memcontrol: move oom task exclusion to tasklist scan

Creates a helper function to return non-zero if a task is a member of a
memory controller:

	int task_in_mem_cgroup(const struct task_struct *task,
			       const struct mem_cgroup *mem);

When the OOM killer is constrained by the memory controller, the exclusion
of tasks that are not a member of that controller was previously misplaced
and appeared in the badness scoring function.  It should be excluded
during the tasklist scan in select_bad_process() instead.

[akpm@linux-foundation.org: build fix]
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 7 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 64751dc..ef5084d 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -65,13 +65,6 @@ unsigned long badness(struct task_struct *p, unsigned long uptime,
 		return 0;
 	}
 
-#ifdef CONFIG_CGROUP_MEM_CONT
-	if (mem != NULL && mm->mem_cgroup != mem) {
-		task_unlock(p);
-		return 0;
-	}
-#endif
-
 	/*
 	 * The memory size of the process is the basis for the badness.
 	 */
@@ -223,6 +216,8 @@ static struct task_struct *select_bad_process(unsigned long *ppoints,
 		/* skip the init task */
 		if (is_global_init(p))
 			continue;
+		if (mem && !task_in_mem_cgroup(p, mem))
+			continue;
 
 		/*
 		 * This task already has access to memory reserves and is