The Linux Kernel Mailing List
 help / color / mirror / Atom feed
From: Frederic Weisbecker <frederic@kernel.org>
To: Joel Fernandes <joel@joelfernandes.org>
Cc: linux-kernel@vger.kernel.org,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	Josh Triplett <josh@joshtriplett.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Neeraj Upadhyay <neeraj.iitr10@gmail.com>,
	rcu@vger.kernel.org
Subject: Re: [PATCH v2] srcu: Improve comments about acceleration leak
Date: Mon, 18 Dec 2023 13:13:30 +0100	[thread overview]
Message-ID: <ZYA3aiWbgzBNH3fZ@localhost.localdomain> (raw)
In-Reply-To: <CAEXW_YQK_ct=kMKSO6XnW1NpSjSAVMiMevL-om_i-au9mpUEyw@mail.gmail.com>

Le Sun, Dec 17, 2023 at 09:00:15PM -0500, Joel Fernandes a écrit :
> "Acceleration can never fail because the state of gp_seq value used
> for acceleration is <= the state of gp_seq used for advancing."
> 
> Does that sound correct now?

That can be confusing since acceleration relies on rcu_seq_snap() while
advance relies on rcu_seq_current(). And rcu_seq_snap() returns a snapshot
that may be above the subsequent rcu_seq_current() return value.

So it should rather be something like:

"The base current gp_seq value used to produce the snapshot has to
be <= the gp_seq used for advancing."

Thanks.

  reply	other threads:[~2023-12-18 12:13 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-11  1:57 [PATCH v2] srcu: Improve comments about acceleration leak Joel Fernandes (Google)
2023-12-12 20:11 ` Joel Fernandes
2023-12-13 18:10   ` Paul E. McKenney
2023-12-16 21:17 ` Frederic Weisbecker
2023-12-18  2:00   ` Joel Fernandes
2023-12-18 12:13     ` Frederic Weisbecker [this message]
2023-12-18 15:27       ` Joel Fernandes
2023-12-18 21:28         ` Frederic Weisbecker

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=ZYA3aiWbgzBNH3fZ@localhost.localdomain \
    --to=frederic@kernel.org \
    --cc=jiangshanlai@gmail.com \
    --cc=joel@joelfernandes.org \
    --cc=josh@joshtriplett.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mathieu.desnoyers@efficios.com \
    --cc=neeraj.iitr10@gmail.com \
    --cc=paulmck@kernel.org \
    --cc=rcu@vger.kernel.org \
    --cc=rostedt@goodmis.org \
    /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