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 054F741A551 for ; Wed, 9 Sep 2026 09:58:56 +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=1788947939; cv=none; b=oF7+eOpLPLfTY43b7ZGLCohyB8+vCrvm5lI2t7T+JIc8AcOG0mphSNTloYE4uCEdHocT4DWANuep0DRX4TbRuQGkjvjnP3ICRnRHHFtZ9Q/+I81DLUEpEDDoOzUZNUmKusrb7rSKxtFDI9bNIMETOMBJQ6v8M9pnMg/Pb+Wq5Lk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788947939; c=relaxed/simple; bh=GLvIDaewLzOWacKj+3r1NrjRiT6/FzQSfHgVkaMrbS8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=IeZE0I6oSOvra1iT4BVO/xlW9po+tun5i1fM389N2tTHQ/P4lVHA77cJ7cJBOiE2NVtb0Ytsq3C08lJGQnIB8JMeFtdoOKpdPZ6b7DNWHCdR0Cf/ei540cOyL67gDNaj8Sbgq+vknWwXgVxucsOtVAA9QGxdkUEoZWeUcWFGqBs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=CDfjT/xT; 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="CDfjT/xT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C0F541F00A3D; Wed, 9 Sep 2026 09:58:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788947934; bh=Q0Z230v0kcWv+KYsA2iisucLz0tAzBFMvCYKOrnjLsE=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=CDfjT/xTNuxQ4VwSHCk/9ETC998WeGmFdDy7oYbTKuIOBhMtZsw7rHkQgNTR8G7MT 5lJlaEHbyGnCMAEI+ZrxxFcdCdji+K1gckZFfrY9An68jOVz80B+YypE5mhbkejLwo cSrjkJ/AkIUXSv1j+c1T85DSzFPFb0h3eK/eSzdE7hW1frC7KaN0IUUWJjhNM+9Nmk LlDhuC7QQTfea8b8ocf1A6xJ7pK62u08E85d8ff/W1sTyGLj/tJN67VeKiM+4oZYF2 PhFUwmuRU3LkW6hWRP0cAoxmDDEA/wftxR6q3sG/Hg7Se4mH5Htc8NmYcE7B/EMrQg JsW0gwMHhyPlw== Message-ID: <67dc7ac8-b39d-4354-8cbf-f2a1c3a369ee@kernel.org> Date: Wed, 9 Sep 2026 11:58:50 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 10/17] mm/hugetlb: switch HugeTLB to section-based vmemmap optimization To: Muchun Song , Andrew Morton , Oscar Salvador Cc: Mike Rapoport , Vlastimil Babka , Lorenzo Stoakes , Michal Hocko , David Laight , "Liam R . Howlett" , Suren Baghdasaryan , Qi Zheng , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Muchun Song References: <20260825084608.47437-1-songmuchun@bytedance.com> <20260825084608.47437-11-songmuchun@bytedance.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: <20260825084608.47437-11-songmuchun@bytedance.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 8/25/26 10:46, Muchun Song wrote: > HugeTLB bootmem vmemmap optimization still carries its own early setup > path, including pre-populating optimized mappings before the generic > sparse-vmemmap code runs. > > Now that the section-based vmemmap optimization can derive HugeTLB > vmemmap deduplication from section metadata, HugeTLB only needs to mark > the bootmem huge page range with the appropriate order. The generic > sparse-vmemmap population path can then allocate and map the shared tail > vmemmap pages without any HugeTLB-specific early population code. > > Do that by setting the section order when a bootmem huge page is > allocated and dropping the dedicated pre-HVO helpers and related > special-casing. > > This removes duplicate early setup logic and switches HugeTLB to the > section-based vmemmap optimization path. > > Signed-off-by: Muchun Song > Acked-by: Mike Rapoport (Microsoft) > --- > v3: > - Use the order-based helper for the bootmem vmemmap-optimized check > > v2: > - Collect Acked-by from Mike Rapoport > --- > include/linux/hugetlb.h | 1 - > include/linux/mm.h | 3 -- > mm/hugetlb.c | 30 ++------------ > mm/hugetlb_vmemmap.c | 90 +++-------------------------------------- > mm/hugetlb_vmemmap.h | 14 +++---- > mm/sparse-vmemmap.c | 31 -------------- > mm/sparse.h | 27 +++++++++++++ > 7 files changed, 42 insertions(+), 154 deletions(-) Nice cleanup. > > diff --git a/mm/sparse.h b/mm/sparse.h > index e4617f9c8876..049272aba84e 100644 > --- a/mm/sparse.h > +++ b/mm/sparse.h > @@ -16,6 +16,24 @@ static inline unsigned int section_order(const struct mem_section *section) > return section->order; > } > > +static inline void section_set_order(struct mem_section *section, unsigned int order) > +{ > + VM_WARN_ON(section_order(section) && order && section_order(section) != order); > + section->order = order; As raised previously "section order" is entirely unclear. If this is a compound page order we should spell that out. -- Cheers, David