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 E983CCCA470 for ; Thu, 9 Oct 2025 10:27:33 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 534E08E0070; Thu, 9 Oct 2025 06:27:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 50C728E0002; Thu, 9 Oct 2025 06:27:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3FB9A8E0070; Thu, 9 Oct 2025 06:27:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 2B5E08E0002 for ; Thu, 9 Oct 2025 06:27:33 -0400 (EDT) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 3C38E13BBE8 for ; Thu, 9 Oct 2025 10:27:32 +0000 (UTC) X-FDA: 83978199144.28.F30EA49 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf07.hostedemail.com (Postfix) with ESMTP id DD5354000C for ; Thu, 9 Oct 2025 10:27:28 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=gorcv2kH; spf=pass (imf07.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1760005649; 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=PnaMSwBDtuymaXBhgXecb0+EmYLZhk15irlwltuvb1Y=; b=bqQsudZO/PHyfZwkP5wj7/X+0NADEod3WqMnTNvq8RKp18ycfxg+HD56UcOzAZ12stMYCc XdFANDvV0AU1eA28aF+yiVfdOsoQSKubNRK+7NP5315sP/uFYcw5wcvwHwTsg5uOnpq+T7 uvtcyKOAKgXbWQtpK9nW5q4Z77NstCY= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1760005649; a=rsa-sha256; cv=none; b=UDkUn8GOL7j3WvHZReYlElBTatWgVPtMQSs+qNHyetYVva4XRidBi4J2WttZ6oTQAhUDzS NNahVeix8L4WtlcQtRjDMKiPpNafEvznNJ2GfDfcRsBpvpc+38QXurbAOM7r0ElpPe3/vH +TonhOBkh7Ol54qceTog1k3h1XJEv14= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=gorcv2kH; spf=pass (imf07.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1760005648; h=from:from: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:autocrypt:autocrypt; bh=PnaMSwBDtuymaXBhgXecb0+EmYLZhk15irlwltuvb1Y=; b=gorcv2kHuKBuohjfXdLCl01tYZFEw7t9MYakKT0fOcXMoG4xG03jwfL38o+6zLCRV1q6Zm 7jplN3rtAba36PrWCRUIzRe58i5paKk5UVgdkPMFHi3z2DqkB3XkK84z5CX6uIn0Xt/Hh3 PX3cBbny2ZXczVE7tihr7vNcnfNv1tw= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-271-yk01HT1PP8WrsT0YXUwmDg-1; Thu, 09 Oct 2025 06:27:24 -0400 X-MC-Unique: yk01HT1PP8WrsT0YXUwmDg-1 X-Mimecast-MFC-AGG-ID: yk01HT1PP8WrsT0YXUwmDg_1760005644 Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-46e4335fa87so4564575e9.0 for ; Thu, 09 Oct 2025 03:27:24 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1760005644; x=1760610444; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :from:references:cc:to:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=PnaMSwBDtuymaXBhgXecb0+EmYLZhk15irlwltuvb1Y=; b=Awqrd7iwoxsJWcDcgVgx8Ma3YwVgPUr1QIQ3JZWRdqjXnENctDjqt4SDLYCVVSuakM +kbdOZhvTVdrdJojUoP6bHCT0zrZ98XCE4wEHEUCaOOcSkZxOdUZDUG1OsK9k6M44+vs 20sXRHH+HNR7xEUfuMZh0Km67Sv7BuIe/2ncA2+FMSJbi0Vcjk8s9DjvfjZmNKV3jFYl UK1zuuI7adJjL3mZZ/LJ+jnrcIFrgGtBqWvpPFyVbI5RgH1FvY/NaFIwMJzFbdNubw8b BYGzT1mUP0dnt/SQEkriwK3kp5k4JGbnXnq7PrCLaGRr493I6UJ3VmBTKqaSw+s51chm OmDA== X-Forwarded-Encrypted: