diff options
| -rw-r--r-- | mm/slab.c | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/mm/slab.c b/mm/slab.c index 37600e91742f..8133ebea77a4 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -965,6 +965,15 @@ static int setup_kmem_cache_node(struct kmem_cache *cachep, spin_unlock_irq(&n->list_lock); slabs_destroy(cachep, &list); + /* + * To protect lockless access to n->shared during irq disabled context. + * If n->shared isn't NULL in irq disabled context, accessing to it is + * guaranteed to be valid until irq is re-enabled, because it will be + * freed after synchronize_sched(). + */ + if (force_change) + synchronize_sched(); + fail: kfree(old_shared); kfree(new_shared); @@ -2893,7 +2902,7 @@ static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags) { int batchcount; struct kmem_cache_node *n; - struct array_cache *ac; + struct array_cache *ac, *shared; int node; void *list = NULL; struct page *page; @@ -2914,11 +2923,16 @@ static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags) n = get_node(cachep, node); BUG_ON(ac->avail > 0 || !n); + shared = READ_ONCE(n->shared); + if (!n->free_objects && (!shared || !shared->avail)) + goto direct_grow; + spin_lock(&n->list_lock); + shared = READ_ONCE(n->shared); /* See if we can refill from the shared array */ - if (n->shared && transfer_objects(ac, n->shared, batchcount)) { - n->shared->touched = 1; + if (shared && transfer_objects(ac, shared, batchcount)) { + shared->touched = 1; goto alloc_done; } @@ -2940,6 +2954,7 @@ alloc_done: spin_unlock(&n->list_lock); fixup_objfreelist_debug(cachep, &list); +direct_grow: if (unlikely(!ac->avail)) { /* Check if we can use obj in pfmemalloc slab */ if (sk_memalloc_socks()) { |