Messages in this thread | | | Date | Mon, 12 Sep 2016 17:01:11 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v3] stop_machine: Make migration_cpu_stop() does useful works for CONFIG_PREEMPT_NONE |
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On Mon, Sep 12, 2016 at 03:05:38PM +0200, Oleg Nesterov wrote:
> But this leads to the question which I wanted to ask many times. > > Why cond_resched() is not NOP if CONFIG_PREEMPT=y ?
Dunno, nobody bothered to do it? We should keep the might_sleep() of course, but the preemption check is pointless.
> Perhaps we have some users like, just for example, > > preempt_enable_no_resched(); > cond_resched(); > > which actually want the should_resched() check even if CONFIG_PREEMPT, > but most callers do not?
I would hope not, the few preempt_enable_no_resched() users _should_ have an actual schedule() call in the _very_ near future.
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