From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) (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 F21AD3019B1; Wed, 10 Dec 2025 08:10:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.251.105.195 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765354226; cv=none; b=kVe1KLU9+a3ePlWQyT4KvXEcrlMhuZ4Y4+umdyNeqOqQKvPFaEPbUUAQkFnl3ls8kO3wbNK5Y6uDXEXotLAuNDYMhxVUHirEs2P4gKBAVS44qumAYrTcujYlDzK/ayV1gVdbDj2yhU2MM2nvocauy8Y6LwTlObbqjg2bgsYzsz0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765354226; c=relaxed/simple; bh=hAQnAi/fXsMW1KyzUEUN13mP8zTSDNw3Zz+EQGCHeQU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=CNL10H+EgfeAhgGxnropvuF7/ZmqSPUThwcVGvGiib0bXPb/3Vtf4gTE1kUKywmwtO5opfLZZj0WXkrspw2aCM9AH2XR0Qk6JYGB41axG7zQ1LpPJ9BKArbAGPybKGXny70kX7m551Mb7qIZAlo5PFLQX+TFV9+dTZkbnY8+l40= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=g7io0Wfb; arc=none smtp.client-ip=148.251.105.195 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="g7io0Wfb" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1765354222; bh=hAQnAi/fXsMW1KyzUEUN13mP8zTSDNw3Zz+EQGCHeQU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=g7io0WfbYA7eXtAQztLl/y1SkRerM9o+T15i4KdR9PMoPoxwUH+vKqTVTWhWN96so P6Wwb9Doam0XT6o3ft8aFw4syl0vsQrFF5QXUg0PEoizysDsYHawC/B7J3qy39J+kC 3gi/B3gifC/+cF1zZz6Ouzgv1+c1jEupzMtDazFt87sZTQ7+aOxSl768943G6SJmWP n9gKrT18/rpqa4r5TtEtmU5elBpQr/wGqjmPfVTIqd4FwaFzlfPBUmHAjH2YYlE1De RaN9RSXCQt6Xa339IroW/u91wnoQLqYUvjtKRWuyLbzcFpgqQATieAujFlfc+2DRU5 iJKVJctxVPyPQ== Received: from [192.168.1.100] (2-237-20-237.ip236.fastwebnet.it [2.237.20.237]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: kholk11) by bali.collaboradmins.com (Postfix) with ESMTPSA id 823E917E1122; Wed, 10 Dec 2025 09:10:21 +0100 (CET) Message-ID: <17d99a64-8648-4fbc-9b7c-581f882d02a1@collabora.com> Date: Wed, 10 Dec 2025 09:10:20 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] media: platform: mtk-mdp3: add WQ_PERCPU to alloc_workqueue users To: Marco Crivellari , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org Cc: Tejun Heo , Lai Jiangshan , Frederic Weisbecker , Sebastian Andrzej Siewior , Michal Hocko , Mauro Carvalho Chehab , Matthias Brugger References: <20251107141303.223254-1-marco.crivellari@suse.com> From: AngeloGioacchino Del Regno Content-Language: en-US In-Reply-To: <20251107141303.223254-1-marco.crivellari@suse.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Il 07/11/25 15:13, Marco Crivellari ha scritto: > Currently if a user enqueues 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 consistency cannot be addressed without refactoring the API. > > alloc_workqueue() treats all queues as per-CPU by default, while unbound > workqueues must opt-in via WQ_UNBOUND. > > This default is suboptimal: most workloads benefit from unbound queues, > allowing the scheduler to place worker threads where they’re needed and > reducing noise when CPUs are isolated. > > This continues the effort to refactor workqueue APIs, which began with > the introduction of new workqueues and a new alloc_workqueue flag in: > > commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq") > commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag") > > This change adds a new WQ_PERCPU flag to explicitly request > alloc_workqueue() to be per-cpu when WQ_UNBOUND has not been specified. > > With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND), > any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND > must now use WQ_PERCPU. > > Once migration is complete, WQ_UNBOUND can be removed and unbound will > become the implicit default. > > Suggested-by: Tejun Heo > Signed-off-by: Marco Crivellari Reviewed-by: AngeloGioacchino Del Regno > --- > drivers/media/platform/mediatek/mdp3/mtk-mdp3-core.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/media/platform/mediatek/mdp3/mtk-mdp3-core.c b/drivers/media/platform/mediatek/mdp3/mtk-mdp3-core.c > index 6559d72d5d42..9083367ae2e4 100644 > --- a/drivers/media/platform/mediatek/mdp3/mtk-mdp3-core.c > +++ b/drivers/media/platform/mediatek/mdp3/mtk-mdp3-core.c > @@ -255,14 +255,16 @@ static int mdp_probe(struct platform_device *pdev) > goto err_free_mutex; > } > > - mdp->job_wq = alloc_workqueue(MDP_MODULE_NAME, WQ_FREEZABLE, 0); > + mdp->job_wq = alloc_workqueue(MDP_MODULE_NAME, > + WQ_FREEZABLE | WQ_PERCPU, 0); > if (!mdp->job_wq) { > dev_err(dev, "Unable to create job workqueue\n"); > ret = -ENOMEM; > goto err_deinit_comp; > } > > - mdp->clock_wq = alloc_workqueue(MDP_MODULE_NAME "-clock", WQ_FREEZABLE, > + mdp->clock_wq = alloc_workqueue(MDP_MODULE_NAME "-clock", > + WQ_FREEZABLE | WQ_PERCPU, > 0); > if (!mdp->clock_wq) { > dev_err(dev, "Unable to create clock workqueue\n");