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Subject: Re: [PATCH V3] selftests: vm: Add test for Soft-Dirty PTE bit
To:     David Hildenbrand <david@redhat.com>,
        Muhammad Usama Anjum <usama.anjum@collabora.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Shuah Khan <shuah@kernel.org>
Cc:     kernel@collabora.com, kernelci@groups.io,
        Will Deacon <will@kernel.org>,
        Gabriel Krisman Bertazi <krisman@collabora.com>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        linux-kselftest@vger.kernel.org,
        Shuah Khan <skhan@linuxfoundation.org>
References: <20220224212335.3045905-1-usama.anjum@collabora.com>
 <3b7c068b-ac7e-62fc-f0cd-a8dbf8642876@redhat.com>
From:   Shuah Khan <skhan@linuxfoundation.org>
Message-ID: <6133317f-4da0-3aae-f352-b75f0f94dbd4@linuxfoundation.org>
Date:   Thu, 3 Mar 2022 11:19:35 -0700
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On 2/28/22 2:37 AM, David Hildenbrand wrote:
> On 24.02.22 22:23, Muhammad Usama Anjum wrote:
>> This introduces three tests:
>> 1) Sanity check soft dirty basic semantics: allocate area, clean, dirty,
>> check if the SD bit flipped.
>> 2) Check VMA reuse: validate the VM_SOFTDIRTY usage
>> 3) Check soft-dirty on huge pages
>>
>> This was motivated by Will Deacon's fix commit 912efa17e512 ("mm: proc:
>> Invalidate TLB after clearing soft-dirty page state"). I was tracking the
>> same issue that he fixed, and this test would have caught it.
>>
> 
> A note that madv_populate.c already contains some SOFTDIRTY tests
> regarding MADV_POPULATE. Eventually we want to factor out
> softdirty/pagemap handling+checks for easier reuse.
> 
> 

Is this patch unnecessary then?

thanks,
-- Shuah