i=1; AJvYcCVrmguUI174NRvxQFwiGPzJKTA6bUPRQz1m1FJd9v/5jGTh1Z4O72VfFl1EYB4MDhdweWjH/lIxFg==@kvack.org X-Gm-Message-State: AOJu0Yw4uUxByDhK/tMHTuFUI0stDREWiZpri5x4Au4atZdXE+zo81s+ pIfmycGvlcX0ZfDP+Wi6bf+x0HL1621SooLCF61iWmV/phMcCx6CpYF5V/32SPeQL4dFKiQC/Nh h2hLlzj+LqarSRLopfkBBzQDGZV43eGVdKeAkYxUFRzG0fO0jEnNd X-Gm-Gg: ASbGncuXWx3IjU5tKvEGu9l5yE8TOoHM0yVOnj8FDxfHBXVhW7bwWQkScu6FimHy1uI /VCHy6YjWykEKrJlST/LMzsum8f3mP6y2wD7BREjMdQZsiz7XHFMDpKUQlgf4uybOyYIXX9kr2r gOsbI+PYsDKXn6oc098r1ZA9qY3V73+UcTzcjv8k9Sxh5Z3qFfcMw90X9TMp3THZu1RbutTIPBe pEXEsgtTbajkCgcwbvM3TMxYY+UXj5H2UqLw24zbWKJebrputOIOCCG02yCl9yoX8SEGGTHe9Jw IsJargGCIL1ncU743joAy9K6K+Fk0GtnLNM744cRZOTdiiJWi5JWIW3CiuOkJOPir1wGOdRxLvM f+GSBhli6 X-Received: by 2002:a05:6000:26c9:b0:425:74e1:25f7 with SMTP id ffacd0b85a97d-4266e8e6d0amr4383258f8f.62.1760005643622; Thu, 09 Oct 2025 03:27:23 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEesLOt7nL3ssClyJORVAYlz8cRc7j7l9rZT7U1D7oG6YdutQizbYz0xgMQfBuUYe2CfhAXag== X-Received: by 2002:a05:6000:26c9:b0:425:74e1:25f7 with SMTP id ffacd0b85a97d-4266e8e6d0amr4383228f8f.62.1760005643040; Thu, 09 Oct 2025 03:27:23 -0700 (PDT) Received: from [192.168.3.141] (tmo-083-189.customers.d1-online.com. [80.187.83.189]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4255d8ab8fdsm33619939f8f.15.2025.10.09.03.27.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 09 Oct 2025 03:27:22 -0700 (PDT) Message-ID: <543e9440-8ee0-4d9e-9b05-0107032d665b@redhat.com> Date: Thu, 9 Oct 2025 12:27:17 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: (bisected) [PATCH v2 08/37] mm/hugetlb: check for unreasonable folio sizes when registering hstate To: Christophe Leroy , linux-kernel@vger.kernel.org Cc: Zi Yan , Lorenzo Stoakes , "Liam R. Howlett" , Alexander Potapenko , Andrew Morton , Brendan Jackman , Christoph Lameter , Dennis Zhou , Dmitry Vyukov , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, iommu@lists.linux.dev, io-uring@vger.kernel.org, Jason Gunthorpe , Jens Axboe , Johannes Weiner , John Hubbard , kasan-dev@googlegroups.com, kvm@vger.kernel.org, Linus Torvalds , linux-arm-kernel@axis.com, linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org, linux-ide@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mips@vger.kernel.org, linux-mmc@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, Marco Elver , Marek Szyprowski , Michal Hocko , Mike Rapoport , Muchun Song , netdev@vger.kernel.org, Oscar Salvador , Peter Xu , Robin Murphy , Suren Baghdasaryan , Tejun Heo , virtualization@lists.linux.dev, Vlastimil Babka , wireguard@lists.zx2c4.com, x86@kernel.org, "linuxppc-dev@lists.ozlabs.org" References: <20250901150359.867252-1-david@redhat.com> <20250901150359.867252-9-david@redhat.com> <3e043453-3f27-48ad-b987-cc39f523060a@csgroup.eu> <9361c75a-ab37-4d7f-8680-9833430d93d4@redhat.com> <03671aa8-4276-4707-9c75-83c96968cbb2@csgroup.eu> <1db15a30-72d6-4045-8aa1-68bd8411b0ba@redhat.com> <0c730c52-97ee-43ea-9697-ac11d2880ab7@csgroup.eu> From: