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 2F4DEC531D0 for ; Mon, 27 Jul 2026 14:05:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 408BE6B009D; Mon, 27 Jul 2026 10:05:52 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 392CD6B009E; Mon, 27 Jul 2026 10:05:52 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 281576B009F; Mon, 27 Jul 2026 10:05:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 052DD6B009D for ; Mon, 27 Jul 2026 10:05:51 -0400 (EDT) Received: from smtpin08.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 6E62A80742 for ; Mon, 27 Jul 2026 14:05:51 +0000 (UTC) X-FDA: 85034730102.08.944CAF7 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf31.hostedemail.com (Postfix) with ESMTP id 823C820011 for ; Mon, 27 Jul 2026 14:05:49 +0000 (UTC) Authentication-Results: imf31.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=niDUXSF0; spf=pass (imf31.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1785161149; b=ow17OfOHZUTTAFDET52j4pWoy0OqemH3DB8EaquYAa1TRpk5mmwIC0lVvfXlB81pFqZupt ctLxyHOTHA/V5OPZ27lk1E1c03pHku23ilntMw+N6lronoLD7sI7KqJT2b1/NFkg+/MQpK wjy9eBgoeS9IbUfFmXXuQ4hyxZrtnIY= ARC-Authentication-Results: i=1; imf31.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=niDUXSF0; spf=pass (imf31.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1785161149; 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=SHR0wK14/4dXsi/tFV+pSIDb0Red1/aui8E/xX1Ll+o=; b=laaB0cUWJKEsalnv3oRaY20UQH2GAq+b5nr4qcYLbhQ5HsLFylhGPBaLVzLZfsCIeZ51oG 703xDGSYSc8FiT+2QT71MsurGxvHHGYOL8BMfnzohp8MvUT8ZURT9pU6YPoIbiRrU0QWNr 7ITxoHhPTmq/zvEUE6EY0EMwztJKk60= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id B50EC4402F; Mon, 27 Jul 2026 14:05:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1CA551F000E9; Mon, 27 Jul 2026 14:05:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785161148; bh=SHR0wK14/4dXsi/tFV+pSIDb0Red1/aui8E/xX1Ll+o=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=niDUXSF0pS2+Q4icyVkjQeECEicW20N7bbljqPs0J/bbAGPthPTJ2dA6qnJ95m/Sa Fwd4YsH0S76pJamz/lR4a+Zb9//2kUtxWFddKMiTI4p/qDfwLaxbAtfu6XbHfSoCS8 KB82tQZH1C9GwxXRmDOG51clurtpzmGM+ZE7YUjuW7p8IpYymWRDFhKcdpAAlD8EFs jLse1g8ot50w5BPFA6sP6J6oPjBeuoO4aUNfJ6CjRBEj7Dpe/Jd279IZYtOl/Wrqd/ lFsVL2RqzdcEPih3MoHTT7z95RM3C7a8sMn1xSHNG+5uO837+3WX6LpwG5dR7CtnA/ 9aOll2xBMLnuA== Message-ID: Date: Mon, 27 Jul 2026 16:05:41 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC v4 12/12] selftests/mm: add a slow-GUP content and COW test for mTHP To: Mike Rapoport , Rik van Riel Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-team@meta.com, Dave Hansen , Peter Zijlstra , Suren Baghdasaryan , Lorenzo Stoakes , Vlastimil Babka , "Liam R. Howlett" , Michal Hocko , Jason Gunthorpe , John Hubbard , Peter Xu , Matthew Wilcox , Usama Arif , Shuah Khan , linux-kselftest@vger.kernel.org References: <20260724222934.1463812-1-riel@surriel.com> <20260724222934.1463812-13-riel@surriel.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: 7bit X-Stat-Signature: hgw8a663c6fn1az5mrkyy659s8qaji9t X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 823C820011 X-Rspam-User: X-HE-Tag: 1785161149-373629 X-HE-Meta: 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 FyMgJ31X ta4tBpoP4NDSBK9lF9s1iWsseqxs6b3Y9nlnowsO4yc5wZR9wvJ2K5daIu9zCyhY/1YBKe1n7XCfZIbuNVWE8CkvbYTxow5n4E2R+f/U0krIhgmHcV0DPWcS21B9fFl3UTS9k2m9MX7ThgtpSIfo0jeF0lV4J14Zr/RBfMVRHDdV0yOIogLldIdyGnJLVpoPxyhYbsCcKG6nFe7F6IhYyYHH/W/R/NffzZo9XtgxFFL5uRRgdpihJP0xqcQO4eTO7+FyyddL89xup9pipMiMA47MxzAclNy5WPo+enN2ocidWtL14p+PoNWWs0dhzEdt/ANHqM2l5908gE9jsiyx0g5NTthaI4qrNIXom Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 7/26/26 13:56, Mike Rapoport wrote: > Hi Rik, > > On Fri, Jul 24, 2026 at 06:29:34PM -0400, Rik van Riel wrote: >> follow_page_mask() now batches a PTE-mapped large folio (mTHP) into one >> contiguous run for the slow get_user_pages() path. A mis-batched run would >> hand back the wrong pages or a stale COW copy, which the existing tests do >> not catch: gup_test checks only pin/unpin integrity, and cow exercises COW >> mostly at PMD size. >> >> Add mthp_gup_cow_test. It forces 64kB-only mTHP, writes a per-page-distinct >> pattern, then pins the region on the slow path (PIN_LONGTERM without >> USE_FAST) and compares the bytes the kernel copies back from the pinned >> pages against that pattern. >> >> The test covers a read pin, a write pin, and COW after fork(): a child >> write-pins to force per-page unshare and checks the copied contents, then >> rewrites its copy while the parent verifies its own contents are intact. >> >> It also reports how many pages sit in contiguous large-folio runs, so a >> kernel without mTHP shows light coverage rather than passing vacuously. >> >> Assisted-by: Claude:claude-opus-4.8 >> Signed-off-by: Rik van Riel >> --- >> tools/testing/selftests/mm/Makefile | 1 + >> .../testing/selftests/mm/mthp_gup_cow_test.c | 213 ++++++++++++++++++ >> tools/testing/selftests/mm/run_vmtests.sh | 1 + >> 3 files changed, 215 insertions(+) >> create mode 100644 tools/testing/selftests/mm/mthp_gup_cow_test.c >> >> + >> +static long PS; >> +static int fails; >> +static int tap; >> + >> +static void ok(int cond, const char *desc) >> +{ >> + printf("%s %d %s\n", cond ? "ok" : "not ok", ++tap, desc); > > Please (instruct claude to) use ksft_* helpers for printing messages and > tracking failed and passed tests. I'm afraid we won't have time to keep repeating the following: Documentation/process/coding-assistants.rst * Reviewing all AI-generated code [...] * Taking full responsibility for the contribution -- Cheers, David