Message-ID: <52E17F7E.1030803@hp.com>
Date: Thu, 23 Jan 2014 15:45:50 -0500
From: Waiman Long <waiman.long@hp.com>
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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
References: <1390426438-31252-1-git-send-email-Waiman.Long@hp.com> <1390426438-31252-2-git-send-email-Waiman.Long@hp.com> <20140123100751.GS30183@twins.programming.kicks-ass.net> <52E14D67.4000202@hp.com> <CA+55aFzhx6K9A62ve6E5X4juvNPewED_g1nWwq+-EY0fd0A-0g@mail.gmail.com> <52E155A8.7000206@hp.com> <CA+55aFyb-qFpUWGZjXJx_V_tr43XYGGL9srfrZf6qhxV_qPfVg@mail.gmail.com>
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On 01/23/2014 12:52 PM, Linus Torvalds wrote:
> On Thu, Jan 23, 2014 at 9:47 AM, Waiman Long<waiman.long@hp.com>  wrote:
>> 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.
> SInce it's the unlock path,. you need to use the "mb__*before*"
> versions, since presumably you want to protect what is inside the lock
> from leaking out, not some random thing after the lock from leaking
> in..
>
>                Linus

My bad. I am a bit sloppy not using the right function in my email. I 
will certainly put the right mb functions depending on whether it is a 
lock or unlock function.

-Longman
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