4 files changed, 93 insertions, 41 deletions

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index c0bff8976a69..2a80544aec99 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -180,7 +180,8 @@ static inline void mem_cgroup_dec_page_stat(struct page *page,
 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
                                                 gfp_t gfp_mask,
                                                 unsigned long *total_scanned);
-u64 mem_cgroup_get_limit(struct mem_cgroup *memcg);
+extern void __mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
+                                       int order);
 
 void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx);
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -364,12 +365,6 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
         return 0;
 }
 
-static inline
-u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
-{
-        return 0;
-}
-
 static inline void mem_cgroup_split_huge_fixup(struct page *head)
 {
 }
diff --git a/include/linux/oom.h b/include/linux/oom.h
index eb9dc14362c5..5dc0e384ae9e 100644
--- a/include/linux/oom.h
+++ b/include/linux/oom.h
@@ -40,17 +40,33 @@ enum oom_constraint {
         CONSTRAINT_MEMCG,
 };
 
+enum oom_scan_t {
+        OOM_SCAN_OK,            /* scan thread and find its badness */
+        OOM_SCAN_CONTINUE,      /* do not consider thread for oom kill */
+        OOM_SCAN_ABORT,         /* abort the iteration and return */
+        OOM_SCAN_SELECT,        /* always select this thread first */
+};
+
 extern void compare_swap_oom_score_adj(int old_val, int new_val);
 extern int test_set_oom_score_adj(int new_val);
 
 extern unsigned long oom_badness(struct task_struct *p,
                 struct mem_cgroup *memcg, const nodemask_t *nodemask,
                 unsigned long totalpages);
+extern void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
+                             unsigned int points, unsigned long totalpages,
+                             struct mem_cgroup *memcg, nodemask_t *nodemask,
+                             const char *message);
+
 extern int try_set_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_flags);
 extern void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_flags);
 
+extern enum oom_scan_t oom_scan_process_thread(struct task_struct *task,
+                unsigned long totalpages, const nodemask_t *nodemask,
+                bool force_kill);
 extern void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
                                      int order);
+
 extern void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
                 int order, nodemask_t *mask, bool force_kill);
 extern int register_oom_notifier(struct notifier_block *nb);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 4f73c823c59f..b78972e2f43f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1453,7 +1453,7 @@ static int mem_cgroup_count_children(struct mem_cgroup *memcg)
 /*
  * Return the memory (and swap, if configured) limit for a memcg.
  */
-u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
+static u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
 {
         u64 limit;
         u64 memsw;
@@ -1469,6 +1469,65 @@ u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
         return min(limit, memsw);
 }
 
+void __mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
+                                int order)
+{
+        struct mem_cgroup *iter;
+        unsigned long chosen_points = 0;
+        unsigned long totalpages;
+        unsigned int points = 0;
+        struct task_struct *chosen = NULL;
+
+        totalpages = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT ? : 1;
+        for_each_mem_cgroup_tree(iter, memcg) {
+                struct cgroup *cgroup = iter->css.cgroup;
+                struct cgroup_iter it;
+                struct task_struct *task;
+
+                cgroup_iter_start(cgroup, &it);
+                while ((task = cgroup_iter_next(cgroup, &it))) {
+                        switch (oom_scan_process_thread(task, totalpages, NULL,
+                                                        false)) {
+                        case OOM_SCAN_SELECT:
+                                if (chosen)
+                                        put_task_struct(chosen);
+                                chosen = task;
+                                chosen_points = ULONG_MAX;
+                                get_task_struct(chosen);
+                                /* fall through */
+                        case OOM_SCAN_CONTINUE:
+                                continue;
+                        case OOM_SCAN_ABORT:
+                                cgroup_iter_end(cgroup, &it);
+                                mem_cgroup_iter_break(memcg, iter);
+                                if (chosen)
+                                        put_task_struct(chosen);
+                                return;
+                        case OOM_SCAN_OK:
+                                break;
+                        };
+                        points = oom_badness(task, memcg, NULL, totalpages);
+                        if (points > chosen_points) {
+                                if (chosen)
+                                        put_task_struct(chosen);
+                                chosen = task;
+                                chosen_points = points;
+                                get_task_struct(chosen);
+                        }
+                }
+                cgroup_iter_end(cgroup, &it);
+        }
+
+        if (!chosen)
+                return;
+        points = chosen_points * 1000 / totalpages;
+        read_lock(&tasklist_lock);
+        oom_kill_process(chosen, gfp_mask, order, points, totalpages, memcg,
+                         NULL, "Memory cgroup out of memory");
+        read_unlock(&tasklist_lock);
+        put_task_struct(chosen);
+}
+
 static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg,
                                         gfp_t gfp_mask,
                                         unsigned long flags)
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index f8eba9651c0c..c0c97aea837f 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -288,20 +288,13 @@ static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
 }
 #endif
 
