[PATCH 2/4] locking/osq_lock: Turn to dynamic switch function from osq_lock/unlock.

[yongli-oc]

To support numa-aware osq lock, the struct optimistic_spin_queue
is accessed as three members, numa_enable, index, tail16, by union.
The size of the struct is the same as before.
If dynamic numa-ware lock enable, turns to the crossing, x_osq_lock to
check contention level and starts dynamic switch.

Signed-off-by: yongli-oc <yongli-oc@xxxxxxxxxxx>
---
 include/linux/osq_lock.h  | 33 ++++++++++++++++++++-
 kernel/locking/osq_lock.c | 62 +++++++++++++++++++++++++++++++++++++--
 2 files changed, 91 insertions(+), 4 deletions(-)

diff --git a/include/linux/osq_lock.h b/include/linux/osq_lock.h
index ea8fb31379e3..37a7bc4ab530 100644
--- a/include/linux/osq_lock.h
+++ b/include/linux/osq_lock.h
@@ -12,14 +12,42 @@ struct optimistic_spin_queue {
 	 * Stores an encoded value of the CPU # of the tail node in the queue.
 	 * If the queue is empty, then it's set to OSQ_UNLOCKED_VAL.
 	 */
+#ifdef CONFIG_LOCK_SPIN_ON_OWNER_NUMA
+	union {
+		atomic_t tail;
+		u32 val;
+#ifdef __LITTLE_ENDIAN
+		struct {
+			u16 tail16;
+			u8 index;
+			u8 numa_enable;
+		};
+#else
+		struct {
+			u8 numa_enable;
+			u8 index;
+			u16 tail16;
+		};
+#endif
+	};
+#else
 	atomic_t tail;
+#endif
 };
 
 #define OSQ_UNLOCKED_VAL (0)
 
 /* Init macro and function. */
+#ifdef CONFIG_LOCK_SPIN_ON_OWNER_NUMA
+
+#define OSQ_LOCK_UNLOCKED { .tail = ATOMIC_INIT(OSQ_UNLOCKED_VAL) }
+
+#else
+
 #define OSQ_LOCK_UNLOCKED { ATOMIC_INIT(OSQ_UNLOCKED_VAL) }
 
+#endif
+
 static inline void osq_lock_init(struct optimistic_spin_queue *lock)
 {
 	atomic_set(&lock->tail, OSQ_UNLOCKED_VAL);
@@ -28,9 +56,12 @@ static inline void osq_lock_init(struct optimistic_spin_queue *lock)
 extern bool osq_lock(struct optimistic_spin_queue *lock);
 extern void osq_unlock(struct optimistic_spin_queue *lock);
 
+#ifdef CONFIG_LOCK_SPIN_ON_OWNER_NUMA
+extern bool osq_is_locked(struct optimistic_spin_queue *lock);
+#else
 static inline bool osq_is_locked(struct optimistic_spin_queue *lock)
 {
 	return atomic_read(&lock->tail) != OSQ_UNLOCKED_VAL;
 }
-
+#endif
 #endif
diff --git a/kernel/locking/osq_lock.c b/kernel/locking/osq_lock.c
index 75a6f6133866..a7b516939e00 100644
--- a/kernel/locking/osq_lock.c
+++ b/kernel/locking/osq_lock.c
@@ -2,7 +2,10 @@
 #include <linux/percpu.h>
 #include <linux/sched.h>
 #include <linux/osq_lock.h>
-
+#ifdef CONFIG_LOCK_SPIN_ON_OWNER_NUMA
+#include "numa.h"
+#include "numa_osq.h"
+#endif
 /*
  * An MCS like lock especially tailored for optimistic spinning for sleeping
  * lock implementations (mutex, rwsem, etc).
@@ -12,12 +15,34 @@
  * spinning.
  */
 
+#ifdef CONFIG_LOCK_SPIN_ON_OWNER_NUMA
+DEFINE_PER_CPU_SHARED_ALIGNED(struct optimistic_spin_node, osq_node);
+/*
+ * We use the value 0 to represent "no CPU", thus the encoded value
+ * will be the CPU number incremented by 1.
+ */
+inline int encode_cpu(int cpu_nr)
+{
+	return cpu_nr + 1;
+}
+
+inline int node_cpu(struct optimistic_spin_node *node)
+{
+	return node->cpu - 1;
+}
+
+inline struct optimistic_spin_node *decode_cpu(int encoded_cpu_val)
+{
+	int cpu_nr = encoded_cpu_val - 1;
+
+	return per_cpu_ptr(&osq_node, cpu_nr);
+}
+#else
 struct optimistic_spin_node {
 	struct optimistic_spin_node *next, *prev;
 	int locked; /* 1 if lock acquired */
 	int cpu; /* encoded CPU # + 1 value */
 };
-
 static DEFINE_PER_CPU_SHARED_ALIGNED(struct optimistic_spin_node, osq_node);
 
 /*
@@ -40,6 +65,7 @@ static inline struct optimistic_spin_node *decode_cpu(int encoded_cpu_val)
 
 	return per_cpu_ptr(&osq_node, cpu_nr);
 }
+#endif
 
 /*
  * Get a stable @node->next pointer, either for unlock() or unqueue() purposes.
@@ -97,6 +123,14 @@ bool osq_lock(struct optimistic_spin_queue *lock)
 	int curr = encode_cpu(smp_processor_id());
 	int old;
 
+#ifdef CONFIG_LOCK_SPIN_ON_OWNER_NUMA
+	if (unlikely(enable_zx_numa_osq_lock > 1)) {
+		node->numa = 1;
+		return x_osq_lock(lock);
+	}
+	node->numa = 0;
+#endif
+
 	node->locked = 0;
 	node->next = NULL;
 	node->cpu = curr;
@@ -108,6 +142,11 @@ bool osq_lock(struct optimistic_spin_queue *lock)
 	 * the lock tail.
 	 */
 	old = atomic_xchg(&lock->tail, curr);
+#ifdef CONFIG_LOCK_SPIN_ON_OWNER_NUMA
+	if (enable_zx_numa_osq_lock > 0)
+	//enable means all cpu cores are less tan 65534.
+		old = old & 0xffff;
+#endif
 	if (old == OSQ_UNLOCKED_VAL)
 		return true;
 
@@ -212,6 +251,14 @@ void osq_unlock(struct optimistic_spin_queue *lock)
 	struct optimistic_spin_node *node, *next;
 	int curr = encode_cpu(smp_processor_id());
 
+	node = this_cpu_ptr(&osq_node);
+
+#ifdef CONFIG_LOCK_SPIN_ON_OWNER_NUMA
+	if (unlikely(enable_zx_numa_osq_lock > 1 &&
+		node->numa == 1))
+		return x_osq_unlock(lock);
+#endif
+
 	/*
 	 * Fast path for the uncontended case.
 	 */
@@ -222,7 +269,6 @@ void osq_unlock(struct optimistic_spin_queue *lock)
 	/*
 	 * Second most likely case.
 	 */
-	node = this_cpu_ptr(&osq_node);
 	next = xchg(&node->next, NULL);
 	if (next) {
 		WRITE_ONCE(next->locked, 1);
@@ -233,3 +279,13 @@ void osq_unlock(struct optimistic_spin_queue *lock)
 	if (next)
 		WRITE_ONCE(next->locked, 1);
 }
+#ifdef CONFIG_LOCK_SPIN_ON_OWNER_NUMA
+bool osq_is_locked(struct optimistic_spin_queue *lock)
+{
+	if (unlikely(enable_zx_numa_osq_lock > 1))
+		return x_osq_is_locked(lock);
+	return atomic_read(&lock->tail) != OSQ_UNLOCKED_VAL;
+}
+#endif
+
+
-- 
2.34.1