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=-7.0 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 4E6D9C18E5B for ; Mon, 16 Mar 2020 14:59:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1491620674 for ; Mon, 16 Mar 2020 14:59:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1491620674 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 934F56B0003; Mon, 16 Mar 2020 10:59:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 90B8C6B0007; Mon, 16 Mar 2020 10:59:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 822276B0008; Mon, 16 Mar 2020 10:59:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0137.hostedemail.com [216.40.44.137]) by kanga.kvack.org (Postfix) with ESMTP id 633486B0003 for ; Mon, 16 Mar 2020 10:59:02 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id E611E181AEF1F for ; Mon, 16 Mar 2020 14:59:01 +0000 (UTC) X-FDA: 76601532882.25.bomb86_6beded8233301 X-HE-Tag: bomb86_6beded8233301 X-Filterd-Recvd-Size: 4510 Received: from mail-wr1-f67.google.com (mail-wr1-f67.google.com [209.85.221.67]) by imf06.hostedemail.com (Postfix) with ESMTP for ; Mon, 16 Mar 2020 14:59:01 +0000 (UTC) Received: by mail-wr1-f67.google.com with SMTP id b2so15393186wrj.10 for ; Mon, 16 Mar 2020 07:59:01 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=pRHZ/81/kzUik27LyIjeUOcKEhttC2wz2iMI5IMU5Lc=; b=HO0a5sbHWcGOQNC9pN0HIjYvO7rB2b78LTcC+XvZHTCPOBvzf3zwcqEbpTHFkEiBY2 3G2BN9qGf+CM511CEtirJrtqszMhFHsI3LMZjRvHub/hxG7IRiU9ZxjggHrufRsBnQJP C5ggDAf1k1v7TtkV64EiyqfhIUiEQNZe3uWiiql92yMdF4SC4tDLDlQtuDH44XvacRqh IfF7RtdKE4/Rd9dWnaPtg0GP+2D3vzvsBXgS+Stkfw0jEYCMBrd1a8pMJBXFXrH/qFVD SwmmVp7J/HfcYMTFw2cAlBT98Q3mbPFYGgplCouqGPBMFKqCGjaypanTGGq8diq2a9xM BnAw== X-Gm-Message-State: ANhLgQ1elIKcisUNw0BDjEleCvogzvjCbPEl18Dar7qZfhVoIdakCuoO jDMjtudzbDMjJ+sopoTC++4= X-Google-Smtp-Source: ADFU+vupN5bWVeVlVahplDj5UFn5L9wamTUU+oZUW+uE+t3SV11JzAtqbznmWnsTdoMiIlJiBl/ItQ== X-Received: by 2002:a5d:5444:: with SMTP id w4mr4679831wrv.387.1584370740577; Mon, 16 Mar 2020 07:59:00 -0700 (PDT) Received: from localhost ([37.188.132.163]) by smtp.gmail.com with ESMTPSA id s127sm31023841wmf.28.2020.03.16.07.58.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Mar 2020 07:58:59 -0700 (PDT) Date: Mon, 16 Mar 2020 15:58:59 +0100 From: Michal Hocko To: Chris Down Cc: Andrew Morton , Johannes Weiner , Tejun Heo , Roman Gushchin , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 5/6] mm, memcg: Prevent memory.swap.max load tearing Message-ID: <20200316145859.GQ11482@dhcp22.suse.cz> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu 12-03-20 17:33:11, Chris Down wrote: > The write side of this is xchg()/smp_mb(), so that's all good. Just a > few sites missing a READ_ONCE. > > Signed-off-by: Chris Down > Cc: Andrew Morton > Cc: Johannes Weiner > Cc: Roman Gushchin > Cc: Tejun Heo > Cc: linux-mm@kvack.org > Cc: cgroups@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Cc: kernel-team@fb.com Acked-by: Michal Hocko > --- > mm/memcontrol.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index e0ed790a2a8c..57048a38c75d 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1511,7 +1511,7 @@ void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg) > if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) > pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n", > K((u64)page_counter_read(&memcg->swap)), > - K((u64)memcg->swap.max), memcg->swap.failcnt); > + K((u64)READ_ONCE(memcg->swap.max)), memcg->swap.failcnt); > else { > pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n", > K((u64)page_counter_read(&memcg->memsw)), > @@ -1544,7 +1544,7 @@ unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg) > unsigned long swap_max; > > memsw_max = memcg->memsw.max; > - swap_max = memcg->swap.max; > + swap_max = READ_ONCE(memcg->swap.max); > swap_max = min(swap_max, (unsigned long)total_swap_pages); > max = min(max + swap_max, memsw_max); > } > @@ -7025,7 +7025,8 @@ bool mem_cgroup_swap_full(struct page *page) > return false; > > for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) > - if (page_counter_read(&memcg->swap) * 2 >= memcg->swap.max) > + if (page_counter_read(&memcg->swap) * 2 >= > + READ_ONCE(memcg->swap.max)) > return true; > > return false; > -- > 2.25.1 > -- Michal Hocko SUSE Labs