Il 26/02/2014 16:14, Waiman Long ha scritto:
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;
+
+ static_key_slow_inc(¶virt_unfairlocks_enabled);
+ printk(KERN_INFO "KVM setup unfair spinlock\n");
+
+ return 0;
+}
+early_initcall(kvm_unfair_locks_init_jump);
+#endif
I think this should apply to all paravirt implementations, unless
pv_lock_ops.kick_cpu != NULL.
Paolo
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