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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0EFD9C433FE for ; Sat, 23 Oct 2021 05:14:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D3D0960E09 for ; Sat, 23 Oct 2021 05:14:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230294AbhJWFFL (ORCPT ); Sat, 23 Oct 2021 01:05:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49712 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229446AbhJWFFK (ORCPT ); Sat, 23 Oct 2021 01:05:10 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 08DECC061764; Fri, 22 Oct 2021 22:02:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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=hKfR3/ryyitNRCxx14thpt1Pe6SRC47enbuHQnqPb6s=; b=ecpD4Qwjh5T3agQ5qTTl8GtazS w8HThPRzeXp2YcS37McMWS94pO36xXo9FG7zvEhc06IFsxSbb2Qwlo7FtOje/iP67fHEZg64yh3vi Mm5TaOJFNsqbf3MjFPFmmsp6iFcOcCKyd9Mafs/Z3z1nTJ0coG3N/xzJ/dpYyTfapY1HadzEXakKI bVw8DDn5qKYrD8XMGtYjvwvM13VlF49ex+gPSA2+TzT7cOpsK/u/V2jKSqnSQ8YWLdSDNbi/JUhmW blKvlxteuJ2MNVZatZET1jlnTSEGTVZpI5E4A3w1fCxoV5NNR66RLiS3yXsSdCPoIt5JorLe8TTVa KxFz70TA==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1me9Av-00CHxV-Uc; Sat, 23 Oct 2021 05:02:33 +0000 Date: Fri, 22 Oct 2021 22:02:33 -0700 From: Christoph Hellwig To: Matthew Wilcox Cc: David Hildenbrand , Johannes Weiner , Kent Overstreet , "Kirill A. Shutemov" , Linus Torvalds , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Andrew Morton , "Darrick J. Wong" , Christoph Hellwig , David Howells , Hugh Dickins Subject: Re: Folios for 5.15 request - Was: re: Folio discussion recap - Message-ID: References: <20211018231627.kqrnalsi74bgpoxu@box.shutemov.name> <326b5796-6ef9-a08f-a671-4da4b04a2b4f@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 23, 2021 at 03:22:35AM +0100, Matthew Wilcox wrote: > You can see folios as a first step to disentangling some of the users > of struct page. It certainly won't be the last step. But I'd really > like to stop having theoretical discussions of memory types and get on > with writing code. Agreed. I think folios are really important to sort out the mess around compound pages ASAP. I'm a lot more lukewarm on the other splits. Yes, struct page is a mess, but I'm not sure creating gazillions of new types solve that mess. Getting rid of a bunch of the crazy optimizations that abuse struct page fields might a better first step - or rather after the first step of folios which fix real bugs in compount handling and do enable sane handling of compound pages in the page cache. > If that means we modify the fs APIs again in twelve > months to replace folios with file_mem, well, I'm OK with that. I suspect we won't even need that so quickly if at all, but I'd rather have a little more churn rather than blocking this important work forever.