* [PATCH -perfbook] defer: remove superfluous preposition @ 2021-07-20 7:17 Zhouyi Zhou 2021-07-20 17:33 ` Paul E. McKenney 0 siblings, 1 reply; 5+ messages in thread From: Zhouyi Zhou @ 2021-07-20 7:17 UTC (permalink / raw) To: paulmck, perfbook, luyang.co; +Cc: Zhouyi Zhou Hi, Paul I think preposition 'on' here is superfluous, correct me if I am wrong. Best Wishes Zhouyi --- defer/rcufundamental.tex | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/defer/rcufundamental.tex b/defer/rcufundamental.tex index 66f9b70..62f31d0 100644 --- a/defer/rcufundamental.tex +++ b/defer/rcufundamental.tex @@ -332,7 +332,7 @@ greater detail in \cref{sec:memorder:RCU}. 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. + example, acquiring a lock 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. -- 2.5.0 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH -perfbook] defer: remove superfluous preposition 2021-07-20 7:17 [PATCH -perfbook] defer: remove superfluous preposition Zhouyi Zhou @ 2021-07-20 17:33 ` Paul E. McKenney 2021-07-20 18:36 ` Zhouyi Zhou 0 siblings, 1 reply; 5+ messages in thread From: Paul E. McKenney @ 2021-07-20 17:33 UTC (permalink / raw) To: Zhouyi Zhou; +Cc: perfbook, luyang.co 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@kernel.org> Date: Tue Jul 20 10:31:03 2021 -0700 defer/rcufundamental: Wordsmith QQ answer about writes in RCU readers Reported-by: Zhouyi Zhou <zhouzhouyi@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> 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 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH -perfbook] defer: remove superfluous preposition 2021-07-20 17:33 ` Paul E. McKenney @ 2021-07-20 18:36 ` Zhouyi Zhou 2021-07-20 19:06 ` Paul E. McKenney 0 siblings, 1 reply; 5+ messages in thread From: Zhouyi Zhou @ 2021-07-20 18:36 UTC (permalink / raw) To: paulmck; +Cc: perfbook, Yang Lu Thanks Paul for reviewing the patch On Wed, Jul 21, 2021 at 1:33 AM Paul E. McKenney <paulmck@kernel.org> 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@kernel.org> > Date: Tue Jul 20 10:31:03 2021 -0700 > > defer/rcufundamental: Wordsmith QQ answer about writes in RCU readers > > Reported-by: Zhouyi Zhou <zhouzhouyi@gmail.com> > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > > 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 ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH -perfbook] defer: remove superfluous preposition 2021-07-20 18:36 ` Zhouyi Zhou @ 2021-07-20 19:06 ` Paul E. McKenney 2021-07-20 19:23 ` Zhouyi Zhou 0 siblings, 1 reply; 5+ messages in thread From: Paul E. McKenney @ 2021-07-20 19:06 UTC (permalink / raw) To: Zhouyi Zhou; +Cc: perfbook, Yang Lu On Wed, Jul 21, 2021 at 02:36:30AM +0800, Zhouyi Zhou wrote: > Thanks Paul for reviewing the patch > > On Wed, Jul 21, 2021 at 1:33 AM Paul E. McKenney <paulmck@kernel.org> 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@kernel.org> > > Date: Tue Jul 20 10:31:03 2021 -0700 > > > > defer/rcufundamental: Wordsmith QQ answer about writes in RCU readers > > > > Reported-by: Zhouyi Zhou <zhouzhouyi@gmail.com> > > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > > > > 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 Glad you like it, and thank you for pointing me at the original awkward sentence! Thanx, Paul ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH -perfbook] defer: remove superfluous preposition 2021-07-20 19:06 ` Paul E. McKenney @ 2021-07-20 19:23 ` Zhouyi Zhou 0 siblings, 0 replies; 5+ messages in thread From: Zhouyi Zhou @ 2021-07-20 19:23 UTC (permalink / raw) To: paulmck; +Cc: perfbook, Yang Lu On Wed, Jul 21, 2021 at 3:06 AM Paul E. McKenney <paulmck@kernel.org> wrote: > > On Wed, Jul 21, 2021 at 02:36:30AM +0800, Zhouyi Zhou wrote: > > Thanks Paul for reviewing the patch > > > > On Wed, Jul 21, 2021 at 1:33 AM Paul E. McKenney <paulmck@kernel.org> 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@kernel.org> > > > Date: Tue Jul 20 10:31:03 2021 -0700 > > > > > > defer/rcufundamental: Wordsmith QQ answer about writes in RCU readers > > > > > > Reported-by: Zhouyi Zhou <zhouzhouyi@gmail.com> > > > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > > > > > > 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 > > Glad you like it, and thank you for pointing me at the original > awkward sentence! You are very welcome ;-), reading the book itself is a self-improvement process, To be honest, by reading the book, I find you are the example worth following in my career life. > > Thanx, Paul Best Wishes Zhouyi ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-07-20 19:23 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-07-20 7:17 [PATCH -perfbook] defer: remove superfluous preposition Zhouyi Zhou 2021-07-20 17:33 ` Paul E. McKenney 2021-07-20 18:36 ` Zhouyi Zhou 2021-07-20 19:06 ` Paul E. McKenney 2021-07-20 19:23 ` Zhouyi Zhou
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