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

KOSAKI Motohiro
2010-06-17T01:56:19Z

> 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.

just cleanup.
ok, I remove this dubious code.

>
> | 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.

ok