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 CAF9538FA3 for ; Fri, 12 Sep 2025 16:06:18 +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=1757693180; cv=none; b=cfsCDX3Kfg6Ue0PL5dLdNdc/K7kIc/i8f6OyPiUy/7X2/aRCh+iuTgC/nvRULMiz0OhuuY5AGKJDqu8skG1OSc3R5BtmY5Rkka0B5czxl/uY/VWObukIe4GCihJg7kGfYCTyR8YtR38/rwM/bZS/UBBq9Dptp915TX8IOxN42A0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757693180; c=relaxed/simple; bh=kKRzEF2tif2Gzp7LphMsgUe/IDu2VeQs/AdiCGVBxPI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=o5hW6FaVCpWQF5HcHV/U22DCrrKiim2m2qx3Fbri/yA6XzV12rpS3gl2NIoGapQb6CFovzRjQkAwu2XpIB1UR0E7u50wVvsQpPd1/1h7+7unciZFE9fNamBqQwHhIA6sEAG2V8/AeFzjsAKfjCNpkv9SE7A2n4Sua212wahYhWM= 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=f56cV9J+; 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="f56cV9J+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1757693177; 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=dxzwguxznvqE0mx+qo75gr4n5bBcbz0Oi4oqNYnLVvU=; b=f56cV9J+Bbma3nFgjyBWOHXaDohY1g2cBPP2WAsmFi9bk3aeCeTE8m7THQbp3u4ho0V44b GjK9i0pH70ogjWQaFWbhtv9vwUIsraVaGk4AQwOzjol+q/PwLpu5FUff2vAKuQcX/R9LQl gsHIuI/gH0quvW6xZjFjZrn/vDp+VHA= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-620-se8O4SdYPyObdV_zeba05w-1; Fri, 12 Sep 2025 12:06:15 -0400 X-MC-Unique: se8O4SdYPyObdV_zeba05w-1 X-Mimecast-MFC-AGG-ID: se8O4SdYPyObdV_zeba05w_1757693174 Received: by mail-wr1-f70.google.com with SMTP id ffacd0b85a97d-3e7696b36d9so475068f8f.0 for ; Fri, 12 Sep 2025 09:06:15 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757693174; x=1758297974; 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=dxzwguxznvqE0mx+qo75gr4n5bBcbz0Oi4oqNYnLVvU=; b=G6UE7NiPxb4kGskVfdNEGK0aP1+e8ggakNlhexTqPpuDgwSYmyaNlYtj2yXjEozhKP /l3D4aTXUdkWIjIY9N146vCijMv7YEwArPdp4z89Im350+LxlO4U4YsrobPB6W+UFzcp KFVVUH8CgB2NVFhjVsNcfVjouzxXW1+RurJXkj99LSwIF/onqF8KsONDXVHmgkO7AgCl QFwIT/CIzVswxnwJtkVRTqVE3uKCTtaqX2PkVdVpQSXhBlCqKaaOr5DLoqm777IBm0r5 3LG83lrrmCGzbanqkIT806KJMmHXeOHF9SaMWVs39shjQJGsNPk1ZM8a54q26v0GeZwz e33g== X-Forwarded-Encrypted: i=1; AJvYcCU+iVpeBCxGBjDo6LreZS/G2eoyllFxkpSV08LGbTcvnsU9opMt4evFnYvSKSlem9y4YOkR32hUm7fzqow=@vger.kernel.org X-Gm-Message-State: AOJu0YyFv0v1u5uX6bgqnrGQhP1+mYautDfj4Hu6sq/TYuZbNpDnf7p4 unI9z1xw6j/hLzsC2mlqpqCMExyPKwdsy3MVcM0D5R+cyfKnm0fcY8zH2y+wyrFMrv6JNp7cW3T gggcwbnYRj7xRhOAcvq9xSA4032aQkyLZg4KFZ56P9yxSgS1DWscq8XnbyLrzn8uQWA== X-Gm-Gg: ASbGncu7Zglcj4bou3Jp+B3iTEgL6BDviDqUAWxHTZnB5xNM8s75i4aPi3X4kI4WKix pXFrGEGBCV3QhAjRPYkCQRLH8Z4dkh/WrS4H3OWsQt5yrOtzHLowEnxBGKgvf+XCwfy1mrtcT7p n+ybhwr+cNjoracNYh6akIGFwWbTdtTQPotjgQmuMBU3ecjoxjBwDnpTRvmV2qle/hbRoaCPSVZ mU8dMYFn+z25lOzkaaSDqWsJb1gkVFsGuWv+8hsOkDOJ2W48wCfeFtb8k1QqwWcDcgcLNElfO2b x/VQDABQCqQVtqncSkP3u+P1PNh2vtdJtTsP3whfxTQBm5qhng9h9q5TNat1cDPhzGNRiz5VO4N 6LL30BoGANCyzHGQ0zkUm9NSxQxccmMLCrTWeIEPq8zaB0+5pWo0njlg1LedYY05UZfc= X-Received: by 2002:a5d:5887:0:b0:3e7:44c7:4bad with SMTP id ffacd0b85a97d-3e765a36ea1mr3659992f8f.31.1757693174140; Fri, 12 Sep 2025 09:06:14 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHhFpAvzAr4h6nHJq/W34QBFAPDcffgJvXu784z1DyQ2B8SVflxg8bLzme2d+Eci71k9K3ttg== X-Received: by 2002:a5d:5887:0:b0:3e7:44c7:4bad with SMTP id ffacd0b85a97d-3e765a36ea1mr3659945f8f.31.1757693173667; Fri, 12 Sep 2025 09:06:13 -0700 (PDT) Received: from ?IPV6:2003:d8:2f20:da00:b70a:d502:3b51:1f2d? (p200300d82f20da00b70ad5023b511f2d.dip0.t-ipconnect.de. [2003:d8:2f20:da00:b70a:d502:3b51:1f2d]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3e760775842sm7308106f8f.7.2025.09.12.09.06.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 12 Sep 2025 09:06:13 -0700 (PDT) Message-ID: Date: Fri, 12 Sep 2025 18:06:11 +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 v3 10/15] mm, swap: wrap swap cache replacement with a helper To: Kairui Song , linux-mm@kvack.org Cc: Andrew Morton , Matthew Wilcox , Hugh Dickins , Chris Li , Barry Song , Baoquan He , Nhat Pham , Kemeng Shi , Baolin Wang , Ying Huang , Johannes Weiner , Yosry Ahmed , Lorenzo Stoakes , Zi Yan , linux-kernel@vger.kernel.org, Kairui Song References: <20250910160833.3464-1-ryncsn@gmail.com> <20250910160833.3464-11-ryncsn@gmail.com> 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 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: <20250910160833.3464-11-ryncsn@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 10.09.25 18:08, Kairui Song wrote: > From: Kairui Song > > There are currently three swap cache users that are trying to replace an > existing folio with a new one: huge memory splitting, migration, and > shmem replacement. What they are doing is quite similar. > > Introduce a common helper for this. In later commits, this can be easily > switched to use the swap table by updating this helper. > > The newly added helper also makes the swap cache API better defined, and > make debugging easier by adding a few more debug checks. > > Migration and shmem replace are meant to clone the folio, including > content, swap entry value, and flags. And splitting will adjust each > sub folio's swap entry according to order, which could be non-uniform in > the future. So document it clearly that it's the caller's responsibility > to set up the new folio's swap entries and flags before calling the helper. > The helper will just follow the new folio's entry value. > > This also prepares for replacing high-order folios in the swap cache. > Currently, only splitting to order 0 is allowed for swap cache folios. > Using the new helper, we can handle high-order folio splitting better. > > Signed-off-by: Kairui Song > Reviewed-by: Baolin Wang > --- Acked-by: David Hildenbrand -- Cheers David / dhildenb