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Mon, 03 Feb 2025 12:22:42 -0800 (PST) MIME-Version: 1.0 References: <20250201163106.28912-1-mjguzik@gmail.com> <20250201163106.28912-3-mjguzik@gmail.com> <2f3gjvg6zwp2xpkhb2e36ux2resnjdtxuinbbgnr57jdqesrm6@oau2dgx63fxy> In-Reply-To: <2f3gjvg6zwp2xpkhb2e36ux2resnjdtxuinbbgnr57jdqesrm6@oau2dgx63fxy> From: Mateusz Guzik Date: Mon, 3 Feb 2025 21:22:31 +0100 X-Gm-Features: AWEUYZlDF3XmDOIROq3wg-O1e8hHx6MTDVWUZYbjsd8zw3fJogSdvfceFOqPckg Message-ID: Subject: Re: [PATCH v3 2/6] exit: hoist get_pid() in release_task() outside of tasklist_lock To: "Liam R. Howlett" , Mateusz Guzik , ebiederm@xmission.com, oleg@redhat.com, brauner@kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 7C083180007 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: 1k85bxzh6seczqhx7dbrye1su91fu3n9 X-HE-Tag: 1738614164-838655 X-HE-Meta: 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 OwI22MYM k436iviw4uzR3gS1ua746jzBGj7LZd4hBHoW/9wn8Qhtyh3AuVNuRyH03WSFRJDSXuMYnDBsd4xQEWOCa6DxR6dQUF6/pNFMlPF4CT/PfXLYyTmH48HrYMTgxk81RD28Bqu5BtDP9AYd+lmqcwDOZopZX/iCE/msvi9IR0s+6rraPBNUBskl+dPqk2pxKUPj3gyB/iXQu3PBRnLlGy0PdvmI1DtA1rp/tFRFjhor8gIHIybeVB8Pc1aoAkn09a0H+0CIuWVxLsNjahfiPR0kBUr35fyUoDWdghOVV5Xl5zKZua6eGdERGmqW653rNOceCHFcJEN6DqMgCK6cWODXgW0l6ASggaW41qdhdWUGac0uu0XYDX5sVWborZLYyy61xsFxFuBfd8ylaDzRFf22OYfEq1b+1suIIZEfa X-Bogosity: Ham, tests=bogofilter, spamicity=0.014721, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Feb 3, 2025 at 9:14=E2=80=AFPM Liam R. Howlett wrote: > > * Mateusz Guzik [250203 14:36]: > > On Mon, Feb 3, 2025 at 8:27=E2=80=AFPM Liam R. Howlett wrote: > > > > > > * Mateusz Guzik [250201 11:31]: > > > > Signed-off-by: Mateusz Guzik > > > > > > Change log is a bit sparse? I get that the subject spells out what i= s > > > 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 --=20 Mateusz Guzik