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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9560BC61DA4 for ; Sun, 5 Mar 2023 04:16:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229489AbjCEEQA (ORCPT ); Sat, 4 Mar 2023 23:16:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39986 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229379AbjCEEP7 (ORCPT ); Sat, 4 Mar 2023 23:15:59 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0CC88D53A; Sat, 4 Mar 2023 20:15:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=XZbX19UIOBgbhN58Zf8KUMwb/xPxPMAlTovGZ1xqlvs=; b=eoNxFie6n2xBw64ti9CbXcM2xL b0tb4yBx1mASTimsEwuaE758mUlXj0hEmnHDU2dj/elmN9DbkLstJgAgR3e+kst9kv3URQWRoDWZE 06LKnkGW0QhvxRpFo089uUxTUYPnvHkeU1miaROA4/8+TQ98LOjYdY+RFh1Nk3WEbijwDX//YySRx B3F/NSY1sBL+YFhewXkzurfqHiYWweaL7i5sYbscaNfolaSTYtBMWrARValsEG1JFsYWICNhoYDQs 3hBQyhQjoeNEbTfn2xqS6DR0Hsr5adK8swmnzUFy8n2c1bQ8KA/LK42GDzBuPkBO0YNH1aWI6/Fi4 jh9FtPpQ==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pYfmo-009oHB-LR; Sun, 05 Mar 2023 04:15:50 +0000 Date: Sat, 4 Mar 2023 20:15:50 -0800 From: Luis Chamberlain To: Matthew Wilcox Cc: James Bottomley , Keith Busch , Theodore Ts'o , lsf-pc@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-block@vger.kernel.org Subject: Re: [LSF/MM/BPF TOPIC] Cloud storage optimizations Message-ID: References: <2600732b9ed0ddabfda5831aff22fd7e4270e3be.camel@HansenPartnership.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Luis Chamberlain Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Sat, Mar 04, 2023 at 04:39:02PM +0000, Matthew Wilcox wrote: > I'm getting more and more > comfortable with the idea that "Linux doesn't support block sizes > > PAGE_SIZE on 32-bit machines" is an acceptable answer. First of all filesystems would need to add support for a larger block sizes > PAGE_SIZE, and that takes effort. It is also a support question too. I think garnering consensus from filesystem developers we don't want to support block sizes > PAGE_SIZE on 32-bit systems would be a good thing to review at LSFMM or even on this list. I hightly doubt anyone is interested in that support. > XFS already works with arbitrary-order folios. But block sizes > PAGE_SIZE is work which is still not merged. It *can* be with time. That would allow one to muck with larger block sizes than 4k on x86-64 for instance. Without this, you can't play ball. > The only needed piece is > specifying to the VFS that there's a minimum order for this particular > inode, and having the VFS honour that everywhere. Other than the above too, don't we still also need to figure out what fs APIs would incur larger order folios? And then what about corner cases with the page cache? I was hoping some of these nooks and crannies could be explored with tmpfs. Luis