3 files changed, 22 insertions, 32 deletions

diff --git a/fs/proc/base.c b/fs/proc/base.c
index d2d3108a611..d7d711876b6 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -411,12 +411,13 @@ static const struct file_operations proc_lstats_operations = {
 
 static int proc_oom_score(struct task_struct *task, char *buffer)
 {
+        unsigned long totalpages = totalram_pages + total_swap_pages;
         unsigned long points = 0;
 
         read_lock(&tasklist_lock);
         if (pid_alive(task))
-                points = oom_badness(task, NULL, NULL,
-                                        totalram_pages + total_swap_pages);
+                points = oom_badness(task, NULL, NULL, totalpages) *
+                                                1000 / totalpages;
         read_unlock(&tasklist_lock);
         return sprintf(buffer, "%lu\n", points);
 }
diff --git a/include/linux/oom.h b/include/linux/oom.h
index 3d7647536b0..e4c29bc72e7 100644
--- a/include/linux/oom.h
+++ b/include/linux/oom.h
@@ -43,8 +43,9 @@ enum oom_constraint {
 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 int oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
-                        const nodemask_t *nodemask, unsigned long totalpages);
+extern unsigned long oom_badness(struct task_struct *p,
+                struct mem_cgroup *memcg, const nodemask_t *nodemask,
+                unsigned long totalpages);
 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);
 
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 9f09a1fde9f..ed0e1967736 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -180,10 +180,10 @@ static bool oom_unkillable_task(struct task_struct *p,
  * predictable as possible.  The goal is to return the highest value for the
  * task consuming the most memory to avoid subsequent oom failures.
  */
-unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
-                      const nodemask_t *nodemask, unsigned long totalpages)
+unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
+                          const nodemask_t *nodemask, unsigned long totalpages)
 {
-        long points;
+        unsigned long points;
 
         if (oom_unkillable_task(p, memcg, nodemask))
                 return 0;
@@ -198,21 +198,11 @@ unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
         }
 
         /*
-         * The memory controller may have a limit of 0 bytes, so avoid a divide
-         * by zero, if necessary.
-         */
-        if (!totalpages)
-                totalpages = 1;
-
-        /*
          * The baseline for the badness score is the proportion of RAM that each
          * task's rss, pagetable and swap space use.
          */
-        points = get_mm_rss(p->mm) + p->mm->nr_ptes;
-        points += get_mm_counter(p->mm, MM_SWAPENTS);
-
-        points *= 1000;
-        points /= totalpages;
+        points = get_mm_rss(p->mm) + p->mm->nr_ptes +
+                 get_mm_counter(p->mm, MM_SWAPENTS);
         task_unlock(p);
 
         /*
@@ -220,23 +210,20 @@ unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
          * implementation used by LSMs.
          */
         if (has_capability_noaudit(p, CAP_SYS_ADMIN))
-                points -= 30;
+                points -= 30 * totalpages / 1000;
 
         /*
          * /proc/pid/oom_score_adj ranges from -1000 to +1000 such that it may
          * either completely disable oom killing or always prefer a certain
          * task.
          */
-        points += p->signal->oom_score_adj;
+        points += p->signal->oom_score_adj * totalpages / 1000;
 
         /*
-         * Never return 0 for an eligible task that may be killed since it's
-         * possible that no single user task uses more than 0.1% of memory and
-         * no single admin tasks uses more than 3.0%.
+         * Never return 0 for an eligible task regardless of the root bonus and
+         * oom_score_adj (oom_score_adj can't be OOM_SCORE_ADJ_MIN here).
          */
-        if (points <= 0)
-                return 1;
-        return (points < 1000) ? points : 1000;
+        return points ? points : 1;
 }
 
 /*
@@ -314,7 +301,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
 {
         struct task_struct *g, *p;
         struct task_struct *chosen = NULL;
-        *ppoints = 0;
+        unsigned long chosen_points = 0;
 
         do_each_thread(g, p) {
                 unsigned int points;
@@ -354,7 +341,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
                          */
                         if (p == current) {
                                 chosen = p;
-                                *ppoints = 1000;
+                                chosen_points = ULONG_MAX;
                         } else if (!force_kill) {
                                 /*
                                  * If this task is not being ptraced on exit,
@@ -367,12 +354,13 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
                 }
 
                 points = oom_badness(p, memcg, nodemask, totalpages);
-                if (points > *ppoints) {
+                if (points > chosen_points) {
                         chosen = p;
-                        *ppoints = points;
+                        chosen_points = points;
                 }
         } while_each_thread(g, p);
 
+        *ppoints = chosen_points * 1000 / totalpages;
         return chosen;
 }
 
@@ -572,7 +560,7 @@ 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;
+        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)