Re: [PATCH 9/9] oom: give the dying task a higher priority

["Luis Claudio R. Goncalves" <lclaudio@uudg.org>]

On Thu, Jun 17, 2010 at 12:31:20AM +0900, Minchan Kim wrote:
| >         /*
| >          * 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);
...
| > +	if (rt_task(p)) {
| > +		p->rt.time_slice = HZ;
| > +		return;

I am not sure the code above will have any real effect for an RT task.
Kosaki-san, was this change motivated by test results or was it just a code
cleanup? I ask that out of curiosity.

| I have a question from long time ago. 
| If we change rt.time_slice _without_ setscheduler, is it effective?
| I mean scheduler pick up the task faster than other normal task?

$ git log --pretty=oneline -Stime_slice mm/oom_kill.c
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2

This code ("time_slice = HZ;") is around for quite a while and
probably comes from a time where having a big time slice was enough to be
sure you would be the next on the line. I would say sched_setscheduler is
indeed necessary.

Regards,
Luis
-- 
[ Luis Claudio R. Goncalves             Red Hat  -  Realtime Team ]
[ Fingerprint: 4FDD B8C4 3C59 34BD 8BE9  2696 7203 D980 A448 C8F8 ]