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 2987120010B for ; Wed, 8 Jan 2025 16:49:23 +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=1736354964; cv=none; b=iDoxbIv0s5nAWnK8ro5gcgck60mX15BD0PFHiKxlN7tT/bbFli4O1wrsug7yZ1uKk/jzPKEzfWqS5l/zLVquVrMgoYXca/ndGDATi5+EfDvf99EXOA8tu0WWlCtwlIIiwCxmlDegQARZ1QFHqZytIMQcNjY3ghbcKV3jlGxNv+8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736354964; c=relaxed/simple; bh=tI7Ps/3+adfmrB7gdd9WXP8OChl7heqJW353jklbpwM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=tAgRpl6pagWwl/kHaQx7zI4W2I9RQavv7DgVG9tA8bw0FnzlScHDXsvE1l+DduRqeIVYYom5IxKRnbnLFdBJNEX9SvnFD3utjBmOT+8ui5R4VH1c2ts9OqyNAC6uLEqHJEpdIoRJe1qBhZcZSGM4Z1uXyIajSgBioFpl3bjnI54= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=azE/VSc6; 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="azE/VSc6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C866C4CED3; Wed, 8 Jan 2025 16:49:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736354963; bh=tI7Ps/3+adfmrB7gdd9WXP8OChl7heqJW353jklbpwM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=azE/VSc6XPJGc4s8UxAXvZFPG6f3zi+4ynGONAK3D+UW+e9kvnBr8zCpUt7arFaHh FfxRQYKd8cS+lmgo6nWmpB3AqA/ctGrYFxV/HxjtMqhuysR90TcsMpSXTqDfZCJ9Y/ zd9gvX2Rr99FkKCcAWFi7xIENLInuV7P5n4bK5hWGLCQEVxNmYlG1IQjRc+m2KF/vP VEHbzV0t4pbIFQEh60rVA5Epu5v6m/fncecRvc4RuNNtyc7UTFM8lmNe07Uzu61eWR PHrr4ATKqwgnF7a2Dk3PmnMNkEZ313Ik6pFqnIrLa5B8OqCWe/EU9ioj6Jz8MWJVrE fPg6HGR9gZfrw== Date: Wed, 8 Jan 2025 06:49:22 -1000 From: Tejun Heo To: Changwoo Min Cc: void@manifault.com, arighi@nvidia.com, kernel-dev@igalia.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] sched_ext: Replace rq_lock() to raw_spin_rq_lock() in scx_ops_bypass() Message-ID: References: <20250108150806.101555-1-changwoo@igalia.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: <20250108150806.101555-1-changwoo@igalia.com> On Thu, Jan 09, 2025 at 12:08:06AM +0900, Changwoo Min wrote: > scx_ops_bypass() iterates all CPUs to re-enqueue all the scx tasks. > For each CPU, it acquires a lock using rq_lock() regardless of whether > a CPU is offline or the CPU is currently running a task in a higher > scheduler class (e.g., deadline). The rq_lock() is supposed to be used > for online CPUs, and the use of rq_lock() may trigger an unnecessary > warning in rq_pin_lock(). Therefore, replace rq_lock() to > raw_spin_rq_lock() in scx_ops_bypass(). > > Without this change, we observe the following warning: > > ===== START ===== > [ 6.615205] rq->balance_callback && rq->balance_callback != &balance_push_callback > [ 6.615208] WARNING: CPU: 2 PID: 0 at kernel/sched/sched.h:1730 __schedule+0x1130/0x1c90 > ===== END ===== > > Fixes: 0e7ffff1b811 ("scx: Fix raciness in scx_ops_bypass()") > Signed-off-by: Changwoo Min Applied to sched_ext/for-6.13-fixes. Thanks. -- tejun