From: Muchun Song <muchun.song@linux.dev>
To: Weilin Tong <tongweilin@linux.alibaba.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Oscar Salvador <osalvador@suse.de>,
David Hildenbrand <david@kernel.org>,
Sidhartha Kumar <sidhartha.kumar@oracle.com>,
Lorenzo Stoakes <ljs@kernel.org>,
Dan Carpenter <error27@gmail.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] ipc/shm: fix RSS accounting for hugetlb shared memory
Date: Wed, 14 Oct 2026 16:23:38 +0800 [thread overview]
Message-ID: <05518093-AA04-4525-96F2-FC7AC327DCDF@linux.dev> (raw)
In-Reply-To: <20261014082218.2236088-1-tongweilin@linux.alibaba.com>
> On Oct 14, 2026, at 16:22, Weilin Tong <tongweilin@linux.alibaba.com> wrote:
>
> Commit a08c7193e4f1 ("mm/filemap: remove hugetlb special casing in
> filemap.c") changed mapping->nrpages to count base pages for hugetlb
> folios. However, shm_add_rss_swap() still multiplies it by
> pages_per_huge_page(), overcounting RSS in both SHM_INFO and
> /proc/sysvipc/shm.
>
> Use mapping->nrpages for RSS accounting across all backing types, and
> account swap only for non-hugetlb shmem. Use READ_ONCE() for both counters
> instead of info->lock, which does not protect nrpages and cannot provide
> a consistent snapshot.
>
> Fixes: a08c7193e4f1 ("mm/filemap: remove hugetlb special casing in filemap.c")
> Suggested-by: Muchun Song <muchun.song@linux.dev>
> Signed-off-by: Weilin Tong <tongweilin@linux.alibaba.com>
Acked-by: Muchun Song <muchun.song@linux.dev>
Thanks.
prev parent reply other threads:[~2026-10-14 8:24 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-14 8:22 [PATCH v2] ipc/shm: fix RSS accounting for hugetlb shared memory Weilin Tong
2026-10-14 8:23 ` Muchun Song [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=05518093-AA04-4525-96F2-FC7AC327DCDF@linux.dev \
--to=muchun.song@linux.dev \
--cc=akpm@linux-foundation.org \
--cc=baolin.wang@linux.alibaba.com \
--cc=david@kernel.org \
--cc=error27@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=ljs@kernel.org \
--cc=osalvador@suse.de \
--cc=sidhartha.kumar@oracle.com \
--cc=tongweilin@linux.alibaba.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox