On Thursday 14 Jun 2018 at 16:11:18 (+0200), Juri Lelli wrote: > On 14/06/18 14:58, Quentin Perret wrote: > > [...] > > > Hmm not sure if this can help but I think that rebuild_sched_domains() > > does _not_ take the hotplug lock before calling partition_sched_domains() > > when CONFIG_CPUSETS=n. But it does take it for CONFIG_CPUSETS=y. > > Did you mean cpuset_mutex? Nope, I really meant the cpu_hotplug_lock ! With CONFIG_CPUSETS=n, rebuild_sched_domains() calls partition_sched_domains() directly: https://elixir.bootlin.com/linux/latest/source/include/linux/cpuset.h#L255 But with CONFIG_CPUSETS=y, rebuild_sched_domains() calls, rebuild_sched_domains_locked(), which calls get_online_cpus() which calls cpus_read_lock(), which does percpu_down_read(&cpu_hotplug_lock). And all that happens before calling partition_sched_domains(). So yeah, the point I was trying to make is that there is an inconsistency here, maybe for a good reason ? Maybe related to the issue you're seeing ? Thanks, Quentin -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
