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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 69F10C7115A for ; Wed, 18 Jun 2025 18:07:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 017C96B00D8; Wed, 18 Jun 2025 14:07:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F09B86B00D9; Wed, 18 Jun 2025 14:07:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DF86A6B00DA; Wed, 18 Jun 2025 14:07:12 -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 CCF8E6B00D8 for ; Wed, 18 Jun 2025 14:07:12 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 7B7C6BC85F for ; Wed, 18 Jun 2025 18:07:12 +0000 (UTC) X-FDA: 83569303104.24.0FC6D62 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf01.hostedemail.com (Postfix) with ESMTP id BEE3C40006 for ; Wed, 18 Jun 2025 18:07:10 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=a6vX8oca; spf=none (imf01.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1750270031; 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=J4aHyFboA5TYykyYa0Jlj3sw+Op0fhB4LmjH5FwOZd4=; b=iZkg8HJu55+ni5igjXZuBeFMZGxZYWzxqWw2g5TOWq1r4xz+UynLEXMAh2RZTE/1zn0yU7 DzWSr/oQYI8RKuJHI/EAniZRBw8G8D90EhVZMaY/hPPvG4mJbUFxH2F3I0tP5G9Is0J5GU nQPxJkJymmdSAuuFGnF6lJyVSCFpiLc= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1750270031; a=rsa-sha256; cv=none; b=2L9qD7247vrKu0lyx/XbKapLiaKM4byxno+SmBvNcsX5i4e6k+V3pFuK9QIBbJo+5XyNdk g7ANVmB5kRmFCVumHM8Pyei9DWtjO7EPEczPma1xtmPVEngS0sHSQjcqonSAky5Z4Vy8eu ZJXeRknA//nGax0VVqi8yT+3AI4vTsw= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=a6vX8oca; spf=none (imf01.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=J4aHyFboA5TYykyYa0Jlj3sw+Op0fhB4LmjH5FwOZd4=; b=a6vX8ocaJ2qS7neeTyXhBP7TAr 68s84eCnuZZugY9yDOtXOq+dInzY5Ri5o1cXxQPO0n8jy33xnrOkeWCEu4QW7VV+U4h64MOtP9fr4 0TidPl1vB3ZLyUTFgZLx8jesTt4rgniAKKkrD6SzwP6j6ysUVfvFh9sUsWlTCWgvHZVAL7ZIqIaVq AsbGHPyCc+UKKfMpxx+/CBEE1jSLbt2G9bE9rKAgdRGaVt2xAqhiarAo33obYqKsLGkEwakZfOz+5 oyN0+y7fCwzCDk1T59eooIug+hjqFPgBzcAXivpBb2u5dmg9CY76FgERkyiExRHDtkJiXJrLseR5r UFeLDxPQ==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uRxBa-00000004U8i-3jag; Wed, 18 Jun 2025 18:06:58 +0000 Date: Wed, 18 Jun 2025 19:06:58 +0100 From: Matthew Wilcox To: Zi Yan Cc: David Hildenbrand , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, virtualization@lists.linux.dev, linux-fsdevel@vger.kernel.org, Andrew Morton , Jonathan Corbet , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Jerrin Shaji George , Arnd Bergmann , Greg Kroah-Hartman , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , Eugenio =?iso-8859-1?Q?P=E9rez?= , Alexander Viro , Christian Brauner , Jan Kara , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Minchan Kim , Sergey Senozhatsky , Brendan Jackman , Johannes Weiner , Jason Gunthorpe , John Hubbard , Peter Xu , Xu Xin , Chengming Zhou , Miaohe Lin , Naoya Horiguchi , Oscar Salvador , Rik van Riel , Harry Yoo , Qi Zheng , Shakeel Butt Subject: Re: [PATCH RFC 04/29] mm/page_alloc: allow for making page types sticky until freed Message-ID: References: <20250618174014.1168640-1-david@redhat.com> <20250618174014.1168640-5-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspamd-Server: rspam03 X-Stat-Signature: p1buhtr3i18k4fepjyagx1bn8kue6bnx X-Rspam-User: X-Rspamd-Queue-Id: BEE3C40006 X-HE-Tag: 1750270030-27439 X-HE-Meta: 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 fhhsYPDQ h8m+UW4iYHSZTos3VUkKiQhrBJ2C0f/Jd2JcZN0kuEFtrPfIe8n9CNZenjw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Jun 18, 2025 at 02:04:18PM -0400, Zi Yan wrote: > > Let's allow for not clearing a page type before freeing a page to the > > buddy. > > > > We'll focus on having a type set on the first page of a larger > > allocation only. > > > > With this change, we can reliably identify typed folios even though > > they might be in the process of getting freed, which will come in handy > > in migration code (at least in the transition phase). > > + if (unlikely(page_has_type(page))) > > + page->page_type = UINT_MAX; > > + > > if (is_check_pages_enabled()) { > > if (free_page_is_bad(page)) > > bad++; > > -- > > 2.49.0 > > How does this preserve page type? Isn’t page->page_type = UINT_MAX clearing > page_type? The point is that the _caller_ used to have to clear the page type. This patch allows the caller to free the page without clearing the page type first.