mm: shmem: save one radix tree lookup when truncating swapped pages

[platform/adaptation/renesas_rcar/renesas_kernel.git] / mm / oom_kill.c

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 0d8ad1e..171c00f 100644 (file)
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -102,14 +102,19 @@ struct task_struct *find_lock_task_mm(struct task_struct *p)
 {
        struct task_struct *t;
 
+       rcu_read_lock();
+
        for_each_thread(p, t) {
                task_lock(t);
                if (likely(t->mm))
-                       return t;
+                       goto found;
                task_unlock(t);
        }
+       t = NULL;
+found:
+       rcu_read_unlock();
 
-       return NULL;
+       return t;
 }
 
 /* return true if the task is not adequate as candidate victim task. */
@@ -173,7 +178,7 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
         * implementation used by LSMs.
         */
        if (has_capability_noaudit(p, CAP_SYS_ADMIN))
-               adj -= 30;
+               points -= (points * 3) / 100;
 
        /* Normalize to oom_score_adj units */
        adj *= totalpages / 1000;
@@ -322,10 +327,14 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
                        break;
                };
                points = oom_badness(p, NULL, nodemask, totalpages);
-               if (points > chosen_points) {
-                       chosen = p;
-                       chosen_points = points;
-               }
+               if (!points || points < chosen_points)
+                       continue;
+               /* Prefer thread group leaders for display purposes */
+               if (points == chosen_points && thread_group_leader(chosen))
+                       continue;
+
+               chosen = p;
+               chosen_points = points;
        }
        if (chosen)
                get_task_struct(chosen);
@@ -397,6 +406,23 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
                dump_tasks(memcg, nodemask);
 }
 
+/*
+ * Number of OOM killer invocations (including memcg OOM killer).
+ * Primarily used by PM freezer to check for potential races with
+ * OOM killed frozen task.
+ */
+static atomic_t oom_kills = ATOMIC_INIT(0);
+
+int oom_kills_count(void)
+{
+       return atomic_read(&oom_kills);
+}
+
+void note_oom_kill(void)
+{
+       atomic_inc(&oom_kills);
+}
+
 #define K(x) ((x) << (PAGE_SHIFT-10))
 /*
  * Must be called while holding a reference to p, which will be released upon
@@ -461,10 +487,8 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
        }
        read_unlock(&tasklist_lock);
 
-       rcu_read_lock();
        p = find_lock_task_mm(victim);
        if (!p) {
-               rcu_read_unlock();
                put_task_struct(victim);
                return;
        } else if (victim != p) {
@@ -490,6 +514,7 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
         * That thread will now get access to memory reserves since it has a
         * pending fatal signal.
         */
+       rcu_read_lock();
        for_each_process(p)
                if (p->mm == mm && !same_thread_group(p, victim) &&
                    !(p->flags & PF_KTHREAD)) {