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Subject: Re: [PATCH v3 1/1] selftests: vm: add process_mrelease tests
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: <20220518204316.13131-1-surenb@google.com>
From:   Shuah Khan <skhan@linuxfoundation.org>
Message-ID: <4b05f63a-c1b7-1b36-4305-8ee9e34f0e04@linuxfoundation.org>
Date:   Wed, 18 May 2022 16:23:46 -0600
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On 5/18/22 2:43 PM, Suren Baghdasaryan wrote:
> Introduce process_mrelease syscall sanity tests which include tests
> which expect to fail:
> - process_mrelease with invalid pidfd and flags inputs
> - process_mrelease on a live process with no pending signals
> and valid process_mrelease usage which is expected to succeed.
> Because process_mrelease has to be used against a process with a pending
> SIGKILL, it's possible that the process exits before process_mrelease
> gets called. In such cases we retry the test with a victim that allocates
> twice more memory up to 1GB. This would require the victim process to
> spend more time during exit and process_mrelease has a better chance of
> catching the process before it exits and succeeding.
> 
> On success the test reports the amount of memory the child had to
> allocate for reaping to succeed. Sample output:
> 
> $ mrelease_test
> Success reaping a child with 1MB of memory allocations
> 
> On failure the test reports the failure. Sample outputs:
> 
> $ mrelease_test
> All process_mrelease attempts failed!
> 
> $ mrelease_test
> process_mrelease: Invalid argument
> 
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
> ---
> Changes in v3:
> - Applied on git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm mm-stable,
> per Andrew
> - Fixed formatting for sample outputs in the description, per Shuah
> - Removed pidfd_open, process_mrelease, write_fault_pages functions, per Shuah
> - Moved child main routine into its own function, per Shuah
> - Followed tools/testing/selftests/pidfd/pidfd.h as a model to deal with
> undefined syscall numbers, per Shuah
> 

Looks good to me Suren. Thank you.

Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>

thanks,
-- Shuah