From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 4B05E3085A6; Wed, 18 Jun 2025 20:04:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750277055; cv=none; b=Towz8McBOLd4Y9MYSJs6H7ZsAmuDuIMzcLXtsSZHICs/qwuq6T11D+P5AyORftfzfSCka7JytIRb4fDtiJhl8tVwd1DJ+t46HAJ1y45WdL9l1Pyxus3QnhUJ+5CoD0Aed1E6QK/BxdJfhAitsceRMe3XpvZ4U+iQInuuh/nRJQM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750277055; c=relaxed/simple; bh=6ZkxjQapZUXSy1w/otyjvrDRv9aX4E97f9yHVY3kDe8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lpSdaEML+MA89oTbkdtWES5TZzrJouJFeyhX0Rn4SEnvSHCUEBv/ArQmphJrNPT0LE7vzdNJXOClDC9njtxJbwmILMUsnHST8iRnWtAdzv1lTQDmpm0DpmfYCt+XXTuAjeIw1Rthq5W5jr3mC1NaPcxJLYrM+KuGqxou8GwxMoc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=ieseRAba; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ieseRAba" 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> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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.