From: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
To: Jann Horn <jannh@google.com>
Cc: mtk.manpages@gmail.com, linux-man <linux-man@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
Mark Mossberg <mark.mossberg@gmail.com>
Subject: Re: [PATCH] proc.5: Document inaccurate RSS due to SPLIT_RSS_COUNTING
Date: Tue, 27 Oct 2020 08:05:32 +0100 [thread overview]
Message-ID: <0a090c14-6b70-4284-bb2d-4fbfd1146aaf@gmail.com> (raw)
In-Reply-To: <CAG48ez17=x9eHLGR-Uyx3xsVJv3W=4WsTs3HG5Fam5UP=CWXbQ@mail.gmail.com>
Hi Jann,
On 10/12/20 4:52 PM, Jann Horn wrote:
> On Mon, Oct 12, 2020 at 1:49 PM Jann Horn <jannh@google.com> wrote:
>> Since 34e55232e59f7b19050267a05ff1226e5cd122a5 (introduced back in
>> v2.6.34), Linux uses per-thread RSS counters to reduce cache contention on
>> the per-mm counters. With a 4K page size, that means that you can end up
>> with the counters off by up to 252KiB per thread.
>
> Actually, as Mark Mossberg pointed out to me off-thread, the counters
> can actually be off by many times more...
So, does your patch to proc.5 need tweaking, or can I just apply as is?
Thanks,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
next prev parent reply other threads:[~2020-10-27 7:05 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-12 11:49 [PATCH] proc.5: Document inaccurate RSS due to SPLIT_RSS_COUNTING Jann Horn
2020-10-12 14:52 ` Jann Horn
2020-10-27 7:05 ` Michael Kerrisk (man-pages) [this message]
2020-10-27 10:35 ` Jann Horn
2020-10-27 12:18 ` Michal Hocko
2020-10-27 13:49 ` Michal Hocko
2020-10-27 13:49 ` Michael Kerrisk (man-pages)
2020-10-12 15:07 ` Michal Hocko
2020-10-12 15:20 ` Jann Horn
2020-10-12 15:33 ` Michal Hocko
2020-10-27 18:56 ` Vlastimil Babka
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