From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=82.195.75.108 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794476358; b=faB28sJmK65nB6T/9Bvtc/H6P2FXT/L9OZJxbiKguZ0ZozFE5bZp2OEnYVZRg1X6MTXS AtN+SQoT2vgAYaW2Oz0N1XaMMeW02/60jbhECCAobar2kBNnETFLkWisRM5xeRtrxaAA3 BJsf+x19iARMKobBo58aJlye7UtDmKWLdEplSVXgSZLmsa8z6/ZnXJ/tVf9aE7BTfIZOJ OmFcQrwf83TNO/J6fNltmSCGJuEor1Iat6iVVJDI58pBQVQGzqQiAlfUueAoumMAiELJP mj6Ph9uXk/nlTHMOVKPrHRO423McN6tlyH/iTaMgtNagv4UH9oYRnlaRo2nPJ/MBkbA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794476358; h=DMARC-Filter:DKIM-Signature:Received:Date:From:To:Cc:Subject: Message-ID:References:MIME-Version:Content-Type:Content-Disposition: In-Reply-To:X-Debian-User; bh=1V/SMDgMNpQSJkqUUUeZckTasGGWiAbNEvt6tPJx2mE=; b=2amH5/g4JuEkqfmGFrUbT3YZh4e8JwuHtTmKhZgxydxSjcetLhPcTNxdgddPd4ojtLfh 7YyH9q7iN1nGYFeu7gdZTcES/ZemDtcA830n1aNP/eutXdisK5DlWnj9eHL2xIancKYS2 rR7TG27QTkW/SOrkL2PM9tAwD0Uzcn+v6c2uY1lthVVBgUxF2o6aFaZeuMQ1Y6I3us/Af RjL4rZX3HUBkhszVu1b7dvAKlA4jVIgcDu6MZGxFTj1CGEA8iUh5JiCVrSfLhfQURKgxE MueYtJl2M1JLvfgh3ly7fZenIQ5gt0LVtaZu6dGTIDv+99XoKznrs9xrKE5qhXx2//g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=debian.org; spf=pass smtp.mailfrom=debian.org; dkim=pass header.d=debian.org header.i=@debian.org header.a=rsa-sha256 header.s=smtpauto.stravinsky header.b=GE3es8v0; arc=none smtp.remote-ip=82.195.75.108 Received: from stravinsky.debian.org (stravinsky.debian.org [82.195.75.108]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8E9A2606A31C; Thu, 12 Nov 2026 09:39:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 8E9A2606A31C Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=debian.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=debian.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=debian.org header.i=@debian.org header.a=rsa-sha256 header.s=smtpauto.stravinsky header.b=GE3es8v0 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=debian.org; s=smtpauto.stravinsky; h=X-Debian-User:In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=1V/SMDgMNpQSJkqUUUeZckTasGGWiAbNEvt6tPJx2mE=; b=GE3es8v0zycW9V7xKJI0M6bYys VHuZPzMhUah+Vrnvd5MgB6tJF/kD5V6fKZ/CLLnPkQTq2+y3eK5RB4qAs1Ycq7zBrhFrPBz2IYI8N eFAkFd2JWuMEHpXosf4YSG8KQLpLTL8qdhvNx799ij4oip3NV/hYaX82gwb703YMFw1Y+V1U/f2CX s3v4V/s7a4jAa2PJYhakPYNeoGdRqkRF6HugMbppb67Q1yk3+pSYEIjOk2JuUgCMDZ3nIVAimPAai 1euocP92RsSh0fedn9KW32GO6wam+KyCk88oj8zF++e/WAlQMWmXdJ0hUqeJQ3IS1PlYNwpjFoLvG Gy+1SHfw==; Received: from authenticated-user by stravinsky.debian.org with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1xRRGy-00DruS-2W; Thu, 12 Nov 2026 09:39:12 +0000 Date: Thu, 12 Nov 2026 01:39:08 -0800 From: Breno Leitao To: Song Liu Cc: rcu@vger.kernel.org, paulmck@kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org, david.dai@linux.dev Subject: Re: [PATCH] rcu-tasks: Use pr_debug() for callback contend/collapse messages Message-ID: References: <20261111053551.3367903-1-song@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261111053551.3367903-1-song@kernel.org> X-Debian-User: leitao On Tue, Nov 10, 2026 at 09:35:51PM -0800, Song Liu wrote: > Commit 5de907d24919 ("rcu-tasks: Disable callback contend/collapse > messages by default") added the rcupdate.rcu_task_collapse_debug module > parameter to gate the three pr_info() messages that report RCU Tasks > switching between CPU-0 and per-CPU callback queuing. > > The kernel already has a mechanism for debug-only messages that are off > by default: pr_debug(). Use pr_debug() for these messages, and remove > the rcu_task_collapse_debug module parameter, its documentation, and > its boot-time announcement. > > The messages stay off by default. On CONFIG_DYNAMIC_DEBUG=y kernels, > they can be enabled at boot with: > > dyndbg="file kernel/rcu/tasks.h +p" > > or at runtime with: > > echo 'file kernel/rcu/tasks.h +p' > /proc/dynamic_debug/control > > Assisted-by: Claude:claude-opus-5 > Signed-off-by: Song Liu Tested-by: Breno Leitao