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authorDmitry Vyukov <dvyukov@google.com>2017-03-10 03:17:28 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-03-10 04:01:10 +0300
commit68fd814a3391c7e017ae6ace8855788748edd981 (patch)
treed7e188b5825eb5ee3d78090bed16891b7cf3c077
parent40e952f9d687928b32db20226f085ae660a7237c (diff)
downloadlinux-68fd814a3391c7e017ae6ace8855788748edd981.tar.xz
kasan: resched in quarantine_remove_cache()
We see reported stalls/lockups in quarantine_remove_cache() on machines with large amounts of RAM. quarantine_remove_cache() needs to scan whole quarantine in order to take out all objects belonging to the cache. Quarantine is currently 1/32-th of RAM, e.g. on a machine with 256GB of memory that will be 8GB. Moreover quarantine scanning is a walk over uncached linked list, which is slow. Add cond_resched() after scanning of each non-empty batch of objects. Batches are specifically kept of reasonable size for quarantine_put(). On a machine with 256GB of RAM we should have ~512 non-empty batches, each with 16MB of objects. Link: http://lkml.kernel.org/r/20170308154239.25440-1-dvyukov@google.com Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Greg Thelen <gthelen@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/kasan/quarantine.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
index 6f1ed1630873..4ac39f20757a 100644
--- a/mm/kasan/quarantine.c
+++ b/mm/kasan/quarantine.c
@@ -283,8 +283,15 @@ void quarantine_remove_cache(struct kmem_cache *cache)
on_each_cpu(per_cpu_remove_cache, cache, 1);
spin_lock_irqsave(&quarantine_lock, flags);
- for (i = 0; i < QUARANTINE_BATCHES; i++)
+ for (i = 0; i < QUARANTINE_BATCHES; i++) {
+ if (qlist_empty(&global_quarantine[i]))
+ continue;
qlist_move_cache(&global_quarantine[i], &to_free, cache);
+ /* Scanning whole quarantine can take a while. */
+ spin_unlock_irqrestore(&quarantine_lock, flags);
+ cond_resched();
+ spin_lock_irqsave(&quarantine_lock, flags);
+ }
spin_unlock_irqrestore(&quarantine_lock, flags);
qlist_free_all(&to_free, cache);