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

Luis Claudio R. Goncalves
2010-06-16T19:55:00Z

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 ]
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