void jrb_free_tree(JRB n)
{
if (!ishead(n)) {
fprintf(stderr, "ERROR: Rb_free_tree called on a non-head node\n");
exit(1);
}
while(jrb_first(n) != jrb_nil(n)) {
jrb_delete_node(jrb_first(n));
}
free(n);
}
void
KtSched()
{
K_t kt;
JRB jb;
unsigned int sp;
unsigned int now;
JRB tmp;
Dllist dtmp;
/*
* start by recording the current stack contents in case
* I'm descheduled
*
* this is where I return to when I'm rescheduled
*/
if(setjmp(ktRunning->jmpbuf) != 0)
{
FreeFinishedThreads();
/*
* if we are being killed by another thread, jump through
* the exitbuf
*/
if(ktRunning->die_now)
{
/* Jim: This used to longjmp to the exitbuf,
but I changed it for two reasons:
1. It wasn't being removed from ktActive
2. Hell will be paid if it is ktOriginal.
I believe kt_exit() is cleaner. I
have not tested it. I should. */
kt_exit();
/* not reached */
}
return;
}
start:
if (!jrb_empty(ktSleeping)) {
now = time(0);
while(!jrb_empty(ktSleeping))
{
kt = (K_t) jval_v(jrb_val(jrb_first(ktSleeping)));
if(kt->wake_time > now)
{
break;
}
WakeKThread(kt);
}
}
/*
* if there is nothing left to run, exit. However, if there
* are sleepers or a joinall, deal with them appropriately
*/
if(dll_empty(ktRunnable))
{
/*
* first, check for sleepers and deal with them
*/
if(!jrb_empty(ktSleeping))
{
kt = jval_v(jrb_val(jrb_first(ktSleeping)));
sleep(kt->wake_time - now);
goto start;
}
/*
* next, see if there is a joinall thread waiting
*/
jb = jrb_find_int(ktBlocked,0);
if(jb != NULL)
{
WakeKThread((K_t)jval_v(jrb_val(jb)));
goto start;
}
if(!jrb_empty(ktBlocked))
{
if(Debug & KT_DEBUG)
{
fprintf(stderr,
"All processes blocked, exiting\n");
fflush(stderr);
}
exit(1);
} else {
if(Debug & KT_DEBUG)
{
fprintf(stderr,
"No runnable threads, exiting\n");
fflush(stderr);
}
exit(0);
}
fprintf(stderr, "We shouldn't get here\n");
exit(1);
}
/* Grab the first job of the ready queue */
dtmp = dll_first(ktRunnable);
kt = (K_t) dtmp->val.v;
dll_delete_node(dtmp);
/* If it is runnable, run it */
if(kt->state == RUNNABLE) {
ktRunning = kt;
ktRunning->state = RUNNING;
longjmp(ktRunning->jmpbuf,1);
/* This doesn't return */
}
/*
* if we have never run before, set up initial stack and go
*/
if(kt->state == STARTING) {
if(setjmp(kt->jmpbuf) == 0)
{
/*
* get double word aligned SP -- stacks grow from high
* to low
*/
sp = (unsigned int)&((kt->stack[kt->stack_size-1]));
while((sp % 8) != 0)
sp--;
#ifdef LINUX
/*
* keep double word aligned but put in enough
* space to handle local variables for KtSched
*/
kt->jmpbuf->__jmpbuf[JB_BP] = (int)sp;
kt->jmpbuf->__jmpbuf[JB_SP] = (int)sp-1024;
PTR_MANGLE(kt->jmpbuf->__jmpbuf[JB_SP]);
#endif
#ifdef SOLARIS
/*
* keep double word aligned but put in enough
* space to handle local variables for KtSched
*/
kt->jmpbuf[JB_FP] = (int)sp;
kt->jmpbuf[JB_SP] = (int)sp-1024;
#endif
/*
* set ktRunning while we still have local variables
*/
kt->state = RUNNING;
ktRunning = kt;
/*
* now jump onto the new stack
*/
longjmp(kt->jmpbuf,1);
}
else
{
/*
* here we are on a new, clean stack -- touch nothing,
* set the state, and call
*
* ktRunning is global so there is no local variable
* problem
*
* borrow this stack to try and free the last thread
* if there was one
*/
FreeFinishedThreads();
if(setjmp(ktRunning->exitbuf) == 0)
{
/*
* if we were killed before we ran, skip the
* function call
*/
if(ktRunning->die_now == 0)
{
ktRunning->func(ktRunning->arg);
}
}
/*
* we are back and this thread is done
*
* make it inactive
*/
jb = jrb_find_int(ktActive,ktRunning->tid);
if(jb == NULL)
{
if(Debug & KT_DEBUG)
{
fprintf(stderr,
"KtSched: panic -- inactive return\n");
fflush(stderr);
}
exit(1);
}
jrb_delete_node(jb);
/*
* look to see if there is a thread waiting for this
* one to exit -- careful with locals
*/
jb = jrb_find_int(ktBlocked,ktRunning->tid);
if(jb != NULL)
{
WakeKThread((K_t)jval_v(jrb_val(jb)));
}
/*
* all we can do now is to commit suicide
*
* don't touch the locals;
*
* and don't free the stack we are running on
*/
FreeFinishedThreads();
ktRunning->state = DEAD;
dll_append(ktFree_me,new_jval_v(ktRunning));
ktRunning = NULL;
goto start;
}
}
/* The only way we get here is if there was a thread on the
runnable queue whose state was not RUNNABLE or STARTING.
Flag that as an error */
fprintf(stderr,
"Error: non-STARTING or RUNNABLE thread on the ready queue\n");
exit(1);
}
