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 6A707CCA462 for ; Fri, 16 Oct 2026 07:46:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 486886B008A; Fri, 16 Oct 2026 03:46:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 457F26B0096; Fri, 16 Oct 2026 03:46:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 370C46B009D; Fri, 16 Oct 2026 03:46:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 0C3966B008A for ; Fri, 16 Oct 2026 03:46:23 -0400 (EDT) Received: from smtpin27.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 8BF0FC02C1 for ; Fri, 16 Oct 2026 07:46:22 +0000 (UTC) X-FDA: 85327706604.27.ADF6210 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf10.hostedemail.com (Postfix) with ESMTP id A21D3C0004 for ; Fri, 16 Oct 2026 07:46:20 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="WJ/WoHq+"; spf=pass (imf10.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=1792136780; b=yF0iOCuaEMEw15Xlo3329dZ+jFW+Ghm84u/KzLKIOUTwG1U6tTjM2Hsm1BztV92vOwRbs7 8ermkgrz6Qk04lcCDWaK3a+JC8OgiHSTOPjVkqPHWKWR3E2pcMM1S61hZL3RXNpqIXO5wU 7yaPz12AlWcJEh3I075xXz4zjqIpp78= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="WJ/WoHq+"; spf=pass (imf10.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=1792136780; 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=/5cfg4kcZ+247ukxIkzBDbMpFjAapYr13Xc1y3GaQfY=; b=JprcrSlEIBnzjfs7KMoU1nhb52lKmBKMpjmvcqEhKZ2ibNjoSjS+YsgqOVxN336kYIbS/6 P9reELLLJohkjnqeX/oSrbmkfiAkMn9l1nJ0wzUuRYy6dHnJioNqcUXRrn4s8/BaoV4FzX YJwXmnJ3venyCTkkECk2WOJz67W3s/4= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 1032E43074; Fri, 16 Oct 2026 07:46:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AE9901F000C4; Fri, 16 Oct 2026 07:46:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792136778; bh=/5cfg4kcZ+247ukxIkzBDbMpFjAapYr13Xc1y3GaQfY=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=WJ/WoHq+G5+/VU7Kyyrai5GRSG6o0JrxOP7WCJ8mNdYN3IKCeHPjzRU/g/Sq+rK/b WU0dWDjdXQglO3oBvt/xna8WCZ7GkvVPBAei43hYv2SsTetD0NoGJZRHVvBVcsbKiZ ftxmS0e9zXm+rotYpp+9YkhA1HFqCd74p5uF4jWkFqbjqMQm4p2WprJoUoAcZecHwx YzUIJ5w3YFFdk3aV7piDjzx5BvYKu5qdLCnlCA1c8qzL9kx7ENvMQYwa8txxakaBpt BUO4zi7Kw1YCF6udev9Kx3Yn8rsPvcoDV1a/VsJ5zafV0GOE7UQTQn1dK/PuPgclUn snZi6t0oPrvvg== Message-ID: <1d850e66-2c8b-4912-829c-ab620de833e5@kernel.org> Date: Fri, 16 Oct 2026 09:46:13 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm/page_vma_mapped: continue past nonmatching huge PMDs To: Kyle Zeng , linux-mm@kvack.org Cc: Andrew Morton , Lorenzo Stoakes , Rik van Riel , "Liam R. Howlett" , Vlastimil Babka , Harry Yoo , Jann Horn , Lance Yang , linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20261016011549.61146-1-kylebot@openai.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: <20261016011549.61146-1-kylebot@openai.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: A21D3C0004 X-Rspam-User: X-Stat-Signature: nok4segubgi8f14y357ykrakz197h4c8 X-HE-Tag: 1792136780-614349 X-HE-Meta: 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 z2JNUEV8 79LaXtIueazUXyXrJh9CzTiWl0C6Lx2nSqpCakhdrc+Qi33VhYxu2jKI6693bptrYb5H72pyfTGg7rcXDiogy8A9qa6/GlVkmXXuXDTtTkj1j7TUr8qGO3KT2gzM3rzffb3cGOSSZgt+h4Wr/zGebLlR4cAnBpVQ68Z9z5Qgik0H+ped7YZuFesJJD8zgqD5W2ryr26YWeXYJct/uWljsLgVsyHOr7gftxILi6EyQ8mVcMQptEgL5NKxIDPXr8BUo/Qh7pPjrKAfmVr5e8DQfiS9IWm++/pocmh8h38kNBzTpagUxlXa9DhEANwUVraeQyJPKdvY0uy1T1QNB9ureGu4eAA5cTI5Nj+7x Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 10/16/26 03:15, Kyle Zeng wrote: > A PTE-mapped large folio can straddle PMD boundaries after an unaligned > mremap(). If the first part is discarded and replaced with an unrelated > huge PMD, page_vma_mapped_walk() stops instead of looking for the rest > of the folio in subsequent PMDs. > > This also affects migration entries. A walk that stops at an unrelated > huge PMD can leave migration PTEs behind when migration or an anonymous > folio split restores the mappings. Those entries do not hold mapping > references and can outlive the source folio. > > Skip the current PMD rather than ending the walk on a flag or PFN > mismatch. Do the same if the PMD became nonpresent before the locked > recheck. Release the PMD lock, clear the per-PMD state and advance with > step_forward(), so the existing range limit controls termination. > This covers present, migration and device-private huge PMDs while > preserving the matching-PMD and split-to-PTE paths. > > Fixes: ace71a19cec5 ("mm: introduce page_vma_mapped_walk()") THP migration was added in 616b8371539 ("mm: thp: enable thp migration in generic path") which was a couple (3?) of release after ace71a19cec5. Doesn't really make a difference for backporting, so we can just keep the Fixes as is (it's the obvious right thing to do :) ). > Cc: > Assisted-by: LLM We can drop these now. > Signed-off-by: Kyle Zeng > --- Thanks! Acked-by: David Hildenbrand (Arm) -- Cheers, David