-enum oom_scan_t {
-        OOM_SCAN_OK,            /* scan thread and find its badness */
-        OOM_SCAN_CONTINUE,      /* do not consider thread for oom kill */
-        OOM_SCAN_ABORT,         /* abort the iteration and return */
-        OOM_SCAN_SELECT,        /* always select this thread first */
-};
-
-static enum oom_scan_t oom_scan_process_thread(struct task_struct *task,
-                struct mem_cgroup *memcg, unsigned long totalpages,
-                const nodemask_t *nodemask, bool force_kill)
+enum oom_scan_t oom_scan_process_thread(struct task_struct *task,
+                unsigned long totalpages, const nodemask_t *nodemask,
+                bool force_kill)
 {
         if (task->exit_state)
                 return OOM_SCAN_CONTINUE;
-        if (oom_unkillable_task(task, memcg, nodemask))
+        if (oom_unkillable_task(task, NULL, nodemask))
                 return OOM_SCAN_CONTINUE;
 
         /*
@@ -348,8 +341,8 @@ static enum oom_scan_t oom_scan_process_thread(struct task_struct *task,
  * (not docbooked, we don't want this one cluttering up the manual)
  */
 static struct task_struct *select_bad_process(unsigned int *ppoints,
-                unsigned long totalpages, struct mem_cgroup *memcg,
-                const nodemask_t *nodemask, bool force_kill)
+                unsigned long totalpages, const nodemask_t *nodemask,
+                bool force_kill)
 {
         struct task_struct *g, *p;
         struct task_struct *chosen = NULL;
@@ -358,7 +351,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
         do_each_thread(g, p) {
                 unsigned int points;
 
-                switch (oom_scan_process_thread(p, memcg, totalpages, nodemask,
+                switch (oom_scan_process_thread(p, totalpages, nodemask,
                                                 force_kill)) {
                 case OOM_SCAN_SELECT:
                         chosen = p;
@@ -371,7 +364,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
                 case OOM_SCAN_OK:
                         break;
                 };
-                points = oom_badness(p, memcg, nodemask, totalpages);
+                points = oom_badness(p, NULL, nodemask, totalpages);
                 if (points > chosen_points) {
                         chosen = p;
                         chosen_points = points;
@@ -443,10 +436,10 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
 }
 
 #define K(x) ((x) << (PAGE_SHIFT-10))
-static void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
-                             unsigned int points, unsigned long totalpages,
-                             struct mem_cgroup *memcg, nodemask_t *nodemask,
-                             const char *message)
+void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
+                      unsigned int points, unsigned long totalpages,
+                      struct mem_cgroup *memcg, nodemask_t *nodemask,
+                      const char *message)
 {
         struct task_struct *victim = p;
         struct task_struct *child;
@@ -564,10 +557,6 @@ static void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask,
 void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
                               int order)
 {
-        unsigned long limit;
-        unsigned int points = 0;
-        struct task_struct *p;
-
         /*
          * If current has a pending SIGKILL, then automatically select it.  The
          * goal is to allow it to allocate so that it may quickly exit and free
@@ -579,13 +568,7 @@ void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
         }
 
         check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
-        limit = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT ? : 1;
-        read_lock(&tasklist_lock);
-        p = select_bad_process(&points, limit, memcg, NULL, false);
-        if (p && PTR_ERR(p) != -1UL)
-                oom_kill_process(p, gfp_mask, order, points, limit, memcg, NULL,
-                                 "Memory cgroup out of memory");
-        read_unlock(&tasklist_lock);
+        __mem_cgroup_out_of_memory(memcg, gfp_mask, order);
 }
 #endif
 
@@ -710,7 +693,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
         struct task_struct *p;
         unsigned long totalpages;
         unsigned long freed = 0;
-        unsigned int points;
+        unsigned int uninitialized_var(points);
         enum oom_constraint constraint = CONSTRAINT_NONE;
         int killed = 0;
 
@@ -748,8 +731,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
                 goto out;
         }
 
-        p = select_bad_process(&points, totalpages, NULL, mpol_mask,
-                               force_kill);
+        p = select_bad_process(&points, totalpages, mpol_mask, force_kill);
         /* Found nothing?!?! Either we hang forever, or we panic. */
         if (!p) {
                 dump_header(NULL, gfp_mask, order, NULL, mpol_mask);