From: Mateusz Guzik <mjguzik@gmail.com>
To: "Liam R. Howlett" <Liam.Howlett@oracle.com>,
Mateusz Guzik <mjguzik@gmail.com>,
ebiederm@xmission.com, oleg@redhat.com, brauner@kernel.org,
akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/6] exit: hoist get_pid() in release_task() outside of tasklist_lock
Date: Mon, 3 Feb 2025 20:35:47 +0100 [thread overview]
Message-ID: <CAGudoHGXR-vnYm-wMs5c8EE448UeuEps3ecrf_g22Mw=9oQtLQ@mail.gmail.com> (raw)
In-Reply-To: <eqoac7dyanvez62nc5ge3lfxxxbjcln3k6nrz4tkrg67v55sdb@sosx2sguy5f6>
On Mon, Feb 3, 2025 at 8:27 PM Liam R. Howlett <Liam.Howlett@oracle.com> wrote:
>
> * Mateusz Guzik <mjguzik@gmail.com> [250201 11:31]:
> > Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
>
> Change log is a bit sparse? I get that the subject spells out what is
> done, but anything to say here at all? Reduces lock contention by
> reducing lock time or something? Maybe even some numbers you have in
> the cover letter?
>
I did not measure this bit *specifically*.
As one can expect get_pid issues an atomic and that's slow. And since
it can happen *prior* to taking the global lock it seems like an
obvious little nit to sort out.
I would argue the change is self-explanatory given the cover-letter.
--
Mateusz Guzik <mjguzik gmail.com>
next prev parent reply other threads:[~2025-02-03 19:36 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-01 16:31 [PATCH v3 0/6] reduce tasklist_lock hold time on exit and do some Mateusz Guzik
2025-02-01 16:31 ` [PATCH v3 1/6] exit: perform add_device_randomness() without tasklist_lock Mateusz Guzik
2025-02-03 17:51 ` Oleg Nesterov
2025-02-03 17:55 ` Mateusz Guzik
2025-02-01 16:31 ` [PATCH v3 2/6] exit: hoist get_pid() in release_task() outside of tasklist_lock Mateusz Guzik
2025-02-03 19:27 ` Liam R. Howlett
2025-02-03 19:35 ` Mateusz Guzik [this message]
2025-02-03 20:13 ` Liam R. Howlett
2025-02-03 20:22 ` Mateusz Guzik
2025-02-03 20:28 ` Liam R. Howlett
2025-02-04 1:51 ` Andrew Morton
2025-02-01 16:31 ` [PATCH v3 3/6] exit: postpone tty_kref_put() until after tasklist_lock is dropped Mateusz Guzik
2025-02-03 18:06 ` Oleg Nesterov
2025-02-03 19:33 ` Mateusz Guzik
2025-02-04 11:22 ` Oleg Nesterov
2025-02-04 12:12 ` Mateusz Guzik
2025-02-01 16:31 ` [PATCH v3 4/6] pid: sprinkle tasklist_lock asserts Mateusz Guzik
2025-02-01 16:31 ` [PATCH v3 5/6] pid: perform free_pid() calls outside of tasklist_lock Mateusz Guzik
2025-02-03 18:49 ` Oleg Nesterov
2025-02-03 19:31 ` Mateusz Guzik
2025-02-03 20:02 ` Oleg Nesterov
2025-02-01 16:31 ` [PATCH v3 6/6] pid: drop irq disablement around pidmap_lock Mateusz Guzik
2025-02-01 17:42 ` Oleg Nesterov
2025-02-01 17:45 ` Oleg Nesterov
2025-02-01 18:19 ` David Laight
2025-02-01 18:42 ` Mateusz Guzik
2025-02-01 21:51 ` David Laight
2025-02-01 22:00 ` Matthew Wilcox
2025-02-02 13:55 ` David Laight
2025-02-02 19:34 ` Mateusz Guzik
2025-02-02 20:44 ` David Laight
2025-02-02 22:06 ` Matthew Wilcox
2025-02-03 17:47 ` [PATCH v3 0/6] reduce tasklist_lock hold time on exit and do some Oleg Nesterov
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='CAGudoHGXR-vnYm-wMs5c8EE448UeuEps3ecrf_g22Mw=9oQtLQ@mail.gmail.com' \
--to=mjguzik@gmail.com \
--cc=Liam.Howlett@oracle.com \
--cc=akpm@linux-foundation.org \
--cc=brauner@kernel.org \
--cc=ebiederm@xmission.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=oleg@redhat.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