[Xen-devel] [PATCH v9 15/19] pvqspinlock, x86: Add PV data structure & methods

[Waiman Long <Waiman.Long@xxxxxx>]

This patch modifies the para-virtualization (PV) infrastructure code
of the x86-64 architecture to support the PV queue spinlock. Three
new virtual methods are added to support PV qspinlock:

 1) kick_cpu - schedule in a virtual CPU
 2) halt_cpu - schedule out a virtual CPU
 3) lockstat - update statistical data for debugfs

Signed-off-by: Waiman Long <Waiman.Long@xxxxxx>
---
 arch/x86/include/asm/paravirt.h       |   18 +++++++++++++++++-
 arch/x86/include/asm/paravirt_types.h |   17 +++++++++++++++++
 arch/x86/kernel/paravirt-spinlocks.c  |    6 ++++++
 3 files changed, 40 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index cd6e161..d71e123 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -711,7 +711,23 @@ static inline void __set_fixmap(unsigned /* enum 
fixed_addresses */ idx,
 }
 
 #if defined(CONFIG_SMP) && defined(CONFIG_PARAVIRT_SPINLOCKS)
+#ifdef CONFIG_QUEUE_SPINLOCK
+static __always_inline void __queue_kick_cpu(int cpu)
+{
+       PVOP_VCALL1(pv_lock_ops.kick_cpu, cpu);
+}
+
+static __always_inline void
+__queue_halt_cpu(enum pv_lock_stats type, s8 *state, s8 sval)
+{
+       PVOP_VCALL3(pv_lock_ops.halt_cpu, type, state, sval);
+}
 
+static __always_inline void __queue_lockstat(enum pv_lock_stats type)
+{
+       PVOP_VCALL1(pv_lock_ops.lockstat, type);
+}
+#else
 static __always_inline void __ticket_lock_spinning(struct arch_spinlock *lock,
                                                        __ticket_t ticket)
 {
@@ -723,7 +739,7 @@ static __always_inline void __ticket_unlock_kick(struct 
arch_spinlock *lock,
 {
        PVOP_VCALL2(pv_lock_ops.unlock_kick, lock, ticket);
 }
-
+#endif
 #endif
 
 #ifdef CONFIG_X86_32
diff --git a/arch/x86/include/asm/paravirt_types.h 
b/arch/x86/include/asm/paravirt_types.h
index 7549b8b..549b3a0 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -333,9 +333,26 @@ struct arch_spinlock;
 typedef u16 __ticket_t;
 #endif
 
+#ifdef CONFIG_QUEUE_SPINLOCK
+enum pv_lock_stats {
+       PV_HALT_QHEAD,          /* Queue head halting       */
+       PV_HALT_QNODE,          /* Other queue node halting */
+       PV_HALT_ABORT,          /* Halting aborted          */
+       PV_WAKE_KICKED,         /* Wakeup by kicking        */
+       PV_WAKE_SPURIOUS,       /* Spurious wakeup          */
+       PV_KICK_NOHALT          /* Kick but CPU not halted  */
+};
+#endif
+
 struct pv_lock_ops {
+#ifdef CONFIG_QUEUE_SPINLOCK
+       void (*kick_cpu)(int cpu);
+       void (*halt_cpu)(enum pv_lock_stats type, s8 *state, s8 sval);
+       void (*lockstat)(enum pv_lock_stats type);
+#else
        struct paravirt_callee_save lock_spinning;
        void (*unlock_kick)(struct arch_spinlock *lock, __ticket_t ticket);
+#endif
 };
 
 /* This contains all the paravirt structures: we get a convenient
diff --git a/arch/x86/kernel/paravirt-spinlocks.c 
b/arch/x86/kernel/paravirt-spinlocks.c
index 6d36731..8d15bea 100644
--- a/arch/x86/kernel/paravirt-spinlocks.c
+++ b/arch/x86/kernel/paravirt-spinlocks.c
@@ -11,9 +11,15 @@
 #ifdef CONFIG_PARAVIRT_SPINLOCKS
 struct pv_lock_ops pv_lock_ops = {
 #ifdef CONFIG_SMP
+#ifdef CONFIG_QUEUE_SPINLOCK
+       .kick_cpu = paravirt_nop,
+       .halt_cpu = paravirt_nop,
+       .lockstat = paravirt_nop,
+#else
        .lock_spinning = __PV_IS_CALLEE_SAVE(paravirt_nop),
        .unlock_kick = paravirt_nop,
 #endif
+#endif
 };
 EXPORT_SYMBOL(pv_lock_ops);
 
-- 
1.7.1


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