Message-ID: <636661.1695969129@warthog.procyon.org.uk>
Date: Fri, 29 Sep 2023 07:32:09 +0100
From: David Howells <dhowells@...hat.com>
To: Jeff Layton <jlayton@...nel.org>
cc: "Darrick J. Wong" <djwong@...nel.org>, Arnd Bergmann <arnd@...db.de>,
    Alexander Viro <viro@...iv.linux.org.uk>,
    Christian Brauner <brauner@...nel.org>,
    Linus Torvalds <torvalds@...ux-foundation.org>,
    David Sterba <dsterba@...e.cz>, Amir Goldstein <amir73il@...il.com>,
    Theodore Ts'o <tytso@....edu>,
    "Eric W.
 Biederman" <ebiederm@...ssion.com>,
    Kees Cook <keescook@...omium.org>, Jeremy Kerr <jk@...abs.org>,
    Michael Ellerman <mpe@...erman.id.au>,
    Nicholas Piggin <npiggin@...il.com>,
    Christophe Leroy <christophe.leroy@...roup.eu>,
    Heiko Carstens <hca@...ux.ibm.com>,
    Vasily Gorbik <gor@...ux.ibm.com>,
    Alexander Gordeev <agordeev@...ux.ibm.com>,
    Christian Borntraeger <borntraeger@...ux.ibm.com>,
    Sven Schnelle <svens@...ux.ibm.com>,
    Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
    Arve Hjønnevåg <arve@...roid.com>,
    Todd Kjos <tkjos@...roid.com>, Martijn Coenen <maco@...roid.com>,
    Joel Fernandes <joel@...lfernandes.org>,
    Carlos Llamas <cmllamas@...gle.com>,
    Suren Baghdasaryan <surenb@...gle.com>,
    Mattia Dongili <malattia@...ux.it>,
    Dennis Dalessandro <dennis.dalessandro@...nelisnetworks.com>,
    Jason Gunthorpe <jgg@...pe.ca>, Leon Romanovsky <leon@...nel.org>,
    Brad Warrum <bwarrum@...ux.ibm.com>,
    Ritu Agarwal <rituagar@...ux.ibm.com>,
    Hans de Goede <hdegoede@...hat.com>,
    Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
    Mark Gross <markgross@...nel.org>, Jiri Slaby <jirislaby@...nel.org>,
    Eric Van Hensbergen <ericvh@...nel.org>,
    Latchesar Ionkov <lucho@...kov.net>,
    Dominique Martinet <asmadeus@...ewreck.org>,
    Christian Schoenebeck <linux_oss@...debyte.com>,
    David Sterba <dsterba@...e.com>, David Howells <dhowells@...hat.com>,
    Marc Dionne <marc.dionne@...istor.com>, Ian Kent <raven@...maw.net>,
    Luis de Bethencourt <luisbg@...nel.org>,
    Salah Triki <salah.triki@...il.com>,
    "Tigran
 A. Aivazian" <aivazian.tigran@...il.com>,
    Chris Mason <clm@...com>, Josef Bacik <josef@...icpanda.com>,
    Xiubo Li <xiubli@...hat.com>, Ilya Dryomov <idryomov@...il.com>,
    Jan Harkes <jaharkes@...cmu.edu>, coda@...cmu.edu,
    Joel Becker <jlbec@...lplan.org>, Christoph Hellwig <hch@....de>,
    Nicolas Pitre <nico@...xnic.net>,
    "Rafael J . Wysocki" <rafael@...nel.org>,
    Ard Biesheuvel <ardb@...nel.org>, Gao Xiang <xiang@...nel.org>,
    Chao Yu <chao@...nel.org>, Yue Hu <huyue2@...lpad.com>,
    Jeffle Xu <jefflexu@...ux.alibaba.com>,
    Namjae Jeon <linkinjeon@...nel.org>,
    Sungjong Seo <sj1557.seo@...sung.com>, Jan Kara <jack@...e.com>,
    Andreas Dilger <adilger.kernel@...ger.ca>,
    Jaegeuk Kim <jaegeuk@...nel.org>,
    OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>,
    Christoph Hellwig <hch@...radead.org>,
    Miklos Szeredi <miklos@...redi.hu>,
    Bob Peterson <rpeterso@...hat.com>,
    Andreas Gruenbacher <agruenba@...hat.com>,
    Richard Weinberger <richard@....at>,
    Anton Ivanov <anton.ivanov@...bridgegreys.com>,
    Johannes Berg <johannes@...solutions.net>,
    Mikulas Patocka <mikulas@...ax.karlin.mff.cuni.cz>,
    Mike Kravetz <mike.kravetz@...cle.com>,
    Muchun Song <muchun.song@...ux.dev>, Jan Kara <jack@...e.cz>,
    David Woodhouse <dwmw2@...radead.org>,
    Dave Kleikamp <shaggy@...nel.org>, Tejun Heo <tj@...nel.org>,
    Trond Myklebust <trond.myklebust@...merspace.com>,
    Anna Schumaker <anna@...nel.org>,
    Chuck Lever <chuck.lever@...cle.com>, Neil Brown <neilb@...e.de>,
    Olga Kornievskaia <kolga@...app.com>, Dai Ngo <Dai.Ngo@...cle.com>,
    Tom Talpey <tom@...pey.com>,
    Ryusuke Konishi <konishi.ryusuke@...il.com>,
    Anton Altaparmakov <anton@...era.com>,
    Konstantin Komarov <almaz.alexandrovich@...agon-software.com>,
    Mark Fasheh <mark@...heh.com>,
    Joseph Qi <joseph.qi@...ux.alibaba.com>,
    Bob Copeland <me@...copeland.com>,
    Mike Marshall <hubcap@...ibond.com>,
    Martin Brandenburg <martin@...ibond.com>,
    Luis Chamberlain <mcgrof@...nel.org>,
    Iurii Zaikin <yzaikin@...gle.com>, Tony Luck <tony.luck@...el.com>,
    "Guilherme G.
