From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH 86/87] fs: switch timespec64 fields in inode to discrete integers
Date: Fri, 29 Sep 2023 07:32:09 +0100
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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> <af047e4a1c6947c59d4a13d4ae221c784a5386b4.camel@kernel.org> <20230928171943.GK11439@frogsfrogsfrogs>
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To: Jeff Layton <jlayton-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: "Darrick J. Wong" <djwong-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>, Alexander Viro <viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>, Christian Brauner <brauner-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, David Sterba <dsterba-AlSwsSmVLrQ@public.gmane.org>, Amir Goldstein <amir73il-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Theodore Ts'o <tytso-3s7WtUTddSA@public.gmane.org>, "Eric W.
 Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>, Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>, Jeremy Kerr <jk-mnsaURCQ41sdnm+yROfE0A@public.gmane.org>, Michael Ellerman <mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org>, Nicholas Piggin <npiggin-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Christophe Leroy <christophe.leroy-2tlSp11Fh4xulxpn9UvDqw@public.gmane.org>, Heiko Carstens <hca-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>, Vasily Gorbik <gor-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>, Alexander Gordeev <agordeev-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>, Christian Borntraeger <borntraeger-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>, Sven Schnelle <svens-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>, Greg Kroah-Hartman <gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>, Arve =?utf-8?B?SGrDuG5uZXbDpWc=?= <arve@an>


Jeff Layton <jlayton-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.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