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Date: Wed, 16 Jun 2010 20:52:44 +0400
From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus <paulus@samba.org>, stephane eranian <eranian@googlemail.com>,
       Robert Richter <robert.richter@amd.com>,
       Will Deacon <will.deacon@arm.com>, Paul Mundt <lethal@linux-sh.org>,
       Frederic Weisbecker <fweisbec@gmail.com>,
       Lin Ming <ming.m.lin@intel.com>, Yanmin <yanmin_zhang@linux.intel.com>,
       Deng-Cheng Zhu <dengcheng.zhu@gmail.com>,
       David Miller <davem@davemloft.net>, linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH 5/8] perf: Reduce perf_disable() usage
Message-ID: <20100616165244.GB6751@lenovo>
References: <20100616160027.590430763@chello.nl> <20100616160238.431137125@chello.nl>
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On Wed, Jun 16, 2010 at 06:00:32PM +0200, Peter Zijlstra wrote:
> Since the current perf_disable() usage is only an optimization, remove
> it for now. This eases the removal of the weak hw_perf_enable
> interface.
> 
> [ Some comments talk about NMI races, but I cannot find any such
>   things. ]
> 

The race was there and was fixed by commit 

| commit 34adc8062227f41b04ade0ff3fbd1dbe3002669e
| Author: Ingo Molnar <mingo@elte.hu>
| Date:   Wed May 20 20:13:28 2009 +0200

then you fixed it further in commit

| commit 3fb2b8ddcc6a7aa62af6bd2cb939edfd4c460506
| Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
| Date:   Mon Mar 8 13:51:01 2010 +0100

which I understand as we don't need perf_disable here for sure.
Just for the record :)

	-- Cyrill