 Piccoli" <gpiccoli@...lia.com>,
    Anders Larsen <al@...rsen.net>, Steve French <sfrench@...ba.org>,
    Paulo Alcantara <pc@...guebit.com>,
    Ronnie Sahlberg <lsahlber@...hat.com>,
    Shyam Prasad N <sprasad@...rosoft.com>,
    Sergey Senozhatsky <senozhatsky@...omium.org>,
    Phillip Lougher <phillip@...ashfs.org.uk>,
    Steven Rostedt <rostedt@...dmis.org>,
    Masami Hiramatsu <mhiramat@...nel.org>,
    Evgeniy Dushistov <dushistov@...l.ru>,
    Chandan Babu R <chandan.babu@...cle.com>,
    Damien Le Moal <dlemoal@...nel.org>,
    Naohiro Aota <naohiro.aota@....com>,
    Johannes Thumshirn <jth@...nel.org>,
    Alexei Starovoitov <ast@...nel.org>,
    Daniel Borkmann <daniel@...earbox.net>,
    Andrii Nakryiko <andrii@...nel.org>,
    Martin KaFai Lau <martin.lau@...ux.dev>, Song Liu <song@...nel.org>,
    Yonghong Song <yonghong.song@...ux.dev>,
    John Fastabend <john.fastabend@...il.com>,
    KP Singh <kpsingh@...nel.org>, Stanislav Fomichev <sdf@...gle.com>,
    Hao Luo <haoluo@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
    Hugh Dickins <hughd@...gle.com>,
    Andrew Morton <akpm@...ux-foundation.org>,
    "David S .
 Miller" <davem@...emloft.net>,
    Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
    Paolo Abeni <pabeni@...hat.com>,
    John Johansen <john.johansen@...onical.com>,
    Paul Moore <paul@...l-moore.com>, James Morris <jmorris@...ei.org>,
    "Serge E. Hallyn" <serge@...lyn.com>,
    Stephen Smalley <stephen.smalley.work@...il.com>,
    Eric Paris <eparis@...isplace.org>, linux-fsdevel@...r.kernel.org,
    linux-kernel@...r.kernel.org, linux-mm@...ck.org,
    linuxppc-dev@...ts.ozlabs.org, linux-s390@...r.kernel.org,
    platform-driver-x86@...r.kernel.org, linux-rdma@...r.kernel.org,
    linux-serial@...r.kernel.org, linux-usb@...r.kernel.org,
    v9fs@...ts.linux.dev, linux-afs@...ts.infradead.org,
    autofs@...r.kernel.org, linux-btrfs@...r.kernel.org,
    ceph-devel@...r.kernel.org, codalist@...a.cs.cmu.edu,
    linux-efi@...r.kernel.org, linux-erofs@...ts.ozlabs.org,
    linux-ext4@...r.kernel.org, linux-f2fs-devel@...ts.sourceforge.net,
    gfs2@...ts.linux.dev, linux-um@...ts.infradead.org,
    linux-mtd@...ts.infradead.org, jfs-discussion@...ts.sourceforge.net,
    linux-nfs@...r.kernel.org, linux-nilfs@...r.kernel.org,
    linux-ntfs-dev@...ts.sourceforge.net, ntfs3@...ts.linux.dev,
    ocfs2-devel@...ts.linux.dev, linux-karma-devel@...ts.sourceforge.net,
    devel@...ts.orangefs.org, linux-unionfs@...r.kernel.org,
    linux-hardening@...r.kernel.org, reiserfs-devel@...r.kernel.org,
    linux-cifs@...r.kernel.org, samba-technical@...ts.samba.org,
    linux-trace-kernel@...r.kernel.org, linux-xfs@...r.kernel.org,
    bpf@...r.kernel.org, Netdev <netdev@...r.kernel.org>,
    apparmor@...ts.ubuntu.com, linux-security-module@...r.kernel.org,
    selinux@...r.kernel.org
Subject: Re: [PATCH 86/87] fs: switch timespec64 fields in inode to discrete integers


Jeff Layton <jlayton@...nel.org> 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

Powered by blists - more mailing lists