On Mon, Dec 13, 2021 at 11:05:29AM -0800, Davidlohr Bueso wrote: > On Mon, 13 Dec 2021, Christoph Hellwig wrote: > > But more importantly: why isn't migrate_disable/enable doing the right > > thing for !PREEMPT_RT to avoid this mess? > > Please see Peter's description of the situation in af449901b84. That explains why migrate_disable is a bad idea in PREEMPT_RT, not why it can't do something sensible for !PREEMPT_RT… > > While I'm not at all a fan of sprinkling migrate_disabling around code, > I didn't want to add any overhead for the common case. If this, however, > were not an issue (if most cases are async runs, for example) the ideal > solution I think would be to just pin current to the hctx->cpumask. sync running is the performance case.
