Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755320AbbKXVwl (ORCPT ); Tue, 24 Nov 2015 16:52:41 -0500 Received: from gum.cmpxchg.org ([85.214.110.215]:45768 "EHLO gum.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755136AbbKXVwh (ORCPT ); Tue, 24 Nov 2015 16:52:37 -0500 From: Johannes Weiner To: Andrew Morton Cc: David Miller , Vladimir Davydov , Michal Hocko , Tejun Heo , Eric Dumazet , netdev@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: [PATCH 02/13] net: tcp_memcontrol: properly detect ancestor socket pressure Date: Tue, 24 Nov 2015 16:51:54 -0500 Message-Id: <1448401925-22501-3-git-send-email-hannes@cmpxchg.org> X-Mailer: git-send-email 2.6.2 In-Reply-To: <1448401925-22501-1-git-send-email-hannes@cmpxchg.org> References: <1448401925-22501-1-git-send-email-hannes@cmpxchg.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1844 Lines: 48 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. Fixes: 3e32cb2e0a12 ("mm: memcontrol: lockless page counters") Signed-off-by: Johannes Weiner Acked-by: David S. Miller Reviewed-by: Vladimir Davydov --- include/net/sock.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/include/net/sock.h b/include/net/sock.h index 7f89e4b..8133c71 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1190,11 +1190,13 @@ static inline void memcg_memory_allocated_add(struct cg_proto *prot, unsigned long amt, int *parent_status) { - page_counter_charge(&prot->memory_allocated, amt); + struct page_counter *counter; + + if (page_counter_try_charge(&prot->memory_allocated, amt, &counter)) + return; - if (page_counter_read(&prot->memory_allocated) > - prot->memory_allocated.limit) - *parent_status = OVER_LIMIT; + page_counter_charge(&prot->memory_allocated, amt); + *parent_status = OVER_LIMIT; } static inline void memcg_memory_allocated_sub(struct cg_proto *prot, -- 2.6.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/