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 51FFC2DC76E for ; Wed, 29 Oct 2025 15:06:48 +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=1761750409; cv=none; b=ECDVTji57Td3MeugWs9dzbvAAR+qvLkJXbj4C9HdHWiO57Ul95X1/xytP6+oyVeLdRmM+p4nEXkeDypWMiadpQlopIMDUE3od2U/W9nKNN2QhppGaH8Z6pLCiXiLfuFFEWJOnXiY9hfeo58XDmhk1zSC6/LsW9TDhzOLFHNo3pQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761750409; c=relaxed/simple; bh=x4tq1577DDMCaHW3fTcMZ1a5KydbuBLTN+yqRePgwcg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Qn1feNZifCdiNF3ORd1EMqQyLAcciMjox2QxHeisGcSd1+axGLlOsbHKwwhIZHXQE8KOyTaEANrUoWhf+kPBS1HR1cdnS2xEg/J+6OIcnCpDhxyCcxx406yIhxVrw4A5+FEdKZS70/OOzVk4Kzr86PWGgVAUQ7vI6G9RHEepKXo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QsqMwvur; 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="QsqMwvur" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9E3F2C4CEF7; Wed, 29 Oct 2025 15:06:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761750408; bh=x4tq1577DDMCaHW3fTcMZ1a5KydbuBLTN+yqRePgwcg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QsqMwvurh6t/xZMpEDwlS2InZJzz9Bh9oJpaJ9ISVQTJWSBOwYn6SZjMQvVyIoxla dbjetpiIGRIu97loeqgJEZMZ/pHBMo7CKIoh+vcjq3HTfcknz/FC/NWpRfIxtWYXcm 21/11Z35cVqHB23xlDJUmHJI62tieaztlO3aOXty41BPNzjd8u/pXYCSRMt3bjVZns EM0zNLHYK0LnzEtmlb+yjBqZ13A5WQknpqvNcIyk2vwPKOC/DwoWJTmab1pGeBUmKw 9uQ1QsgUkwzlMgBUzsGXIWtWLRX0lJ0jiUy7u0ZrgjTOhUyQ0TbKCu81PN5QaSJX9A eNCReRnTcEkfA== Date: Wed, 29 Oct 2025 05:06:46 -1000 From: Tejun Heo To: Matthew Brost Cc: Christian =?iso-8859-1?Q?K=F6nig?= , intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, jiangshanlai@gmail.com, simona.vetter@ffwll.ch, pstanner@redhat.com, dakr@kernel.org Subject: Re: [RFC PATCH 1/3] workqueue: Add an interface to taint workqueue lockdep with reclaim Message-ID: References: <20251021213952.746900-1-matthew.brost@intel.com> <20251021213952.746900-2-matthew.brost@intel.com> <2e1e9d6f-4f9e-49f7-90f0-6759c260701f@amd.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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Hello, On Tue, Oct 28, 2025 at 01:16:43PM -0700, Matthew Brost wrote: > On Tue, Oct 28, 2025 at 10:32:54AM +0100, Christian König wrote: > > On 10/21/25 23:39, Matthew Brost wrote: > > > Drivers often use workqueues that are in the reclaim path (e.g., DRM > > > scheduler workqueues). It is useful to teach lockdep that memory cannot > > > be allocated on these workqueues. Add an interface to taint workqueue > > > lockdep with reclaim. > > > > Oh that is so wonderfully evil. I'm absolutely in favor of doing this. > > > > But can't we check for the existing WQ_MEM_RECLAIM flag in the workqueue handling instead? > > > > Tejun suggested tying the lockdep annotation to WQ_MEM_RECLAIM, but the > entire kernel explodes because many workqueues throughout Linux don’t > adhere to this rule. Here's a link to my latest reply to Tejun [1]. How about making it a WQ flag? Thanks. -- tejun