From: Thomas Gleixner <tglx@linutronix.de>
To: Jeff Layton <jlayton@kernel.org>,
John Stultz <jstultz@google.com>, Stephen Boyd <sboyd@kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Jonathan Corbet <corbet@lwn.net>,
Chandan Babu R <chandan.babu@oracle.com>,
"Darrick J. Wong" <djwong@kernel.org>,
Theodore Ts'o <tytso@mit.edu>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
David Sterba <dsterba@suse.com>, Hugh Dickins <hughd@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Chuck Lever <chuck.lever@oracle.com>,
Vadim Fedorenko <vadim.fedorenko@linux.dev>
Cc: Randy Dunlap <rdunlap@infradead.org>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-trace-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-btrfs@vger.kernel.org, linux-nfs@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH v8 01/11] timekeeping: move multigrain timestamp floor handling into timekeeper
Date: Mon, 30 Sep 2024 21:16:07 +0200 [thread overview]
Message-ID: <878qv90x6w.ffs@tglx> (raw)
In-Reply-To: <b300fec8b6f611662195e0339f290d473a41607c.camel@kernel.org>
On Mon, Sep 16 2024 at 06:57, Jeff Layton wrote:
> On Mon, 2024-09-16 at 12:32 +0200, Thomas Gleixner wrote:
>> > 'Something has changed' is a truly understandable technical
>> > explanation.
>>
>> old = mg_floor
>> mono = T1;
>> mg_floor = mono
>> preemption
>>
>> do {
>> mono = T2;
>> }
>>
>> cmpxchg fails and the function returns a value based on T1
>>
>> No?
>>
>>
>
> Packing for LPC, so I can't respond to all of these just now, but I
> will later. You're correct, but either outcome is OK.
>
> The requirement is that we don't hand out any values that were below
> the floor at the time that the task entered the kernel. Since the time
> changed while the task was already inside the kernel, either T1 or T2
> would be valid timestamps.
That really needs to be documented. A similar scenario exists
vs. ktime_get_coarse_real_ts64_mg().
Thanks,
tglx
next prev parent reply other threads:[~2024-09-30 19:16 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-09-14 17:07 [PATCH v8 00/11] fs: multigrain timestamp redux Jeff Layton
2024-09-14 17:07 ` [PATCH v8 01/11] timekeeping: move multigrain timestamp floor handling into timekeeper Jeff Layton
2024-09-14 20:10 ` John Stultz
2024-09-14 23:14 ` Jeff Layton
2024-09-16 10:12 ` Thomas Gleixner
2024-09-16 10:32 ` Thomas Gleixner
2024-09-16 10:57 ` Jeff Layton
2024-09-30 19:16 ` Thomas Gleixner [this message]
2024-09-30 19:37 ` Jeff Layton
2024-09-30 20:19 ` Thomas Gleixner
2024-09-30 20:53 ` Jeff Layton
2024-09-30 21:35 ` Thomas Gleixner
2024-10-01 9:45 ` Jeff Layton
2024-10-01 12:45 ` Thomas Gleixner
2024-10-02 12:41 ` Jeff Layton
2024-09-19 16:50 ` Jeff Layton
2024-09-30 19:43 ` Thomas Gleixner
2024-09-30 20:12 ` Jeff Layton
2024-09-30 19:13 ` Thomas Gleixner
2024-09-30 19:27 ` Jeff Layton
2024-09-30 20:15 ` Thomas Gleixner
2024-09-14 17:07 ` [PATCH v8 02/11] fs: add infrastructure for multigrain timestamps Jeff Layton
2024-09-14 17:07 ` [PATCH v8 03/11] fs: have setattr_copy handle multigrain timestamps appropriately Jeff Layton
2024-09-14 17:07 ` [PATCH v8 04/11] fs: handle delegated timestamps in setattr_copy_mgtime Jeff Layton
2024-09-14 17:07 ` [PATCH v8 05/11] fs: tracepoints around multigrain timestamp events Jeff Layton
2024-09-15 8:21 ` Steven Rostedt
2024-09-14 17:07 ` [PATCH v8 06/11] fs: add percpu counters for significant " Jeff Layton
2024-09-16 10:20 ` Thomas Gleixner
2024-09-14 17:07 ` [PATCH v8 07/11] Documentation: add a new file documenting multigrain timestamps Jeff Layton
2024-09-16 1:01 ` Bagas Sanjaya
2024-09-19 16:53 ` Jeff Layton
2024-09-14 17:07 ` [PATCH v8 08/11] xfs: switch to " Jeff Layton
2024-09-14 17:07 ` [PATCH v8 09/11] ext4: " Jeff Layton
2024-09-14 17:07 ` [PATCH v8 10/11] btrfs: convert " Jeff Layton
2024-09-14 17:07 ` [PATCH v8 11/11] tmpfs: add support for " Jeff Layton
2024-09-26 16:59 ` [PATCH v8 00/11] fs: multigrain timestamp redux Randy Dunlap
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=878qv90x6w.ffs@tglx \
--to=tglx@linutronix.de \
--cc=adilger.kernel@dilger.ca \
--cc=akpm@linux-foundation.org \
--cc=brauner@kernel.org \
--cc=chandan.babu@oracle.com \
--cc=chuck.lever@oracle.com \
--cc=clm@fb.com \
--cc=corbet@lwn.net \
--cc=djwong@kernel.org \
--cc=dsterba@suse.com \
--cc=hughd@google.com \
--cc=jack@suse.cz \
--cc=jlayton@kernel.org \
--cc=josef@toxicpanda.com \
--cc=jstultz@google.com \
--cc=linux-btrfs@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-nfs@vger.kernel.org \
--cc=linux-trace-kernel@vger.kernel.org \
--cc=linux-xfs@vger.kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=mhiramat@kernel.org \
--cc=rdunlap@infradead.org \
--cc=rostedt@goodmis.org \
--cc=sboyd@kernel.org \
--cc=tytso@mit.edu \
--cc=vadim.fedorenko@linux.dev \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox