From: Will Deacon <will.deacon@arm.com>
To: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E.McKenney" <paulmck@linux.vnet.ibm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Waiman Long <waiman.long@hp.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Alex Shi <alex.shi@linaro.org>, Andi Kleen <andi@firstfloor.org>,
Michel Lespinasse <walken@google.com>,
Davidlohr Bueso <davidlohr.bueso@hp.com>,
Matthew R Wilcox <matthew.r.wilcox@intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Rik van Riel <riel@redhat.com>,
Peter Hurley <peter@hurleysoftware.com>,
Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
George Spelvin <linux@horizon.com>,
"H. Peter Anvin" <hpa@zytor.com>, Arnd Bergmann <arnd@arndb.de>,
Aswin Chandramouleeswaran <aswin@hp.com>,
Scott J Norton <scott.norton@hp.com>,
"Figo.zhang" <figo1802@gmail.com>
Subject: Re: [PATCH v9 1/6] MCS Lock: Barrier corrections
Date: Wed, 22 Jan 2014 10:13:01 +0000 [thread overview]
Message-ID: <20140122101301.GA1621@mudshark.cambridge.arm.com> (raw)
In-Reply-To: <1390347353.3138.62.camel@schen9-DESK>
On Tue, Jan 21, 2014 at 11:35:53PM +0000, Tim Chen wrote:
> From: Waiman Long <Waiman.Long@hp.com>
>
> This patch corrects the way memory barriers are used in the MCS lock
> with smp_load_acquire and smp_store_release fucnctions. The previous
> barriers could leak critical sections if mcs lock is used by itself.
> It is not a problem when mcs lock is embedded in mutex but will be an
> issue when the mcs_lock is used elsewhere.
>
> The patch removes the incorrect barriers and put in correct
> barriers with the pair of functions smp_load_acquire and smp_store_release.
>
> Suggested-by: Michel Lespinasse <walken@google.com>
> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> Signed-off-by: Waiman Long <Waiman.Long@hp.com>
> Signed-off-by: Jason Low <jason.low2@hp.com>
> Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
> ---
> kernel/locking/mutex.c | 18 +++++++++++++-----
> 1 file changed, 13 insertions(+), 5 deletions(-)
Reviewed-by: Will Deacon <will.deacon@arm.com>
Will
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next prev parent reply other threads:[~2014-01-22 10:14 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1390320729.git.tim.c.chen@linux.intel.com>
2014-01-21 23:35 ` [PATCH v9 0/6] MCS Lock: MCS lock code cleanup and optimizations Tim Chen
2014-01-21 23:35 ` [PATCH v9 1/6] MCS Lock: Barrier corrections Tim Chen
2014-01-22 10:13 ` Will Deacon [this message]
2014-01-21 23:36 ` [PATCH v9 2/6] MCS Lock: Restructure the MCS lock defines and locking code into its own file Tim Chen
2014-01-21 23:36 ` [PATCH v9 3/6] MCS Lock: Optimizations and extra comments Tim Chen
2014-01-21 23:36 ` [PATCH v9 4/6] MCS Lock: Allow architectures to hook in to contended paths Tim Chen
2014-01-21 23:36 ` [PATCH v9 5/6] MCS Lock: Order the header files in Kbuild of each architecture in alphabetical order Tim Chen
2014-01-22 13:08 ` Peter Zijlstra
2014-01-22 17:41 ` Tim Chen
2014-01-22 17:51 ` Peter Zijlstra
2014-01-22 18:18 ` Peter Zijlstra
2014-01-22 18:25 ` Peter Zijlstra
2014-01-22 18:41 ` Tim Chen
2014-01-21 23:36 ` [PATCH v9 6/6] MCS Lock: Allow architecture specific asm files to be used for contended case Tim Chen
2014-01-22 18:35 ` Peter Zijlstra
2014-01-24 17:03 ` Tim Chen
2014-01-24 17:07 ` Peter Zijlstra
2014-01-24 17:33 ` Linus Torvalds
2014-01-24 17:37 ` Will Deacon
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