From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gabriel Krisman Bertazi Subject: Re: [PATCH V3] selftests: vm: Add test for Soft-Dirty PTE bit References: <20220224212335.3045905-1-usama.anjum@collabora.com> <3b7c068b-ac7e-62fc-f0cd-a8dbf8642876@redhat.com> <6133317f-4da0-3aae-f352-b75f0f94dbd4@linuxfoundation.org> Date: Thu, 03 Mar 2022 13:39:20 -0500 In-Reply-To: <6133317f-4da0-3aae-f352-b75f0f94dbd4@linuxfoundation.org> (Shuah Khan's message of "Thu, 3 Mar 2022 11:19:35 -0700") Message-ID: <87o82mkhif.fsf@collabora.com> MIME-Version: 1.0 Content-Type: text/plain List-ID: To: Shuah Khan Cc: David Hildenbrand , Muhammad Usama Anjum , Andrew Morton , Shuah Khan , kernel@collabora.com, kernelci@groups.io, Will Deacon , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Shuah Khan writes: > 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? It is not unnecessary since the madv test doesn't cover the bug tested here, afaik. But, as mentioned when I originally submitted this patch, it should be merged into selftests/vm/madv_populate.c or, at least, reuse that existing infrastructure. https://lore.kernel.org/lkml/87lf553z5g.fsf@collabora.com/ -- Gabriel Krisman Bertazi