Re: [PATCH] kvm: add halt_poll_ns module parameter

From: Paolo Bonzini
Date: Mon Feb 09 2015 - 04:07:11 EST

On 09/02/2015 09:22, Xiao Guangrong wrote:
> On 02/06/2015 08:48 PM, Paolo Bonzini wrote:
>> +unsigned int halt_poll_ns = 0;
>> +module_param(halt_poll_ns, uint, S_IRUGO | S_IWUSR);
>> +
> Can we make this parameter be changeable? So that we can tune it
> on the fly.

It is changeable (S_IWUSR).

>> finish_wait(&vcpu->wq, &wait);
>> + cur = ktime_get();
> We can move this into the tracepoint to avoid the workload if the
> tracepoint is not enabled.

You have a point. I didn't do it because I expect that halt_poll_ns
will be always enabled as soon as it auto-tunes, and in that case you'll
always have to do the ktime_get() for autotuning purposes.

> Otherwise looks good to me.
> Reviewed-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>


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