From: "Paul E. McKenney" <paulmck@kernel.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
kernel-team@fb.com, mingo@kernel.org, parri.andrea@gmail.com,
will@kernel.org, peterz@infradead.org, boqun.feng@gmail.com,
npiggin@gmail.com, dhowells@redhat.com, j.alglave@ucl.ac.uk,
luc.maranget@inria.fr, akiyks@gmail.com
Subject: Re: [PATCH kcsan 8/9] tools/memory-model: Document categories of ordering primitives
Date: Mon, 31 Aug 2020 19:58:54 -0700 [thread overview]
Message-ID: <20200901025854.GA29330@paulmck-ThinkPad-P72> (raw)
In-Reply-To: <20200901012309.GA571008@rowland.harvard.edu>
On Mon, Aug 31, 2020 at 09:23:09PM -0400, Alan Stern wrote:
> On Mon, Aug 31, 2020 at 11:20:36AM -0700, paulmck@kernel.org wrote:
> > From: "Paul E. McKenney" <paulmck@kernel.org>
> >
> > The Linux kernel has a number of categories of ordering primitives, which
> > are recorded in the LKMM implementation and hinted at by cheatsheet.txt.
> > But there is no overview of these categories, and such an overview
> > is needed in order to understand multithreaded LKMM litmus tests.
> > This commit therefore adds an ordering.txt as well as extracting a
> > control-dependencies.txt from memory-barriers.txt. It also updates the
> > README file.
> >
> > Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> > ---
>
> This document could use some careful editing. But one pair of errors
> stands out in particular:
>
> > diff --git a/tools/memory-model/Documentation/ordering.txt b/tools/memory-model/Documentation/ordering.txt
> > new file mode 100644
> > index 0000000..4b2cc55
> > --- /dev/null
> > +++ b/tools/memory-model/Documentation/ordering.txt
>
> > +2. Ordered memory accesses. These operations order themselves
> > + against some or all of the CPUs prior or subsequent accesses,
> > + depending on the category of operation.
> > +
> > + a. Release operations. This category includes
> > + smp_store_release(), atomic_set_release(),
> > + rcu_assign_pointer(), and value-returning RMW operations
> > + whose names end in _release. These operations order
> > + their own store against all of the CPU's subsequent
> ---------------------------------------------------------^^^^^^^^^^
> > + memory accesses.
> > +
> > + b. Acquire operations. This category includes
> > + smp_load_acquire(), atomic_read_acquire(), and
> > + value-returning RMW operations whose names end in
> > + _acquire. These operations order their own load against
> > + all of the CPU's prior memory accesses.
> ---------------------------------^^^^^
>
> Double-oops!
Hey, at least I am consistently wrong! ;-)
Fixed, thank you!
Thanx, Paul
next prev parent reply other threads:[~2020-09-01 2:58 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-31 18:20 [PATCH memory-model 0/9] LKMM updates for v5.10 Paul E. McKenney
2020-08-31 18:20 ` [PATCH kcsan 1/9] docs: fix references for DMA*.txt files paulmck
2020-08-31 18:20 ` [PATCH kcsan 2/9] Replace HTTP links with HTTPS ones: LKMM paulmck
2020-08-31 18:20 ` [PATCH kcsan 3/9] tools/memory-model: Update recipes.txt prime_numbers.c path paulmck
2020-08-31 18:20 ` [PATCH kcsan 4/9] tools/memory-model: Improve litmus-test documentation paulmck
2020-08-31 18:20 ` [PATCH kcsan 5/9] tools/memory-model: Add a simple entry point document paulmck
2020-08-31 18:20 ` [PATCH kcsan 6/9] tools/memory-model: Expand the cheatsheet.txt notion of relaxed paulmck
2020-09-02 3:54 ` Boqun Feng
2020-09-02 10:14 ` peterz
2020-09-02 12:37 ` Boqun Feng
2020-09-02 12:47 ` peterz
2020-09-03 23:30 ` Paul E. McKenney
2020-09-04 0:59 ` Boqun Feng
2020-09-04 2:39 ` Paul E. McKenney
2020-09-04 2:47 ` Boqun Feng
2020-09-04 19:56 ` Paul E. McKenney
2020-08-31 18:20 ` [PATCH kcsan 7/9] tools/memory-model: Move Documentation description to Documentation/README paulmck
2020-08-31 18:20 ` [PATCH kcsan 8/9] tools/memory-model: Document categories of ordering primitives paulmck
2020-08-31 22:34 ` Akira Yokosawa
2020-08-31 23:12 ` Paul E. McKenney
2020-09-01 1:23 ` Alan Stern
2020-09-01 2:58 ` Paul E. McKenney [this message]
2020-08-31 18:20 ` [PATCH kcsan 9/9] tools/memory-model: Document locking corner cases paulmck
2020-08-31 20:17 ` Alan Stern
2020-08-31 21:47 ` Paul E. McKenney
2020-09-01 1:45 ` Alan Stern
2020-09-01 17:04 ` Paul E. McKenney
2020-09-01 20:11 ` Alan Stern
2020-09-03 23:45 ` Paul E. McKenney
2020-09-04 19:52 ` Alan Stern
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