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=-8.5 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 E2199C04EB9 for ; Mon, 3 Dec 2018 11:54:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A7264206B7 for ; Mon, 3 Dec 2018 11:54:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A7264206B7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726383AbeLCLzk (ORCPT ); Mon, 3 Dec 2018 06:55:40 -0500 Received: from mx2.suse.de ([195.135.220.15]:59758 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725975AbeLCLzk (ORCPT ); Mon, 3 Dec 2018 06:55:40 -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 79AEBAC66; Mon, 3 Dec 2018 11:54:54 +0000 (UTC) Date: Mon, 3 Dec 2018 12:54:53 +0100 From: Michal Hocko To: Xunlei Pang Cc: Roman Gushchin , Johannes Weiner , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/3] mm/memcg: Fix min/low usage in propagate_protected_usage() Message-ID: <20181203115453.GO31738@dhcp22.suse.cz> References: <20181203080119.18989-1-xlpang@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181203080119.18989-1-xlpang@linux.alibaba.com> 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 Mon 03-12-18 16:01:17, Xunlei Pang wrote: > When usage exceeds min, min usage should be min other than 0. > Apply the same for low. Why? What is the actual problem. > Signed-off-by: Xunlei Pang > --- > mm/page_counter.c | 12 ++---------- > 1 file changed, 2 insertions(+), 10 deletions(-) > > diff --git a/mm/page_counter.c b/mm/page_counter.c > index de31470655f6..75d53f15f040 100644 > --- a/mm/page_counter.c > +++ b/mm/page_counter.c > @@ -23,11 +23,7 @@ static void propagate_protected_usage(struct page_counter *c, > return; > > if (c->min || atomic_long_read(&c->min_usage)) { > - if (usage <= c->min) > - protected = usage; > - else > - protected = 0; > - > + protected = min(usage, c->min); > old_protected = atomic_long_xchg(&c->min_usage, protected); > delta = protected - old_protected; > if (delta) > @@ -35,11 +31,7 @@ static void propagate_protected_usage(struct page_counter *c, > } > > if (c->low || atomic_long_read(&c->low_usage)) { > - if (usage <= c->low) > - protected = usage; > - else > - protected = 0; > - > + protected = min(usage, c->low); > old_protected = atomic_long_xchg(&c->low_usage, protected); > delta = protected - old_protected; > if (delta) > -- > 2.13.5 (Apple Git-94) > -- Michal Hocko SUSE Labs