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 A816331159C; Thu, 11 Jun 2026 13:20:14 +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=1781184016; cv=none; b=DhVfR0epHdDvPpYrRhlGrDfA4ke+tWNEne+59QOSGZviyqQmmFX368FxEfNo+k/DBAbBHXuY57c6UXg/JPGWQyz8RF6jmWANEPdpf/AgPj+M+h+lik5+qWaZlWift1GYSl+OQz2/xN1nKETwTD2Oj30igL14l0JiSHSOs60vBkI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781184016; c=relaxed/simple; bh=qFp0DgtqJFu7V60SyyXf0iSP77K2gx7nAeh9jJ/IEnE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=g/eTGSvfiTSGxDU3iTjLWOGoOU4iY2iDXLdyRiIP5DIs8EV2hMsB6VbG45BTytVeTbaDZEWmHt/PM2TemrLC5yZpEKGl5x/fQN/Z9vxnycuR0blReW9fOiCoyi/2Z45Dm0F63puNjZ/TMB5hGdObu9cQgockcDA2ph44th+Opog= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mZmXI4TC; 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="mZmXI4TC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 53A371F00893; Thu, 11 Jun 2026 13:20:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781184014; bh=DbAs11x6sdjRPCa1WwOoOtiOTXFWzk8XHr9nWsO7jas=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=mZmXI4TCsyxa4sX5pM4DsRByQaaOs3d7C8Ljua/wvAKN9TPmcu2iaMcw9mgsddKo8 dJ4w1P/oR1cXj+hgY/Ibtz3BqRn0ClHXphR+0hydZmdlRauhCf1o1OJ7ODS5JywLgl 0vBVbGss6G3iP07870uUkV8E7U/nHrA/mbl+/7DrGlnxkgh/pwwLTjU35X8ci/C7MN KGxWrMnh2F5orJmyEBmsIhFS0coXBk5XYZD5Q01TrNkodmYflZXuratoNjUAKLgqfC aJTurNg7u2noGQsvfpB4MqpiRz0KI3NtZuWgHcDcG7aE2f3zQUB+W68+dmVZQvlYd/ B6Kwbc72AqZRw== Message-ID: Date: Thu, 11 Jun 2026 15:20:02 +0200 Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH splitout] mm: memory-failure: serialize TestSetPageHWPoison with zone->lock To: Miaohe Lin , "Michael S. Tsirkin" Cc: Zi Yan , Andrew Morton , linux-kernel@vger.kernel.org, Jason Wang , Xuan Zhuo , =?UTF-8?Q?Eugenio_P=C3=A9rez?= , Muchun Song , Oscar Salvador , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Hugh Dickins , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo , Axel Rasmussen , Yuanchu Xie , Wei Xu , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , virtualization@lists.linux.dev, linux-mm@kvack.org, Andrea Arcangeli , Naoya Horiguchi References: <20260609111020.e88f51a7b6ebc37360d66fdc@linux-foundation.org> <8c1f468e-b50a-487a-a267-8d1ea5a61c87@kernel.org> <38C84F23-E881-4DB2-86BA-93F39D44AE1B@nvidia.com> <20260609162437-mutt-send-email-mst@kernel.org> <4BA276D9-9EB9-4E2A-8A05-657ACACFF227@nvidia.com> <20260609165829-mutt-send-email-mst@kernel.org> <20260610171646-mutt-send-email-mst@kernel.org> <14537566-94d9-eac5-2636-35f925a9d159@huawei.com> <20260611013644-mutt-send-email-mst@kernel.org> <1b5676ab-0dc5-ef33-9d79-a2bd6090a62d@huawei.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: <1b5676ab-0dc5-ef33-9d79-a2bd6090a62d@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/11/26 09:36, Miaohe Lin wrote: > On 2026/6/11 13:43, Michael S. Tsirkin wrote: >> On Thu, Jun 11, 2026 at 11:35:36AM +0800, Miaohe Lin wrote: >>> >>> Do you mean repeating SetPageHWPoison on every branch? >> >> Right. >> >>> Is it possible >>> to make __free_pages_prepare changes page->flags atomically or this race >>> is specified to memory_failure? >>> >>> Thanks. >>> . >> >> >> Adding an atomic op on every fast path page allocation is, I am >> guessing, going to slow down Linux measureably. >> >> Doing it for the benefit of memory_failure, which is the slowest of >> slow paths, seems unpalatable, to me. > > Agree, it's not worth to do so. > >> >> Neither am I sure it's the only racy place - >> grep for __SetPage and __ClearPage - all these have the same issue, I >> suspect. >> >> At the same time, I'm not an mm maintainer. If you disagree, try to >> upstream a change converting all non atomics in mm to atomics, and see >> what others say. > > Since memory_failure might be the only place, this change would be unacceptable. > We should come up with a better solution. Maybe we can try repeating SetPageHWPoison > and ClearPageHWPoison at a first attempt though it looks somewhat weird to me and makes > code more complicated. And I am fairly sure we could still have some remaining races ... it's shaky. Hm ... -- Cheers, David