From: Suren Baghdasaryan <surenb@google.com>
To: Michal Hocko <mhocko@suse.com>
Cc: akpm@linux-foundation.org, rientjes@google.com,
willy@infradead.org, hannes@cmpxchg.org, guro@fb.com,
riel@surriel.com, minchan@kernel.org, kirill@shutemov.name,
aarcange@redhat.com, christian@brauner.io, hch@infradead.org,
oleg@redhat.com, david@redhat.com, jannh@google.com,
shakeelb@google.com, luto@kernel.org,
christian.brauner@ubuntu.com, fweimer@redhat.com,
jengelh@inai.de, timmurray@google.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, kernel-team@android.com
Subject: Re: [PATCH 4/3] mm: drop MMF_OOM_SKIP from exit_mmap
Date: Thu, 9 Dec 2021 09:06:52 -0800 [thread overview]
Message-ID: <CAJuCfpHs_25TQ7pHDhPXghA46jmXa5N2OOeBByE-sn+dQ-aM2w@mail.gmail.com> (raw)
In-Reply-To: <YbIzOR13uPOI5EMB@dhcp22.suse.cz>
On Thu, Dec 9, 2021 at 8:47 AM Michal Hocko <mhocko@suse.com> wrote:
>
> On Thu 09-12-21 08:24:04, Suren Baghdasaryan wrote:
> > On Thu, Dec 9, 2021 at 1:12 AM Michal Hocko <mhocko@suse.com> wrote:
> > >
> > > Do we want this on top?
> >
> > As we discussed in this thread
> > https://lore.kernel.org/all/YY4snVzZZZYhbigV@dhcp22.suse.cz,
> > __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
next prev parent reply other threads:[~2021-12-09 17:07 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-08 21:22 [PATCH v4 1/3] mm: protect free_pgtables with mmap_lock write lock in exit_mmap Suren Baghdasaryan
2021-12-08 21:22 ` [PATCH v4 2/3] mm: document locking restrictions for vm_operations_struct::close Suren Baghdasaryan
2021-12-09 8:55 ` Michal Hocko
2021-12-08 21:22 ` [PATCH v4 3/3] mm/oom_kill: allow process_mrelease to run under mmap_lock protection Suren Baghdasaryan
2021-12-09 8:59 ` Michal Hocko
2021-12-09 19:03 ` Suren Baghdasaryan
2021-12-09 8:55 ` [PATCH v4 1/3] mm: protect free_pgtables with mmap_lock write lock in exit_mmap Michal Hocko
2021-12-09 19:03 ` Suren Baghdasaryan
2021-12-10 9:20 ` Michal Hocko
2021-12-09 9:12 ` [PATCH 4/3] mm: drop MMF_OOM_SKIP from exit_mmap Michal Hocko
2021-12-09 16:24 ` Suren Baghdasaryan
2021-12-09 16:47 ` Michal Hocko
2021-12-09 17:06 ` Suren Baghdasaryan [this message]
2021-12-16 2:26 ` Suren Baghdasaryan
2021-12-16 11:49 ` Johannes Weiner
2021-12-16 17:23 ` Suren Baghdasaryan
2021-12-30 5:59 ` Suren Baghdasaryan
2021-12-30 8:24 ` Michal Hocko
2021-12-30 17:29 ` Suren Baghdasaryan
2022-01-03 12:11 ` Michal Hocko
2022-01-03 21:16 ` Hugh Dickins
2022-01-04 22:24 ` Suren Baghdasaryan
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