X-Git-Url: http://git.cascardo.eti.br/?a=blobdiff_plain;f=mm%2Fslab.c;h=8133ebea77a48e11366f11304119158d82815688;hb=801faf0db894;hp=37600e91742f6f087402422337992433b80b13e4;hpb=213b46958c65c7adaaf3201102da16ce0264e9cf;p=cascardo%2Flinux.git

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()) {