Messages in this thread | | | Subject | Re: [PATCH v2 1/2] mm: drop oom code from exit_mmap | From | Shuah Khan <> | Date | Mon, 16 May 2022 21:12:14 -0600 |
| |
On 5/16/22 1:56 AM, Suren Baghdasaryan wrote: > The primary reason to invoke the oom reaper from the exit_mmap path used > to be a prevention of an excessive oom killing if the oom victim exit > races with the oom reaper (see [1] for more details). The invocation has > moved around since then because of the interaction with the munlock > logic but the underlying reason has remained the same (see [2]). > > Munlock code is no longer a problem since [3] and there shouldn't be > any blocking operation before the memory is unmapped by exit_mmap so > the oom reaper invocation can be dropped. The unmapping part can be done > with the non-exclusive mmap_sem and the exclusive one is only required > when page tables are freed. > > Remove the oom_reaper from exit_mmap which will make the code easier to > read. This is really unlikely to make any observable difference although > some microbenchmarks could benefit from one less branch that needs to be > evaluated even though it almost never is true. > > [1] 212925802454 ("mm: oom: let oom_reap_task and exit_mmap run concurrently") > [2] 27ae357fa82b ("mm, oom: fix concurrent munlock and oom reaper unmap, v3") > [3] a213e5cf71cb ("mm/munlock: delete munlock_vma_pages_all(), allow oomreap") > > Signed-off-by: Suren Baghdasaryan <surenb@google.com> > Acked-by: Michal Hocko <mhocko@suse.com> > --- Looks good to me.
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
thanks, -- Shuah
| |