From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751336AbbKNMqL (ORCPT ); Sat, 14 Nov 2015 07:46:11 -0500 Received: from relay.parallels.com ([195.214.232.42]:45574 "EHLO relay.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750998AbbKNMqJ (ORCPT ); Sat, 14 Nov 2015 07:46:09 -0500 Date: Sat, 14 Nov 2015 15:45:52 +0300 From: Vladimir Davydov To: Johannes Weiner CC: David Miller , Andrew Morton , Tejun Heo , Michal Hocko , , , , , Subject: Re: [PATCH 03/14] net: tcp_memcontrol: properly detect ancestor socket pressure Message-ID: <20151114124552.GI31308@esperanza> References: <1447371693-25143-1-git-send-email-hannes@cmpxchg.org> <1447371693-25143-4-git-send-email-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <1447371693-25143-4-git-send-email-hannes@cmpxchg.org> X-ClientProxiedBy: US-EXCH2.sw.swsoft.com (10.255.249.46) To MSK-EXCH1.sw.swsoft.com (10.67.48.55) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 12, 2015 at 06:41:22PM -0500, Johannes Weiner wrote: > When charging socket memory, the code currently checks only the local > page counter for excess to determine whether the memcg is under socket > pressure. But even if the local counter is fine, one of the ancestors > could have breached its limit, which should also force this child to > enter socket pressure. This currently doesn't happen. > > Fix this by using page_counter_try_charge() first. If that fails, it > means that either the local counter or one of the ancestors are in > excess of their limit, and the child should enter socket pressure. > > Signed-off-by: Johannes Weiner Reviewed-by: Vladimir Davydov For the record: it was broken by commit 3e32cb2e0a12 ("mm: memcontrol: lockless page counters").