From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793176795; b=wPSqrLZF/23HWRcaXTuEccfXnCvIhoE4wOhhZFZoM3yx/mEThzLg3DBRoDy1EE50kDip lush4m2oO3AFPN9Ev+9zrVb/vvoGD9lqI4Va/5HKPVt2wN1uyg6EhFRqhC2YYfjWWC01g 6/cvs8RtjeBb39+BZHniLH6JajWOdXAaFjLEXX437YoHplIhX8lRYbLDTL7jnOFWe4XRr m2p3D7kWRkwszTfG58wGWZZSpS1VwPIZwHro5WhaIC7q8v/L1zPKUAlJve+hi3I3ttH2K N8mradZHw2Iemf516Zlc/4zOUmvQ1+Y9LpFoAQDYVd2R9jO/RZCaHVdRi++rZgRM/og== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793176795; h=Received:DKIM-Signature:Message-ID:Date:MIME-Version:User-Agent: Subject:To:Cc:References:From:Content-Language:Autocrypt:In-Reply-To: Content-Type:Content-Transfer-Encoding; bh=EuSPBpfPiwDzYLE9j3bMQIok2xPGQVDesPuFSULAs28=; b=c8t1RsEhTzmVkjIbwHV/UjQijG3dzmD2DfJYpt+VV69drjAUsCusgGf3c7TRhGj93bjT icfp2JBmhunwxGh4TYbJZas9WAWgKgGgMvKAXIMOYCTdklDJ79uOVus8RrwIgLr0eyEtX UnsVQw4xDMXBRVUh6RyKEXKPQIfab5Ay6tLrcrfNu1cn8x7FxUaT0EbIz7Ely6E3AY/9N ticod/+chC8zOX/ygz4selH/2rlJ/VUbGOjSBZgHLwwZ8ApovNYywA9laVnSopxbTo3LI RZghq9sPjdfKP7qhHC8pHb70gUBGPvOJNqxvBFrrY/HXaLd8VOG+xfeX9QXlcAxKZhw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=mie8jh39; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2F100606A31A; Wed, 28 Oct 2026 08:39:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=mie8jh39 Received: by smtp.kernel.org (Postfix) with ESMTPSA id E0C5C1F01825; Wed, 28 Oct 2026 08:39:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793176794; bh=EuSPBpfPiwDzYLE9j3bMQIok2xPGQVDesPuFSULAs28=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=mie8jh39y/BQE69uPA+3u6b6UyI8Nt1ralfAIWhFNNTRSMdv0XI1QmX/FC3Ny7Qhc ZhQ9zZCJWtKIugv7K14H8T+1uM1GyTD2K+4besn4VLQgQkW0azexi8qFk91TF3cfTh W9sNM5Dbkm4U6TAmERY2uj+6WxDmECEAcWSNnpza1ypv+e+bAHytezpfAPK4IflUL5 jgnR5HSXmZ7J/8+Y6XMGRBhEhR4u8Ie9eq1TsMurpfZOGG3BEhRgQYQuQy05WH3QLU lsPjzcgAhHRLG8M9IZ0wwLs9qt3S+cNesJUmdjM1eCXsrG6MUKIAfMCaOzb4Q9OrCD yVBzjZZdFzzVg== Message-ID: <524ee7d9-790d-48b6-8613-841da042c32a@kernel.org> Date: Wed, 28 Oct 2026 09:39:42 +0100 X-Mailing-List: driver-core@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 4/7] mm/memblock: add a reserved-region flag for poisoned frames To: Mike Rapoport , Breno Leitao Cc: Ard Biesheuvel , Ilias Apalodimas , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Miaohe Lin , Naoya Horiguchi , Oscar Salvador , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , Catalin Marinas , Will Deacon , Mark Rutland , kas@kernel.org, kexec@lists.infradead.org, Brendan Jackman , Johannes Weiner , Zi Yan , shakeel.butt@linux.dev, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-cxl@vger.kernel.org, driver-core@lists.linux.dev, linux-arm-kernel@lists.infradead.org, rmikey@meta.com, riel@surriel.com, harry@kernel.org, kernel-team@meta.com References: <20261016-hwpoison-kho-v6-0-f304255147da@debian.org> <20261016-hwpoison-kho-v6-4-f304255147da@debian.org> 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 On 10/22/26 18:33, Mike Rapoport wrote: > Hi Breno, > > On Fri, Oct 16, 2026 at 05:15:44AM -0700, Breno Leitao wrote: >> memblock allocates from and frees to buddy whatever is not reserved, and >> knows nothing about frames an earlier kernel found hardware-poisoned. >> Such a frame can back the memmap, a page table or a percpu area before >> any hwpoison code runs, and otherwise reaches the buddy allocator like >> any other free frame. >> >> Add MEMBLOCK_RSRV_HWPOISON for a reserved range holding those frames. > > How much this would fragment memblock.reserved? > > memblock is not very scalable, to say the least, and each new flag > increases the size of memblock arrays which obviously hurts performance. I assume that if you have too many regions there, you have different problems than scalability problems. We should cut out larger chunks, and if they are all over your address space you should scrap that machine. -- Cheers, David