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authorKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>2010-08-09 17:19:37 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-08-09 20:45:01 -0700
commit26ebc984913b6a8d86d724b3a79d2ed4ed574612 (patch)
tree9d293c6f8b1bc5120beaa173590dcd83cd0e2eb0 /mm/oom_kill.c
parentf88ccad5886d5a864b8b0d48c666ee9998dec53f (diff)
downloadlinux-26ebc984913b6a8d86d724b3a79d2ed4ed574612.tar.gz
oom: /proc/<pid>/oom_score treat kernel thread honestly
If a kernel thread is using use_mm(), badness() returns a positive value.
This is not a big issue because caller take care of it correctly.  But
there is one exception, /proc/<pid>/oom_score calls badness() directly and
doesn't care that the task is a regular process.

Another example, /proc/1/oom_score return !0 value.  But it's unkillable.
This incorrectness makes administration a little confusing.

This patch fixes it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/oom_kill.c')
-rw-r--r--mm/oom_kill.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 3999747aef48..867bd26274b4 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -139,8 +139,8 @@ static bool oom_unkillable_task(struct task_struct *p, struct mem_cgroup *mem,
  *    algorithm has been meticulously tuned to meet the principle
  *    of least surprise ... (be careful when you change it)
  */
-
-unsigned long badness(struct task_struct *p, unsigned long uptime)
+unsigned long badness(struct task_struct *p, struct mem_cgroup *mem,
+		      const nodemask_t *nodemask, unsigned long uptime)
 {
 	unsigned long points, cpu_time, run_time;
 	struct task_struct *child;
@@ -150,6 +150,8 @@ unsigned long badness(struct task_struct *p, unsigned long uptime)
 	unsigned long utime;
 	unsigned long stime;
 
+	if (oom_unkillable_task(p, mem, nodemask))
+		return 0;
 	if (oom_adj == OOM_DISABLE)
 		return 0;
 
@@ -351,7 +353,7 @@ static struct task_struct *select_bad_process(unsigned long *ppoints,
 		if (p->signal->oom_adj == OOM_DISABLE)
 			continue;
 
-		points = badness(p, uptime.tv_sec);
+		points = badness(p, mem, nodemask, uptime.tv_sec);
 		if (points > *ppoints || !chosen) {
 			chosen = p;
 			*ppoints = points;
@@ -482,11 +484,10 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
 
 			if (child->mm == p->mm)
 				continue;
-			if (oom_unkillable_task(p, mem, nodemask))
-				continue;
 
 			/* badness() returns 0 if the thread is unkillable */
-			child_points = badness(child, uptime.tv_sec);
+			child_points = badness(child, mem, nodemask,
+					       uptime.tv_sec);
 			if (child_points > victim_points) {
 				victim = child;
 				victim_points = child_points;