[Linux-kernel-mentees] [PATCH] Documentation: RCU: arrayRCU: Converted arrayRCU.txt to arrayRCU.rst
Madhuparna Bhowmik
madhuparnabhowmik04 at gmail.com
Tue Nov 5 21:35:43 UTC 2019
Thank you Amol and Phong for your valuable feedback. I have made the
changes requested and sent the patch.
https://lists.linuxfoundation.org/pipermail/linux-kernel-mentees/2019-November/001055.html
Regards,
Madhuparna
ᐧ
On Tue, Nov 5, 2019 at 8:15 PM Paul E. McKenney <paulmck at kernel.org> wrote:
> On Tue, Nov 05, 2019 at 08:03:44PM +0530, Amol Grover wrote:
> > On Tue, Nov 05, 2019 at 06:04:11AM -0800, Paul E. McKenney wrote:
> > > On Tue, Nov 05, 2019 at 08:49:47PM +0700, Phong Tran wrote:
> > > > On 10/29/19 3:24 AM, madhuparnabhowmik04 at gmail.com wrote:
> > > > > From: Madhuparna Bhowmik <madhuparnabhowmik04 at gmail.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 at gmail.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
> > >
> > > Madhuparna, could you please put a patch together creating these
> > > cross-references and handling Phong's comments below (probably
> > > by getting rid of the "." so that the resulting ":" doesn't look
> > > strange)?
> > >
> > > Then I will fold that patch into your original commit in -rcu and
> > > add Phong's Tested-by.
> > >
> > > Thanx, Paul
> > >
> > > > > 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 at gmail.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
> > > > >
> > > _______________________________________________
> > > Linux-kernel-mentees mailing list
> > > Linux-kernel-mentees at lists.linuxfoundation.org
> > >
> https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
> >
> > Hey,
> > There are a few instances in the document where words are
> > emphasized. Example, -not- in the first paragraph. The
> > previous emphasis was correct wrt txt format, but this
> > could be converted to italicize/bold to keep up with the
> > reST format. Other than this and what Phong suggested,
> > everything looks good!
> >
> > Tested-by: Amol Grover <frextrite at gmail.com>
>
> Thank you, Amol!
>
> Madhuparna, could you please also include a fix to the "-not-"
> text-emphasis issue (and any other occurrences) that Amol located?
>
> I can then add both Phong's and Amol's Tested-by.
>
> Thanx, Paul
>
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