Messages in this thread | | | Subject | Re: [PATCH] sched: remove starvation in check_preempt_equal_prio() | From | Steven Rostedt <> | Date | Tue, 24 May 2011 10:46:41 -0400 |
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On Tue, 2011-05-24 at 22:33 +0800, Hillf Danton wrote: > On Tue, May 24, 2011 at 10:24 PM, Steven Rostedt <rostedt@goodmis.org> wrote: > > On Tue, 2011-05-24 at 22:01 +0800, Hillf Danton wrote: > >> On Tue, May 24, 2011 at 9:47 PM, Peter Zijlstra <peterz@infradead.org> wrote: > >> > On Tue, 2011-05-24 at 21:34 +0800, Hillf Danton wrote: > >> >> If there are pushable tasks and they are high enough in priority, in which > >> >> case task p is covered, the current could keep holding its CPU. > >> > > >> > -ENOPARSE.. > >> > > >> > >> Here the priority is same, then pushing task p off has little difference from > >> pushing any other pushable. > > > > If task p is currently running and is a FIFO task, you do not push it > > off for another task of same prio. > > > If it is one of the current principles in RT schedule, the patch has > to be dropped. >
Yes, that is the definition of FIFO (First In First Out). The tasks that get to the CPU first run till they voluntarily schedule away, or are preempted by an even high priority task. Tasks of the same priority must wait till the previous task has finished.
-- Steve
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