David Hildenbrand Autocrypt: addr=david@redhat.com; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZoEEwEIAEQCGwMCF4ACGQEFCwkIBwICIgIG FQoJCAsCBBYCAwECHgcWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaJzangUJJlgIpAAKCRBN 3hD3AP+DWhAxD/9wcL0A+2rtaAmutaKTfxhTP0b4AAp1r/eLxjrbfbCCmh4pqzBhmSX/4z11 opn2KqcOsueRF1t2ENLOWzQu3Roiny2HOU7DajqB4dm1BVMaXQya5ae2ghzlJN9SIoopTWlR 0Af3hPj5E2PYvQhlcqeoehKlBo9rROJv/rjmr2x0yOM8qeTroH/ZzNlCtJ56AsE6Tvl+r7cW 3x7/Jq5WvWeudKrhFh7/yQ7eRvHCjd9bBrZTlgAfiHmX9AnCCPRPpNGNedV9Yty2Jnxhfmbv Pw37LA/jef8zlCDyUh2KCU1xVEOWqg15o1RtTyGV1nXV2O/mfuQJud5vIgzBvHhypc3p6VZJ lEf8YmT+Ol5P7SfCs5/uGdWUYQEMqOlg6w9R4Pe8d+mk8KGvfE9/zTwGg0nRgKqlQXrWRERv cuEwQbridlPAoQHrFWtwpgYMXx2TaZ3sihcIPo9uU5eBs0rf4mOERY75SK+Ekayv2ucTfjxr Kf014py2aoRJHuvy85ee/zIyLmve5hngZTTe3Wg3TInT9UTFzTPhItam6dZ1xqdTGHZYGU0O otRHcwLGt470grdiob6PfVTXoHlBvkWRadMhSuG4RORCDpq89vu5QralFNIf3EysNohoFy2A LYg2/D53xbU/aa4DDzBb5b1Rkg/udO1gZocVQWrDh6I2K3+cCs7BTQRVy5+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: <0c730c52-97ee-43ea-9697-ac11d2880ab7@csgroup.eu> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: I8EccZWbbcF_CxHMp3-23CPA_50o83rkqzt_qKujMIw_1760005644 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Stat-Signature: gyymbixmmky75h7e8kdby851b4w9dco3 X-Rspam-User: X-Rspamd-Queue-Id: DD5354000C X-HE-Tag: 1760005648-535511 X-HE-Meta: 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 doJ2+DQM 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 09.10.25 12:01, Christophe Leroy wrote: > > > Le 09/10/2025 à 11:20, David Hildenbrand a écrit : >> On 09.10.25 11:16, Christophe Leroy wrote: >>> >>> >>> Le 09/10/2025 à 10:14, David Hildenbrand a écrit : >>>> On 09.10.25 10:04, Christophe Leroy wrote: >>>>> >>>>> >>>>> Le 09/10/2025 à 09:22, David Hildenbrand a écrit : >>>>>> On 09.10.25 09:14, Christophe Leroy wrote: >>>>>>> Hi David, >>>>>>> >>>>>>> Le 01/09/2025 à 17:03, David Hildenbrand a écrit : >>>>>>>> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >>>>>>>> index 1e777cc51ad04..d3542e92a712e 100644 >>>>>>>> --- a/mm/hugetlb.c >>>>>>>> +++ b/mm/hugetlb.c >>>>>>>> @@ -4657,6 +4657,7 @@ static int __init hugetlb_init(void) >>>>>>>>          BUILD_BUG_ON(sizeof_field(struct page, private) * >>>>>>>> BITS_PER_BYTE < >>>>>>>>                  __NR_HPAGEFLAGS); >>>>>>>> +    BUILD_BUG_ON_INVALID(HUGETLB_PAGE_ORDER > MAX_FOLIO_ORDER); >>>>>>>>          if (!hugepages_supported()) { >>>>>>>>              if (hugetlb_max_hstate || >>>>>>>> default_hstate_max_huge_pages) >>>>>>>> @@ -4740,6 +4741,7 @@ void __init hugetlb_add_hstate(unsigned int >>>>>>>> order) >>>>>>>>          } >>>>>>>>          BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE); >>>>>>>>          BUG_ON(order < order_base_2(__NR_USED_SUBPAGE)); >>>>>>>> +    WARN_ON(order > MAX_FOLIO_ORDER); >>>>>>>>          h = &hstates[hugetlb_max_hstate++]; >>>>>>>>          __mutex_init(&h->resize_lock, "resize mutex", &h- >>>>>>>>> resize_key); >>>>>>>>          h->order = order; >>>>>> >>>>>> We end up registering hugetlb folios that are bigger than >>>>>> MAX_FOLIO_ORDER. So we have to figure out how a config can trigger >>>>>> that >>>>>> (and if we have to support that). >>>>>> >>>>> >>>>> MAX_FOLIO_ORDER is defined as: >>>>> >>>>> #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE >>>>> #define MAX_FOLIO_ORDER        PUD_ORDER >>>>> #else >>>>> #define MAX_FOLIO_ORDER        MAX_PAGE_ORDER >>>>> #endif >>>>> >>>>> MAX_PAGE_ORDER is the limit for dynamic creation of hugepages via >>>>> /sys/kernel/mm/hugepages/ but bigger pages can be created at boottime >>>>> with kernel boot parameters without CONFIG_ARCH_HAS_GIGANTIC_PAGE: >>>>> >>>>>      hugepagesz=64m hugepages=1 hugepagesz=256m hugepages=1 >>>>> >>>>> Gives: >>>>> >>>>> HugeTLB: registered 1.00 GiB page size, pre-allocated 0 pages >>>>> HugeTLB: 0 KiB vmemmap can be freed for a 1.00 GiB page >>>>> HugeTLB: registered 64.0 MiB page size, pre-allocated 1 pages >>>>> HugeTLB: 0 KiB vmemmap can be freed for a 64.0 MiB page >>>>> HugeTLB: registered 256 MiB page size, pre-allocated 1 pages >>>>> HugeTLB: 0 KiB vmemmap can be freed for a 256 MiB page >>>>> HugeTLB: registered 4.00 MiB page size, pre-allocated 0 pages >>>>> HugeTLB: 0 KiB vmemmap can be freed for a 4.00 MiB page >>>>> HugeTLB: registered 16.0 MiB page size, pre-allocated 0 pages >>>>> HugeTLB: 0 KiB vmemmap can be freed for a 16.0 MiB page >>>> >>>> I think it's a violation of CONFIG_ARCH_HAS_GIGANTIC_PAGE. The existing >>>> folio_dump() code would not handle it correctly as well. >>> >>> I'm trying to dig into history and when looking at commit 4eb0716e868e >>> ("hugetlb: allow to free gigantic pages regardless of the >>> configuration") I understand that CONFIG_ARCH_HAS_GIGANTIC_PAGE is >>> needed to be able to allocate gigantic pages at runtime. It is not >>> needed to reserve gigantic pages at boottime. >>> >>> What am I missing ? >> >> That CONFIG_ARCH_HAS_GIGANTIC_PAGE has nothing runtime-specific in its >> name. > > In its name for sure, but the commit I mention says: > > On systems without CONTIG_ALLOC activated but that support gigantic > pages, > boottime reserved gigantic pages can not be freed at all. This patch > simply enables the possibility to hand back those pages to memory > allocator. Right, I think it was a historical artifact. > > And one of the hunks is: > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 7f7fbd8bd9d5b..7a1aa53d188d3 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -19,7 +19,7 @@ config ARM64 > select ARCH_HAS_FAST_MULTIPLIER > select ARCH_HAS_FORTIFY_SOURCE > select ARCH_HAS_GCOV_PROFILE_ALL > - select ARCH_HAS_GIGANTIC_PAGE if CONTIG_ALLOC > + select ARCH_HAS_GIGANTIC_PAGE > select