>
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