From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Suren Baghdasaryan <surenb@google.com>, akpm@linux-foundation.org
Cc: liam@infradead.org, ljs@kernel.org, vbabka@kernel.org,
willy@infradead.org, jannh@google.com, paulmck@kernel.org,
pfalcato@suse.de, shuah@kernel.org, hsukrut3@gmail.com,
richard.weiyang@gmail.com, reddybalavignesh9979@gmail.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v2 0/3] use vma locks for proc/pid/{smaps|numa_maps} reads
Date: Tue, 12 May 2026 11:28:20 +0200 [thread overview]
Message-ID: <a27344e1-6f0c-4686-99ac-fc2cfcc5bb06@kernel.org> (raw)
In-Reply-To: <20260426062718.1238437-1-surenb@google.com>
On 4/26/26 08:27, Suren Baghdasaryan wrote:
> Use per-vma locks when reading /proc/pid/smaps and /proc/pid/numa_maps
> similar to /proc/pid/maps to reduce contention on central mmap_lock. One
> major difference between maps and smaps/numa_maps reading is that the
> latter executes page table walk which can't be done under RCU due to a
> possibility of sleeping. Therefore we drop RCU read lock before this walk
> while keeping the VMA locked. After the walk we retake RCU read lock,
> reset VMA iterator and proceed with the next VMA.
With many small VMAs, is that overhead noticable?
--
Cheers,
David
prev parent reply other threads:[~2026-05-12 9:28 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-26 6:27 [PATCH v2 0/3] use vma locks for proc/pid/{smaps|numa_maps} reads Suren Baghdasaryan
2026-04-26 6:27 ` [PATCH v2 1/3] fs/proc/task_mmu: read proc/pid/{smaps|numa_maps} under per-vma lock Suren Baghdasaryan
2026-04-26 6:27 ` [PATCH v2 2/3] selftests/proc: ensure the test is performed at the right page boundary Suren Baghdasaryan
2026-04-26 6:27 ` [PATCH v2 3/3] selftests/proc: add /proc/pid/smaps tearing tests Suren Baghdasaryan
2026-04-26 19:59 ` [PATCH v2 0/3] use vma locks for proc/pid/{smaps|numa_maps} reads Andrew Morton
2026-05-12 9:28 ` David Hildenbrand (Arm) [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=a27344e1-6f0c-4686-99ac-fc2cfcc5bb06@kernel.org \
--to=david@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=hsukrut3@gmail.com \
--cc=jannh@google.com \
--cc=liam@infradead.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=ljs@kernel.org \
--cc=paulmck@kernel.org \
--cc=pfalcato@suse.de \
--cc=reddybalavignesh9979@gmail.com \
--cc=richard.weiyang@gmail.com \
--cc=shuah@kernel.org \
--cc=surenb@google.com \
--cc=vbabka@kernel.org \
--cc=willy@infradead.org \
/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