+ mm-oom-terminate-the-oom_evaluate_task-loop-early.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm: oom: terminate the oom_evaluate_task() loop early
has been added to the -mm mm-unstable branch.  Its filename is
     mm-oom-terminate-the-oom_evaluate_task-loop-early.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-oom-terminate-the-oom_evaluate_task-loop-early.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: ZhangPeng <zhangpeng362@huawei.com>
Subject: mm: oom: terminate the oom_evaluate_task() loop early
Date: Mon, 14 Aug 2023 14:34:28 +0800

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().

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.

Link: https://lkml.kernel.org/r/20230814063428.4111206-3-zhangpeng362@huawei.com
Signed-off-by: ZhangPeng <zhangpeng362@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/oom_kill.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/mm/oom_kill.c~mm-oom-terminate-the-oom_evaluate_task-loop-early
+++ a/mm/oom_kill.c
@@ -346,6 +346,8 @@ static int oom_evaluate_task(struct task
 	get_task_struct(task);
 	oc->chosen = task;
 	oc->chosen_points = points;
+	if (points == LONG_MAX)
+		return 1;
 next:
 	return 0;
 abort:
_

Patches currently in -mm which might be from zhangpeng362@huawei.com are

mm-kmsan-use-helper-function-page_size.patch
mm-kmsan-use-helper-macro-offset_in_page.patch
mm-kmsan-use-helper-macros-page_align-and-page_align_down.patch
mm-remove-redundant-k-macro-definition.patch
mm-swapfilec-use-helper-macro-k.patch
mm-swap_statec-use-helper-macro-k.patch
mm-shmemc-use-helper-macro-k.patch
mm-nommuc-use-helper-macro-k.patch
mm-mmapc-use-helper-macro-k.patch
mm-hugetlbc-use-helper-macro-k.patch
mm-page_alloc-remove-unused-parameter-from-reserve_highatomic_pageblock.patch
mm-oom-remove-unnecessary-goto-in-oom_evaluate_task.patch
mm-oom-terminate-the-oom_evaluate_task-loop-early.patch