On Tue, Oct 29, 2019 at 01:54:17AM +0530, madhuparnabhowmik04@xxxxxxxxx wrote:
> From: Madhuparna Bhowmik <madhuparnabhowmik04@xxxxxxxxx>
>
> 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@xxxxxxxxx>
Much better, thank you!
I queued this with a small but important change called out below.
> ---
> .../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.
>
>
> 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:
The above line added trailing whitespace. I removed it for you, but
please check for this on future submissions. ;-)
Thanx, Paul
> + 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.::
>
> 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.::
>
> 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
> --
> 2.17.1
>
