linux-kernel - Re: [Linux-kernel-mentees] [PATCH] Documentation: RCU: arrayRCU: Converted arrayRCU.txt to arrayRCU.rst

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Message-ID: <ac8da2f5-4cda-8985-ff90-061478a4e2c9@gmail.com>
Date:   Tue, 5 Nov 2019 20:49:47 +0700
From:   Phong Tran <tranmanphong@...il.com>
To:     madhuparnabhowmik04@...il.com
Cc:     paulmck@...nel.org, joel@...lfernandes.org, corbet@....net,
        tranmanphong@...il.com, rcu@...r.kernel.org,
        linux-kernel-mentees@...ts.linuxfoundation.org,
        linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org
Subject: Re: [Linux-kernel-mentees] [PATCH] Documentation: RCU: arrayRCU:
 Converted arrayRCU.txt to arrayRCU.rst

On 10/29/19 3:24 AM, madhuparnabhowmik04@...il.com wrote:
> From: Madhuparna Bhowmik <madhuparnabhowmik04@...il.com>
> 
> This patch converts arrayRCU from txt to rst format.
> arrayRCU.rst is also added in the index.rst file.
> 
> Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik04@...il.com>
> ---
>   .../RCU/{arrayRCU.txt => arrayRCU.rst}         | 18 +++++++++++++-----
>   Documentation/RCU/index.rst                    |  1 +
>   2 files changed, 14 insertions(+), 5 deletions(-)
>   rename Documentation/RCU/{arrayRCU.txt => arrayRCU.rst} (91%)
> 
> diff --git a/Documentation/RCU/arrayRCU.txt b/Documentation/RCU/arrayRCU.rst
> similarity index 91%
> rename from Documentation/RCU/arrayRCU.txt
> rename to Documentation/RCU/arrayRCU.rst
> index f05a9afb2c39..ed5ae24b196e 100644
> --- a/Documentation/RCU/arrayRCU.txt
> +++ b/Documentation/RCU/arrayRCU.rst
> @@ -1,5 +1,7 @@
> -Using RCU to Protect Read-Mostly Arrays
> +.. _array_rcu_doc:
>   
> +Using RCU to Protect Read-Mostly Arrays
> +=======================================
>   
>   Although RCU is more commonly used to protect linked lists, it can
>   also be used to protect arrays.  Three situations are as follows:
> @@ -26,6 +28,7 @@ described in the following sections.
>   
>   

It will be better to have the cross reference for each situation.

Hash Tables
Static Arrays
Resizeable Arrays

>   Situation 1: Hash Tables
> +------------------------
>   
>   Hash tables are often implemented as an array, where each array entry
>   has a linked-list hash chain.  Each hash chain can be protected by RCU
> @@ -34,6 +37,7 @@ to other array-of-list situations, such as radix trees.
>   
>   
>   Situation 2: Static Arrays
> +--------------------------
>   
>   Static arrays, where the data (rather than a pointer to the data) is
>   located in each array element, and where the array is never resized,
> @@ -41,11 +45,13 @@ have not been used with RCU.  Rik van Riel recommends using seqlock in
>   this situation, which would also have minimal read-side overhead as long
>   as updates are rare.
>   
> -Quick Quiz:  Why is it so important that updates be rare when
> -	     using seqlock?
> +Quick Quiz:
> +		Why is it so important that updates be rare when using seqlock?
>   
> +:ref:`Answer to Quick Quiz <answer_quick_quiz_seqlock>`
>   
>   Situation 3: Resizeable Arrays
> +------------------------------
>   
>   Use of RCU for resizeable arrays is demonstrated by the grow_ary()
>   function formerly used by the System V IPC code.  The array is used
> @@ -60,7 +66,7 @@ the remainder of the new, updates the ids->entries pointer to point to
>   the new array, and invokes ipc_rcu_putref() to free up the old array.
>   Note that rcu_assign_pointer() is used to update the ids->entries pointer,
>   which includes any memory barriers required on whatever architecture
> -you are running on.
> +you are running on.::
>   

a redundant ":" in here with html page.




>   	static int grow_ary(struct ipc_ids* ids, int newsize)
>   	{
> @@ -112,7 +118,7 @@ a simple check suffices.  The pointer to the structure corresponding
>   to the desired IPC object is placed in "out", with NULL indicating
>   a non-existent entry.  After acquiring "out->lock", the "out->deleted"
>   flag indicates whether the IPC object is in the process of being
> -deleted, and, if not, the pointer is returned.
> +deleted, and, if not, the pointer is returned.::
>   

same as above


Tested-by: Phong Tran <tranmanphong@...il.com>

Regards,
Phong.

>   	struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id)
>   	{
> @@ -144,8 +150,10 @@ deleted, and, if not, the pointer is returned.
>   		return out;
>   	}
>   
> +.. _answer_quick_quiz_seqlock:
>   
>   Answer to Quick Quiz:
> +	Why is it so important that updates be rare when using seqlock?
>   
>   	The reason that it is important that updates be rare when
>   	using seqlock is that frequent updates can livelock readers.
> diff --git a/Documentation/RCU/index.rst b/Documentation/RCU/index.rst
> index 5c99185710fa..8d20d44f8fd4 100644
> --- a/Documentation/RCU/index.rst
> +++ b/Documentation/RCU/index.rst
> @@ -7,6 +7,7 @@ RCU concepts
>   .. toctree::
>      :maxdepth: 3
>   
> +   arrayRCU
>      rcu
>      listRCU
>      UP
>