linux-kernel - Re: [PATCH 2/3] mm: drop oom code from exit

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Message-ID: <3e847a15-e8c0-41fd-9518-2ae3d4a39092@linuxfoundation.org>
Date:   Tue, 10 May 2022 09:46:05 -0600
From:   Shuah Khan <skhan@...uxfoundation.org>
To:     Suren Baghdasaryan <surenb@...gle.com>, akpm@...ux-foundation.org
Cc:     mhocko@...e.com, rientjes@...gle.com, willy@...radead.org,
        hannes@...xchg.org, guro@...com, minchan@...nel.org,
        kirill@...temov.name, aarcange@...hat.com, brauner@...nel.org,
        hch@...radead.org, oleg@...hat.com, david@...hat.com,
        jannh@...gle.com, shakeelb@...gle.com, peterx@...hat.com,
        jhubbard@...dia.com, shuah@...nel.org,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        linux-kselftest@...r.kernel.org, kernel-team@...roid.com,
        Shuah Khan <skhan@...uxfoundation.org>
Subject: Re: [PATCH 2/3] mm: drop oom code from exit_mmap

On 5/9/22 9:00 PM, Suren Baghdasaryan wrote:
> With the oom-killer being able to operate on locked pages, exit_mmap
> does not need to ensure that oom_reap_task_mm is done before it can
> proceed. Instead it can rely on mmap_lock write lock to prevent
> oom-killer from operating on the vma tree while it's freeing page
> tables. exit_mmap can hold mmap_lock read lock when unmapping vmas
> and then take mmap_lock write lock before freeing page tables.
> 
> Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
> ---
>   include/linux/oom.h |  2 --
>   mm/mmap.c           | 25 ++++++-------------------
>   mm/oom_kill.c       |  2 +-
>   3 files changed, 7 insertions(+), 22 deletions(-)
> 

How does this improve the test? Include the information on why this
change is needed as opposed describing what this does?

thanks,
-- Shuah