Re: [PATCH 4/3] docs: litmus-tests: Clarify about the RCU pre-initialization test

From: "Paul E. McKenney" <paulmck@kernel.org>
To: Joel Fernandes <joel@joelfernandes.org>
Cc: Akira Yokosawa <akiyks@gmail.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Vineeth Remanan Pillai <vpillai@digitalocean.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Alan Stern <stern@rowland.harvard.edu>,
	Andrea Parri <parri.andrea@gmail.com>,
	Will Deacon <will@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Nicholas Piggin <npiggin@gmail.com>,
	David Howells <dhowells@redhat.com>,
	Jade Alglave <j.alglave@ucl.ac.uk>,
	Luc Maranget <luc.maranget@inria.fr>,
	Daniel Lustig <dlustig@nvidia.com>,
	"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>
Subject: Re: [PATCH 4/3] docs: litmus-tests: Clarify about the RCU pre-initialization test
Date: Tue, 12 May 2020 09:30:22 -0700	[thread overview]
Message-ID: <20200512163022.GI2869@paulmck-ThinkPad-P72> (raw)
In-Reply-To: <CAEXW_YSjo2hgvg-FN_MR7FVEcp-7gH17jb0-262k+ydSuuDjuQ@mail.gmail.com>

On Tue, May 12, 2020 at 11:41:01AM -0400, Joel Fernandes wrote:
> On Tue, May 12, 2020 at 11:07 AM Akira Yokosawa <akiyks@gmail.com> wrote:
> >
> > From 7bb979aacd8788d174df8a56e9803ba9e5b7a381 Mon Sep 17 00:00:00 2001
> > From: Joel Fernandes (Google) <joel@joelfernandes.org>
> > Date: Mon, 11 May 2020 22:06:46 -0400
> > Subject: [PATCH 4/3] docs: litmus-tests: Clarify about the RCU pre-initialization test
> >
> > Since this test returned to tools/memory-model/, make sure that it is
> > at least referenced from Documentation/litmus-tests/'s README.
> >
> > Co-developed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> > Co-developed-by: Akira Yokosawa <akiyks@gmail.com>
> > [Alan: grammar nit]
> > Suggested-by: Alan Stern <stern@rowland.harvard.edu>
> > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
> > Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
> > ---
> > I said in the earlier message:
> >
> > > The explanation under tools/memory-model/litmus-tests/README also need the same
> > > rewording.
> >
> > , but obviously I was confused. It is good as is.
> >
> > This is on top of my earlier patch series.
> >
> > Joel, Alan, does this work with you?
> 
> Yes, thanks a lot for doing it. Paul are you Ok with it too?

Looks good to me!

Could one of you please send a patch series and instructions, which I
-think- will be of the form:

o	Revert a5cca3485d92 ("Documentation: LKMM: Move
	MP+onceassign+derefonce to new litmus-tests/rcu/")

o	Apply a series of patches.

(My head is deep within some ring-buffer code that I am reviewing, so I
guarantee that if I try to piece this together from the current set of
patches, I will end up producing a spectacular display of destructive
creativity.)

							Thanx, Paul

> thanks,
> 
>  - Joel
> 
> 
> >
> >         Thanks, Akira
> > --
> >  Documentation/litmus-tests/README | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/Documentation/litmus-tests/README b/Documentation/litmus-tests/README
> > index ac0b270b456c..b79e640214b9 100644
> > --- a/Documentation/litmus-tests/README
> > +++ b/Documentation/litmus-tests/README
> > @@ -24,6 +24,10 @@ Atomic-RMW-ops-are-atomic-WRT-atomic_set.litmus
> >  RCU (/rcu directory)
> >  --------------------
> >
> > +MP+onceassign+derefonce.litmus (under tools/memory-model/litmus-tests/)
> > +    Demonstrates the use of rcu_assign_pointer() and rcu_dereference() to
> > +    ensure that an RCU reader will not see pre-initialization garbage.
> > +
> >  RCU+sync+read.litmus
> >  RCU+sync+free.litmus
> >      Both the above litmus tests demonstrate the RCU grace period guarantee
> > --
> > 2.17.1
> >
> >