pv-qspinlock core has pv_wait/pv_kick which will give a better
performace by yielding and kicking cpu at some cases.
lets support them by adding two corresponding helper functions.
Signed-off-by: Pan Xinhui <xinhui.pan@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/include/asm/spinlock.h | 4 ++++
arch/powerpc/lib/locks.c | 33 +++++++++++++++++++++++++++++++++
2 files changed, 37 insertions(+)
diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h
index 4359ee6..3b65372 100644
--- a/arch/powerpc/include/asm/spinlock.h
+++ b/arch/powerpc/include/asm/spinlock.h
@@ -56,9 +56,13 @@
/* We only yield to the hypervisor if we are in shared processor mode */
#define SHARED_PROCESSOR (lppaca_shared_proc(local_paca->lppaca_ptr))
extern void __spin_yield(arch_spinlock_t *lock);
+extern void __spin_yield_cpu(int cpu);
+extern void __spin_wake_cpu(int cpu);
extern void __rw_yield(arch_rwlock_t *lock);
#else /* SPLPAR */
#define __spin_yield(x) barrier()
+#define __spin_yield_cpu(x) barrier()
+#define __spin_wake_cpu(x) barrier()
#define __rw_yield(x) barrier()
#define SHARED_PROCESSOR 0
#endif
diff --git a/arch/powerpc/lib/locks.c b/arch/powerpc/lib/locks.c
index a9ebd71..3a58834 100644
--- a/arch/powerpc/lib/locks.c
+++ b/arch/powerpc/lib/locks.c
@@ -23,6 +23,39 @@
#include <asm/hvcall.h>
#include <asm/smp.h>
+void __spin_yield_cpu(int cpu)
+{
+ unsigned int holder_cpu = cpu, yield_count;
+
+ if (cpu == -1) {
+ plpar_hcall_norets(H_CONFER, -1, 0);
+ return;
+ }
+ BUG_ON(holder_cpu >= nr_cpu_ids);
+ yield_count = be32_to_cpu(lppaca_of(holder_cpu).yield_count);
+ if ((yield_count & 1) == 0) {
+ /* if target cpu is running, confer slices to lpar*/
+ plpar_hcall_norets(H_CONFER, -1, 0);
+ return;
+ }
+ plpar_hcall_norets(H_CONFER,
+ get_hard_smp_processor_id(holder_cpu), yield_count);
+}
+EXPORT_SYMBOL_GPL(__spin_yield_cpu);
+
+void __spin_wake_cpu(int cpu)
+{
+ unsigned int holder_cpu = cpu, yield_count;
+
+ BUG_ON(holder_cpu >= nr_cpu_ids);
+ yield_count = be32_to_cpu(lppaca_of(holder_cpu).yield_count);
+ if ((yield_count & 1) == 0)
+ return; /* virtual cpu is currently running */
+ plpar_hcall_norets(H_PROD,
+ get_hard_smp_processor_id(holder_cpu));
+}
+EXPORT_SYMBOL_GPL(__spin_wake_cpu);
+
#ifndef CONFIG_QUEUED_SPINLOCKS
void __spin_yield(arch_spinlock_t *lock)
{
--
1.9.1
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