[PATCH v2 2/3] locking/osq_lock: Define osq by union to support dynamic numa-aware lock.

yongli-oc
2024-09-30T07:24:56Z

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.

Signed-off-by: yongli-oc <yongli-oc@zhaoxin.com>
---
include/linux/osq_lock.h | 33 ++++++++++++++++++++++++++++++++-
1 file changed, 32 insertions(+), 1 deletion(-)

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
--
2.34.1