On Tue 07-02-17 13:43:39, Vlastimil Babka wrote: [...] > > Anyway, shouldn't be it sufficient to disable preemption > > on drain_local_pages_wq? The CPU hotplug callback will not preempt us > > and so we cannot work on the same cpus, right? > > I thought the problem here was that the callback races with the work item > that has been migrated to a different cpu. Once we are not working on the > local cpu, disabling preempt/irq's won't help?
If the worker is racing with the callback than only one of can run on a _particular_ cpu. So they cannot race. Or am I missing something? -- Michal Hocko SUSE Labs
