Re: [PATCH 1/1] locking/qspinlock/x86: Avoid test-and-set when PV_DEDICATED is set

[Waiman Long]

On 10/24/2017 11:37 AM, Eduardo Valentin wrote:
> Hello Peter,
> On Tue, Oct 24, 2017 at 10:13:45AM +0200, Peter Zijlstra wrote:
>> On Mon, Oct 23, 2017 at 05:44:27PM -0700, Eduardo Valentin wrote:
>>> @@ -46,6 +48,8 @@ static inline bool virt_spin_lock(struct qspinlock *lock)
>>>  	if (!static_cpu_has(X86_FEATURE_HYPERVISOR))
>>>  		return false;
>>>  
>>> +	if (kvm_para_has_feature(KVM_FEATURE_PV_DEDICATED))
>>> +		return false;
>>>  	/*
>>>  	 * On hypervisors without PARAVIRT_SPINLOCKS support we fall
>>>  	 * back to a Test-and-Set spinlock, because fair locks have
>> This does not apply. Much has been changed here recently.
>>
>  I checked against Linus master branch before sending. Which tree/branch are you referring to / should I based this?
>
Please check the tip tree
(https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git) which has
the latest changes in locking code.

Cheers,
Longman