Re: [PATCH v2] oprofile: add SMP barriers for hrtimer hotplug code
From: Ming Lei
Date: Tue Feb 01 2011 - 03:03:59 EST
Hi,
2011/2/1 Santosh Shilimkar <santosh.shilimkar@xxxxxx>:
>> -----Original Message-----
>> From: Will Deacon [mailto:will.deacon@xxxxxxx]
>> 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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/