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 06C01C282C4 for ; Thu, 7 Feb 2019 10:27:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D401C20823 for ; Thu, 7 Feb 2019 10:27:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726699AbfBGK1x (ORCPT ); Thu, 7 Feb 2019 05:27:53 -0500 Received: from mx2.suse.de ([195.135.220.15]:44864 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726186AbfBGK1x (ORCPT ); Thu, 7 Feb 2019 05:27:53 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 87F11ACC7; Thu, 7 Feb 2019 10:27:51 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id C6B041E3DB5; Thu, 7 Feb 2019 11:27:50 +0100 (CET) Date: Thu, 7 Feb 2019 11:27:50 +0100 From: Jan Kara To: Dave Chinner Cc: 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" , "akpm@linux-foundation.org" , "vdavydov.dev@gmail.com" Subject: Re: [PATCH 1/2] Revert "mm: don't reclaim inodes with many attached pages" Message-ID: <20190207102750.GA4570@quack2.suse.cz> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190131221904.GL4205@dastard> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org 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. Honza -- Jan Kara SUSE Labs, CR