linux-kernel - Re: [PATCH v3 2/6] exit: hoist get_pid() in release_task() outside of tasklist

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Message-ID: <CAGudoHE4vTUQtSnp01ziqCXVm_qw9sBYnKe2Gbwp6Kz5NOp3Gw@mail.gmail.com>
Date: Mon, 3 Feb 2025 21:22:31 +0100
From: Mateusz Guzik <mjguzik@...il.com>
To: "Liam R. Howlett" <Liam.Howlett@...cle.com>, Mateusz Guzik <mjguzik@...il.com>, ebiederm@...ssion.com, 
	oleg@...hat.com, brauner@...nel.org, akpm@...ux-foundation.org, 
	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/6] exit: hoist get_pid() in release_task() outside of tasklist_lock

On Mon, Feb 3, 2025 at 9:14 PM Liam R. Howlett <Liam.Howlett@...cle.com> wrote:
>
> * Mateusz Guzik <mjguzik@...il.com> [250203 14:36]:
> > On Mon, Feb 3, 2025 at 8:27 PM Liam R. Howlett <Liam.Howlett@...cle.com> wrote:
> > >
> > > * Mateusz Guzik <mjguzik@...il.com> [250201 11:31]:
> > > > Signed-off-by: Mateusz Guzik <mjguzik@...il.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.

if this lands, I presume it is going to go through Andrew who uses
tooling pulling in the cover letter for each commit

but i'm not going to argue this bit, just provide with a commit
message which you think works and I'll use it

-- 
Mateusz Guzik <mjguzik gmail.com>