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 B20E0C5DF82 for ; Thu, 20 Aug 2026 11:11:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CA3066B0095; Thu, 20 Aug 2026 07:11:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C7A536B009F; Thu, 20 Aug 2026 07:11:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B934C6B00A0; Thu, 20 Aug 2026 07:11:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 925EE6B0095 for ; Thu, 20 Aug 2026 07:11:23 -0400 (EDT) Received: from smtpin15.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 3D2351C1B47 for ; Thu, 20 Aug 2026 11:11:23 +0000 (UTC) X-FDA: 85121381646.15.4981511 Received: from flow-b7-smtp.messagingengine.com (flow-b7-smtp.messagingengine.com [202.12.124.142]) by imf26.hostedemail.com (Postfix) with ESMTP id 90DA214000C for ; Thu, 20 Aug 2026 11:11:20 +0000 (UTC) Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=shutemov.name header.s=fm1 header.b="K U1+i7z"; dkim=pass header.d=messagingengine.com header.s=fm3 header.b=PagUZJvm; spf=pass (imf26.hostedemail.com: domain of kirill@shutemov.name designates 202.12.124.142 as permitted sender) smtp.mailfrom=kirill@shutemov.name; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1787224280; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=g9xsCX0WBUUnfBOKB0w7/8Sors9fi6e3DmVtM4E2/4M=; b=udy6np14J7qtgJEJQMeNlC8NxKonbgETBQjVSgNgdb4bzWSoDte5nwhWH8MuFbdSf3D+IW ZmH4VCMOqZlyr34yISJoBkK6T52BCw2iuPhlI2GXUgHSSBXPVimkh7dw1ZX2q4Wfr2DVky iNzO9oHd/Ul0JnUb8ToCH3UcxRM9BWM= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=shutemov.name header.s=fm1 header.b="K U1+i7z"; dkim=pass header.d=messagingengine.com header.s=fm3 header.b=PagUZJvm; spf=pass (imf26.hostedemail.com: domain of kirill@shutemov.name designates 202.12.124.142 as permitted sender) smtp.mailfrom=kirill@shutemov.name; dmarc=none ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1787224280; b=3aruScm/lTAeEm4SSSU5r4FLvVgXXKe4MLW592CXxum5c5D8l1+tezBLrG/fw0QUV+3pnV Y0w6+JjS1Bj49J8Fq2mBMWc4UeChg/KDhHsam954DFmzLqEIOnLb9IakHXLXyt365Dyrom Zlm8Y1cIzUWAcVXEdSle5Lom+XS19Nc= Received: from phl-compute-04.internal (phl-compute-04.internal [10.202.2.44]) by mailflow.stl.internal (Postfix) with ESMTP id 701571300542; Thu, 20 Aug 2026 07:11:18 -0400 (EDT) Received: from phl-frontend-03 ([10.202.2.162]) by phl-compute-04.internal (MEProxy); Thu, 20 Aug 2026 07:11:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=shutemov.name; h=cc:cc:content-type:content-type:date:date:from:from :in-reply-to:in-reply-to:message-id:mime-version:references :reply-to:subject:subject:to:to; s=fm1; t=1787224278; x= 1787231478; bh=g9xsCX0WBUUnfBOKB0w7/8Sors9fi6e3DmVtM4E2/4M=; b=K U1+i7z47jS/fBLaFTfoj6mmFdxh6iUw05H+jTqBZiQF5VD4GNTURHHD3Nsl3AkNf q440lJTbNRyuHU70y+RTw/qwLg5QgQMHPOoY/YvYj12IhydCO98I1j9JUHshw+f1 FkwJSWWoZPKmbZOt3r3+2kdfxcNLPndbGwIpnOxfnZaOZyD/Iiptnx1f9/tY4bTC K4JyAVplLEZ/dzLgQ9p+iJh8PF61P63//nMc6Yex0dW/J2L9shCsDDdzSdcwQu6o VeppE28WnaHc/Q0tliWFkq5EVCcaiRlLYWP4Ka0roDg/h2eYZ3jCI/aMtPBdBb2a RAIpRNXn0XXRz57GM4gFw== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:subject:subject:to :to:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; t= 1787224278; x=1787231478; bh=g9xsCX0WBUUnfBOKB0w7/8Sors9fi6e3DmV tM4E2/4M=; b=PagUZJvmqFmQep9zijjZCNDOkk2VTJM6cXWjSMGUp70gTevh8wI GB8PSELsZV52BP+N+2MiA1+CrSaBHjmSIp9FoJhIfDvfaNCWCXQjrmVO4SDNdDlv C5cxPXf8yUsQkFECN+CSS+/mN/RIfaxYNG/pVO5zPBXfTGnECOg16q9XnQ8i4me1 uu6ZOwuV5MVQYEs5ASUXCeBCiSeabZpGbXYv15iiVUzmdanVvJ2P6kVDS3WngoU+ /TBPIFKL83avXU5pC9goRqM/Wtgj4Hgy3tYRvtzh8Y6wxaxasQRXXpjeMAikscY+ CSQp4LpVHUWY67gM+Ulw2nTy9qNQFsMxhdA== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: dmFkZTE0kLAPelY3PhKKgfOZReZlwUXCE2P+0W3Lsq0wn1U8jgUAUWTZGyhI7tcRZnVTCb PshjWZOgj5Oe8lG1fycLvPkM2WPvj3VvahId3o3ZrQfFqXv1hczkf19HxS/ojoQQHQMG4E Td+uhh0fXapAah0ml84fpRB7tzK8Yw3eEnpDiyM09M80hT7656Wy1r8DPVWW5UkwozcDgc