On Mon, May 18, 2020 at 08:38:04PM +0200, Thomas Gleixner wrote: > > Shouldn't all the per-cpu kthreads also stop as part of the offlining? > > If they don't quiesce before the new blk-mq stop state I think we need > > to make sure they do. It is rather pointless to quiesce the requests > > if a thread that can submit I/O is still live. > > Which kthreads are you talking about? I think PF_KTHREAD threads bound to single cpu will usually be workqueues, yes. > Workqueues? CPU bound workqueues are shut down in > CPUHP_AP_WORKQUEUE_ONLINE state. That's what I mean. If we shut down I/O before that happend we'd have a problem, but as I expected your state machine is smarter than that :)
