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 E02C4C98307 for ; Wed, 23 Sep 2026 11:56:43 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D8D3E6B009B; Wed, 23 Sep 2026 07:56:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D3EAE6B009D; Wed, 23 Sep 2026 07:56:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C54BA6B009E; Wed, 23 Sep 2026 07:56:42 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 9E4D86B009B for ; Wed, 23 Sep 2026 07:56:42 -0400 (EDT) Received: from smtpin14.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 1AB5014077A for ; Wed, 23 Sep 2026 11:56:42 +0000 (UTC) X-FDA: 85244875044.14.FFB2099 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf24.hostedemail.com (Postfix) with ESMTP id 54EF5180004 for ; Wed, 23 Sep 2026 11:56:40 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=ETF1ISNk; spf=pass (imf24.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1790164600; 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=PTz+E07TzqHeAqnACQmu7RNQTLYVCyexbot+9YlUnhI=; b=zSVXo9JaYbTB5UvritSZeSqsXUA+La34X9JYF7BFIVSPksrdbkV31f7RgLEbAiFK0OXq7m XSc5eVuFWfcWzJa79REHQJEK7d6a1WUhXBfjICFw8by3UjXA5vkKLQHcPq8CG9dS77sAHJ j/vfRFi8FB4vZqGACtUIHKErV0AI4bg= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=ETF1ISNk; spf=pass (imf24.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1790164600; b=wWaRHc+MSYwx3rrCcj2+QR6Oo9HCl9h2EXS/Jar9PjbcyUFmTstkhsfExhm8vIZRO6UQp7 fEUTqaAJJmPJAHI+mYeqRvOdOtiubrFJ1c3K+ek+MuhWTIsSpUymAcMLhcCWQmtVvURaW4 OleRFuu3c68D3zNMhCeWCQRLnvfKKM8= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 886C341B4A; Wed, 23 Sep 2026 11:56:39 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E4331F00893; Wed, 23 Sep 2026 11:56:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790164599; bh=PTz+E07TzqHeAqnACQmu7RNQTLYVCyexbot+9YlUnhI=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=ETF1ISNkd+WN1Vj3Q4fE2Qc/T7On3xxZi5dYugH6mPcf5CY4Wk38bnGutRM9Fg8jn +LClWCgt+w0vFDYUK9weRzP7oBK3LlaZ0mXWXYOiiS+Xe+pj/Cd6vI67zKnuquBF5W TQFIDWRYawjK11gwt2mdcOE4MUiY8sgi96ot/N6iC9g6onCmMvwJRkPIXvyZ4JOM+c pHgrL0jY52HR8cJmfCTTGv1Uf8Ts890hgd7Mzcq6S3Wfskbcay2yYPqU+WKfFs+f/u 0keA8sqw9WZjmJdGpqveztmRIvuMZ1GLL91+Dl2+WcIojWlENld/mKMXNC/nXrjHOl f6kEEqETrJQZA== Message-ID: <2a2c7c17-82bd-44eb-a3d6-cad263c01b62@kernel.org> Date: Wed, 23 Sep 2026 13:56:31 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 04/12] mm/collapse: add collapse.h for the collapse interface To: Kiryl Shutsemau , Andrew Morton , Lorenzo Stoakes , Zi Yan , Baolin Wang Cc: "Kiryl Shutsemau (Meta)" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Vlastimil Babka , Jann Horn References: <20260916093145.4022188-1-kirill@shutemov.name> <20260916093145.4022188-5-kirill@shutemov.name> 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: <20260916093145.4022188-5-kirill@shutemov.name> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 54EF5180004 X-Stat-Signature: ffgx7d8zc1pohzp76n7bku51wjr6iips X-Rspam-User: X-HE-Tag: 1790164600-36248 X-HE-Meta: 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 rGYNsZCd V+4qnDAiGYyoBXD/TJ/RkbE+X6b8lmeGdnmO11QPsj17LZd7c12pxi4BZbMS2PV2RlvsZWdlNg6DBElTYvieeDuCJr5SDZo4thjpYhYUERuZ8RSYnhLlGOI4Dru0Zs7ambK6MfDkOAZuKcfqAwhTt89AB8LLsEZfxJqsVQYoyZFHrEKVE/TXND0i3fhIoUQ1qtw5zw5GNbSULQW3xcNz2RB/BEpW9uPAzYwsKnx8teF2XOXAMpSckfQri2t+FteZtmGwxooEjv9JNKoYoy+gPKhztMTmm8hlMSxTU Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/16/26 11:31, Kiryl Shutsemau wrote: > From: "Kiryl Shutsemau (Meta)" > > khugepaged.c holds both the users of collapse and the machinery that > performs it. The daemon's scan loop, the sysfs tunables, MADV_COLLAPSE's > entry point and the collapse itself all sit in one file and reach into > each other freely. Nothing marks where a user ends and the engine > begins. > > Start drawing that line. > > Add mm/collapse.h for what the two sides have to agree on: > > - enum scan_result - what the engine hands back; > - struct collapse_control - the state a request carries. > > And two constants move with them: > > - KHUGEPAGED_MAX_PTES_LIMIT -> COLLAPSE_MAX_PTES_LIMIT; > - KHUGEPAGED_MIN_MTHP_ORDER -> COLLAPSE_MIN_MTHP_ORDER. > These look a bit odd when thinking about the "user" aspect. These are rather collapse internals? > Neither is a fact about the daemon, so both lose the KHUGEPAGED_ prefix. Acked-by: David Hildenbrand (Arm) -- Cheers, David