Messages in this thread | | | Date | Wed, 4 Sep 2019 13:11:27 +0200 | From | Oleg Nesterov <> | Subject | Re: [RFC PATCH 1/2] Fix: sched/membarrier: p->mm->membarrier_state racy load |
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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?
Oleg.
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