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 83664CD4F55 for ; Fri, 22 Sep 2023 10:26:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231767AbjIVK0a (ORCPT ); Fri, 22 Sep 2023 06:26:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57768 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229953AbjIVK00 (ORCPT ); Fri, 22 Sep 2023 06:26:26 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [IPv6:2001:67c:2178:6::1d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2D1EFA9; Fri, 22 Sep 2023 03:26:20 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id AC5D51F8A8; Fri, 22 Sep 2023 10:26:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1695378378; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=b4AvMudYjwCrVMWQjwvaN8DzatOa9/zfzofVKveg1pg=; b=tsiD5VsQYcpHO8ajHr1h3pxzqNxc+L9pmaBiM0rQZCs7rGr/NVrbcx0s9pOvGSoph67yY/ TebdOVih+9mG225vKDsLMd7IuktVSwMKBEsPgWt+eGDAL84r8Xo3336db9sdwz6lTmHr8n sHZN0fd1bnU4SPXj2aSsaExqk1UH2yg= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1695378378; h=from:from:reply-to:reply-to:date:date:message-id:message-id:to:to: cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=b4AvMudYjwCrVMWQjwvaN8DzatOa9/zfzofVKveg1pg=; b=OsVHhogZ2UOSBN5YsdPA5MQ6ypl+w+Nbiyen+aKWeOYqa2bZaWyOMjUqYAAXrrh073XWg2 UowJPBEpC/gevuAg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 793F913597; Fri, 22 Sep 2023 10:26:18 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id uO7AHMprDWXregAAMHmgww (envelope-from ); Fri, 22 Sep 2023 10:26:18 +0000 Date: Fri, 22 Sep 2023 12:19:43 +0200 From: David Sterba To: Linus Torvalds Cc: Jeff Layton , Christian Brauner , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Jan Kara Subject: Re: [GIT PULL v2] timestamp fixes Message-ID: <20230922101943.GA13697@twin.jikos.cz> Reply-To: dsterba@suse.cz References: <20230921-umgekehrt-buden-a8718451ef7c@brauner> <0d006954b698cb1cea3a93c1662b5913a0ded3b1.camel@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 21, 2023 at 12:28:13PM -0700, Linus Torvalds wrote: > On Thu, 21 Sept 2023 at 11:51, Jeff Layton wrote: > > > > We have many, many inodes though, and 12 bytes per adds up! > > That was my thinking, but honestly, who knows what other alignment > issues might eat up some - or all - of the theoreteical 12 bytes. > > It might be, for example, that the inode is already some aligned size, > and that the allocation alignment means that the size wouldn't > *really* shrink at all. > > So I just want to make clear that I think the 12 bytes isn't > necessarily there. Maybe you'd get it, maybe it would be hidden by > other things. I think all filesystem developers appreciate when struct inode shrinks, it's usually embedded with additional data and the size grows. I'm on a mission to squeeze btrfs_inode under 1024 so it fits better to the slab pages and currently it's about 1100 bytes. 1024 is within reach but it gets harder to find potential space savings.