Michal Hocko wrote: > > > > Then, I'm tempted to call __oom_reap_task_mm() before holding mmap_sem for write. > > > > It would be OK to call __oom_reap_task_mm() at the beginning of __mmput()... > > > > > > I am not sure I understand. > > > > To reduce possibility of __oom_reap_task_mm() giving up reclaim and > > setting MMF_OOM_SKIP. > > Still do not understand. Do you want to call __oom_reap_task_mm from > __mmput? Yes. > If yes why would you do so when exit_mmap does a stronger > version of it? Because memory which can be reclaimed by the OOM reaper is guaranteed to be reclaimed before setting MMF_OOM_SKIP when the OOM reaper and exit_mmap() contended, because the OOM reaper (weak reclaim) sets MMF_OOM_SKIP after one second for safety in case of exit_mmap() (strong reclaim) failing to make forward progress.
