From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161562AbcA0Uvh (ORCPT ); Wed, 27 Jan 2016 15:51:37 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:43743 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161279AbcA0UkS (ORCPT ); Wed, 27 Jan 2016 15:40:18 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Johannes Weiner , Andrew Morton , Linus Torvalds , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 232/268] net: tcp_memcontrol: properly detect ancestor socket pressure Date: Wed, 27 Jan 2016 12:34:53 -0800 Message-Id: <1453926929-17663-233-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1453926929-17663-1-git-send-email-kamal@canonical.com> References: <1453926929-17663-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.2.8-ckt3 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Johannes Weiner commit 8c2c2358b236530bc2c79b4c2a447cbdbc3d96d7 upstream. 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Kamal Mostafa --- 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 639138b..591d303 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1209,11 +1209,13 @@ 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, -- 1.9.1