ARCH_HAS_KCOV > select ARCH_HAS_KEEPINITRD > select ARCH_HAS_MEMBARRIER_SYNC_CORE > > So I understand from the commit message that it was possible at that > time to have gigantic pages without ARCH_HAS_GIGANTIC_PAGE as long as > you didn't have to be able to free them during runtime. Yes, I agree. > >> >> Can't we just select CONFIG_ARCH_HAS_GIGANTIC_PAGE for the relevant >> hugetlb config that allows for *gigantic pages*. >> > > We probably can, but I'd really like to understand history and how we > ended up in the situation we are now. > Because blind fixes often lead to more problems. Yes, let's figure out how to to it cleanly. > > If I follow things correctly I see a helper gigantic_page_supported() > added by commit 944d9fec8d7a ("hugetlb: add support for gigantic page > allocation at runtime"). > > And then commit 461a7184320a ("mm/hugetlb: introduce > ARCH_HAS_GIGANTIC_PAGE") is added to wrap gigantic_page_supported() > > Then commit 4eb0716e868e ("hugetlb: allow to free gigantic pages > regardless of the configuration") changed gigantic_page_supported() to > gigantic_page_runtime_supported() > > So where are we now ? In commit fae7d834c43ccdb9fcecaf4d0f33145d884b3e5c Author: Matthew Wilcox (Oracle) Date: Tue Feb 27 19:23:31 2024 +0000 mm: add __dump_folio() We started assuming that a folio in the system (boottime, dynamic, whatever) has a maximum of MAX_FOLIO_NR_PAGES. Any other interpretation doesn't make any sense for MAX_FOLIO_NR_PAGES. So we have two questions: 1) How to teach MAX_FOLIO_NR_PAGES that hugetlb supports gigantic pages 2) How do we handle CONFIG_ARCH_HAS_GIGANTIC_PAGE We have the following options (A) Rename existing CONFIG_ARCH_HAS_GIGANTIC_PAGE to something else that is clearer and add a new CONFIG_ARCH_HAS_GIGANTIC_PAGE. (B) Rename existing CONFIG_ARCH_HAS_GIGANTIC_PAGE -> to something else that is clearer and derive somehow else that hugetlb in that config supports gigantic pages. (c) Just use CONFIG_ARCH_HAS_GIGANTIC_PAGE if hugetlb on an architecture supports gigantic pages. I don't quite see why an architecture should be able to opt in into dynamically allocating+freeing gigantic pages. That's just CONTIG_ALLOC magic and not some arch-specific thing IIRC. Note that in mm/hugetlb.c it is #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE #ifdef CONFIG_CONTIG_ALLOC Meaning that at least the allocation side is guarded by CONTIG_ALLOC. So I think (C) is just the right thing to do. diff --git a/fs/Kconfig b/fs/Kconfig index 0bfdaecaa8775..12c11eb9279d3 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -283,6 +283,8 @@ config HUGETLB_PMD_PAGE_TABLE_SHARING def_bool HUGETLB_PAGE depends on ARCH_WANT_HUGE_PMD_SHARE && SPLIT_PMD_PTLOCKS +# An architecture must select this option if there is any mechanism (esp. hugetlb) +# could obtain gigantic folios. config ARCH_HAS_GIGANTIC_PAGE bool -- Cheers David / dhildenb