i386/junos/ucla/src/lab4/user/spin.c

   1 // Test preemption by forking off a child process that just spins forever.
   2 // Let it run for a couple time slices, then kill it.
   3
   4 #include <inc/lib.h>
   5
   6 asmlinkage void
   7 umain(int argc, char **argv)
   8 {
   9         envid_t env;
  10
  11         cprintf("I am the parent.  Forking the child...\n");
  12         if ((env = fork()) == 0) {
  13                 cprintf("I am the child.  Spinning...\n");
  14                 while (1)
  15                         /* do nothing */;
  16         }
  17
  18         cprintf("I am the parent.  Running the child...\n");
  19         sys_yield();
  20         sys_yield();
  21         sys_yield();
  22         sys_yield();
  23         sys_yield();
  24         sys_yield();
  25         sys_yield();
  26         sys_yield();
  27
  28         cprintf("I am the parent.  Killing the child...\n");
  29         sys_env_destroy(env);
  30 }
  31