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authorJohannes Weiner <hannes@cmpxchg.org>2016-01-14 15:20:59 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-14 16:00:49 -0800
commit8c2c2358b236530bc2c79b4c2a447cbdbc3d96d7 (patch)
treebdaa3a9f9d0535c07d1dfd8f055cca8d63d61b2d
parent7d828602e5ef3297a69392a2d31264e4ab9c8bb7 (diff)
net: tcp_memcontrol: properly detect ancestor socket pressure
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 <hannes@cmpxchg.org> Acked-by: David S. Miller <davem@davemloft.net> Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/net/sock.h10
1 files changed, 6 insertions, 4 deletions
diff --git a/include/net/sock.h b/include/net/sock.h
index e830c1006935..9ef3d7c984b4 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1193,11 +1193,13 @@ 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,