From: "Paul E. McKenney" <paulmck@kernel.org>
To: Will Deacon <will@kernel.org>
Cc: Parav Pandit <parav@nvidia.com>,
bagasdotme@gmail.com, arnd@arndb.de, stern@rowland.harvard.edu,
parri.andrea@gmail.com, 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,
dlustig@nvidia.com, joel@joelfernandes.org, corbet@lwn.net,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
linux-doc@vger.kernel.org
Subject: Re: [PATCH v5] locking/memory-barriers.txt: Improve documentation for writel() example
Date: Wed, 2 Nov 2022 13:30:45 -0700 [thread overview]
Message-ID: <20221102203045.GS5600@paulmck-ThinkPad-P17-Gen-1> (raw)
In-Reply-To: <20221102060553.GA15438@willie-the-truck>
On Wed, Nov 02, 2022 at 06:05:54AM +0000, Will Deacon wrote:
> On Thu, Oct 27, 2022 at 11:10:00PM +0300, Parav Pandit wrote:
> > The cited commit describes that when using writel(), explicit wmb()
> > is not needed. wmb() is an expensive barrier. writel() uses the needed
> > platform specific barrier instead of wmb().
> >
> > writeX() section of "KERNEL I/O BARRIER EFFECTS" already describes
> > ordering of I/O accessors with MMIO writes.
> >
> > Hence add the comment for pseudo code of writel() and remove confusing
> > text around writel() and wmb().
> >
> > commit 5846581e3563 ("locking/memory-barriers.txt: Fix broken DMA vs. MMIO ordering example")
> >
> > Signed-off-by: Parav Pandit <parav@nvidia.com>
> > ---
> > changelog:
> > v4->v5:
> > - Used suggested documentation update from Will
> > - Added comment to the writel() pseudo code example
> > - updated commit log for newer changes
>
> Sorry for the delay on this, I'm really behind on patches at the moment.
> This patch looks good to me, so thanks for doing it. You can either add
> my:
>
> Acked-by: Will Deacon <will@kernel.org>
>
> or, since we worked on this together:
>
> Co-developed-by: Will Deacon <will@kernel.org>
> Signed-off-by: Will Deacon <will@kernel.org>
Thank you! I will apply these tags on the next rebase.
Thanx, Paul
prev parent reply other threads:[~2022-11-02 20:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-27 20:10 [PATCH v5] locking/memory-barriers.txt: Improve documentation for writel() example Parav Pandit
2022-10-28 17:56 ` Paul E. McKenney
2022-10-28 17:59 ` Parav Pandit
2022-11-02 6:05 ` Will Deacon
2022-11-02 20:30 ` Paul E. McKenney [this message]
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