From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 16FBC4825A0; Thu, 1 Oct 2026 13:19:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790860786; cv=none; b=H65AxF87Wi+T0k//U+QIrkAweh1L7LZkn4Qx0h1XY0aNFJzvJJQmaLmLXXhlypsPzYCoIaVN60h0j8Z9CVGpIc9CmGIjzZQTLurzWIXRTYjtLD57EsLHMNByli0H9xbcJ1H+yi8Z7f+1L5kUckXrIiFxe2UBpuSB9PiAdKE69Xg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790860786; c=relaxed/simple; bh=jPio3m5HNytL6Iasjaic/CXCeNNGOD17runOp6nh/jE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ETNKnpyM2CxhuIZVAxuEdFTRRwzZeEDXQKR0D61ELaZZkjk2XUnkMFzum7dlLNW0cQYbZgxnBOhdbDwz3RCLqIqgcFItuAVUXDRWrfBBwx9M8rwIxkm5IWLurQNcZq28PiOGZRPBaV9xDsiG9CqDPEMbuiCH6ZWp4fBeDxJWPV8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=H/iq83bw; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="H/iq83bw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C3AE1F000FF; Thu, 1 Oct 2026 13:19:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790860784; bh=WnWeqdfJvPaLO0zxZ1rgF6uSlPv8HCyAEObGRlF1V7g=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=H/iq83bwefWg6YEAvBt3p5OoC8YuQlDellwlZVxRxocA19xDtjYbDftQq2+9afzpU 2dSmkLHYtQEL6BxMmml2z7htQ6WXLMvuY3q9G7vHRnS0bxGs+LNr1DruQaiEGWKdQO 3iJx0A/h1lnwTr+963Bm6se+E233H5pmut38TKIZ+cbCKIlBZCpJRe+DwpiccYJ1/g 4lwpQsj4c3QQ8MtafACUqrRtwSZpSgehqu68vWU1U4JmGT0G3AkHJrrEHJSxxuPZgU RQsYMoxstF5ODCSgQs6lEbB5QFfB0S/h6t2ZDZD1U6JKsERLxDe/a8/YQW0rZKxpOd RKYk0kP56XC+w== Message-ID: <32ce43e7-ca22-4275-ac2d-b0fdd942c7a9@kernel.org> Date: Thu, 1 Oct 2026 15:19:37 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RESEND 6/9] selftests/mm: mremap_test: replace random data with deterministic pattern To: Sarthak Sharma , Andrew Morton Cc: Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , John Hubbard , Kalesh Singh , Anshuman Khandual , Park Tae-sun , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260924050009.19974-1-sarthak.sharma@arm.com> <20260924050009.19974-7-sarthak.sharma@arm.com> <54f1d9b8-948a-482d-8fa5-694fd937c9e8@arm.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: <54f1d9b8-948a-482d-8fa5-694fd937c9e8@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/1/26 15:16, Sarthak Sharma wrote: > > > On 10/1/26 5:30 PM, David Hildenbrand (Arm) wrote: >> On 9/24/26 07:00, Sarthak Sharma wrote: >>> mremap_test uses a random data stream to detect corruption after remap >>> operations. This requires seed handling and byte by byte validation, >>> which is inefficient. >>> >>> Replace it with a deterministic pattern where every word in a page >>> contains its one-based page index. Use memcpy() and memcmp() to >>> initialize and validate the mappings. Remove the pattern seed and >>> its command line option. Also update the comment diagrams to >>> reflect the new deterministic pattern. >>> >>> Suggested-by: David Hildenbrand (Arm) >>> Signed-off-by: Sarthak Sharma >>> --- >> >> How will this patch change with the change in threshold handling? Does it make >> sense to reshuffle the patches? > > From an intermediate patch POV, both ways of doing should be identical: > > a) Remove threshold first, then remove randomization: > i) Adjust random buffer size according to what the test requires > and implement the start, mid end pages checking > ii) Replace rand approach with fixed pattern > > b) Remove randomization first, then remove threshold: > i) Adjust fixed pattern size according to threshold > ii) Implement the new logic of start, mid and end pages checking > and adjust pattern size > > But if we plan to remove perf and timing infrastructure before (which I > plan to do in v2), yes removing threshold first would be neater, since > it will keep both the removal patches together. Please let me know if I > am missing something. No, looks good. I'll take a look at the patches again in a v2. -- Cheers, David