veEgvxmSeLwe1C1/u6343GWpJWQcEESNTABMaj282WuViN7jYhRdvbjsZz6StVtV5sUpMo 5rWloeYRfSADBeGXkVLM+Kh/s+R0/bZngF+2STWRGn791FSVF1pf1ChlwkUilcOAiDxntZ dxRzYJBEyyPadtn4QGMYxkODvUaEP9m6+Ecx0DINgUHxNK0Hhnacv6+Dz0MHehkbu39EVv Zy9q4iPh0OAK5uFaGrzt4one4rabz38n2w1H2Cggve/3mOswlytYQCbdIdU64fiyBBAJvH e0ioudfoJz65Rf6nSruDUGIce598LTvLwTJS1EcoTnUPXLRvVAoejecmJqFTmc+SAOLcu4 ipx+Nv7CcBi1uUzY6hjAZNdd+K5sAGPBh+uaSHgC+TjYE/snlo5SsVZWLZKjZOpbQitDhb C+HLQ/XTGjJbkQRtYtnwLnpDeChP/3qcB9DG8JvHh5AzDUYACf/rzJnr+h/A X-ME-Proxy: Feedback-ID: ie3994620:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Thu, 20 Aug 2026 07:11:16 -0400 (EDT) Date: Thu, 20 Aug 2026 12:11:15 +0100 From: Kiryl Shutsemau To: "David Hildenbrand (Arm)" Cc: akpm@linux-foundation.org, ljs@kernel.org, nico.pache@linux.dev, baolin.wang@linux.alibaba.com, baohua@kernel.org, dev.jain@arm.com, hughd@google.com, lance.yang@linux.dev, liam@infradead.org, mhocko@suse.com, rppt@kernel.org, ryan.roberts@arm.com, shuah@kernel.org, surenb@google.com, usama.arif@linux.dev, vbabka@kernel.org, ziy@nvidia.com, usama.anjum@arm.com, agordeev@linux.ibm.com, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, jannh@google.com, willy@infradead.org, pfalcato@suse.de, rostedt@goodmis.org, mhiramat@kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org Subject: Re: [RFC PATCH 03/57] mm/collapse: add collapse.h for the shared collapse state Message-ID: References: <20260816224609.308019-1-kirill@shutemov.name> <20260816224609.308019-4-kirill@shutemov.name> <3113ac8b-c1ce-4577-9e93-449b70818918@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3113ac8b-c1ce-4577-9e93-449b70818918@kernel.org> X-Stat-Signature: gzwrkia6zkmt7i5g4uuk13f53fr1f6xr X-Rspamd-Queue-Id: 90DA214000C X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1787224280-649596 X-HE-Meta: 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 OMMQReDZ Sw2WsQ2JHwlNFrrIZqSFJ7Ud55+9s+TgiwN38+QLvU1rXEJFZgWUXBWMBvUZDvKRb0L2TsTvpiqJEmzk6L9wxQYrinpNUMaavaHD4b8zenTKH9tdFs+qgZfGaPzO6WeRvbuLuGwLt0hAZdsWd8jZTu3k1/zVRcYLfGTotF5XII93AGgI2Qxdt9b3D4WNyH/sjXYg1KLlHQTb8SY+S/rqpnskd7W4sqyB+BL5kP6BwKZlZjch+xdXkcikEKg87LoA7yKbkN1mh854QdE7xYo2Y4yLm6qN6YbirlvBuvsdFvPzirHfHJGRASul1Atpryyg3QDFZmwd2rAqngH40nkBsJMNkLZ0H8XYdBwADXkwdblPd3ZRp3vNmbh1WUALlM1ZSZ2Rv12QrQ0RfrXD2UzWiepdXfmPKcxbXCO65rt/lTW5VW9Dpn1gqJXqx/LV9YB/M/kHLJGAcOthp97xEYET6lRDZBQ== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Aug 19, 2026 at 04:19:41PM +0200, David Hildenbrand (Arm) wrote: > On 8/17/26 00:45, Kiryl Shutsemau wrote: > > From: "Kiryl Shutsemau (Meta)" > > > > Preparation for building the new collapse engine in its own file. The > > engine and khugepaged.c need to agree on what a collapse result is and > > what state a scan carries. > > > > Move enum scan_result and struct collapse_control into a new > > mm/collapse.h. > > > > No functional change intended. > > > > Assisted-by: Claude-Code:claude-opus-5 > > Signed-off-by: Kiryl Shutsemau (Meta) > > --- > > BTW, I'm wondering whether it would result in less churn (independent of the > other changes) to > > a) Rename mm/khugeapged.c to mm/collapse.c > > b) Move stuff into mm/collapse.h that a new ... > > c) mm/khugapegd.c will need. I went for a clean collapse.c on purpose: the engine is new code, and a new file keeps it readable while both mechanisms are in the tree, with 28 as a plain delete from khugepaged.c. Your shape is less churn, though, and it keeps blame: 29-35 move about 1700 lines as add-and-delete today, and most of that would stay put, with only the daemon -- mm_slot, the scan loop, sysfs -- extracted into a new khugepaged.c. If you prefer it that way, I can give it a try for v2. The rename has to open the series, so it will collide with anything in flight that touches khugepaged.c. -- Kiryl Shutsemau / Kirill A. Shutemov