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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 71CB9E81815 for ; Fri, 29 Sep 2023 15:36:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Date:Cc:To:From:Subject:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=1epTYlc0Y57NsyAVy6VIOvfo1Lllcv4vzpjUKKdRqJc=; b=kiAMvRTXb6R/Vy DxK7kjs81ckJ5l2HdptfPxcdYiPamnVhuD3CrO5HvUKbz7sQY5TiNMg2SqWFaE75CqbLj4grnTDzj X0ozHIqL1+BSarsP6eXgTjbLo9l3AI+Qwuz5fN4G7vKl5JeZH0u8IXHCcTki7DFuFnAQRN76GkEPL AlfGqypxtdHiOTOh9VN4OoF3O5A+jhT3ph+VBYRFgiLvZHJCSCAU5L8kHS41ramFpWlyqNLf2RT8r u1i4Zc1GDq8pONLGY6FuOANyOBOFROpIWmyPN0DjY1FLgxxFDA/uou64FDaLzmfQ9lYFTifL+Dn14 ssh8UqFdulFNSihHi++g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qmFXg-008CWZ-0G; Fri, 29 Sep 2023 15:36:36 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qluSy-006MER-2b; Thu, 28 Sep 2023 17:06:23 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id A10FF61D47; Thu, 28 Sep 2023 17:06:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B9B31C433C8; Thu, 28 Sep 2023 17:06:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1695920779; bh=DNM/VlOuUT51G0bnMvXw+94sqfHee3c68K5vLwQuau4=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=T1EG9wCsmdavqbCDgZQmRYDY2hTjqQ8HvqU7HakqZRoba0+m8x7Xb0PPxNH54fTbK gxOvKBrhR/NUHAqOFYLgQFvCS4fbqqpdpyJ0meCz+VJBZB5WwUDXaofxixCnDwGA2b xVhvTR3lvjwhcUNCr4cL+zM4prum42dBj/EqssN3wQ5xwZohTtnO5wenm4djJ5rTsg au+O/I2DWLjGqSGQ9+pJFDrXNkgJ5uSZlH8zfxoOHymWjEqjSumVZbYplcXqZfm3+f KDfZ0aAr31be94G8szYCClaMWLFdZEYGpG76Y3w4tHoT3E7mgxWznMj5HFQTi8O+xa SaKUjb/2UX2Ww== Message-ID: Subject: Re: [PATCH 86/87] fs: switch timespec64 fields in inode to discrete integers From: Jeff Layton To: Arnd Bergmann , Alexander Viro , Christian Brauner , Linus Torvalds , David Sterba , Amir Goldstein , Theodore Ts'o , "Eric W. Biederman" , Kees Cook , Jeremy Kerr , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Greg Kroah-Hartman , Arve =?ISO-8859-1?Q?Hj=F8nnev=E5g?= , Todd Kjos , Martijn Coenen , Joel Fernandes , Carlos Llamas , Suren Baghdasaryan , Mattia Dongili , Dennis Dalessandro , Jason Gunthorpe , Leon Romanovsky , Brad Warrum , Ritu Agarwal , Hans de Goede , Ilpo =?ISO-8859-1?Q?J=E4rvinen?= , Mark Gross , Jiri Slaby , Eric Van Hensbergen , Latchesar Ionkov , Dominique Martinet , Christian Schoenebeck , David Sterba , David Howells , Marc Dionne , Ian Kent , Luis de Bethencourt , Salah Triki , "Tigran A. Aivazian" , Chris Mason , Josef Bacik , Xiubo Li , Ilya Dryomov , Jan Harkes , coda@cs.cmu.edu, Joel Becker , Christoph Hellwig , Nicolas Pitre , "Rafael J . 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Hallyn" , Stephen Smalley , Eric Paris Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-rdma@vger.kernel.org, linux-serial@vger.kernel.org, linux-usb@vger.kernel.org, v9fs@lists.linux.dev, linux-afs@lists.infradead.org, autofs@vger.kernel.org, linux-btrfs@vger.kernel.org, ceph-devel@vger.kernel.org, codalist@coda.cs.cmu.edu, linux-efi@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, gfs2@lists.linux.dev, linux-um@lists.infradead.org, linux-mtd@lists.infradead.org, jfs-discussion@lists.sourceforge.net, linux-nfs@vger.kernel.org, linux-nilfs@vger.kernel.org, linux-ntfs-dev@lists.sourceforge.net, ntfs3@lists.linux.dev, ocfs2-devel@lists.linux.dev, linux-karma-devel@lists.sourceforge.net, devel@lists.orangefs.org, linux-unionfs@vger.kernel.org, linux-hardening@vger.kernel.org, reiserfs-devel@vger.kernel.org, linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-trace-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, bpf@vger.kernel.org, Netdev , apparmor@lists.ubuntu.com, linux-security-module@vger.kernel.org, selinux@vger.kernel.org Date: Thu, 28 Sep 2023 13:06:03 -0400 In-Reply-To: <6020d6e7-b187-4abb-bf38-dc09d8bd0f6d@app.fastmail.com> References: <20230928110554.34758-1-jlayton@kernel.org> <20230928110554.34758-2-jlayton@kernel.org> <6020d6e7-b187-4abb-bf38-dc09d8bd0f6d@app.fastmail.com> User-Agent: Evolution 3.48.4 (3.48.4-1.fc38) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230928_100620_959132_6A03D630 X-CRM114-Status: GOOD ( 18.34 ) X-Mailman-Approved-At: Fri, 29 Sep 2023 08:36:32 -0700 X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org On Thu, 2023-09-28 at 11:48 -0400, Arnd Bergmann wrote: > On Thu, Sep 28, 2023, at 07:05, Jeff Layton wrote: > > This shaves 8 bytes off struct inode, according to pahole. > > > > Signed-off-by: Jeff Layton > > FWIW, this is similar to the approach that Deepa suggested > back in 2016: > > https://lore.kernel.org/lkml/1452144972-15802-3-git-send-email-deepa.kernel@gmail.com/ > > It was NaKed at the time because of the added complexity, > though it would have been much easier to do it then, > as we had to touch all the timespec references anyway. > > The approach still seems ok to me, but I'm not sure it's worth > doing it now if we didn't do it then. > I remember seeing those patches go by. I don't remember that change being NaK'ed, but I wasn't paying close attention at the time Looking at it objectively now, I think it's worth it to recover 8 bytes per inode and open a 4 byte hole that Amir can use to grow the i_fsnotify_mask. We might even able to shave off another 12 bytes eventually if we can move to a single 64-bit word per timestamp. It is a lot of churn though. -- Jeff Layton _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um