Messages in this thread | | | Date | Thu, 11 Nov 2021 10:20:36 +0100 | From | Michal Hocko <> | Subject | Re: [PATCH 1/1] mm: prevent a race between process_mrelease and exit_mmap |
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On Wed 10-11-21 17:49:37, Suren Baghdasaryan wrote: > On Tue, Nov 9, 2021 at 1:10 PM Suren Baghdasaryan <surenb@google.com> wrote: > > > > On Tue, Nov 9, 2021 at 12:10 PM Michal Hocko <mhocko@suse.com> wrote: [...] > > > Yes, those can run concurrently. One thing I completely forgot about is > > > 27ae357fa82b ("mm, oom: fix concurrent munlock and oom reaper unmap, v3") > > > which is about interaction with the munlock. > > Agrh! This interaction with the munlock you mentioned requires us to > take mmap_write_lock before munlock_vma_pages_all and that prevents > __oom_reap_task_mm from running concurrently with unmap_vmas. The > reapers would not be as effective as they are now after such a change > :(
__oom_reap_task_mm will not run concurrently with unmap_vmas even with the current code. The mmap_sem barrier right before munlock code prevents that.
-- Michal Hocko SUSE Labs
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