Re: [profile] fix timer interrupt livelock on 512x Altix

[William Lee Irwin III <wli@holomorphy.com>]

On Tue, 2004-09-21 at 07:30, William Lee Irwin III wrote:
>> +static void __profile_flip_buffers(void *unused)
>> +{
>> +	int cpu = smp_processor_id();
>> +
>> +	per_cpu(cpu_profile_flip, cpu) = !per_cpu(cpu_profile_flip, cpu);
>> +}

On Fri, Oct 15, 2004 at 11:46:22AM +1000, Rusty Russell wrote:
> Please: one point of per-cpu vars is that archs can choose to hold the
> per-cpu offset in a reg, and derive smp_processor_id() from that.  By
> doing the reverse, manually, you defeat this.  How about:
> 	int *flip = __get_cpu_var(cpu_profile_flip);
> 	*flip = !*flip;

Proof once more that sustained and repeated exposure to shitty
architectures degrades intelligence. I'll send in a correction shortly.


-- wli