From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD145C433C1 for ; Mon, 29 Mar 2021 05:45:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8383961964 for ; Mon, 29 Mar 2021 05:45:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229750AbhC2FpU (ORCPT ); Mon, 29 Mar 2021 01:45:20 -0400 Received: from verein.lst.de ([213.95.11.211]:52043 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230420AbhC2FpQ (ORCPT ); Mon, 29 Mar 2021 01:45:16 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 86D7168BEB; Mon, 29 Mar 2021 07:45:13 +0200 (CEST) Date: Mon, 29 Mar 2021 07:45:13 +0200 From: Christoph Hellwig To: Brian Foster Cc: linux-xfs@vger.kernel.org, "Darrick J. Wong" , Christoph Hellwig Subject: Re: xfs ioend batching log reservation deadlock Message-ID: <20210329054513.GA26736@lst.de> References: 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) Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Fri, Mar 26, 2021 at 11:39:38AM -0400, Brian Foster wrote: > 1. Optimize current append transaction processing with an inode field as > noted above. > > 2. Replace the submission side append transaction entirely with a flag > or some such on the ioend that allocates the transaction at completion > time, but otherwise preserves batching behavior instituted in patch 1. I'm pretty sure I had a patch to kill off the transaction reservation a while ago and Dave objected, mostly in performance grounds in that we might have tons of reservations coming from the I/O completion workqueue that would all be blocked on the transaction reservations. This would probably be much better with the ioend merging, which should significantly reduce the amount of transactions reservations - to probably not more than common workloads using unwritten extents. I'm all for killing the transaction pre-reservations as they have created a lot of pain for us.