From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 58DC5495037; Wed, 23 Sep 2026 18:59:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790189958; cv=none; b=kzX1oJRg2dmAd0L5iy72b1DPKoJH++9JZ5XpoISCrw7KHtN9tbshphU53D1+F+zQlDkVQg3BXsX3oLkgoXQnzg6NgWUXVgt7c7NR8nsY8Vyfv09uiedWmhc7l6UNWSH3gZABHbSNQXwtA7CNJ90/gITqOVOIuy4rZ32KKvY5nmE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790189958; c=relaxed/simple; bh=YnzNba1uuRhllBwFJYI8SdVTn2LoAWh2vPE0KLyn/xg=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References; b=ZmZLqnh/FNRrmJ5u6zEouWzilANyUdRGW3E3eDHmYiL9ojVtsu5noaiIWC+pkov47hHNmLUzR83YMpKKdguu8BygsU7t9JCV4C+ZDQ/974h6I8fUsrQP40oSMLqlVxsh4J3Xrj9R5CX7ubF8qe30X95MXzvSrgjYw5nGvYNLzcM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JRx1BQmd; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="JRx1BQmd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C21931F000FF; Wed, 23 Sep 2026 18:59:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790189956; bh=/NeSA8DVk2ilaVt7KJ+BPCe9UE1my0uOPhiixkwDHNc=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=JRx1BQmdnRvG0noJzX/iqrNQtgNaV7TdzUfIlImfzU4t9v7DWWRrtw6J9qVgmmmlU nhk54zDQi8dN7eaYbNkBzWvW9KBW9hx7nxgGNdIBbMGVPyFk9rUhtsYzSCgNsDjX+r wEZa8JU7VjJqfVmRVM/sS6ZOhl4s5fpLQskOUNmsX3E1d3oi+AIC7iSYd2w6s9Oor/ Jkt+l1s3h+8hB6hG764abMXhK0jQ+eOxKHUzCMOyLDTFln2eXwpVeMABXFHZGNJQB+ wJq49LINmdmmcsITwtDit5sWmIolB6igtuv3/hl5skVZFFHMNlWv8ApABAOwGDwEow X75JX5xaUFglQ== Date: Wed, 23 Sep 2026 08:59:15 -1000 Message-ID: <15d491d4d4fb481941e8495d48b5c610@kernel.org> From: Tejun Heo To: Usama Arif Cc: arighi@nvidia.com, bsegall@google.com, changwoo@igalia.com, dietmar.eggemann@arm.com, etsal@meta.com, juri.lelli@redhat.com, kprateek.nayak@amd.com, linux-kernel@vger.kernel.org, mgorman@suse.de, mingo@redhat.com, peterz@infradead.org, rostedt@goodmis.org, sched-ext@lists.linux.dev, tj@kernel.org, vincent.guittot@linaro.org, void@manifault.com, vschneid@redhat.com, yphbchou0911@gmail.com, emil@etsalapatis.com, david.dai@linux.dev Subject: Re: [PATCH] sched_ext: Avoid relocking DSQ during remote consumption In-Reply-To: <20260923140750.2128382-1-usama.arif@linux.dev> References: <20260923140750.2128382-1-usama.arif@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Applied to sched_ext/for-7.4 with an unnecessary line break removed. Possible follow-ups: - The !dsq branch comment in scx_dispatch_dequeue() only mentions direct dispatch as a source of holding_cpu. Remote consume now reaches it too. Can you update the comment? The dsq branch comment also names dispatch_to_local_dsq() as the racer when it's unlink_dsq_and_switch_rq_lock(). - The remote local DSQ branch of move_task_between_dsqs() has the same relock. Calling dispatch_dequeue_locked() before dropping src_dsq->lock would avoid it. scx_bpf_dsq_move() isn't widely used, but it'd still be nice. Thanks. -- tejun