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Mon, 03 Feb 2025 11:35:59 -0800 (PST) MIME-Version: 1.0 References: <20250201163106.28912-1-mjguzik@gmail.com> <20250201163106.28912-3-mjguzik@gmail.com> In-Reply-To: From: Mateusz Guzik Date: Mon, 3 Feb 2025 20:35:47 +0100 X-Gm-Features: AWEUYZlN5FLN86dLDxhRIFZLTCtjwPj4wT1oi8RLc3hX9V9tMRTeDz0lWOGiJt4 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-Server: rspam02 X-Rspamd-Queue-Id: 33A911A0006 X-Stat-Signature: usgfo4rayquoq6i6outkhrgtu1b6re1u X-Rspam-User: X-HE-Tag: 1738611360-3681 X-HE-Meta: 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 a/FoJ0Jy BdB+Cp9q2VR9MIqyUK8iH+gG43mOghBMGst25DSI0SVDYDD8re1z61jWtMyIyYQtMcSy5Z69aBl0j3OmBUOsvIjy11OysjqT5Zdp4Vh5T4k9AmSPCAReAeRhJdsN6vIKE5x6OPomcWUSjMdnY3ip93LSYEToQPiAZ59hrpDvzzPRPQ9gZsDOrK4k8ojxJfaGNJ2tjzgKovLJ228SKOTB+ztE5w6oZK8SqE7XwTHYg1SMfZBbc24aGptv0Nv+RpZLCa0UvnaSQjhvLQKf+htmNxF7yfRdS/WGD53R5RBLathzFkb13PY7pdF9TQhmKZ4KVuAZtAmW//GpA1iclfwvv0xZWmFgpZSvkuGH8DMx0oERKWZAOPNXs3kw+q37NeiOW8KZwsVwSLEBiI3r9mJV9/TT0ZX25ND9pI+oZ X-Bogosity: Ham, tests=bogofilter, spamicity=0.098912, 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 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 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. --=20 Mateusz Guzik