From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 82E2EC9832A for ; Tue, 29 Sep 2026 07:47:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 65A456B0098; Tue, 29 Sep 2026 03:47:45 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 633256B0099; Tue, 29 Sep 2026 03:47:45 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 549046B009E; Tue, 29 Sep 2026 03:47:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 2D7936B0098 for ; Tue, 29 Sep 2026 03:47:45 -0400 (EDT) Received: from smtpin21.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id AD7FE1C2CE4 for ; Tue, 29 Sep 2026 07:47:44 +0000 (UTC) X-FDA: 85266020448.21.80D58C5 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf30.hostedemail.com (Postfix) with ESMTP id E0E8480002 for ; Tue, 29 Sep 2026 07:47:42 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=gg5xZePM; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf30.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1790668063; b=Twd3mQA5l79mvvAyZKQ+U+75JkQed/Vl4LV4hG87TVICvEh3G8nUM2laJ43roDMYsktgc6 anDfPFQK6zq9WeVWob5+EP2EtaFw8hVGnw7+zq/ekdmtquJk1/FwacIEdQsS4wopFFKPq/ 4op5FYlrF8TXRknnUoMNgnTjgIIcoJQ= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=gg5xZePM; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf30.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1790668063; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=mLNdmFrM1t3FQWmwFYe8TkIte1jls2u/1QCzj1F20EY=; b=M2nj/D5Bh2rro/k7nmGTHG9s9MRbCbS/sUuc36/W85ffXspA8n7dscjxHfqAt5KEPgCc5g qKR5FQHvxHvnpRlMXEG1MGb4sWa76YH6Cu7VZhfNwfxANgcl2jcKi/5heHzZxIhUjJl2nu fw6Ksx7rMPbUrI3PyuYKlLYY3BdL1Bk= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 139CF401F4; Tue, 29 Sep 2026 07:47:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 269FF1F000FF; Tue, 29 Sep 2026 07:47:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790668062; bh=mLNdmFrM1t3FQWmwFYe8TkIte1jls2u/1QCzj1F20EY=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=gg5xZePM0dIkrhC1PdGvJcGV+oFHBPWdh25qEyGA/kv1arZLYUnlWIg8wYuuY2JMv 0Cv8TB0Q443gxxo1iT1HdyRBGyaNgNImagvoVmhbTl97GAVsPW/gCeBReirTK6Gmc+ z3/aCs5FelgEO1RJ+5g49VeJ9Q3KDuYnWzfwdptnkL5L2UOkvG0UaHfpj2mWcFAdG+ oNsbmTfZzPB+ZYrpR8qZJGzzptj+mMD4CC2TNVZItnO3Lx9qH4U4ku3moBnlZ4Y5v3 to3Ypf7+EnuF3CDkDuLWSVKxqoXh4n7einnw7diI2GmBZ5IcyjK67gW42MUdXYEI+i N0JNy58OXWQtg== Message-ID: <92ec3966-e68c-4dda-9d8b-9462f22c9e93@kernel.org> Date: Tue, 29 Sep 2026 09:47:36 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RESEND 0/9] selftests/mm: improve mremap_test To: Kalesh Singh , Sarthak Sharma Cc: Andrew Morton , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , John Hubbard , 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> 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: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam06 X-Stat-Signature: 33rjitidrj8zkrgj6wiq1hyxuh6jkpnz X-Rspam-User: X-Rspamd-Queue-Id: E0E8480002 X-HE-Tag: 1790668062-959184 X-HE-Meta: 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 aFSUEkPA gnRDg/DBifpVKM+56D+YbO9IRAZjun2RbkCrJQOZvqBr+LmGicDdeddd6S7+IERcv1EvUWZ0anoj+/T7mix6lykdCgrc34SrKQFchwG4FIgylPVPu7ODxQuEYJzBA1Bb1wg9EPcUXxEocoAD16h5H0tvBp5N0IRVrKd1nb/bLFSWQh/kgD3tQqZleXe7t5Hao46yRHpjhyldjBMzFRX+T2WhWUAHYSRYFEJMJyNwtYtrD+V60ATNNkMXQU3/E0bRqL7/PxA/2IWCGLuN27uSe6i9QQ9mbGq4pyQGKBpWRxZrk1b8Fv3mBrNCK7dIRQOo9lpIvTUmaT/Q3Zm1HPApZ7G+Hpv2qMGF5EvTOAnsX5HlCnJ7ECmy4M1vdd84AcN6sD2tuwBWcipfJouU= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/29/26 09:32, Kalesh Singh wrote: > On Mon, Sep 28, 2026 at 10:54 PM Sarthak Sharma wrote: >> >> >> >> On 9/24/26 10:30 AM, Sarthak Sharma wrote: >>> This series fixes several correctness issues in mremap_test and >>> simplifies and strengthens its data validation. >>> >>> Patch 1 converts the mremap_test to use kselftest helpers, removes >>> manual tracking of failed tests and corrects some spelling errors. >>> >>> Patches 2 to 5 fix userfaultfd skipping, unexpected mremap success >>> handling, multi-VMA data validation and failure reporting when data >>> corruption is detected. >>> >>> Patch 6 removes the randomization and uses a simple pattern based approach. >>> >>> Patch 7 removes perf tests and timing infrastructure. >>> >>> Patch 8 removes validation threshold and always validates complete mappings. >>> >>> Patch 9 strengthens the multi VMA validation by also checking the >>> mapping state of holes after remapping. >> >> Hello everyone! Just wanted to check if someone has had a chance to look >> at the series. >> >> Also, Sashiko has a concern [1], and I had the same while posting the >> series. I hope I can get some opinion from the community. >> >> Currently, for PUD remap tests, we allocate a source mapping of 2GB. We >> only fault in the first threshold_mb amount of memory, remap the whole >> region, and validate the already faulted threshold_mb amount of memory, >> which is, by default, equal to 4MB and can be changed by the user by >> supplying a command line option. >> >> Since we plan to remove all command line options from teh selftests, I >> removed threshold_mb altogether, following some discussion on the list >> [2]. This would now cause a 2GB source mapping, and its contents copied >> from another 2GB buffer. This causes the process to have a 4GB RSS. Yeah, that's a lot for small CI systems indeed. >> Sashiko says that this can cause OOM killing in small CI machines. >> >> Would it be okay to keep a 4GB RSS in this case, or should we find some >> other way of validating a part of the whole range instead? > > Hi Sarthak, > > IIRC when I initially introduced the test, John was concerned that > validating the whole range would significantly increase the duration > of the mm selftests; this is why the threshold was introduced. Please > check how much it increases if we validate the full range (with > David's suggestions) and if it's no longer a concern from other folks. > I am fine with removing the threshold. As discussed off-list, I guess it makes more sense to validate a couple of pages at the beginning, the middle and the end? -- Cheers, David