diff options
| author | Sahitya Tummala <stummala@codeaurora.org> | 2017-07-10 15:49:57 -0700 |
|---|---|---|
| committer | Sasha Levin <alexander.levin@verizon.com> | 2017-07-31 13:37:54 -0400 |
| commit | eb8e478e472c57ed02dc5705779298e421b7d96f (patch) | |
| tree | d052f2fb3957c051c3b37af43a299fb486a4f0a7 /mm/list_lru.c | |
| parent | 9052d52e8bce71fd5cfd78f79b26f90831dbd7ba (diff) | |
mm/list_lru.c: fix list_lru_count_node() to be race free
[ Upstream commit 2c80cd57c74339889a8752b20862a16c28929c3a ]
list_lru_count_node() iterates over all memcgs to get the total number of
entries on the node but it can race with memcg_drain_all_list_lrus(),
which migrates the entries from a dead cgroup to another. This can return
incorrect number of entries from list_lru_count_node().
Fix this by keeping track of entries per node and simply return it in
list_lru_count_node().
Link: http://lkml.kernel.org/r/1498707555-30525-1-git-send-email-stummala@codeaurora.org
Signed-off-by: Sahitya Tummala <stummala@codeaurora.org>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Alexander Polakov <apolyakov@beget.ru>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Diffstat (limited to 'mm/list_lru.c')
| -rw-r--r-- | mm/list_lru.c | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/mm/list_lru.c b/mm/list_lru.c index 84b4c21d78d7..2a6a2e4b64ba 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -103,6 +103,7 @@ bool list_lru_add(struct list_lru *lru, struct list_head *item) if (list_empty(item)) { list_add_tail(item, &l->list); l->nr_items++; + nlru->nr_items++; spin_unlock(&nlru->lock); return true; } @@ -122,6 +123,7 @@ bool list_lru_del(struct list_lru *lru, struct list_head *item) if (!list_empty(item)) { list_del_init(item); l->nr_items--; + nlru->nr_items--; spin_unlock(&nlru->lock); return true; } @@ -169,15 +171,10 @@ EXPORT_SYMBOL_GPL(list_lru_count_one); unsigned long list_lru_count_node(struct list_lru *lru, int nid) { - long count = 0; - int memcg_idx; + struct list_lru_node *nlru; - count += __list_lru_count_one(lru, nid, -1); - if (list_lru_memcg_aware(lru)) { - for_each_memcg_cache_index(memcg_idx) - count += __list_lru_count_one(lru, nid, memcg_idx); - } - return count; + nlru = &lru->node[nid]; + return nlru->nr_items; } EXPORT_SYMBOL_GPL(list_lru_count_node); @@ -212,6 +209,7 @@ restart: assert_spin_locked(&nlru->lock); case LRU_REMOVED: isolated++; + nlru->nr_items--; /* * If the lru lock has been dropped, our list * traversal is now invalid and so we have to |