From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DB7FA25A640 for ; Tue, 4 Feb 2025 01:51:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738633890; cv=none; b=A0UGq3mgk1RiSXJ80GZa3fVBrb5cDufNdrato/qVwp2WNdgL2JSdB0YKjqd50XzAoHVPnfmY2/uDo2ZqaRxA/z1zV7UsMQQ5IsKgdAAoDhyLfDLiJvvLeJhXY6QI5XWWjignbUTo1pOlCaAlpVYiSMAerJYX/0762D6CGwZxOkQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738633890; c=relaxed/simple; bh=Qv8I10e6NzpV/XOLKMWGOAmu84bftLnx0mtmOcpehJo=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=r4n1HhLVgCjN4xEvvggBoDP8AEcrsSACphxZYuI2Y1fR1lmhNs50bLwfzFjw9KZNF5yfL8EuKRWZcLrlxZkwLUEtj+MjLDu9tZ6Z+uRF4gVed7im4VhiQ3Ociim92ycRYnBcvPO9/yT9mcl+x9x5V7xNFlSDKnbTuGVdpayTZJ0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=G2Tu4S9P; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="G2Tu4S9P" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EB2BDC4CEE0; Tue, 4 Feb 2025 01:51:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1738633889; bh=Qv8I10e6NzpV/XOLKMWGOAmu84bftLnx0mtmOcpehJo=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=G2Tu4S9PDsRV1y2QSs0A47NdpX2OyQCk10H29Jlp/tb1fOtX8Pe8HexFJWHSSyPK/ k33Iz/CbX8bXfQ011Ta/G3HgNwFLuf5U1f2r5DvFDdJixxBtFvagX5EgY2pPn05158 gInq7+3iBgMMSAF9rXrfwfFPv6/8pVuy2cLp4oYI= Date: Mon, 3 Feb 2025 17:51:28 -0800 From: Andrew Morton To: Mateusz Guzik Cc: "Liam R. Howlett" , ebiederm@xmission.com, oleg@redhat.com, brauner@kernel.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 Message-Id: <20250203175128.80319b42c9739f0d420080a4@linux-foundation.org> In-Reply-To: References: <20250201163106.28912-1-mjguzik@gmail.com> <20250201163106.28912-3-mjguzik@gmail.com> <2f3gjvg6zwp2xpkhb2e36ux2resnjdtxuinbbgnr57jdqesrm6@oau2dgx63fxy> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On Mon, 3 Feb 2025 21:22:31 +0100 Mateusz Guzik wrote: > On Mon, Feb 3, 2025 at 9:14 PM Liam R. Howlett wrote: > > > > * Mateusz Guzik [250203 14:36]: > > > On Mon, Feb 3, 2025 at 8:27 PM 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. > > > > 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 No, I copy the [0/n] description into the [1/n] changelog only. > but i'm not going to argue this bit, just provide with a commit > message which you think works and I'll use it It's rather irregular to ask Liam to explain your patch! The Subject: describes what the patch does (which was obvious from the code anyway) but the changelog fails to explain *why* the change was made. You've explained "why" adequately within this discussion so I suggest you condense those words into this patch's changelog. General muse: if a reviewer asks questions regarding a patch then we should treat those questions as bug reports against the changelogs and code comments: required information is missing. So please let's go through reviewer questions as we prepare the next revision of a patchset and make sure that all those questions are fully answered,