Thanks Paul for reviewing the patch
On Wed, Jul 21, 2021 at 1:33 AM Paul E. McKenney <paulmck@xxxxxxxxxx> wrote:
>
> On Tue, Jul 20, 2021 at 03:17:25PM +0800, Zhouyi Zhou wrote:
> > Hi, Paul
> > I think preposition 'on' here is superfluous, correct me if I am wrong.
> > Best Wishes
> > Zhouyi
>
> The current text is technically grammatically correct, but as you
> noticed, rather awkward. I should rework that sentence and the one
> following. Huh. Actually, I should rework that entire paragraph.
>
> How about the following?
>
> Thanx, Paul
>
> ------------------------------------------------------------------------
>
> commit 5eb7525e2f7338ea6b817c145a9b4da60e6871d1
> Author: Paul E. McKenney <paulmck@xxxxxxxxxx>
> Date: Tue Jul 20 10:31:03 2021 -0700
>
> defer/rcufundamental: Wordsmith QQ answer about writes in RCU readers
>
> Reported-by: Zhouyi Zhou <zhouzhouyi@xxxxxxxxx>
> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
>
> diff --git a/defer/rcufundamental.tex b/defer/rcufundamental.tex
> index 66f9b702..054512e0 100644
> --- a/defer/rcufundamental.tex
> +++ b/defer/rcufundamental.tex
> @@ -330,12 +330,17 @@ greater detail in \cref{sec:memorder:RCU}.
> \co{P1()}'s grace period.
>
> It might seem strange to have RCU read-side critical sections
> - containing writes, but RCU is just fine with this.
> - This capability is used frequently in the Linux kernel, for
> - example, acquiring a lock on or reference to a data structure.
> - Acquiring either a lock or a reference results in a write
> - to memory, and it is OK to do these within an RCU read-side
> - critical section.
> + containing writes, but this capability is not only permitted,
> + but also highly useful.
> + For example, the Linux kernel frequently carries out an
> + RCU-protected traversal of a linked data structure and then
> + acquires a reference to the destination data element.
> + Because this data element must not be freed in the meantime,
> + that element's reference counter must necessarily be incremented
> + within the traversal's RCU read-side critical section.
> + However, that increment entails a write to memory.
> + Therefore, it is a very good thing that memory writes are
> + permitted within RCU read-side critical sections.
The revised paragraph is easier for me to understand, especially why acquiring
a reference to a data structure entails a write ;-)
>
> If having writes in RCU read-side critical sections still seems
> strange, please review
The revised edition looks wonderful, thank you
Thanks again
Zhouyi
