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,USER_AGENT_MUTT autolearn=ham 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 4568FC282D7 for ; Thu, 31 Jan 2019 01:44:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 111312184D for ; Thu, 31 Jan 2019 01:44:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726163AbfAaBoo (ORCPT ); Wed, 30 Jan 2019 20:44:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54728 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725535AbfAaBoo (ORCPT ); Wed, 30 Jan 2019 20:44:44 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C12F1C0669AC; Thu, 31 Jan 2019 01:44:43 +0000 (UTC) Received: from rh (ovpn-116-146.phx2.redhat.com [10.3.116.146]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6CAD76019F; Thu, 31 Jan 2019 01:44:43 +0000 (UTC) Received: from [::1] (helo=rh) by rh with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1gp1PB-0003Fh-UY; Thu, 31 Jan 2019 12:44:37 +1100 Date: Thu, 31 Jan 2019 12:44:35 +1100 From: Dave Chinner To: Roman Gushchin Cc: "akpm@linux-foundation.org" , "dairinin@gmail.com" , "mhocko@kernel.org" , "mm-commits@vger.kernel.org" , "riel@surriel.com" , "stable@vger.kernel.org" Subject: Re: + revert-mm-dont-reclaim-inodes-with-many-attached-pages.patch added to -mm tree Message-ID: <20190131014435.GM31397@rh> References: <20190130051009.vMQ1lujVl%akpm@linux-foundation.org> <20190130055420.GB2107@castle.DHCP.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190130055420.GB2107@castle.DHCP.thefacebook.com> User-Agent: Mutt/1.9.1 (2017-09-22) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Thu, 31 Jan 2019 01:44:43 +0000 (UTC) Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Wed, Jan 30, 2019 at 05:54:27AM +0000, Roman Gushchin wrote: > Hi, Andrew! > > I believe, that Rik's patch ( https://lkml.org/lkml/2019/1/28/1865 ) can make > a difference here, and might fix the regression. I'd give it a chance, before > reverting these two patches. Reverting will re-introduce the memcg-leak, which > is quite bad. Rik's change is just another hack that will still have effects on reclaim behaviour. Indeed, the fs/inode.c change definitely needs reverting, because that is just *plain wrong* and breaks long-standing memory reclaim behaviour. I seriously disagree with shovelling a different, largely untested and contentious change to the shrinker algorithm to try and patch over the symptoms of the original change. It leaves the underlying problem unfixed (dying memcgs need a reaper to shrink the remaining slab objects that pin that specific memcg) and instead plays "whack-a-mole" on what we alreayd know is a fundamentally broken assumption (i.e. that shrinking small slabs more agressively is side-effect free). -Dave. -- Dave Chinner dchinner@redhat.com