Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Thu, 12 Dec 2019 17:49:54 +0100 | Subject | Re: [PATCH] cpufreq: Avoid leaving stale IRQ work items during CPU offline |
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On Wed, Dec 11, 2019 at 2:53 PM Peng Fan <peng.fan@nxp.com> wrote: > > > Subject: [PATCH] cpufreq: Avoid leaving stale IRQ work items during CPU > > offline > > > > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > > > The scheduler code calling cpufreq_update_util() may run during CPU offline > > on the target CPU after the IRQ work lists have been flushed for it, so the > > target CPU should be prevented from running code that may queue up an IRQ > > work item on it at that point. > > > > Unfortunately, that may not be the case if dvfs_possible_from_any_cpu is set > > for at least one cpufreq policy in the system, because that allows the CPU > > going offline to run the utilization update callback of the cpufreq governor on > > behalf of another (online) CPU in some cases. > > > > If that happens, the cpufreq governor callback may queue up an IRQ work on > > the CPU running it, which is going offline, and the IRQ work will not be flushed > > "will" -> "might"
Well, I'm not sure, but OK.
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