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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 96AFBE748E6 for ; Sat, 30 Sep 2023 22:25:41 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20230601 header.b=gjcaotBC; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Ryhcg4j8zz3cbm for ; Sun, 1 Oct 2023 09:25:39 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20230601 header.b=gjcaotBC; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=gmail.com (client-ip=2a00:1450:4864:20::12a; helo=mail-lf1-x12a.google.com; envelope-from=smfrench@gmail.com; receiver=lists.ozlabs.org) Received: from mail-lf1-x12a.google.com (mail-lf1-x12a.google.com [IPv6:2a00:1450:4864:20::12a]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4RyVX90WP1z3cLQ; Sun, 1 Oct 2023 00:51:03 +1000 (AEST) Received: by mail-lf1-x12a.google.com with SMTP id 2adb3069b0e04-50336768615so24733648e87.0; Sat, 30 Sep 2023 07:51:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1696085453; x=1696690253; darn=lists.ozlabs.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=gjcaotBC/h+kTpmaMT1baWqN2IeUR9Jd4fza/Uu+uku0mBfkvKzw7mrAonGbM9Ro4F xUdTHY2F3aAVx+dHpZjcXetE6+J7tv5oywWEAePfvGhJu1/6/x8FeAkmPNpMvulXVygZ kHgcxB3OImoR8rJjqV65xmU0faELjUFUfvT3mv3M3lwyhC22Ct9VVlsU/6krB8uAm5+r d007cDEXoX8DjNCcsYYfGuM7H2epjE6SuUypSL0KCau59cLonLEibQ/HHnEEhSikNAwL Xa7+otlelnWTpNRcdh6D6iORty7tyBrRaPhQnRRRNQdAI0IQX/GUDSO/25gyMbStYv9x v4cw== 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=O9A2ANCIWGnckqQFLj+0DS3AbBWBOx6GGgNE4DybCvgTe9nCJq2bpD8Z/K34eoh+rb QWsTchgcnEgU3Gsnp0zviH3aiiVoiWNUc1xReaekPOWikuo5YOgxOzgWxxOBKVuVepYw BNX+LR5wmWR+IfCmdQs1LtTb/kDulanCtmPqSNhau+zMSWaALf+BNTPlUFDNcj7ADx/c 0lJmTo7st1cQbwQ+S/8ifPstf/og8oH/uVDeNkqIIlV+mQJcVehB7G0VqzNlvG8eDQ5k x17awSI2hgkU97ZC3TZc/gMxsuphGbNPRdc+67fCIEtMth13Np0Xug5k/LYcIt/FNClz y2Ag== X-Gm-Message-State: AOJu0YzSKil4DBDoNlgYhsddi6lMFP4b0vKsvYyonfxBaVTH/pXxYVYh 5GiYztwRSDOOuklJXYscuBFYJiNcCba2zPCS22w= 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) 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 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Mailman-Approved-At: Sun, 01 Oct 2023 09:24:51 +1100 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 , "Rafael J . Wysocki" , "Darrick J. Wong" , Anders Larsen , Carlos Llamas , Sven Schnelle , Mattia Dongili , Yonghong Song , Alexander Gordeev , Christoph Hellwig , Mike Marshall , Paulo Alcantara , Jason Gunthorpe , James Morris , Christian Borntraeger , devel@lists.orangefs.org, Shyam Prasad N , Jan Harkes , linux-um@lists.infradead.org, Nicholas Piggin , Alexander Viro , Eric Van Hensbergen , Suren Baghdasaryan , Trond Myklebust , Anton Altaparmakov , Christian Brauner , Greg Kr oah-Hartman , Stephen Smalley , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Ronnie Sahlberg , Sergey Senozhatsky , Luis Chamberlain , Chuck Lever , Masami Hiramatsu , Jiri Olsa , Jan Kara , Tejun Heo , Andrew Morton , Linus Torvalds , Dave Kleikamp , samba-technical@lists.samba.org, Marc Dionne , Eric Dumazet , Stanislav Fomichev , linux-s390@vger.kernel.org, linux-nilfs@vger.kernel.org, Paul Moore , Leon Romanovsky , Hugh Dickins , Andrii Nakryiko , codalist@coda.cs.cmu.edu, Iurii Zaikin , Namjae Jeon , linux-trace-kernel@vger.kernel.org, Todd Kjos , Vasily Gorbik , selinux@vger.kernel.org, reiserfs-devel@vger.kernel.org, Sungjong Seo , ocfs2-devel@lists.linux.dev, 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" , "Eric W. Biederman" , Anna Schumaker , David Woodhouse , Brad Warrum , Mike Kravetz , linux-efi@vger.kernel.org, Martin Brandenburg , Alexei Starovoitov , platform-driver-x86@vger.kernel.or g, Joseph Qi , Chris Mason , linux-mtd@lists.infradead.org, linux-hardening@vger.kernel.org, Joel Fernandes , Jiri Slaby , linux-afs@lists.infradead.org, Ian Kent , Naohiro Aota , Daniel Borkmann , Miklos Szeredi , linux-rdma@vger.kernel.org, coda@cs.cmu.edu, =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= , Ilya Dryomov , Paolo Abeni , "Serge E. Hallyn" , Amir Goldstein , Kees Cook , Arnd Bergmann , autofs@vger.kernel.org, Steven Rostedt , Mark Gross , Damien Le Moal , Eric Paris , ceph-devel@vger.kernel.org, Gao Xiang , gfs2@lists.linux.dev, linux-nfs@vger.kernel.org, linux-ext4@vger.ker nel.org, Olga Kornievskaia , Song Liu , Jeff Layton , Martin KaFai Lau , linux-xfs@vger.kernel.org, Jeremy Kerr , 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 , Christian Schoenebeck , Bob Copeland , KP Singh , David Sterba , Konstantin Komarov , linux-mm@kvack.org, Andreas Dilger , =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= , Mikulas Patocka , Ard Biesheuvel , Anton Ivanov < anton.ivanov@cambridgegreys.com>, Andreas Gruenbacher , Richard Weinberger , Mark Fasheh , Dai Ngo , Steve French , linux-serial@vger.kernel.org, Jakub Kicinski , Salah Triki , John Fastabend , 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 , Dennis Dalessandro , John Johansen , Ritu Agarwal , Luis de Bethencourt , Netdev , v9fs@li sts.linux.dev, linux-unionfs@vger.kernel.org, linux-security-module@vger.kernel.org, Jeffle Xu , Phillip Lougher , Johannes Berg , Johannes Thumshirn , linuxppc-dev@lists.ozlabs.org, 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" 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