Messages in this thread | | | Date | Mon, 14 Dec 2020 18:36:46 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 00/10] workqueue: break affinity initiatively |
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On Mon, Dec 14, 2020 at 11:54:47PM +0800, Lai Jiangshan wrote: > From: Lai Jiangshan <laijs@linux.alibaba.com> > > 06249738a41a ("workqueue: Manually break affinity on hotplug") > said that scheduler will not force break affinity for us. > > But workqueue highly depends on the old behavior. Many parts of the codes > relies on it, 06249738a41a ("workqueue: Manually break affinity on hotplug") > is not enough to change it, and the commit has flaws in itself too. > > We need to thoroughly update the way workqueue handles affinity > in cpu hot[un]plug, what is this patchset intends to do and > replace the Valentin Schneider's patch [1].
So the actual problem is with per-cpu kthreads, the new assumption is that hot-un-plug will make all per-cpu kthreads for the dying CPU go away.
Workqueues violated that. I fixed the obvious site, and Valentin's patch avoids workqueues from quickly creating new ones while we're not looking.
What other problems did you find?
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