From: "Liam R. Howlett" <Liam.Howlett@oracle.com>
To: Mateusz Guzik <mjguzik@gmail.com>
Cc: 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 15:13:39 -0500 [thread overview]
Message-ID: <2f3gjvg6zwp2xpkhb2e36ux2resnjdtxuinbbgnr57jdqesrm6@oau2dgx63fxy> (raw)
In-Reply-To: <CAGudoHGXR-vnYm-wMs5c8EE448UeuEps3ecrf_g22Mw=9oQtLQ@mail.gmail.com>
* Mateusz Guzik <mjguzik@gmail.com> [250203 14:36]:
> 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.
But when you git blame on the file, you will not see that cover letter.
>
> --
> Mateusz Guzik <mjguzik gmail.com>
next prev parent reply other threads:[~2025-02-03 20:14 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
2025-02-03 20:13 ` Liam R. Howlett [this message]
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
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