Re: [Xen-devel] [PATCH v3 0/2] guard virt_spin_lock() with a static key

2017-10-02 Thread Peter Zijlstra 
On Wed, Sep 06, 2017 at 07:36:23PM +0200, Juergen Gross wrote:
> With virt_spin_lock() being guarded by a static key the bare metal case
> can be optimized by patching the call away completely. In case a kernel
> running as a guest it can decide whether to use paravitualized
> spinlocks, the current fallback to the unfair test-and-set scheme, or
> to mimic the bare metal behavior.
> 
> V3:
> - remove test for hypervisor environment from virt_spin_lock(9 as
>   suggested by Waiman Long
> 
> V2:
> - use static key instead of making virt_spin_lock() a pvops function
> 
> Juergen Gross (2):
>   paravirt/locks: use new static key for controlling call of
> virt_spin_lock()
>   paravirt,xen: correct xen_nopvspin case
> 
>  arch/x86/include/asm/qspinlock.h | 11 ++-
>  arch/x86/kernel/paravirt-spinlocks.c |  6 ++
>  arch/x86/kernel/smpboot.c|  2 ++
>  arch/x86/xen/spinlock.c  |  2 ++
>  kernel/locking/qspinlock.c   |  4 
>  5 files changed, 24 insertions(+), 1 deletion(-)

Sorry for the delay, picked it up now.

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Re: [Xen-devel] [PATCH v3 0/2] guard virt_spin_lock() with a static key

2017-09-25 Thread Waiman Long 
On 09/25/2017 09:59 AM, Juergen Gross wrote:
> Ping?
>
> On 06/09/17 19:36, Juergen Gross wrote:
>> With virt_spin_lock() being guarded by a static key the bare metal case
>> can be optimized by patching the call away completely. In case a kernel
>> running as a guest it can decide whether to use paravitualized
>> spinlocks, the current fallback to the unfair test-and-set scheme, or
>> to mimic the bare metal behavior.
>>
>> V3:
>> - remove test for hypervisor environment from virt_spin_lock(9 as
>>   suggested by Waiman Long
>>
>> V2:
>> - use static key instead of making virt_spin_lock() a pvops function
>>
>> Juergen Gross (2):
>>   paravirt/locks: use new static key for controlling call of
>> virt_spin_lock()
>>   paravirt,xen: correct xen_nopvspin case
>>
>>  arch/x86/include/asm/qspinlock.h | 11 ++-
>>  arch/x86/kernel/paravirt-spinlocks.c |  6 ++
>>  arch/x86/kernel/smpboot.c|  2 ++
>>  arch/x86/xen/spinlock.c  |  2 ++
>>  kernel/locking/qspinlock.c   |  4 
>>  5 files changed, 24 insertions(+), 1 deletion(-)
>>
Acked-by: Waiman Long 


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Re: [Xen-devel] [PATCH v3 0/2] guard virt_spin_lock() with a static key

2017-09-25 Thread Juergen Gross 
Ping?

On 06/09/17 19:36, Juergen Gross wrote:
> With virt_spin_lock() being guarded by a static key the bare metal case
> can be optimized by patching the call away completely. In case a kernel
> running as a guest it can decide whether to use paravitualized
> spinlocks, the current fallback to the unfair test-and-set scheme, or
> to mimic the bare metal behavior.
> 
> V3:
> - remove test for hypervisor environment from virt_spin_lock(9 as
>   suggested by Waiman Long
> 
> V2:
> - use static key instead of making virt_spin_lock() a pvops function
> 
> Juergen Gross (2):
>   paravirt/locks: use new static key for controlling call of
> virt_spin_lock()
>   paravirt,xen: correct xen_nopvspin case
> 
>  arch/x86/include/asm/qspinlock.h | 11 ++-
>  arch/x86/kernel/paravirt-spinlocks.c |  6 ++
>  arch/x86/kernel/smpboot.c|  2 ++
>  arch/x86/xen/spinlock.c  |  2 ++
>  kernel/locking/qspinlock.c   |  4 
>  5 files changed, 24 insertions(+), 1 deletion(-)
> 


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