Re: [PATCH 1/2] mm, oom: introduce oom reaper

[Andrew Morton]

On Fri, 18 Dec 2015 12:54:55 +0100 Michal Hocko <mhocko@xxxxxxxxxx> wrote:

>  	/* Retry the down_read_trylock(mmap_sem) a few times */
> -	while (attempts++ < 10 && !__oom_reap_vmas(mm))
> -		msleep_interruptible(100);
> +	while (attempts++ < 10 && !__oom_reap_vmas(mm)) {
> +		__set_task_state(current, TASK_IDLE);
> +		schedule_timeout(HZ/10);
> +	}

If you won't, I shall ;)


From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Subject: sched: add schedule_timeout_idle()

This will be needed in the patch "mm, oom: introduce oom reaper".

Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 include/linux/sched.h |    1 +
 kernel/time/timer.c   |   11 +++++++++++
 2 files changed, 12 insertions(+)

diff -puN kernel/time/timer.c~sched-add-schedule_timeout_idle kernel/time/timer.c
--- a/kernel/time/timer.c~sched-add-schedule_timeout_idle
+++ a/kernel/time/timer.c
@@ -1566,6 +1566,17 @@ signed long __sched schedule_timeout_uni
 }
 EXPORT_SYMBOL(schedule_timeout_uninterruptible);
 
+/*
+ * Like schedule_timeout_uninterruptible(), except this task will not contribute
+ * to load average.
+ */
+signed long __sched schedule_timeout_idle(signed long timeout)
+{
+	__set_current_state(TASK_IDLE);
+	return schedule_timeout(timeout);
+}
+EXPORT_SYMBOL(schedule_timeout_idle);
+
 #ifdef CONFIG_HOTPLUG_CPU
 static void migrate_timer_list(struct tvec_base *new_base, struct hlist_head *head)
 {
diff -puN include/linux/sched.h~sched-add-schedule_timeout_idle include/linux/sched.h
--- a/include/linux/sched.h~sched-add-schedule_timeout_idle
+++ a/include/linux/sched.h
@@ -423,6 +423,7 @@ extern signed long schedule_timeout(sign
 extern signed long schedule_timeout_interruptible(signed long timeout);
 extern signed long schedule_timeout_killable(signed long timeout);
 extern signed long schedule_timeout_uninterruptible(signed long timeout);
+extern signed long schedule_timeout_idle(signed long timeout);
 asmlinkage void schedule(void);
 extern void schedule_preempt_disabled(void);
 
_

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