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Hallyn" , Stephen Smalley , Eric Paris 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-Headers-End: 1qluT3-00ALxD-95 Subject: Re: [f2fs-dev] [PATCH 86/87] fs: switch timespec64 fields in inode to discrete integers X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: jfs-discussion@lists.sourceforge.net, linux-efi@vger.kernel.org, platform-driver-x86@vger.kernel.org, gfs2@lists.linux.dev, linux-mm@kvack.org, linux-mtd@lists.infradead.org, linux-hardening@vger.kernel.org, linux-afs@lists.infradead.org, linux-s390@vger.kernel.org, linux-nilfs@vger.kernel.org, linux-rdma@vger.kernel.org, linux-unionfs@vger.kernel.org, codalist@coda.cs.cmu.edu, linux-serial@vger.kernel.org, linux-ext4@vger.kernel.org, devel@lists.orangefs.org, linux-trace-kernel@vger.kernel.org, linux-cifs@vger.kernel.org, selinux@vger.kernel.org, apparmor@lists.ubuntu.com, autofs@vger.kernel.org, linux-um@lists.infradead.org, reiserfs-devel@vger.kernel.org, ocfs2-devel@lists.linux.dev, ceph-devel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-ntfs-dev@lists.sourceforge.net, linuxppc-dev@lists.ozlabs.org, v9fs@lists.linux.dev, linux-usb@vger.kernel.org, samba-technical@lists.samba.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, linux-security-module@vger.kernel.org, Netdev , linux-fsdevel@vger.kernel.org, bpf@vger.kernel.org, ntfs3@lists.linux.dev, linux-erofs@lists.ozlabs.org, linux-karma-devel@lists.sourceforge.net, linux-btrfs@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net 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-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel