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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 C8402C43331 for ; Thu, 2 Apr 2020 01:23:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 92CA62072E for ; Thu, 2 Apr 2020 01:23:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585790589; bh=/XWfr8B2+Gdq9aBiaTze7oFSffBCOQXALgeP7OSUoQQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=vEh7iB/UFrNzuTC3MbCV9luJCI+zsjbA5xLLfl/mgbi7l2EryWxHVQZS5AMOS5tQw Zfcca8nOG09V/E/vvc3UY0koh8vQzCrP0aPt/eqHSZoeLjbx13MTECscEdwULpZqPX jRtW+Lz5Rc+HKdhUcauK22xwYNn1F8MDA4jeJYck= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732872AbgDBBXI (ORCPT ); Wed, 1 Apr 2020 21:23:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:49050 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732462AbgDBBXI (ORCPT ); Wed, 1 Apr 2020 21:23:08 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5BA5A20675; Thu, 2 Apr 2020 01:23:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585790587; bh=/XWfr8B2+Gdq9aBiaTze7oFSffBCOQXALgeP7OSUoQQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=M+kfbZ9UrQu3G+ELPmQ1UpQH6jzItlc6P2SWjstji9UaUSHoI42uhLz0GCrHwnyx/ ZwI8RIGgcPMexnOXuBDWj4+S+SxyZPVlNjjQ0mkCAeQ4t7v7YUjvLhrUdv5sSQOl4I vy4yB6xaC3seVhG8xKwbIV0+jkhCZBTUuL4EW8tc= Date: Wed, 1 Apr 2020 18:23:06 -0700 From: Andrew Morton To: Chris Down Cc: Johannes Weiner , Tejun Heo , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, Michal Hocko Subject: Re: [PATCH] mm, memcg: Bypass high reclaim iteration for cgroup hierarchy root Message-Id: <20200401182306.724698b74692b5d31f66ad10@linux-foundation.org> In-Reply-To: <20200312164137.GA1753625@chrisdown.name> References: <20200312164137.GA1753625@chrisdown.name> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 12 Mar 2020 16:41:37 +0000 Chris Down wrote: > The root of the hierarchy cannot have high set, so we will never reclaim > based on it. This makes that clearer and avoids another entry. > > ... > > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2232,7 +2232,8 @@ static void reclaim_high(struct mem_cgroup *memcg, > continue; > memcg_memory_event(memcg, MEMCG_HIGH); > try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask, true); > - } while ((memcg = parent_mem_cgroup(memcg))); > + } while ((memcg = parent_mem_cgroup(memcg)) && > + !mem_cgroup_is_root(memcg)); > } > > static void high_work_func(struct work_struct *work) Does someone have time to review this one? Thanks.