Peter Zijlstra <peterz@xxxxxxxxxxxxx> writes: > On Thu, Feb 04, 2021 at 12:50:34PM +0000, Alexey Klimov wrote: >> On Thu, Feb 4, 2021 at 9:46 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: >> > >> > On Thu, Feb 04, 2021 at 01:01:57AM +0000, Alexey Klimov wrote: >> > > @@ -1281,6 +1282,11 @@ static int cpu_up(unsigned int cpu, enum cpuhp_state target) >> > > err = _cpu_up(cpu, 0, target); >> > > out: >> > > cpu_maps_update_done(); >> > > + >> > > + /* To avoid out of line uevent */ >> > > + if (!err) >> > > + cpuset_wait_for_hotplug(); >> > > + >> > > return err; >> > > } >> > > >> > >> > > @@ -2071,14 +2075,18 @@ static void cpuhp_online_cpu_device(unsigned int cpu) >> > > struct device *dev = get_cpu_device(cpu); >> > > >> > > dev->offline = false; >> > > - /* Tell user space about the state change */ >> > > - kobject_uevent(&dev->kobj, KOBJ_ONLINE); >> > > } >> > > >> > >> > One concequence of this is that you'll now get a bunch of notifications >> > across things like suspend/hybernate. >> >> The patch doesn't change the number of kobject_uevent()s. The >> userspace will get the same number of uevents as before the patch (at >> least if I can rely on my eyes). > > bringup_hibernate_cpu() didn't used to generate an event, it does now. > Same for bringup_nonboot_cpus(). Both of those call cpu_up(), which only gets a cpuset_wait_for_hotplug() in this patch. No new events generated from that, right, it's just a wrapper for a flush_work()? > Also, looking again, you don't seem to be reinstating the OFFLINE event > you took out. It seems to be reinstated in cpuhp_smt_disable()?
