oom: do not dump task state for non thread group leaders

When /proc/sys/vm/oom_dump_tasks is enabled, it's only necessary to dump
task state information for thread group leaders.  The kernel log gets
quickly overwhelmed on machines with a massive number of threads by
dumping non-thread group leaders.

Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
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, 0 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 64e5b4bcd964..2846a58e5de9 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -295,6 +295,8 @@ static void dump_tasks(const struct mem_cgroup *mem)
                         continue;
                 if (mem && !task_in_mem_cgroup(p, mem))
                         continue;
+                if (!thread_group_leader(p))
+                        continue;
 
                 task_lock(p);
                 printk(KERN_INFO "[%5d] %5d %5d %8lu %8lu %3d     %3d %s\n",