From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 8FA6042A82 for ; Mon, 4 Aug 2025 18:50:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754333407; cv=none; b=KKPdJbaR4dzRRXLZyCjAktM5hgizq2HgbPSw9xpDpjVcBw1A3JHQLLuoEHJd6NPLx1AVGHVbOvVQ8sBi3AZlmFDCbKfE0mA0GuOlFZd31lR552R2kbZcrqSISoiIFPbrGEXyy4LONUKe5Q5rq5+B1MFHHEIYHP0DTdW4Rt03Iok= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754333407; c=relaxed/simple; bh=jHrIF7fBrQjx1WYOv08IkMlgG0qiq/c3w6QVOToHheg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ABM0ta2ejFAT0bZFQE0NhXu2ap6FgrX+PoJKMXO4jTzpF0HA+Fl753svL2smgqXU1c07U04WE9caZsEhiAFb89x4zByEnSsOn96BXweUBo1Q8r8OFb5sWYHm+dV2mpeHNGlGnQOJNhD/HVqx77WVUzvn7Qm391ERsl6O4ydnEZE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=iUyjlQjU; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="iUyjlQjU" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1754333404; 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=T7UUfiKeOYlsuGZHT7CWAZbKMNooPk/lkfRZ63Id3bE=; b=iUyjlQjUfkfrZONjTtzR75EqjG7NdQjqLYN5VEhXK1va1Zsx6OU/+4dKxWHZSAkxlRsrpq dhmuqrrWjule8Oz01sFI/TdxkMlDHTKCf8ExPkR9leFnDiaq0wCsIIqCOr2zNS9tqp3p/1 COko4aC1apeEMRq1Rv4VOGxzSabBuPs= Received: from mail-wm1-f72.google.com (mail-wm1-f72.google.com [209.85.128.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-656-ohHcdPggNeyLinStahAfmg-1; Mon, 04 Aug 2025 14:50:01 -0400 X-MC-Unique: ohHcdPggNeyLinStahAfmg-1 X-Mimecast-MFC-AGG-ID: ohHcdPggNeyLinStahAfmg_1754333400 Received: by mail-wm1-f72.google.com with SMTP id 5b1f17b1804b1-459d3abb2b5so6331105e9.3 for ; Mon, 04 Aug 2025 11:50:00 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1754333399; x=1754938199; h=content-transfer-encoding:in-reply-to:organization: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=T7UUfiKeOYlsuGZHT7CWAZbKMNooPk/lkfRZ63Id3bE=; b=NU8GCV2n4hAWI8xTp+Wp9U+FXHsZLO2Yul3/FcyyzkHXdofK5hDlX8C8kuoUJOByg6 4M7ZVHHwI86ylkYmtoXTaxDiQ3YXpvTXSMx9L0/8agz4QOytyYBpjwzFpG3KU8ctVUWg p8qyi2FldtOzQY/TN26PIjb6oP3lPHFiMhxu0xVdoU2J0vKYv48w7BvkMGhs9PkHspdF VxOypSC1PUGGaIk8t/ZJA4rFt3F6cUPEqkezxCnDox3WWNd6v0ACsSA+pCYmP2L0LSZh uw6s0oyk/SBYsn7BV+meMfSBz3w68R4tivhQmrHjOVwXis7vS66FgayezGR7w099RsYf H5yg== X-Forwarded-Encrypted: i=1; AJvYcCXVPq3Pb0tKxI8UHPAMVbElOGSxFrnjKtIYxoHVeIazyAdBLr4/yWdYQF1Sd8dR/veryWDQaQnxWuT8RC4=@vger.kernel.org X-Gm-Message-State: AOJu0Yykgqqburtb4MSeF3q1s+yUHVVqQWuYbO+mKODQ35XEPhBhbr/N VQa+r3k94+iw9PVotKCLCn5A2FLE6or4lvDMSN3yfgNDmdHHKVPmoSXj6Y/NOMJ4FeHDJ9wyWpL L7UvazCK5ueRNev3SZ1icGe0UJ5Jm8nvIVA1nvE1poNbZzM/R9xCjRywey6p7J8igLQ== X-Gm-Gg: ASbGncsq70NknYcnxIFziZWRzTotcK0flYujpKhi+NRFnKW4kIIuv42wrQJeHrXzKpn 84noHIi5ed5vnRGFSaYdw9j3khTkVmta1SVZ0lKwObSt/T8UVlskf1NxtxfM/DLsoBF7zJihhFx QSu5kH3T07AVUz4LPxwhqbymxZYW4o8aIBxTridRsGQSeTMRSnN/Ta8//dZMCXR3cMTzNJnD5aN oOUjoVVuRsnDJvFm3suY10byuzfAp+Qcttez2QSlbI1t0KGXgRN83IB0vch5TNL4uuIDJTtOdZw Xy0ZdeLyaGVN7bWXCustS2vZvpygJFqdmtvzDMSll8mWUqRKjAKHf+K4urg+E5XzY0HqI9c= X-Received: by 2002:a05:600c:4e10:b0:459:443e:b180 with SMTP id 5b1f17b1804b1-459443eb330mr58589105e9.8.1754333399547; Mon, 04 Aug 2025 11:49:59 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEP5GKxPERgMzvVb32ee5lNTwOD6PwhOAZJzd+FoxhfvfxFD7V+1+8Wo8Q6qFIfAKQ4FNeWAg== X-Received: by 2002:a05:600c:4e10:b0:459:443e:b180 with SMTP id 5b1f17b1804b1-459443eb330mr58588875e9.8.1754333399118; Mon, 04 Aug 2025 11:49:59 -0700 (PDT) Received: from [192.168.3.141] (p4ff1f1eb.dip0.t-ipconnect.de. [79.241.241.235]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3b79c47b10asm16101568f8f.60.2025.08.04.11.49.