From: Waiman Long <waiman.long@hp.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Arnd Bergmann <arnd@arndb.de>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
the arch/x86 maintainers <x86@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Andrew Morton <akpm@linux-foundation.org>,
Michel Lespinasse <walken@google.com>,
Andi Kleen <andi@firstfloor.org>, Rik van Riel <riel@redhat.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
George Spelvin <linux@horizon.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
"Chandramouleeswaran, Aswin" <aswin@hp.com>,
Scott J Norton <scott.norton@hp.com>
Subject: Re: [PATCH v10 1/4] qrwlock: A queue read/write lock implementation
Date: Thu, 23 Jan 2014 12:47:20 -0500 [thread overview]
Message-ID: <52E155A8.7000206@hp.com> (raw)
In-Reply-To: <CA+55aFzhx6K9A62ve6E5X4juvNPewED_g1nWwq+-EY0fd0A-0g@mail.gmail.com>
On 01/23/2014 12:15 PM, Linus Torvalds wrote:
> On Thu, Jan 23, 2014 at 9:12 AM, Waiman Long<waiman.long@hp.com> wrote:
>> I thought that all atomic RMW instructions are memory barrier.
> On x86 they are. Not necessarily elsewhere.
>
>> If they are not, what kind of barrier should be added?
> smp_mb__before_atomic_xyz() and smp_mb__after_atomic_xyz() will do it,
> and are no-op (well, barriers - I don't think it matters) on x86.
>
> Linus
> -
Thank for the info. I am less familiar with that kind of issues on other
architecture. I will add a smp_mb__after_atomic_dec() & send out a new
patch.
-Longman
next prev parent reply other threads:[~2014-01-23 17:47 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-22 21:33 [PATCH v10 0/4] Introducing a queue read/write lock implementation Waiman Long
2014-01-22 21:33 ` [PATCH v10 1/4] qrwlock: A " Waiman Long
2014-01-23 10:07 ` Peter Zijlstra
2014-01-23 17:12 ` Waiman Long
2014-01-23 17:12 ` Waiman Long
2014-01-23 17:15 ` Linus Torvalds
2014-01-23 17:38 ` Peter Zijlstra
2014-01-23 17:47 ` Waiman Long [this message]
2014-01-23 17:52 ` Linus Torvalds
2014-01-23 20:45 ` Waiman Long
2014-01-22 21:33 ` [PATCH v10 2/4] qrwlock, x86: Enable x86 to use queue read/write lock Waiman Long
2014-01-22 21:33 ` [PATCH v10 3/4] qrwlock, x86: Add char and short as atomic data type in x86 Waiman Long
2014-01-22 21:33 ` [PATCH v10 4/4] qrwlock: Use the mcs_spinlock helper functions for MCS queuing Waiman Long
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