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.
If having writes in RCU read-side critical sections still seems
strange, please review
