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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable 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 5E644C282CB for ; Fri, 8 Feb 2019 21:25:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3A0C5218FF for ; Fri, 8 Feb 2019 21:25:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727294AbfBHVZf (ORCPT ); Fri, 8 Feb 2019 16:25:35 -0500 Received: from ipmail07.adl2.internode.on.net ([150.101.137.131]:2288 "EHLO ipmail07.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727176AbfBHVZf (ORCPT ); Fri, 8 Feb 2019 16:25:35 -0500 Received: from ppp59-167-129-252.static.internode.on.net (HELO dastard) ([59.167.129.252]) by ipmail07.adl2.internode.on.net with ESMTP; 09 Feb 2019 07:55:31 +1030 Received: from dave by dastard with local (Exim 4.80) (envelope-from ) id 1gsDeN-0006PR-2l; Sat, 09 Feb 2019 08:25:31 +1100 Date: Sat, 9 Feb 2019 08:25:31 +1100 From: Dave Chinner To: Andrew Morton Cc: Jan Kara , Roman Gushchin , Michal Hocko , Chris Mason , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-xfs@vger.kernel.org" , "vdavydov.dev@gmail.com" Subject: Re: [PATCH 1/2] Revert "mm: don't reclaim inodes with many attached pages" Message-ID: <20190208212531.GN14116@dastard> References: <20190130041707.27750-1-david@fromorbit.com> <20190130041707.27750-2-david@fromorbit.com> <25EAF93D-BC63-4409-AF21-F45B2DDF5D66@fb.com> <20190131013403.GI4205@dastard> <20190131091011.GP18811@dhcp22.suse.cz> <20190131185704.GA8755@castle.DHCP.thefacebook.com> <20190131221904.GL4205@dastard> <20190207102750.GA4570@quack2.suse.cz> <20190207213727.a791db810341cec2c013ba93@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190207213727.a791db810341cec2c013ba93@linux-foundation.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Feb 07, 2019 at 09:37:27PM -0800, Andrew Morton wrote: > On Thu, 7 Feb 2019 11:27:50 +0100 Jan Kara wrote: > > > On Fri 01-02-19 09:19:04, Dave Chinner wrote: > > > Maybe for memcgs, but that's exactly the oppose of what we want to > > > do for global caches (e.g. filesystem metadata caches). We need to > > > make sure that a single, heavily pressured cache doesn't evict small > > > caches that lower pressure but are equally important for > > > performance. > > > > > > e.g. I've noticed recently a significant increase in RMW cycles in > > > XFS inode cache writeback during various benchmarks. It hasn't > > > affected performance because the machine has IO and CPU to burn, but > > > on slower machines and storage, it will have a major impact. > > > > Just as a data point, our performance testing infrastructure has bisected > > down to the commits discussed in this thread as the cause of about 40% > > regression in XFS file delete performance in bonnie++ benchmark. > > > > Has anyone done significant testing with Rik's maybe-fix? Apart from pointing out all the bugs and incorrect algorithmic assumptions it makes, no. Cheers, Dave. -- Dave Chinner david@fromorbit.com