On 2023/8/16 14:48, Michal Hocko wrote:
On Mon 14-08-23 14:34:28, Peng Zhang wrote:
From: ZhangPeng <zhangpeng362@xxxxxxxxxx>
If task is allocating a lot of memory and has been marked to be killed
first, then it gets the highest score (LONG_MAX). Therefore, there is no
need to continue to calculate the points of other tasks. Just terminate
the oom_evaluate_task() loop early, when the task with the highest score
is found. By doing this, we can get some performance gains in
select_bad_process().
The point of evaluating all tasks is that there might be pre-existing
oom victim still being torn down. If you cut this short you might kill
more tasks than necessary.
Indeed. Thanks for your feedback.
So I do not think we want this patch.
To implement it, the return value of oom_evaluate_task() is modified.
When the task with the highest score is found (points == LONG_MAX),
oom_evaluate_task() will return 1 and the loop will terminate early.
Signed-off-by: ZhangPeng <zhangpeng362@xxxxxxxxxx>
---
mm/oom_kill.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 10f7826c4035..02d11ae043aa 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -346,6 +346,8 @@ static int oom_evaluate_task(struct task_struct *task, void *arg)
get_task_struct(task);
oc->chosen = task;
oc->chosen_points = points;
+ if (points == LONG_MAX)
+ return 1;
next:
return 0;
abort:
--
2.25.1
--
Best Regards,
Peng
