背景

在Linux Arm kernel实现原子读写64位数据；

接口代码

#include <linux/atomic.h>
atomic64_t my_atomic_var = ATOMIC64_INIT(0);void atomic_write_64(atomic64_t *v, int64_t new_value) {atomic64_set(v, new_value);
}int64_t atomic_read_64(atomic64_t *v) {return atomic64_read(v);
}

使用自旋锁

#include <linux/spinlock.h>spinlock_t my_lock = SPIN_LOCK_UNLOCKED;
uint64_t my_shared_var = 0;void write_64(uint64_t new_value) {spin_lock(&my_lock);my_shared_var = new_value;spin_unlock(&my_lock);
}uint64_t read_64(void) {uint64_t value;spin_lock(&my_lock);value = my_shared_var;spin_unlock(&my_lock);return value;
}

使用读写锁

#include <linux/rwlock.h>rwlock_t my_rwlock = RW_LOCK_UNLOCKED;
uint64_t my_shared_var = 0;void write_64(uint64_t new_value) {write_lock(&my_rwlock);my_shared_var = new_value;write_unlock(&my_rwlock);
}uint64_t read_64(void) {uint64_t value;read_lock(&my_rwlock);value = my_shared_var;read_unlock(&my_rwlock);return value;
}