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.
