linux-2.6.16.RT.x下semaphore结构

linux-2.6.16.RT.x
如果定义了CONFIG_PREEMPT_RT，那么
struct semaphore {
    atomic_t count;
    struct rt_mutex lock;
};
struct compat_semaphore {
    atomic_t count;
    int sleepers;
    wait_queue_head_t wait;
};
如果没有定义CONFIG_PREEMPT_RT，那么
# define semaphore compat_semaphore
struct compat_semaphore {
    atomic_t count;
    int sleepers;
    wait_queue_head_t wait;
};


linux-2.6.29.RT.x
如果定义了CONFIG_PREEMPT_RT，那么
struct semaphore {
    atomic_t        count;
    struct rt_mutex        lock;
};
#define DECLARE_MUTEX(name) \
struct semaphore name = \
    { .count = { 1 }, .lock = __RT_MUTEX_INITIALIZER(name.lock) }
#define DECLARE_MUTEX_LOCKED(name) \
struct semaphore name = \
    { .count = { 0 }, .lock = __RT_MUTEX_INITIALIZER(name.lock) }

struct compat_semaphore {
    spinlock_t        lock;
    unsigned int        count;
    struct list_head    wait_list;
};
如果没有定义CONFIG_PREEMPT_RT，那么:
没有对semaphore的相关定义
#define compat_semaphore semaphore
因而也没有对compat_semaphore的相关定义