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References: <1296496389-30647-1-git-send-email-will.deacon@arm.com>
	<1db705ac90529708ef559eee9708b648@mail.gmail.com>
Date: Tue, 1 Feb 2011 16:03:54 +0800
Message-ID: <AANLkTimBTrqOk_ctBKmT0c=teZ8oG3c7Ai6-BmZwOj+g@mail.gmail.com>
Subject: Re: [PATCH v2] oprofile: add SMP barriers for hrtimer hotplug code
From: Ming Lei <tom.leiming@gmail.com>
To: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Will Deacon <will.deacon@arm.com>, linux-kernel@vger.kernel.org,
        oprofile-list@lists.sf.net, Robert Richter <robert.richter@amd.com>
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Hi,

2011/2/1 Santosh Shilimkar <santosh.shilimkar@ti.com>:
>> -----Original Message-----
>> From: Will Deacon [mailto:will.deacon@arm.com]
>> diff --git a/drivers/oprofile/timer_int.c
>> b/drivers/oprofile/timer_int.c
>> index 0107251..a3a94ea 100644
>> --- a/drivers/oprofile/timer_int.c
>> +++ b/drivers/oprofile/timer_int.c
>> @@ -48,6 +48,7 @@ static int oprofile_hrtimer_start(void)
>> ?{
>> ? ? ? get_online_cpus();
>> ? ? ? ctr_running = 1;
>> + ? ? smp_mb();
>> ? ? ? on_each_cpu(__oprofile_hrtimer_start, NULL, 1);

Just a little question:

Before calling __oprofile_hrtimer_start in other CPUs,
there have been some smp_mb executed already, such as called by
smp_call_function_many in current CPU, and called by
generic_smp_call_function_interrupt in the func-calling CPU,
so are these smp_mb enough for correct order of access
for 'ctr_running' ?

>> ? ? ? put_online_cpus();
>> ? ? ? return 0;

thanks,
-- 
Lei Ming
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