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,URIBL_BLOCKED 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 5D432C32750 for ; Tue, 13 Aug 2019 21:31:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1ED292067D for ; Tue, 13 Aug 2019 21:31:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="elLSkOtT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1ED292067D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B3D426B028A; Tue, 13 Aug 2019 17:31:20 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AECFD6B028B; Tue, 13 Aug 2019 17:31:20 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A029C6B028C; Tue, 13 Aug 2019 17:31:20 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0037.hostedemail.com [216.40.44.37]) by kanga.kvack.org (Postfix) with ESMTP id 797676B028A for ; Tue, 13 Aug 2019 17:31:20 -0400 (EDT) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id 10EBD180AD7C3 for ; Tue, 13 Aug 2019 21:31:20 +0000 (UTC) X-FDA: 75818700720.18.noise08_800256f3ef42e X-HE-Tag: noise08_800256f3ef42e X-Filterd-Recvd-Size: 2320 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf24.hostedemail.com (Postfix) with ESMTP for ; Tue, 13 Aug 2019 21:31:19 +0000 (UTC) Received: from akpm3.svl.corp.google.com (unknown [104.133.8.65]) (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 79C9720665; Tue, 13 Aug 2019 21:31:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565731877; bh=tjFvWLPSSfcPrnSoEvYPNR+1ax/3i9N/XRtulBqxupU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=elLSkOtT891o1HflqX+iByvvwV+ByIjKKmOU9b3NfLMnPa+9erUcWokJI6XD7ymEU 7ttmBIX9VYtOUp1ZHrefdIAH/Fihhm2AVf11jHkHeMmAS4U4DpyTMpsY4VCoLMZmW9 alzjY58nI17Dwzg+5PuPNEm4GPMQO6UQnyFpzSPs= Date: Tue, 13 Aug 2019 14:31:17 -0700 From: Andrew Morton To: Roman Gushchin Cc: , Michal Hocko , Johannes Weiner , , Subject: Re: [PATCH] mm: memcontrol: flush percpu vmevents before releasing memcg Message-Id: <20190813143117.885bef5929813445ef39fa61@linux-foundation.org> In-Reply-To: <20190812233754.2570543-1-guro@fb.com> References: <20190812233754.2570543-1-guro@fb.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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 Mon, 12 Aug 2019 16:37:54 -0700 Roman Gushchin wrote: > Similar to vmstats, percpu caching of local vmevents leads to an > accumulation of errors on non-leaf levels. This happens because > some leftovers may remain in percpu caches, so that they are > never propagated up by the cgroup tree and just disappear into > nonexistence with on releasing of the memory cgroup. > > To fix this issue let's accumulate and propagate percpu vmevents > values before releasing the memory cgroup similar to what we're > doing with vmstats. > > Since on cpu hotplug we do flush percpu vmstats anyway, we can > iterate only over online cpus. > > Fixes: 42a300353577 ("mm: memcontrol: fix recursive statistics correctness & scalabilty") No cc:stable?