void mill_choose_out(void *clause, chan ch, void *val, size_t sz, int idx) {
if(mill_slow(!ch))
mill_panic("null channel used");
if(mill_slow(ch->done))
mill_panic("send to done-with channel");
if(mill_slow(ch->sz != sz))
mill_panic("send of a type not matching the channel");
/* Find out whether the clause is immediately available. */
int available = !mill_list_empty(&ch->receiver.clauses) ||
ch->items < ch->bufsz ? 1 : 0;
if(available)
++mill_running->u_choose.available;
/* If there are available clauses don't bother with non-available ones. */
if(!available && mill_running->u_choose.available)
return;
/* Fill in the clause entry. */
struct mill_clause *cl = (struct mill_clause*) clause;
cl->cr = mill_running;
cl->ep = &ch->sender;
cl->val = val;
cl->available = available;
cl->idx = idx;
cl->used = 1;
mill_slist_push_back(&mill_running->u_choose.clauses, &cl->chitem);
if(cl->ep->seqnum == mill_choose_seqnum) {
++cl->ep->refs;
return;
}
cl->ep->seqnum = mill_choose_seqnum;
cl->ep->refs = 1;
cl->ep->tmp = -1;
}
void mill_freestack(void *stack) {
/* Put the stack to the list of cached stacks. */
struct mill_slist_item *item = ((struct mill_slist_item*)stack) - 1;
mill_slist_push_back(&mill_cached_stacks, item);
if(mill_num_cached_stacks < MILL_MAX_CACHED_STACKS) {
++mill_num_cached_stacks;
return;
}
/* We can't deallocate the stack we are running on at the moment.
Standard C free() is not required to work when it deallocates its
own stack from underneath itself. Instead, we'll deallocate one of
the unused cached stacks. */
item = mill_slist_pop(&mill_cached_stacks);
free(((char*)(item + 1)) - MILL_STACK_SIZE);
}
void mill_freestack(void *stack) {
/* Put the stack to the list of cached stacks. */
struct mill_slist_item *item = ((struct mill_slist_item*)stack) - 1;
mill_slist_push_back(&mill_cached_stacks, item);
if(mill_num_cached_stacks < mill_max_cached_stacks) {
++mill_num_cached_stacks;
return;
}
/* We can't deallocate the stack we are running on at the moment.
Standard C free() is not required to work when it deallocates its
own stack from underneath itself. Instead, we'll deallocate one of
the unused cached stacks. */
item = mill_slist_pop(&mill_cached_stacks);
void *ptr = ((char*)(item + 1)) - mill_get_stack_size();
#if HAVE_POSIX_MEMALIGN && HAVE_MPROTECT
int rc = mprotect(ptr, mill_page_size(), PROT_READ|PROT_WRITE);
mill_assert(rc == 0);
#endif
free(ptr);
}
void mill_preparestacks(int count, size_t stack_size) {
/* Purge the cached stacks. */
while(1) {
struct mill_slist_item *item = mill_slist_pop(&mill_cached_stacks);
if(!item)
break;
free(((char*)(item + 1)) - mill_get_stack_size());
}
/* Now that there are no stacks allocated, we can adjust the stack size. */
size_t old_stack_size = mill_stack_size;
size_t old_sanitised_stack_size = mill_sanitised_stack_size;
mill_stack_size = stack_size;
mill_sanitised_stack_size = 0;
/* Allocate the new stacks. */
int i;
for(i = 0; i != count; ++i) {
void *ptr = mill_allocstackmem();
if(!ptr) goto error;
struct mill_slist_item *item = ((struct mill_slist_item*)ptr) - 1;
mill_slist_push_back(&mill_cached_stacks, item);
}
mill_num_cached_stacks = count;
/* Make sure that the stacks won't get deallocated even if they aren't used
at the moment. */
mill_max_cached_stacks = count;
errno = 0;
return;
error:
/* If we can't allocate all the stacks, allocate none, restore state and
return error. */
while(1) {
struct mill_slist_item *item = mill_slist_pop(&mill_cached_stacks);
if(!item)
break;
free(((char*)(item + 1)) - mill_get_stack_size());
}
mill_num_cached_stacks = 0;
mill_stack_size = old_stack_size;
mill_sanitised_stack_size = old_sanitised_stack_size;
errno = ENOMEM;
}
