int mill_suspend(void) {
/* Even if process never gets idle, we have to process external events
once in a while. The external signal may very well be a deadline or
a user-issued command that cancels the CPU intensive operation. */
static int counter = 0;
if(counter >= 103) {
mill_wait(0);
counter = 0;
}
/* Store the context of the current coroutine, if any. */
if(mill_running && sigsetjmp(mill_running->ctx, 0))
return mill_running->result;
while(1) {
/* If there's a coroutine ready to be executed go for it. */
if(!mill_slist_empty(&mill_ready)) {
++counter;
struct mill_slist_item *it = mill_slist_pop(&mill_ready);
mill_running = mill_cont(it, struct mill_cr, ready);
siglongjmp(mill_running->ctx, 1);
}
/* Otherwise, we are going to wait for sleeping coroutines
and for external events. */
mill_wait(1);
mill_assert(!mill_slist_empty(&mill_ready));
counter = 0;
}
void *mill_allocstack(void) {
if(!mill_slist_empty(&mill_cached_stacks)) {
--mill_num_cached_stacks;
return (void*)(mill_slist_pop(&mill_cached_stacks) + 1);
}
char *ptr = malloc(MILL_STACK_SIZE);
assert(ptr);
return ptr + MILL_STACK_SIZE;
}
void *mill_allocstack(void) {
if(!mill_slist_empty(&mill_cached_stacks)) {
--mill_num_cached_stacks;
return (void*)(mill_slist_pop(&mill_cached_stacks) + 1);
}
void *ptr = mill_allocstackmem();
if(!ptr)
mill_panic("not enough memory to allocate coroutine stack");
return ptr;
}
