From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 Date: Sat, 9 Feb 2019 08:25:31 +1100 From: Dave Chinner 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> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs 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" 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