Re: [RFC] oom-kill: give the dying task a higher priority

[KAMEZAWA Hiroyuki]

On Mon, 31 May 2010 14:01:03 +0900
Minchan Kim <minchan.kim@xxxxxxxxx> wrote:

> Hi, Kame.
> 
> On Mon, May 31, 2010 at 9:21 AM, KAMEZAWA Hiroyuki
> <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> > On Fri, 28 May 2010 13:48:26 -0300
> > "Luis Claudio R. Goncalves" <lclaudio@xxxxxxxx> wrote:
> >>
> >> oom-killer: give the dying task rt priority (v3)
> >>
> >> Give the dying task RT priority so that it can be scheduled quickly and die,
> >> freeing needed memory.
> >>
> >> Signed-off-by: Luis Claudio R. GonÃalves <lgoncalv@xxxxxxxxxx>
> >>
> >> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> >> index 84bbba2..2b0204f 100644
> >> --- a/mm/oom_kill.c
> >> +++ b/mm/oom_kill.c
> >> @@ -266,6 +266,8 @@ static struct task_struct *select_bad_process(unsigned long *ppoints)
> >> Â */
> >> Âstatic void __oom_kill_task(struct task_struct *p, int verbose)
> >> Â{
> >> + Â Â struct sched_param param;
> >> +
> >> Â Â Â if (is_global_init(p)) {
> >> Â Â Â Â Â Â Â WARN_ON(1);
> >> Â Â Â Â Â Â Â printk(KERN_WARNING "tried to kill init!\n");
> >> @@ -288,6 +290,8 @@ static void __oom_kill_task(struct task_struct *p, int verbose)
> >> Â Â Â Â* exit() and clear out its resources quickly...
> >> Â Â Â Â*/
> >> Â Â Â p->time_slice = HZ;
> >> + Â Â param.sched_priority = MAX_RT_PRIO-10;
> >> + Â Â sched_setscheduler(p, SCHED_FIFO, &param);
> >> Â Â Â set_tsk_thread_flag(p, TIF_MEMDIE);
> >>
> >
> > BTW, how about the other threads which share mm_struct ?
> 
> Could you elaborate your intention? :)
> 

IIUC, the purpose of rising priority is to accerate dying thread to exit()
for freeing memory AFAP. But to free memory, exit, all threads which share
mm_struct should exit, too. I'm sorry if I miss something.

Thanks,
-Kame



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