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From: Amol Grover <frextrite@gmail.com>
To: Jonathan Corbet <corbet@lwn.net>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
	Josh Triplett <josh@joshtriplett.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	Joel Fernandes <joel@joelfernandes.org>,
	rcu@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	Shuah Khan <skhan@linuxfoundation.org>,
	Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>
Subject: Re: [PATCH] doc: listRCU: Add some more listRCU patterns in the kernel
Date: Wed, 4 Dec 2019 13:54:12 +0530
Message-ID: <20191204082412.GA6959@workstation-kernel-dev> (raw)
In-Reply-To: <20191203064132.38d75348@lwn.net>

On Tue, Dec 03, 2019 at 06:41:32AM -0700, Jonathan Corbet wrote:
> On Tue,  3 Dec 2019 12:09:43 +0530
> Amol Grover <frextrite@gmail.com> wrote:
> 
> > - Add more information about listRCU patterns taking examples
> > from audit subsystem in the linux kernel.
> > 
> > - The initially written audit examples are kept, even though they are
> > slightly different in the kernel.
> > 
> > - Modify inline text for better passage quality.
> > 
> > - Fix typo in code-blocks and improve code comments.
> > 
> > - Add text formatting (italics, bold and code) for better emphasis.
> 
> Thanks for improving the documentation!  I'll leave the RCU stuff to the
> experts, but I do have one request...
> 
> [...]
> 
> > +When a process exits, ``release_task()`` calls ``list_del_rcu(&p->tasks)`` under
> > +``tasklist_lock`` writer lock protection, to remove the task from the list of
> > +all tasks. The ``tasklist_lock`` prevents concurrent list additions/removals
> > +from corrupting the list. Readers using ``for_each_process()`` are not protected
> > +with the ``tasklist_lock``. To prevent readers from noticing changes in the list
> > +pointers, the ``task_struct`` object is freed only after one or more grace
> > +periods elapse (with the help of ``call_rcu()``). This deferring of destruction
> > +ensures that any readers traversing the list will see valid ``p->tasks.next``
> > +pointers and deletion/freeing can happen in parallel with traversal of the list.
> > +This pattern is also called an **existence lock**, since RCU pins the object in
> > +memory until all existing readers finish.
> 
> Please don't put function names as literal text.  If you just say
> call_rcu(), it will be formatted correctly and cross-linked to the
> appropriate kerneldoc entry.  Saying ``call_rcu()`` defeats that and
> clutters the plain-text reading experience.
> 

Hi Jon,

The cross-reference of the functions should be done automatically by sphinx
while generating HTML, right? But when compiled none of the functions were
cross-referenced hence "``" was added around the methods (and other symbols)
to distinguish them from normal text.

Thanks
Amol

> Thanks,
> 
> jon

  reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-03  6:39 Amol Grover
2019-12-03 13:41 ` Jonathan Corbet
2019-12-04  8:24   ` Amol Grover [this message]
2019-12-04 14:48     ` Jonathan Corbet
2019-12-04 15:39       ` Joel Fernandes
2019-12-04 15:47         ` Jonathan Corbet
2019-12-04 16:35           ` Joel Fernandes
2019-12-05 15:14             ` Amol Grover
2019-12-06  1:08               ` Joel Fernandes
2019-12-06  8:07 ` [PATCH v2] " Amol Grover

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