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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
parentf88ccad5886d5a864b8b0d48c666ee9998dec53f (diff)
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>
-rw-r--r--fs/proc/base.c5
-rw-r--r--mm/oom_kill.c13
2 files changed, 10 insertions, 8 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c
index acb7ef80ea4f..fc23f62bb0b8 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -428,7 +428,8 @@ static const struct file_operations proc_lstats_operations = {
#endif
/* The badness from the OOM killer */
-unsigned long badness(struct task_struct *p, unsigned long uptime);
+unsigned long badness(struct task_struct *p, struct mem_cgroup *mem,
+ nodemask_t *nodemask, unsigned long uptime);
static int proc_oom_score(struct task_struct *task, char *buffer)
{
unsigned long points = 0;
@@ -437,7 +438,7 @@ static int proc_oom_score(struct task_struct *task, char *buffer)
do_posix_clock_monotonic_gettime(&uptime);
read_lock(&tasklist_lock);
if (pid_alive(task))
- points = badness(task, uptime.tv_sec);
+ points = badness(task, NULL, NULL, uptime.tv_sec);
read_unlock(&tasklist_lock);
return sprintf(buffer, "%lu\n", points);
}
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;