On 02/26/2014 12:08 PM, Konrad Rzeszutek Wilk wrote:
On Wed, Feb 26, 2014 at 10:14:25AM -0500, Waiman Long wrote:This patch adds a KVM init function to activate the unfair queue spinlock in a KVM guest when the PARAVIRT_UNFAIR_LOCKS kernel config option is selected. Signed-off-by: Waiman Long<Waiman.Long@xxxxxx> --- arch/x86/kernel/kvm.c | 17 +++++++++++++++++ 1 files changed, 17 insertions(+), 0 deletions(-) diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 713f1b3..a489140 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -826,3 +826,20 @@ static __init int kvm_spinlock_init_jump(void) early_initcall(kvm_spinlock_init_jump); #endif /* CONFIG_PARAVIRT_SPINLOCKS */ + +#ifdef CONFIG_PARAVIRT_UNFAIR_LOCKS +/* + * Enable unfair lock if running in a real para-virtualized environment + */ +static __init int kvm_unfair_locks_init_jump(void) +{ + if (!kvm_para_available()) + return 0;I think you also need to check for !kvm_para_has_feature(KVM_FEATURE_PV_UNHALT)? Otherwise you might enable this, but the kicker function won't be enabled.
The unfair lock code doesn't need to use the CPU kicker function. That is why the KVM_FEATURE_PV_UNHALT feature is not checked.
-Longman _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
