Messages in this thread | | | Date | Tue, 14 Dec 2021 00:08:05 -0800 | From | Christoph Hellwig <> | Subject | Re: [PATCH] blk-mq: make synchronous hw_queue runs RT friendly |
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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.
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