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imf03.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=NY22Njy5; spf=pass (imf03.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1777370860; a=rsa-sha256; cv=none; b=oIFpmwCWhZDW446n2O6FajOgPRtzBoqkZeORI73cpcEoxn3uo1volQ+xT4BtOlQ/kFEXfU 8Nn09KDzwAeodD57r9P33KBVSpFWLp7kbWjPDGMKrJxnsWkx8SBBO6rWheNA6S5dG1stCn d3LXOXyHB+KQbaMkQI5WuwlNvLl1Q9A= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 4C5DA60141; Tue, 28 Apr 2026 10:07:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DB894C2BCAF; Tue, 28 Apr 2026 10:07:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777370860; bh=we5RUTtK9BBrAx6WOi8PWHN82eXXZYUIrgpPPhKr5yc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=NY22Njy5Q5KdvpVPewa/YRTnvi9owrLVBDACvvAwqjrcc1inXnRJDvTYNfJ/CaPMi g+soSXkNpHK32TgY2YDOWww6Rs26KRPvQ07I0q/oxo/6LvZMGGvulfak5zAN1wMEDy 6ZxxnJM6e9PbiYw/xnqDeC3PR3ZewkC35mIfglVmPXg7D5aveR50qIrifvuTMCdA+4 EFUM0r6WkaNO28Tt9WtaMmV+lkJKLc+jfB/SVTqRf5oW1Qpo863r78sYuVTECQ6NHb J014Du9XlPcz/YhNcBy0ZrImxZbXYo5S4Fh7Y+xDJ+/sDQW0ZEPAlEz2yO8fPiDC5E i3gOAZnWEsCqw== Message-ID: <5b1defae-fa59-4088-96cd-d769ad475907@kernel.org> Date: Tue, 28 Apr 2026 12:07:35 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] selftests/mm: khugepaged: initialize file contents via mmap To: Vineet Agarwal , akpm@linux-foundation.org, ljs@kernel.org, shuah@kernel.org Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org References: <3abf09d8-a98e-4f1b-b8d9-77879a8a2733@kernel.org> <20260428100058.62554-1-agarwal.vineet2006@gmail.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260428100058.62554-1-agarwal.vineet2006@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: E701120006 X-Stat-Signature: itkkcnn6ie3skd775m9b1qwacmhoo7hg X-HE-Tag: 1777370860-210025 X-HE-Meta: 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 ykKzfpix E+qBkED3oC9lSjrFOWshx+tcc6f86q0JpD8dyrx5DBmq120XpjqRbkFlqsZV5iMunXiN5QmgZl2HkdgkWOUrapANecb3edgyqqV+hg6ZsMH+9jZcqZXW+yGEHhfKWxnjn6g6xquFic+H/EaA8Do5KhxZRKbJlelTUwN6ymq00s/C212AH4+FwMLFRFx88hxBCpt72CByCEvxD79nGqFZiJIHj0lkMd2pcv4lPOuu6TEBwwuZi/4btFQ8JfOmtzrSv3OTSs4HWb/rXphIrqaHcbpAxtQB4qgXFd34wm+6TvcIrfgBo7IqhJzfIEG+j1wiR1eGMlONns8UO9mFn/1eo+kYnnnGvvwaMUsxZ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/28/26 12:00, Vineet Agarwal wrote: > file_setup_area() currently allocates anonymous memory, fills it, > and writes it into the backing file used for collapse testing. > > Instead of copying data through write(), resize the file with > ftruncate(), map it directly with MAP_SHARED, and initialize the > mapped area in place. > > This simplifies the setup path and avoids the need for explicit > partial write handling. Please a) Wait a bit longer before you resend. b) Don't send as reply to earlier revisions. > > Signed-off-by: Vineet Agarwal > --- > tools/testing/selftests/mm/khugepaged.c | 17 +++++++++++++---- > 1 file changed, 13 insertions(+), 4 deletions(-) > > diff --git a/tools/testing/selftests/mm/khugepaged.c b/tools/testing/selftests/mm/khugepaged.c > index 3fe7ef04ac62..57ca4224bd5a 100644 > --- a/tools/testing/selftests/mm/khugepaged.c > +++ b/tools/testing/selftests/mm/khugepaged.c > @@ -369,7 +369,6 @@ static void *file_setup_area(int nr_hpages) > int fd; > void *p; > unsigned long size; > - Unrelated change. > unlink(finfo.path); /* Cleanup from previous failed tests */ > printf("Creating %s for collapse%s...", finfo.path, > finfo.type == VMA_SHMEM ? " (tmpfs)" : ""); > @@ -381,11 +380,21 @@ static void *file_setup_area(int nr_hpages) > } > > size = nr_hpages * hpage_pmd_size; > - p = alloc_mapping(nr_hpages); > + if (ftruncate(fd, size)) { > + perror("ftruncate()"); > + close(fd); > + exit(EXIT_FAILURE); > + } > + p = mmap(BASE_ADDR, size, PROT_READ | PROT_WRITE, > + MAP_SHARED, fd, 0); > + if (p == MAP_FAILED || p != BASE_ADDR) { > + perror("mmap()"); > + close(fd); > + exit(EXIT_FAILURE); > + } > fill_memory(p, 0, size); > - write(fd, p, size); > - close(fd); > munmap(p, size); > + close(fd); That change is not strictly required. We can munmap() after close(). Apart from that LGTM. -- Cheers, David