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 04 Aug 2025 11:49:58 -0700 (PDT) Message-ID: Date: Mon, 4 Aug 2025 20:49:57 +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: [RFC PATCH] mm/page_alloc: Add PCP list for THP CMA To: Juan Yescas Cc: akash.tyagi@mediatek.com, Andrew Morton , angelogioacchino.delregno@collabora.com, hannes@cmpxchg.org, Brendan Jackman , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, Linux Memory Management List , matthias.bgg@gmail.com, Michal Hocko , Suren Baghdasaryan , Vlastimil Babka , wsd_upstream@mediatek.com, Zi Yan , Kalesh Singh , "T.J. Mercier" , Isaac Manjarres References: From: David Hildenbrand Content-Language: en-US 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 ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAmgsLPQFCRvGjuMACgkQTd4Q 9wD/g1o0bxAAqYC7gTyGj5rZwvy1VesF6YoQncH0yI79lvXUYOX+Nngko4v4dTlOQvrd/vhb 02e9FtpA1CxgwdgIPFKIuXvdSyXAp0xXuIuRPQYbgNriQFkaBlHe9mSf8O09J3SCVa/5ezKM OLW/OONSV/Fr2VI1wxAYj3/Rb+U6rpzqIQ3Uh/5Rjmla6pTl7Z9/o1zKlVOX1SxVGSrlXhqt kwdbjdj/csSzoAbUF/duDuhyEl11/xStm/lBMzVuf3ZhV5SSgLAflLBo4l6mR5RolpPv5wad GpYS/hm7HsmEA0PBAPNb5DvZQ7vNaX23FlgylSXyv72UVsObHsu6pT4sfoxvJ5nJxvzGi69U s1uryvlAfS6E+D5ULrV35taTwSpcBAh0/RqRbV0mTc57vvAoXofBDcs3Z30IReFS34QSpjvl Hxbe7itHGuuhEVM1qmq2U72ezOQ7MzADbwCtn+yGeISQqeFn9QMAZVAkXsc9Wp0SW/WQKb76 FkSRalBZcc2vXM0VqhFVzTb6iNqYXqVKyuPKwhBunhTt6XnIfhpRgqveCPNIasSX05VQR6/a OBHZX3seTikp7A1z9iZIsdtJxB88dGkpeMj6qJ5RLzUsPUVPodEcz1B5aTEbYK6428H8MeLq NFPwmknOlDzQNC6RND8Ez7YEhzqvw7263MojcmmPcLelYbfOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCaCwtJQUJG8aPFAAKCRBN3hD3AP+DWlDnD/4k2TW+HyOOOePVm23F5HOhNNd7nNv3 Vq2cLcW1DteHUdxMO0X+zqrKDHI5hgnE/E2QH9jyV8mB8l/ndElobciaJcbl1cM43vVzPIWn 01vW62oxUNtEvzLLxGLPTrnMxWdZgxr7ACCWKUnMGE2E8eca0cT2pnIJoQRz242xqe/nYxBB /BAK+dsxHIfcQzl88G83oaO7vb7s/cWMYRKOg+WIgp0MJ8DO2IU5JmUtyJB+V3YzzM4cMic3 bNn8nHjTWw/9+QQ5vg3TXHZ5XMu9mtfw2La3bHJ6AybL0DvEkdGxk6YHqJVEukciLMWDWqQQ RtbBhqcprgUxipNvdn9KwNpGciM+hNtM9kf9gt0fjv79l/FiSw6KbCPX9b636GzgNy0Ev2UV m00EtcpRXXMlEpbP4V947ufWVK2Mz7RFUfU4+ETDd1scMQDHzrXItryHLZWhopPI4Z+ps0rB CQHfSpl+wG4XbJJu1D8/Ww3FsO42TMFrNr2/cmqwuUZ0a0uxrpkNYrsGjkEu7a+9MheyTzcm vyU2knz5/stkTN2LKz5REqOe24oRnypjpAfaoxRYXs+F8wml519InWlwCra49IUSxD1hXPxO WBe5lqcozu9LpNDH/brVSzHCSb7vjNGvvSVESDuoiHK8gNlf0v+epy5WYd7CGAgODPvDShGN g3eXuA== Organization: Red Hat In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 04.08.25 20:20, Juan Yescas wrote: > Hi David/Zi, > > Is there any reason why the MIGRATE_CMA pages are not in the PCP lists? > > There are many devices that need fast allocation of MIGRATE_CMA pages, > and they have to get them from the buddy allocator, which is a bit > slower in comparison to the PCP lists. > > We also have cases where the MIGRATE_CMA memory requirements are big. > For example, GPUs need MIGRATE_CMA memory in the ranges of 30MiB to 500MiBs. > These cases would benefit if we have THPs for CMAs. > > Could we add the support for MIGRATE_CMA pages on the PCP and THP lists? Remember how CMA memory is used: The owner allocates it through cma_alloc() and friends, where the CMA allocator will try allocating *specific physical memory regions* using alloc_contig_range(). It doesn't just go ahead and pick a random CMA page from the buddy (or PCP) lists. Doesn't work (just imagine having different CMA areas etc). Anybody else is free to use CMA pages for MOVABLE allocations. So we treat them as being MOVABLE on the PCP. Having a separate CMA PCP list doesn't solve or speedup anything, really. I still have no clue what this patch here tried to solve: it doesn't make any sense. -- Cheers, David / dhildenb