Messages in this thread | | | Date | Sun, 8 Sep 2019 09:46:04 -0400 (EDT) | From | Mathieu Desnoyers <> | Subject | Re: [RFC PATCH 1/2] Fix: sched/membarrier: p->mm->membarrier_state racy load |
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----- On Sep 4, 2019, at 12:11 PM, Oleg Nesterov oleg@redhat.com wrote:
> with or without these changes... > > Why do membarrier_register_*_expedited() check get_nr_threads() == 1? > This makes no sense to me, atomic_read(mm_users) == 1 should be enough. > > > And I am not sure I understand membarrier_mm_sync_core_before_usermode(). > OK, membarrier_private_expedited() can race with user -> kernel -> user > transition, but we do not care unless both user's above have the same mm? > Shouldn't membarrier_mm_sync_core_before_usermode() do > > if (current->mm != mm) > return; > > at the start to make it more clear and avoid sync_core_before_usermode() > if possible?
I think I missed replying to your email. Indeed, you are right, I've added 2 cleanup patches taking care of this in my latest round.
Thanks,
Mathieu
-- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
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