在哪里可以找到函数 __swtch_pri 的实现代码?
void
__spin_lock_solid (spin_lock_t *lock)
{
while (__spin_lock_locked (lock) || ! __spin_try_lock (lock))
/* Yield to another thread (system call). */
__swtch_pri (0);
}
只能在 glibc 中找到声明,见下文。
/* Attempt to context switch the current thread off the processor. Lower
the thread's priority as much as possible. The thread's priority will
be restored when it runs again. PRIORITY is currently unused. Return
true if there are other threads that can be run and false if not. */
extern boolean_t swtch_pri (int priority);
extern boolean_t __swtch_pri (int priority);