From mboxrd@z Thu Jan 1 00:00:00 1970 From: Johannes Weiner Subject: [PATCH 03/14] net: tcp_memcontrol: properly detect ancestor socket pressure Date: Thu, 12 Nov 2015 18:41:22 -0500 Message-ID: <1447371693-25143-4-git-send-email-hannes@cmpxchg.org> References: <1447371693-25143-1-git-send-email-hannes@cmpxchg.org> Cc: Vladimir Davydov , Tejun Heo , Michal Hocko , netdev@vger.kernel.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com To: David Miller , Andrew Morton Return-path: In-Reply-To: <1447371693-25143-1-git-send-email-hannes@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-Id: netdev.vger.kernel.org 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 --- 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 bbf7c2c..c4b33c9 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org