On 2020-10-27 17:23:09 [+0000], Christoph Hellwig wrote: > On Tue, Oct 27, 2020 at 06:05:15PM +0100, Thomas Gleixner wrote: > > > Is there a way to raise a softirq and preferably place it on a given > > > CPU without our IPI dance? That should be a win-win situation for > > > everyone. > > > > Not really. Softirq pending bits are strictly per cpu and we don't have > > locking or atomics to set them remotely. Even if we had that, then you'd > > still need a mechanism to make sure that the remote CPU actually > > processes them. So you'd still need an IPI of some sorts. > > Ok. I was hoping we could hide this in core code somehow, especially > a peterz didn't like the use of smp_call_function_single_async in the > blk-mq completion code very much. > > Sebastian, would this solve your preempt-rt and lockdep issues? second. I'm cooking something. Sebastian
