oom: make oom_score to per-process value

oom-killer kills a process, not task.  Then oom_score should be calculated
as per-process too.  it makes consistency more and makes speed up
select_bad_process().

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Paul Menage <menage@google.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>

1 files changed, 29 insertions, 6 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 630b77fe862f..372692294844 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -34,6 +34,23 @@ int sysctl_oom_dump_tasks;
 static DEFINE_SPINLOCK(zone_scan_lock);
 /* #define DEBUG */
 
+/*
+ * Is all threads of the target process nodes overlap ours?
+ */
+static int has_intersects_mems_allowed(struct task_struct *tsk)
+{
+        struct task_struct *t;
+
+        t = tsk;
+        do {
+                if (cpuset_mems_allowed_intersects(current, t))
+                        return 1;
+                t = next_thread(t);
+        } while (t != tsk);
+
+        return 0;
+}
+
 /**
  * badness - calculate a numeric value for how bad this task has been
  * @p: task struct of which task we should calculate
@@ -59,6 +76,9 @@ unsigned long badness(struct task_struct *p, unsigned long uptime)
         struct mm_struct *mm;
         struct task_struct *child;
         int oom_adj = p->signal->oom_adj;
+        struct task_cputime task_time;
+        unsigned long utime;
+        unsigned long stime;
 
         if (oom_adj == OOM_DISABLE)
                 return 0;
@@ -106,8 +126,11 @@ unsigned long badness(struct task_struct *p, unsigned long uptime)
          * of seconds. There is no particular reason for this other than
          * that it turned out to work very well in practice.
          */
-        cpu_time = (cputime_to_jiffies(p->utime) + cputime_to_jiffies(p->stime))
-                >> (SHIFT_HZ + 3);
+        thread_group_cputime(p, &task_time);
+        utime = cputime_to_jiffies(task_time.utime);
+        stime = cputime_to_jiffies(task_time.stime);
+        cpu_time = (utime + stime) >> (SHIFT_HZ + 3);
+
 
         if (uptime >= p->start_time.tv_sec)
                 run_time = (uptime - p->start_time.tv_sec) >> 10;
@@ -148,7 +171,7 @@ unsigned long badness(struct task_struct *p, unsigned long uptime)
          * because p may have allocated or otherwise mapped memory on
          * this node before. However it will be less likely.
          */
-        if (!cpuset_mems_allowed_intersects(current, p))
+        if (!has_intersects_mems_allowed(p))
                 points /= 8;
 
         /*
@@ -204,13 +227,13 @@ static inline enum oom_constraint constrained_alloc(struct zonelist *zonelist,
 static struct task_struct *select_bad_process(unsigned long *ppoints,
                                                 struct mem_cgroup *mem)
 {
-        struct task_struct *g, *p;
+        struct task_struct *p;
         struct task_struct *chosen = NULL;
         struct timespec uptime;
         *ppoints = 0;
 
         do_posix_clock_monotonic_gettime(&uptime);
-        do_each_thread(g, p) {
+        for_each_process(p) {
                 unsigned long points;
 
                 /*
@@ -263,7 +286,7 @@ static struct task_struct *select_bad_process(unsigned long *ppoints,
                         chosen = p;
                         *ppoints = points;
                 }
-        } while_each_thread(g, p);
+        }
 
         return chosen;
 }