| Message ID | 1447371693-25143-4-git-send-email-hannes@cmpxchg.org |
|---|---|
| State | RFC, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Johannes Weiner <hannes@cmpxchg.org> Date: Thu, 12 Nov 2015 18:41:22 -0500 > 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 <hannes@cmpxchg.org> Acked-by: David S. Miller <davem@davemloft.net> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 <hannes@cmpxchg.org> Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com> For the record: it was broken by commit 3e32cb2e0a12 ("mm: memcontrol: lockless page counters"). -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sat, Nov 14, 2015 at 03:45:52PM +0300, Vladimir Davydov wrote: > 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 <hannes@cmpxchg.org> > > Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com> Thanks Vladimir! > For the record: it was broken by commit 3e32cb2e0a12 ("mm: memcontrol: > lockless page counters"). I didn't realize that. Fixes: 3e32cb2e0a12 ("mm: memcontrol: lockless page counters") -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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,
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 <hannes@cmpxchg.org> --- include/net/sock.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)