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Mon, 30 Mar 2026 03:10:26 -0700 (PDT) Received: from redhat.com ([209.132.188.88]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2b24277e8d3sm74371865ad.55.2026.03.30.03.10.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Mar 2026 03:10:25 -0700 (PDT) Date: Mon, 30 Mar 2026 18:10:23 +0800 From: Li Wang To: "David Hildenbrand (Arm)" Cc: akpm@linux-foundation.org, rppt@kernel.org, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, surenb@google.com, mhocko@suse.com, shuah@kernel.org, aubaker@redhat.com, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v3] selftests/mm: skip hugetlb_dio tests when DIO alignment is incompatible Message-ID: References: <20260330053915.75442-1-liwang@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: > > Why can't we simply open the file once and pass the fd to run_dio_using_hugetlb()? > > > > fd = open("/tmp", O_TMPFILE | O_RDWR | O_DIRECT, 0664); > > if (fd < 0) > > ksft_exit_skip("Unable to allocate file: %s\n", strerror(errno)); > > dio_align = get_dio_alignment(fd); > > if (dio_align <= 0) > > ksft_exit_skip("Unable to obtain DIO alignment: %s\n", strerror(errno)); > > Yes, apparently this is a good suggestion. Thanks! And, to make the test elegant, I'm going to add check_dio_alignment() dedicated to alignment checking. Then we don't need to pass too many args. Tell me your thoughts if you don't like this: static int get_dio_alignment(int fd) {...} static bool check_dio_alignment(unsigned int start_off, unsigned int end_off) {...} static void run_test(int fd, unsigned int start_off, unsigned int end_off) { if (!check_dio_alignment(start_off, end_off)) return; run_dio_using_hugetlb(fd, start_off, end_off); } int main(void) { ... fd = open("/tmp", O_TMPFILE | O_RDWR | O_DIRECT, 0664); if (fd < 0) ksft_exit_skip("Unable to allocate file: %s\n", strerror(errno)); if (get_dio_alignment(fd) < 0) ... run_test(fd, 0, (pagesize * 3)); } -- Regards, Li Wang