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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EFD61C433EF for ; Tue, 4 Jan 2022 13:36:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229841AbiADNgs (ORCPT ); Tue, 4 Jan 2022 08:36:48 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:31830 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229700AbiADNgr (ORCPT ); Tue, 4 Jan 2022 08:36:47 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1641303406; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=KzTPGW2JymMzrDS1j8vpaZmq1mjrtuWjLdCBriVQUJ8=; b=NNhZsLraAT+ZC8RXGIip0dpih8S2p7Wu0F8CSno3gqQu3Dlus/BCFMDTpIx8dEuwkSfvCp 0m0RjVvot+JEFDzzLpmPI7UWC76HLaVCat9a7pqqXoiQCxYnPmCyIiVhs/3UMXYGqfT+JH ZjnoB5OBNSyS45en38WItMpx482yrdo= Received: from mail-qk1-f197.google.com (mail-qk1-f197.google.com [209.85.222.197]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-19-SajF8DTDNVuQSnddCaZyiA-1; Tue, 04 Jan 2022 08:36:45 -0500 X-MC-Unique: SajF8DTDNVuQSnddCaZyiA-1 Received: by mail-qk1-f197.google.com with SMTP id u12-20020a05620a0c4c00b00475a9324977so20877113qki.13 for ; Tue, 04 Jan 2022 05:36:45 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=KzTPGW2JymMzrDS1j8vpaZmq1mjrtuWjLdCBriVQUJ8=; b=XP6XFK17A6et0TzJ+hQnp0Uwtmv6zVc7rAY8YEQlV+buEWcGTAMCEQL+ekQNManqir pqwtWeXnCb/q8+GlNcEMDrDfbdnwPTIw1Z5tulteUzNPYbzZB177thBylceQ6pWBS8Hm vOwbOfk/hFwLrf+L57s1sIUl+aBB7FnrfpPtplNeh+fQapYCCqEbTPhK9zO2QufnH+zZ wKLXfyonbrCUhpM2SXY4sQ3yHUSijYxKxowQPZNHgnZyx/HxBXjwn5ZYY8GOy5+sIOCN 1xOuS9bCAHlosxHUuRzftPLprI64Rm0yX3SnuOED1k2amOIUV7bvdueSUeDYMeJWW/ME +FDw== X-Gm-Message-State: AOAM530QzeAETWsUSSfIjn0/I4gelBpVCpuhVsM8mHIykJJxDHw2w/5G PggzKrM1M5qsZaVK0s0KoXiXGnZHSzIta3SryyzAQC5WFZiEFkQhFS7l0/XmctTcLcZQleD6Z4q vS4vcK1idPVpS9qQeTahQ X-Received: by 2002:a37:a716:: with SMTP id q22mr35188719qke.249.1641303405040; Tue, 04 Jan 2022 05:36:45 -0800 (PST) X-Google-Smtp-Source: ABdhPJzr3X6E0Hb2ZXIDS/jRCm7BkGNJvh1DTGyzsgltkU4PR76XM32hvopdA+7cQ3D59BZXMHh/Ow== X-Received: by 2002:a37:a716:: with SMTP id q22mr35188706qke.249.1641303404844; Tue, 04 Jan 2022 05:36:44 -0800 (PST) Received: from bfoster (c-24-61-119-116.hsd1.ma.comcast.net. [24.61.119.116]) by smtp.gmail.com with ESMTPSA id 8sm33838927qtz.28.2022.01.04.05.36.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Jan 2022 05:36:44 -0800 (PST) Date: Tue, 4 Jan 2022 08:36:42 -0500 From: Brian Foster To: Trond Myklebust Cc: "david@fromorbit.com" , "linux-fsdevel@vger.kernel.org" , "trondmy@kernel.org" , "hch@infradead.org" , "axboe@kernel.dk" , "djwong@kernel.org" , "linux-xfs@vger.kernel.org" , "willy@infradead.org" Subject: Re: [PATCH] iomap: Address soft lockup in iomap_finish_ioend() Message-ID: References: <20211230193522.55520-1-trondmy@kernel.org> <6f746786a3928844fbe644e7e409008b4f50c239.camel@hammerspace.com> <20220101035516.GE945095@dread.disaster.area> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Sat, Jan 01, 2022 at 05:39:45PM +0000, Trond Myklebust wrote: ... > > Fair enough. As long as someone is working on a solution, then I'm > happy. Just a couple of things: > > Firstly, we've verified that the cond_resched() in the bio loop does > suffice to resolve the issue with XFS, which would tend to confirm what > you're saying above about the underlying issue being the ioend chain > length. > > Secondly, note that we've tested this issue with a variety of older > kernels, including 4.18.x, 5.1.x and 5.15.x, so please bear in mind > that it would be useful for any fix to be backward portable through the > stable mechanism. > I've sent a couple or so different variants of this in the past. The last I believe was here [1], but still never seemed to go anywhere (despite having reviews on the first couple patches). That one was essentially a sequence of adding a cond_resched() call in the iomap code to address the soft lockup warning followed by capping the ioend size for latency reasons. Brian [1] https://lore.kernel.org/linux-xfs/20210517171722.1266878-1-bfoster@redhat.com/ > > Thanks, and Happy New Year! > > Trond > > -- > Trond Myklebust > Linux NFS client maintainer, Hammerspace > trond.myklebust@hammerspace.com > >