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Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <6a6f37d16b55a3003af3f3dbb7778a367f68cd8d.camel@kernel.org> References: <6a6f37d16b55a3003af3f3dbb7778a367f68cd8d.camel@kernel.org> <20230928110554.34758-1-jlayton@kernel.org> <20230928110554.34758-2-jlayton@kernel.org> <6020d6e7-b187-4abb-bf38-dc09d8bd0f6d@app.fastmail.com> <20230928171943.GK11439@frogsfrogsfrogs> To: Jeff Layton Subject: Re: [PATCH 86/87] fs: switch timespec64 fields in inode to discrete integers MIME-Version: 1.0 Content-Type: text/plain Date: Fri, 29 Sep 2023 07:32:09 +0100 Message-ID: <636661.1695969129@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 X-Mailman-Approved-At: Fri, 29 Sep 2023 18:23:45 +1000 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Latchesar Ionkov , Konstantin Komarov , "Rafael J . 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Piccoli" , gfs2@lists.linux.dev, "Eric W. Biederman" , Anna Schumaker , Brad Warrum , Mike Kravetz , linux-efi@vger.kernel.org, Martin Brandenburg , ocfs2-devel@lists.linux.dev, Alexei Starovoitov , platform-driver-x86@vger.kernel.org, Chris Mason , linux-mtd@lists.infradead.org, linux-hardening@vger.kernel.org, Marc Dionne , Jiri Slaby , linux-afs@lists.infradead.org, Ian Kent , Naohiro Aota , Daniel Borkmann , Dennis Dalessandro , linux-rdma@vger.kernel.org, coda@cs.cmu.edu, Ilpo =?utf-8?Q?J=C3=A4rvinen?= , Ilya Dryomov , Paolo Abeni , "Serge E. Hallyn" , Christian Schoenebeck , Kees Cook , Arnd Bergmann < arnd@arndb.de>, autofs@vger.kernel.org, Steven Rostedt , Mark Gross , Damien Le Moal , Eric Paris , ceph-devel@vger.kernel.org, Gao Xiang , Jan Harkes , linux-nfs@vger.kernel.org, linux-ext4@vger.kernel.org, Olga Kornievskaia , Song Liu , samba-technical@lists.samba.org, Steve French , Jeremy Kerr , Netdev , Bob Peterson , linux-fsdevel@vger.kernel.org, bpf@vger.kernel.org, ntfs3@lists.linux.dev, linux-erofs@lists.ozlabs.org, "David S . Miller" , Chandan Babu R , jfs-discussion@lists.sourceforge.net, Jan Kara , Neil Brown , Dominique Martinet , Amir Goldstein , Bob Copeland , KP Singh , linux-unionfs@vger.kernel.org, David Howells , Joseph Qi , Andreas Dilger , Mikulas Patocka , Ard Biesheuvel , Anton Ivanov , Andreas Gruenbacher , Richard Weinberger , Mark Fasheh , Dai Ngo , Jason Gunthorpe , linux-serial@vger.kernel.org, Jakub Kicinski , Salah Triki , Evgeniy Dushistov , linux-cifs@vger.kernel.org, Heiko Carstens , Chao Yu , apparmor@lists.ubuntu.com, Josef Bacik , Tom Talpey , Hans de Goede , "Tigran A. Aivazian" , David Sterba , Xiubo Li , Ryusuke Konishi , Johannes Thumshirn , Ritu Agarwal , Luis de Bethencourt , Martin KaFai Lau , v9fs@lists.linux.dev, David Sterba , linux-security-module@vger.kernel.org, Jeffle Xu , Phillip Lougher , Johannes Berg , Sungjong Seo , David Woodhouse , linux-karma-devel@lists.sourceforge.net, linux-btrfs@vger.kernel.org, Joel Becker Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Jeff Layton wrote: > Correct. We'd lose some fidelity in currently stored timestamps, but as > Linus and Ted pointed out, anything below ~100ns granularity is > effectively just noise, as that's the floor overhead for calling into > the kernel. It's hard to argue that any application needs that sort of > timestamp resolution, at least with contemporary hardware. Albeit with the danger of making Steve French very happy;-), would it make sense to switch internally to Microsoft-style 64-bit timestamps with their 100ns granularity? David