mm, oom: change type of oom_score_adj to short

The maximum oom_score_adj is 1000 and the minimum oom_score_adj is -1000,
so this range can be represented by the signed short type with no
functional change.  The extra space this frees up in struct signal_struct
will be used for per-thread oom kill flags in the next patch.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 7e9e911..37ab4c5 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -53,7 +53,7 @@
  * @old_val.  Usually used to reinstate a previous value to prevent racing with
  * userspacing tuning the value in the interim.
  */
-void compare_swap_oom_score_adj(int old_val, int new_val)
+void compare_swap_oom_score_adj(short old_val, short new_val)
 {
 	struct sighand_struct *sighand = current->sighand;
 
@@ -72,7 +72,7 @@
  * synchronization and returns the old value.  Usually used to temporarily
  * set a value, save the old value in the caller, and then reinstate it later.
  */
-int test_set_oom_score_adj(int new_val)
+short test_set_oom_score_adj(short new_val)
 {
 	struct sighand_struct *sighand = current->sighand;
 	int old_val;
@@ -193,7 +193,7 @@
 	if (!p)
 		return 0;
 
-	adj = p->signal->oom_score_adj;
+	adj = (long)p->signal->oom_score_adj;
 	if (adj == OOM_SCORE_ADJ_MIN) {
 		task_unlock(p);
 		return 0;
@@ -399,7 +399,7 @@
 			continue;
 		}
 
-		pr_info("[%5d] %5d %5d %8lu %8lu %7lu %8lu         %5d %s\n",
+		pr_info("[%5d] %5d %5d %8lu %8lu %7lu %8lu         %5hd %s\n",
 			task->pid, from_kuid(&init_user_ns, task_uid(task)),
 			task->tgid, task->mm->total_vm, get_mm_rss(task->mm),
 			task->mm->nr_ptes,
@@ -415,7 +415,7 @@
 {
 	task_lock(current);
 	pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, "
-		"oom_score_adj=%d\n",
+		"oom_score_adj=%hd\n",
 		current->comm, gfp_mask, order,
 		current->signal->oom_score_adj);
 	cpuset_print_task_mems_allowed(current);