Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Subject: Re: [PATCH 2/3] mm: drop oom code from exit_mmap
To:     Suren Baghdasaryan <surenb@google.com>, akpm@linux-foundation.org
Cc:     mhocko@suse.com, rientjes@google.com, willy@infradead.org,
        hannes@cmpxchg.org, guro@fb.com, minchan@kernel.org,
        kirill@shutemov.name, aarcange@redhat.com, brauner@kernel.org,
        hch@infradead.org, oleg@redhat.com, david@redhat.com,
        jannh@google.com, shakeelb@google.com, peterx@redhat.com,
        jhubbard@nvidia.com, shuah@kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        linux-kselftest@vger.kernel.org, kernel-team@android.com,
        Shuah Khan <skhan@linuxfoundation.org>
References: <20220510030014.3842475-1-surenb@google.com>
 <20220510030014.3842475-2-surenb@google.com>
From:   Shuah Khan <skhan@linuxfoundation.org>
Message-ID: <3e847a15-e8c0-41fd-9518-2ae3d4a39092@linuxfoundation.org>
Date:   Tue, 10 May 2022 09:46:05 -0600
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.8.1
MIME-Version: 1.0
In-Reply-To: <20220510030014.3842475-2-surenb@google.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

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@google.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