X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=mm%2Fmemcontrol.c;h=7f1a356153c013349ce520c7763002838c02fb76;hb=695c60830764945cf61a2cc623eb1392d137223e;hp=f1a0ae6e11b86b3020c90d7241ba12d47d2bbaa8;hpb=278717909d47d86fbb20ab66dfeaa84560a2f8f2;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f1a0ae6..7f1a356 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -338,7 +338,7 @@ struct mem_cgroup {
 static size_t memcg_size(void)
 {
 	return sizeof(struct mem_cgroup) +
-		nr_node_ids * sizeof(struct mem_cgroup_per_node);
+		nr_node_ids * sizeof(struct mem_cgroup_per_node *);
 }
 
 /* internal only representation about the status of kmem accounting. */
@@ -2694,7 +2694,10 @@ static int __mem_cgroup_try_charge(struct mm_struct *mm,
 		goto bypass;
 
 	if (unlikely(task_in_memcg_oom(current)))
-		goto bypass;
+		goto nomem;
+
+	if (gfp_mask & __GFP_NOFAIL)
+		oom = false;
 
 	/*
 	 * We always charge the cgroup the mm_struct belongs to.
@@ -6352,6 +6355,42 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
 static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
 {
 	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+	/*
+	 * XXX: css_offline() would be where we should reparent all
+	 * memory to prepare the cgroup for destruction.  However,
+	 * memcg does not do css_tryget() and res_counter charging
+	 * under the same RCU lock region, which means that charging
+	 * could race with offlining.  Offlining only happens to
+	 * cgroups with no tasks in them but charges can show up
+	 * without any tasks from the swapin path when the target
+	 * memcg is looked up from the swapout record and not from the
+	 * current task as it usually is.  A race like this can leak
+	 * charges and put pages with stale cgroup pointers into
+	 * circulation:
+	 *
+	 * #0                        #1
+	 *                           lookup_swap_cgroup_id()
+	 *                           rcu_read_lock()
+	 *                           mem_cgroup_lookup()
+	 *                           css_tryget()
+	 *                           rcu_read_unlock()
+	 * disable css_tryget()
+	 * call_rcu()
+	 *   offline_css()
+	 *     reparent_charges()
+	 *                           res_counter_charge()
+	 *                           css_put()
+	 *                             css_free()
+	 *                           pc->mem_cgroup = dead memcg
+	 *                           add page to lru
+	 *
+	 * The bulk of the charges are still moved in offline_css() to
+	 * avoid pinning a lot of pages in case a long-term reference
+	 * like a swapout record is deferring the css_free() to long
+	 * after offlining.  But this makes sure we catch any charges
+	 * made after offlining:
+	 */
+	mem_cgroup_reparent_charges(memcg);
 
 	memcg_destroy_kmem(memcg);
 	__mem_cgroup_free(memcg);