From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D0201F9CF; Sat, 30 Sep 2023 14:50:57 +0000 (UTC) Received: from mail-lf1-x12c.google.com (mail-lf1-x12c.google.com [IPv6:2a00:1450:4864:20::12c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4DB1CB7; Sat, 30 Sep 2023 07:50:55 -0700 (PDT) Received: by mail-lf1-x12c.google.com with SMTP id 2adb3069b0e04-5046bf37daeso14337382e87.1; Sat, 30 Sep 2023 07:50:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1696085453; x=1696690253; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=laSU2ptF5dJtGJTOfsu2vTDoKsI4bo31YwsLIpMZHsY=; b=MwDUKEd6QG0EtvDSCKf1uxGsuk6yCPhM15PYIYhqDJOgasuaT7+4Oh6GiJZ/vmFugy lmSCSLc0F+hG3ukOAM3WdNdBnEAtspfwfQIzIK1Wl+hsYj7CnlRK1SN0CwP2toV4bow4 LCG2gYB2ozawxJ9b/KfUJbxAn6Xa7t4YEVAl9uocXX1Jw3qs6c/EXfaIr8Rz78OCo8KR 46YxdeGs8zmcFe+Db4BddvMZE57ZBrJ3u+0YeAZwI0lUMX0nfUrsuM9wr1T+Cx+4tFCh 43LmQPeSUyLxSTkiFSJ67LGdePIyZblA6OKDAQ/vyk5/2yD5+W+J95PEpgI6GVNdDKdn 9Sww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1696085453; x=1696690253; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=laSU2ptF5dJtGJTOfsu2vTDoKsI4bo31YwsLIpMZHsY=; b=T8inobxiaergECByFFZ1CXDbC3XpIp10sjfxquseZvUOFeu2160pvxp0AzdP6cwpsW 2kGV7KJk9GIz1Oj9AnixG0avheyT4r8wY1P+7mDouL4LbpFsN872mecuBdlfe7NvnDab GVoo3WnsccIQpZ/XcHAdxWvc0C/REEi9X+IEwN2c1ii0X+WC4DGXGa6GwNPTKxqdIBet A334oKWX3Ex4J8ygtgZKUbCrnpRs8SMDnD0/WXU+7QCJl4wyW29GabzCdhVuOYa/0CGr fQvavOmh3je7pojydXHqJ+BKy6MuKRDfSGS4f/Azl+4tfeMHRvqFQCuuvAwXMD6ztg51 hRKA== X-Gm-Message-State: AOJu0YwxCCE2ZdXfvn+fN9bDB86YP0y09EvvFI143pYlVp4qXIMaSumB jxSh19bFZGCMwTmkGL2yJGIgODIRi2Yhl2GhGJQ= X-Google-Smtp-Source: AGHT+IFKxuEfsWI2Hoye015VefDxXDDWWovJHhYR0GsRnul5m9+uvo7GWv6zNWozBrWHqGB+PwbJIGFbA8W5CapoIHU= X-Received: by 2002:a05:6512:124a:b0:503:5cd:998b with SMTP id fb10-20020a056512124a00b0050305cd998bmr7557694lfb.28.1696085453195; Sat, 30 Sep 2023 07:50:53 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20230928110554.34758-1-jlayton@kernel.org> <20230928110554.34758-2-jlayton@kernel.org> <6020d6e7-b187-4abb-bf38-dc09d8bd0f6d@app.fastmail.com> <20230928171943.GK11439@frogsfrogsfrogs> <6a6f37d16b55a3003af3f3dbb7778a367f68cd8d.camel@kernel.org> <636661.1695969129@warthog.procyon.org.uk> In-Reply-To: <636661.1695969129@warthog.procyon.org.uk> From: Steve French Date: Sat, 30 Sep 2023 09:50:41 -0500 Message-ID: Subject: Re: [PATCH 86/87] fs: switch timespec64 fields in inode to discrete integers To: David Howells Cc: Jeff Layton , Latchesar Ionkov , Konstantin Komarov , "Rafael J . Wysocki" , "Darrick J. Wong" , Anders Larsen , Carlos Llamas , Andrii Nakryiko , Mattia Dongili , Hugh Dickins , John Johansen , Yonghong Song , Alexander Gordeev , Christoph Hellwig , Mike Marshall , Paulo Alcantara , linux-xfs@vger.kernel.org, Michael Ellerman , James Morris , Christophe Leroy , Christian Borntraeger , devel@lists.orangefs.org, Shyam Prasad N , linux-um@lists.infradead.org, Nicholas Piggin , Alexander Viro , Eric Van Hensbergen , Suren Baghdasaryan , Trond Myklebust , Anton Altaparmakov , Christian Brauner , Greg Kroah-Hartman , Stephen Smalley , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Ronnie Sahlberg , Sergey Senozhatsky , =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= , Chuck Lever , Sven Schnelle , Jiri Olsa , Jan Kara , Tejun Heo , Andrew Morton , linux-trace-kernel@vger.kernel.org, Linus Torvalds , Dave Kleikamp , linux-mm@kvack.org, Joel Fernandes , Eric Dumazet , Stanislav Fomichev , linux-s390@vger.kernel.org, linux-nilfs@vger.kernel.org, Paul Moore , Leon Romanovsky , John Fastabend , Luis Chamberlain , codalist@coda.cs.cmu.edu, Iurii Zaikin , Namjae Jeon , Masami Hiramatsu , Todd Kjos , Vasily Gorbik , selinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, reiserfs-devel@vger.kernel.org, Miklos Szeredi , Yue Hu , Jaegeuk Kim , Martijn Coenen , OGAWA Hirofumi , Hao Luo , Tony Luck , "Theodore Ts'o" , Nicolas Pitre , linux-ntfs-dev@lists.sourceforge.net, Muchun Song , linux-f2fs-devel@lists.sourceforge.net, "Guilherme G. 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, =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= , Ilya Dryomov , Paolo Abeni , "Serge E. Hallyn" , Christian Schoenebeck , Kees Cook , Arnd Bergmann , 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, 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 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Fri, Sep 29, 2023 at 3:06=E2=80=AFAM David Howells via samba-technical wrote: > > > 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 mak= e > sense to switch internally to Microsoft-style 64-bit timestamps with thei= r > 100ns granularity? 100ns granularity does seem to make sense and IIRC was used by various DCE standards in the 90s and 2000s (not just used for SMB2/SMB3 protocol an= d various Windows filesystems) --=20 Thanks, Steve