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 5E19530B507 for ; Fri, 5 Sep 2025 17:24:13 +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=1757093053; cv=none; b=BCITklEr+2s6RvZJm/GR/rYafiI67KOFV4pqOG1Y/2hGyoLtWEJ/hGEl0q3ZkT/Jhf6vOzrlyMLQoYerOP/qRRWFOJ3ioxfxcTYNc94RRR+G8WsynAY0hTmhMFcvvEM2I3Zk+wnDBkyjl0mEw8WzzQK8LmOQqh/XrSmytIuvaFU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757093053; c=relaxed/simple; bh=LFG9QiUgt+ymXhzv0BXKuROD54gJ69W+WTz6Ff6/l9c=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=PeKe00lSWd167XFnDc7/bQMV/84xOc8ogfzpL/bi9lIufGFz2jybaWAxN9BjggI6dL4Y8zL2UZXGYvDdvOQPTzqmSHGfXRn7W7WHemm/F0bZ+V+AncPSOnOTvN9NmlOUeBlZ6QPiUXn8nDoyA4w0m5hNVKwA7zBoB52gYbskwgY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TB2V6XtT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TB2V6XtT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F0E2FC4CEF1; Fri, 5 Sep 2025 17:24:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757093053; bh=LFG9QiUgt+ymXhzv0BXKuROD54gJ69W+WTz6Ff6/l9c=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=TB2V6XtTFbXI258LPJiV/9grht+No8/4SHhq8vW9pC17kKUKooZOfRV2WlYR2fnDU W0wx15ljj9PY8Okh3wEk4+aZlcEFy+gCRczaNx6iZNSz9T7mxb+JMoAnFdyfughAaV 1DYCljowQR0N4/YMcQIvPhJ2lndvGweXWWIqBao8yBdywL560sEPExg/pPbPIreC7w zmQ7StW63vOC8BQbdQi7ejrZMW0CJDQcz/8qNWbHjUx4DRGaypBXtQrMVdGaNPgpW/ tVR+gU6PRL7BCVK+YXrEwkfPLRIejl4S70h2suwDAnAoTf1tdkRHen0CBeVmyqNW8J XOO+JzF5i6GqA== Date: Fri, 5 Sep 2025 07:24:11 -1000 From: Tejun Heo To: Marco Crivellari Cc: linux-kernel@vger.kernel.org, Lai Jiangshan , Frederic Weisbecker , Sebastian Andrzej Siewior , Michal Hocko Subject: Re: [PATCH 2/3] workqueue: replace use of system_wq with system_percpu_wq Message-ID: References: <20250905091325.112168-1-marco.crivellari@suse.com> <20250905091325.112168-3-marco.crivellari@suse.com> 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=us-ascii Content-Disposition: inline In-Reply-To: <20250905091325.112168-3-marco.crivellari@suse.com> On Fri, Sep 05, 2025 at 11:13:24AM +0200, Marco Crivellari wrote: > Currently if a user enqueue a work item using schedule_delayed_work() the > used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use > WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to > schedule_work() that is using system_wq and queue_work(), that makes use > again of WORK_CPU_UNBOUND. > > This lack of consistentcy cannot be addressed without refactoring the API. > > system_wq is a per-CPU worqueue, yet nothing in its name tells about that > CPU affinity constraint, which is very often not required by users. Make > it clear by adding a system_percpu_wq. > > queue_work() / queue_delayed_work() mod_delayed_work() will now use the > new per-cpu wq: whether the user still stick on the old name a warn will > be printed along a wq redirect to the new one. > > This patch add the new system_percpu_wq except for mm, fs and net > subsystem, whom are handled in separated patches. > > The old wq will be kept for a few release cylces. > > Suggested-by: Tejun Heo > Signed-off-by: Marco Crivellari Applied 1-2 to wq/for-6.18. Thanks. -- tejun