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[74.12.30.48]) by smtp.gmail.com with ESMTPSA id t18-20020a05620a451200b006a6b374d8bbsm1797249qkp.69.2022.07.19.14.23.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 Jul 2022 14:23:35 -0700 (PDT) Date: Tue, 19 Jul 2022 17:23:33 -0400 From: Peter Xu To: Axel Rasmussen Cc: Alexander Viro , Andrew Morton , Dave Hansen , "Dmitry V . Levin" , Gleb Fotengauer-Malinovskiy , Hugh Dickins , Jan Kara , Jonathan Corbet , Mel Gorman , Mike Kravetz , Mike Rapoport , Nadav Amit , Shuah Khan , Suren Baghdasaryan , Vlastimil Babka , zhangyi , linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v4 3/5] userfaultfd: selftests: modify selftest to use /dev/userfaultfd Message-ID: References: <20220719195628.3415852-1-axelrasmussen@google.com> <20220719195628.3415852-4-axelrasmussen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220719195628.3415852-4-axelrasmussen@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Tue, Jul 19, 2022 at 12:56:26PM -0700, Axel Rasmussen wrote: > We clearly want to ensure both userfaultfd(2) and /dev/userfaultfd keep > working into the future, so just run the test twice, using each > interface. > > Instead of always testing both userfaultfd(2) and /dev/userfaultfd, > let the user choose which to test. > > As with other test features, change the behavior based on a new > command line flag. Introduce the idea of "test mods", which are > generic (not specific to a test type) modifications to the behavior of > the test. This is sort of borrowed from this RFC patch series [1], but > simplified a bit. > > The benefit is, in "typical" configurations this test is somewhat slow > (say, 30sec or something). Testing both clearly doubles it, so it may > not always be desirable, as users are likely to use one or the other, > but never both, in the "real world". > > [1]: https://patchwork.kernel.org/project/linux-mm/patch/20201129004548.1619714-14-namit@vmware.com/ > > Signed-off-by: Axel Rasmussen Acked-by: Peter Xu -- Peter Xu