On Thu, Dec 9, 2021 at 8:47 AM Michal Hocko <mhocko@xxxxxxxx> wrote: > > On Thu 09-12-21 08:24:04, Suren Baghdasaryan wrote: > > On Thu, Dec 9, 2021 at 1:12 AM Michal Hocko <mhocko@xxxxxxxx> wrote: > > > > > > Do we want this on top? > > > > As we discussed in this thread > > https://lore.kernel.org/all/YY4snVzZZZYhbigV@xxxxxxxxxxxxxx, > > __oom_reap_task_mm in exit_mmap allows oom-reaper/process_mrelease to > > unmap pages in parallel with exit_mmap without blocking each other. > > Removal of __oom_reap_task_mm from exit_mmap prevents this parallelism > > and has a negative impact on performance. So the conclusion of that > > thread I thought was to keep that part. My understanding is that we > > also wanted to remove MMF_OOM_SKIP as a follow-up patch but > > __oom_reap_task_mm would stay. > > OK, then we were talking past each other, I am afraid. I really wanted > to get rid of this oom specific stuff from exit_mmap. It was there out > of necessity. With a proper locking we can finally get rid of the crud. > As I've said previously oom reaping has never been a hot path. > > If we really want to optimize this path then I would much rather see a > generic solution which would allow to move the write lock down after > unmap_vmas. That would require oom reaper to be able to handle mlocked > memory. Ok, let's work on that and when that's done we can get rid of the oom stuff in exit_mmap. I'll look into this over the weekend and will likely be back with questions. Thanks! > -- > Michal Hocko > SUSE Labs
