From: Luis Claudio R. Goncalves on
Hello,

Could you please review this patch?

The idea behind it is quite simple: give the dying task a higher priority
so that it can be scheduled sooner and die to free memory.


oom-kill: give the dying task a higher priority

In a system under heavy load it was observed that even after the
oom-killer selects a task to die, the task may take a long time to die.

Right before sending a SIGKILL to the selected task the oom-killer
increases the task priority so that it can exit quickly, freeing memory.
That is accomplished by:

/*
* We give our sacrificial lamb high priority and access to
* all the memory it needs. That way it should be able to
* exit() and clear out its resources quickly...
*/
p->rt.time_slice = HZ;
set_tsk_thread_flag(p, TIF_MEMDIE);

It sounds plausible giving the dying task an even higher priority to be
sure it will be scheduled sooner and free the desired memory.

Signed-off-by: Luis Claudio R. Gon�alves <lclaudio(a)uudg.org>

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index b68e802..8047309 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -382,6 +382,8 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
*/
static void __oom_kill_task(struct task_struct *p, int verbose)
{
+ struct sched_param param;
+
if (is_global_init(p)) {
WARN_ON(1);
printk(KERN_WARNING "tried to kill init!\n");
@@ -413,6 +415,8 @@ static void __oom_kill_task(struct task_struct *p, int verbose)
*/
p->rt.time_slice = HZ;
set_tsk_thread_flag(p, TIF_MEMDIE);
+ param.sched_priority = MAX_RT_PRIO-1;
+ sched_setscheduler(p, SCHED_FIFO, &param);

force_sig(SIGKILL, p);
}


Thanks,
Luis
--
[ Luis Claudio R. Goncalves Bass - Gospel - RT ]
[ Fingerprint: 4FDD B8C4 3C59 34BD 8BE9 2696 7203 D980 A448 C8F8 ]

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