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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 D68E1C432C1 for ; Tue, 24 Sep 2019 12:27:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9E9B421655 for ; Tue, 24 Sep 2019 12:27:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569328070; bh=UkoYPSvoNbyEGz8D99UJ45H7fpqACMqVy4xrbMiSILc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=ChsIvRvaKma8Do7S9kui1b6mIkukIHMp6lceOQfD3xSWM8n2hcDYvpeXEghwp3c7O jOApwwnMeXuvS/4LUb4YT56Qw/LoaDmrFTwnsYVijqK7s99kPsF7xWi3x3JkOc3iby +O7RYpD0PEV+hFpCTZE13UK12kT6aPh2YLEcGEXg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2436592AbfIXM1t (ORCPT ); Tue, 24 Sep 2019 08:27:49 -0400 Received: from mx2.suse.de ([195.135.220.15]:52202 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2390187AbfIXM1t (ORCPT ); Tue, 24 Sep 2019 08:27:49 -0400 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 F0D6DB0E2; Tue, 24 Sep 2019 12:27:47 +0000 (UTC) Date: Tue, 24 Sep 2019 14:27:47 +0200 From: Michal Hocko To: Baoquan He Cc: akpm@linux-foundation.org, tj@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2] memcg: Only record foreign writebacks with dirty pages when memcg is not disabled Message-ID: <20190924122747.GQ23050@dhcp22.suse.cz> References: <20190923083030.6442-1-bhe@redhat.com> <20190924111138.GA31919@MiWiFi-R3L-srv> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190924111138.GA31919@MiWiFi-R3L-srv> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 24-09-19 19:11:51, Baoquan He wrote: > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index f3c15bb07cce..84e3fdb1ccb4 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -4317,6 +4317,9 @@ void mem_cgroup_track_foreign_dirty_slowpath(struct page *page, > > trace_track_foreign_dirty(page, wb); > > + if (mem_cgroup_disabled()) > + return; > + This doesn't seem correct. We shouldn't even enter the slowpath with memcg disabled AFAIC. The check should be done at mem_cgroup_track_foreign_dirty level. -- Michal Hocko SUSE Labs