// try_free_pages - calculate pressure to estimate the number(pressure<<5) of needed page frames in ucore currently,
// - then call kswapd kernel thread.
bool
try_free_pages(size_t n) {
struct proc_struct *current = pls_read(current);
if (!swap_init_ok || kswapd == NULL) {
return 0;
}
if (current == kswapd) {
panic("kswapd call try_free_pages!!.\n");
}
if (n >= (1 << 7)) {
return 0;
}
pressure += n;
wait_t __wait, *wait = &__wait;
bool intr_flag;
local_intr_save(intr_flag);
{
wait_init(wait, current);
current->state = PROC_SLEEPING;
current->wait_state = WT_KSWAPD;
wait_queue_add(&kswapd_done, wait);
if (kswapd->wait_state == WT_TIMER) {
wakeup_proc(kswapd);
}
}
local_intr_restore(intr_flag);
schedule();
assert(!wait_in_queue(wait) && wait->wakeup_flags == WT_KSWAPD);
return 1;
}
void
wait_current_set(wait_queue_t *queue, wait_t *wait, uint32_t wait_state) {
assert(current != NULL);
wait_init(wait, current);
current->state = PROC_SLEEPING;
current->wait_state = wait_state;
wait_queue_add(queue, wait);
}
//TODO: Should be moved to a pipe_state function.
static int pipe_inode_poll(struct inode *node, wait_t *wait, int io_requests)
{
struct pipe_inode *pipe_inode = vop_info(node, pipe_inode);
struct pipe_state *state= pipe_inode->state;
if(pipe_inode->pin_type == PIN_WRONLY) {
if(io_requests | POLL_WRITE_AVAILABLE) {
//TODO: This is ugly, should be using pipe_state macros.
if (state->p_wpos - state->p_rpos >= PGSIZE - sizeof(struct pipe_state)) {
if (state->isclosed) {
return 0;
} else {
//unlock_state(state);
if(wait != NULL) wait_queue_add(&state->writer_queue, wait);
return 0;
}
}
else {
return POLL_WRITE_AVAILABLE;
}
}
else {
return 0;
}
}
else {
if(io_requests | POLL_READ_AVAILABLE) {
//lock_state(state);
if (state->p_rpos == state->p_wpos) {
if (state->isclosed) {
return 0;
} else {
//unlock_state(state);
if(wait != NULL) wait_queue_add(&state->reader_queue, wait);
return 0;
}
}
else {
return POLL_READ_AVAILABLE;
}
}
else {
return 0;
}
}
}
void
sleep_on(struct wait_queue *queue,
struct task_struct *task)
{
assert(queue && task);
//assert(task->pid != 0);
if (!task->pid)
return;
wait_queue_add(queue,task);
task->task_status = TASK_UNINTERRUPTIBLE;
schedule_delete_task(task);
schedule();
}
