Messages in this thread | | | Date | Wed, 29 Apr 2020 01:02:04 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC PATCH 1/3] sched/fair: Call newidle_balance() from finish_task_switch() |
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On Tue, Apr 28, 2020 at 05:55:03PM -0500, Scott Wood wrote: > On Wed, 2020-04-29 at 00:09 +0200, Peter Zijlstra wrote:
> > Also, if you move it this late, this is entirely the wrong place. If you > > do it after the context switch either use the balance_callback or put it > > in the idle path. > > > > But what Valentin said; this needs a fair bit of support, the whole > > reason we've never done this is to avoid that double context switch... > > > > balance_callback() enters with the rq lock held but BH not separately
BH? softirqs you mean? Pray tell more.
> disabled, which interferes with the ability to enable interrupts but not BH. > It also gets called from rt_mutex_setprio() and __sched_setscheduler(), and > I didn't want the caller of those to be stuck with the latency.
You're not reading it right.
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