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 X-Spam-Level: X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10C7BC433DB for ; Wed, 20 Jan 2021 17:58:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BF951223E0 for ; Wed, 20 Jan 2021 17:58:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390855AbhATR6e (ORCPT ); Wed, 20 Jan 2021 12:58:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41506 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729050AbhATR6A (ORCPT ); Wed, 20 Jan 2021 12:58:00 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7962AC061757; Wed, 20 Jan 2021 09:57:15 -0800 (PST) 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=pUnziRy/TcrH98npVbZkez1LzWGAocfrqdjT4NTwcIw=; b=skUQ+xxSKtRRyAldNILOAj5MVs uowju0zOwSmH1OMrQWg/aWfjCTQUmlLzum+Lxg8Ueu+yd8m5xjBF4UP7wtrqTPKAsePZ+E4rpHZK/ MLKeJ2J8rHRTyEGxZnT9gtHgVZ7b62DJl01FoxsKcRiLO/lMfjR7xlQ6Q13Wf/Ce8wepxaCtKrISG +I8AAfVArrIa8IPwwF9gg4tJIEkn++CLj8Jl7EE2XxggIaTTMdizW9VxwT0WJqfhGuPKOhGavbIy1 AyXRBugLXjFCmNkdRNJQlfw2z9qgH1AiZE02mwVKAOHqgfKSWD4OwenLQnA0CIEwuoLV0t33gNv17 uHV9vK9g==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1l2HiS-00G1HZ-K2; Wed, 20 Jan 2021 17:56:26 +0000 Date: Wed, 20 Jan 2021 17:56:24 +0000 From: Matthew Wilcox To: Christoph Hellwig Cc: Jan Kara , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org Subject: Re: [PATCH 2/3] mm: Provide address_space operation for filling pages for read Message-ID: <20210120175624.GL2260413@casper.infradead.org> References: <20210120160611.26853-1-jack@suse.cz> <20210120160611.26853-3-jack@suse.cz> <20210120162001.GB3790454@infradead.org> <20210120172705.GC24063@quack2.suse.cz> <20210120172836.GA3809508@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210120172836.GA3809508@infradead.org> Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Wed, Jan 20, 2021 at 05:28:36PM +0000, Christoph Hellwig wrote: > On Wed, Jan 20, 2021 at 06:27:05PM +0100, Jan Kara wrote: > > This would mean pulling i_mmap_sem out from ext4/XFS/F2FS private inode > > into the VFS inode. Which is fine by me but it would grow struct inode for > > proc / tmpfs / btrfs (although for btrfs I'm not convinced it isn't > > actually prone to the race and doesn't need similar protection as xfs / > > ext4) so some people may object. > > The btrfs folks are already looking into lifting it to common code. > > Also I have a patch pending to remove a list_head from the inode to > counter the size increase :) We can get rid of nrexceptional as well: https://lore.kernel.org/linux-fsdevel/20201026151849.24232-1-willy@infradead.org/ We can also reduce the size of the rwsem by one word by replacing the list_head with a single pointer. https://git.infradead.org/users/willy/pagecache.git/shortlog/refs/heads/wlist (haven't touched it in almost four years, seemed to have a bug last time i looked at it).