From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (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 D1BB52D8375 for ; Tue, 12 Aug 2025 07:43:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.95.11.211 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754984636; cv=none; b=hiMEVcUW2CWzqJd+/T+nWiUipINQ9FtzAn2f57bJ5oYnSJxwZrJYhIG9qXonbJ9zZVmKe43XY9t4ML5QqUh2Y0umrrI/CG3fgHLm3N5LEGufEd1jt8Da2zA99rw8028a7UZF9chZUFsM/BiZPkbsAsIgoLoQqtBnTeKLQu/HFL0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754984636; c=relaxed/simple; bh=bqM/4wRwEzoxQlCRe3b94XAem80UH0+YgjAbaGhuyCQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kAX7Gx0x/vUMY13EAZu9agKhrDD2Tx/cIvfXV5bB+Rzs+CSMeZSwc1d2KihFVMTQtt1X0wIJT+2yijixSMTKw1UdtvxQiT3LPiST7AJc6JlOLhaJasM4z79o5/K6cCB/agKXOP0tygpj+BB7CnftixSSTcCW8vfxTwZrjPFcLsk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de; spf=pass smtp.mailfrom=lst.de; arc=none smtp.client-ip=213.95.11.211 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lst.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lst.de Received: by verein.lst.de (Postfix, from userid 2407) id 043A4227A87; Tue, 12 Aug 2025 09:43:51 +0200 (CEST) Date: Tue, 12 Aug 2025 09:43:50 +0200 From: Christoph Hellwig To: Tejun Heo Cc: Christoph Hellwig , Andrey Albershteyn , fsverity@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, david@fromorbit.com, djwong@kernel.org, ebiggers@kernel.org, Lai Jiangshan , linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC 04/29] fsverity: add per-sb workqueue for post read processing Message-ID: <20250812074350.GC18413@lst.de> References: <20250728-fsverity-v1-0-9e5443af0e34@kernel.org> <20250728-fsverity-v1-4-9e5443af0e34@kernel.org> <20250811114519.GA8969@lst.de> Precedence: bulk X-Mailing-List: fsverity@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) > On Mon, Aug 11, 2025 at 01:45:19PM +0200, Christoph Hellwig wrote: > > On Mon, Jul 28, 2025 at 10:30:08PM +0200, Andrey Albershteyn wrote: > > > From: Andrey Albershteyn > > > > > > For XFS, fsverity's global workqueue is not really suitable due to: > > > > > > 1. High priority workqueues are used within XFS to ensure that data > > > IO completion cannot stall processing of journal IO completions. > > > Hence using a WQ_HIGHPRI workqueue directly in the user data IO > > > path is a potential filesystem livelock/deadlock vector. > > > > Do they? I though the whole point of WQ_HIGHPRI was that they'd > > have separate rescue workers to avoid any global pool effects. > > HIGHPRI and MEM_RECLAIM are orthogonal. HIGHPRI makes the workqueue use > worker pools with high priority, so all work items would execute at MIN_NICE > (-20). Hmm... actually, rescuer doesn't set priority according to the > workqueue's, which seems buggy. Andrey (or others involved with previous versions): is interference with the log completion workqueue what you ran into? Tejun, are you going to prepare a patch to fix the rescuer priority?