libc-top-half/musl/src/thread/vmlock.c

   1 #include "pthread_impl.h"
   2 #include "fork_impl.h"
   3
   4 static volatile int vmlock[2];
   5 volatile int *const __vmlock_lockptr = vmlock;
   6
   7 void __vm_wait()
   8 {
   9         int tmp;
  10         while ((tmp=vmlock[0]))
  11                 __wait(vmlock, vmlock+1, tmp, 1);
  12 }
  13
  14 void __vm_lock()
  15 {
  16         a_inc(vmlock);
  17 }
  18
  19 void __vm_unlock()
  20 {
  21         if (a_fetch_add(vmlock, -1)==1 && vmlock[1])
  22                 __wake(vmlock, -1, 1);
  23 }