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 8D71EC7115A for ; Wed, 18 Jun 2025 20:04:15 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 27F296B00D9; Wed, 18 Jun 2025 16:04:15 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 22EA06B00DA; Wed, 18 Jun 2025 16:04:15 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 11E266B00DB; Wed, 18 Jun 2025 16:04:15 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id F1D6C6B00D9 for ; Wed, 18 Jun 2025 16:04:14 -0400 (EDT) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 81BF1120C47 for ; Wed, 18 Jun 2025 20:04:14 +0000 (UTC) X-FDA: 83569598028.20.6156297 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf09.hostedemail.com (Postfix) with ESMTP id 895AE140009 for ; Wed, 18 Jun 2025 20:04:12 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=ieseRAba; dmarc=none; spf=none (imf09.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1750277052; a=rsa-sha256; cv=none; b=JsPO6VuDTBFHxRRVMl8pZpsnI+7Q2t6NtoFT0O5aMBMwPiN4luGMIvmlE4AAJdy6hjfyn0 T13mi7Df5iHUrl7HwzAv8SgTzvE9G68R2aYcFg/mnLJxPPXqeH4g2IkwxVBh4cQUN0uV12 OEGUrq+o06jDYtd8YpfwIsxbnxpTh3A= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=ieseRAba; dmarc=none; spf=none (imf09.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1750277052; 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=r+yILtYkX3FnYrUMXwUjtoYSq4aCkMrSL4SJ7/KGbLA=; b=bWHEUp66cui9wpppCBZZFiUsPERKVFmNUBv1flAJVuZOzoNyL9ShCTgdVKPgejNaCLMG+n +kCVA/taW9Al7uMErVaWD89mhH5ir8/msZ0TdsO/toQ2rruHHxBRKzksMwGRDyyfLLo9Lh yPdl1Io1owC13nWQHrTyxp7Xv3gDJzY= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=r+yILtYkX3FnYrUMXwUjtoYSq4aCkMrSL4SJ7/KGbLA=; b=ieseRAbaE2EB/gg0UrA4lAg0ya OMIrk68qActWNIrlU4+o3MUxlOdzs0sAzy8pvh0C+/FzDPucczlLfYPfD00o24KCkCuH+FFOkwmhp R1YimiUoY/XcQ89JvDBIwxhHk6PC6vuXgeyDcRBuG+/scNqdcGd/AmB3MCUJEVczHYhsFH/HtCuBD QUWwg5HM3SO54YGjy9XPxlOrywxz6rlNYI4GbAr78NL3JYgieExT9cy4hxQWUtJGM3OQ5TZX+EmC6 ynJh94nA0G2clxmoy3o2IEFglpHpJc0flDhE2COS7zRIswWNpdaBNi0IJZT6aqdC3OgNSoC27mXmb kXWvpJxQ==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uRz0r-00000004xfj-0q6I; Wed, 18 Jun 2025 20:04:01 +0000 Date: Wed, 18 Jun 2025 21:04:01 +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 08/29] mm/migrate: rename putback_movable_folio() to putback_movable_ops_page() Message-ID: References: <20250618174014.1168640-1-david@redhat.com> <20250618174014.1168640-9-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 895AE140009 X-Stat-Signature: obt3azahkwpwbs66h5hieanqfkto8urk X-Rspam-User: X-HE-Tag: 1750277052-315205 X-HE-Meta: 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 nmDCEeoO t76BbCRovmqF9Nl0rtaZqjZh4o27ddMGu8QmJGpemdx11cHPrSESxU55g1+5pay4q2Po5Sa82Kh7JRzAT20DFaAM2ojIDBpb5qUZ66s/S7JxFgoB11HPwi6MUC/W0kKvrnFc/esFPeXLvVOzoQ7cMnlUOJToKHpCBlo53j6vJuDttUAfK9m+PDedoGNj7Y14tRgExnJVY3uFa6b8AAPaUPvi5gmjGPOgJab7gwdQ1Ujn8v5DPZnwgECb9rzOPNU2OWtpCIdTBsGnTkA9aTSIa9Y15Tq+aSuykmIBZAzz+wZ52UNoyDhfYxRVjFrYQ1Z19tE+9FfR0apu7QCElhvCow+NLO40dSjAuxf/p+Rz1CYJ5CT5/iKc1e93c4JxZRc9dLJes3FLDF/Kd7S2K5mGlFw+2LA== 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 03:25:46PM -0400, Zi Yan wrote: > On 18 Jun 2025, at 15:18, Matthew Wilcox wrote: > >> Why not use page version of lock, unlock, and put? Especially you are > >> thinking about not using folio for these pages. Just a question, > >> I am OK with current patch. > > > > That would reintroduce unnecessary calls to compound_head(). > > Got it. But here page is not folio, so it cannot be a compound page. > Then, we will need page versions without compound_head() for > non compound pages. Could that happen in the future when only folio > can be compound and page is only order-0? I think the assumption that we'll only see compound pages as part of folios is untrue. For example, slabs will still allocate multiple pages (though slabs aren't migratable at this point). The sketch at https://kernelnewbies.org/MatthewWilcox/Memdescs supports "misc pages" with an order stored in bits 12-17 of the memdesc. I don't know how useful that will turn out to be; maybe we'll never implement that.