/*
* stride_pick_next pick the element from the ``run-queue'', with the
* minimum value of stride, and returns the corresponding process
* pointer. The process pointer would be calculated by macro le2proc,
* see kern/process/proc.h for definition. Return NULL if
* there is no process in the queue.
*
* When one proc structure is selected, remember to update the stride
* property of the proc. (stride += BIG_STRIDE / priority)
*
* hint: see libs/skew_heap.h for routines of the priority
* queue structures.
*/
static struct proc_struct *
stride_pick_next(struct run_queue *rq) {
/* LAB6: 2013011377
* (1) get a proc_struct pointer p with the minimum value of stride
(1.1) If using skew_heap, we can use le2proc get the p from rq->lab6_run_poll
(1.2) If using list, we have to search list to find the p with minimum stride value
* (2) update p;s stride value: p->lab6_stride
* (3) return p
*/
struct proc_struct *p = NULL;
#if USE_SKEW_HEAP
if(!rq->lab6_run_pool) return NULL;
p = le2proc(rq->lab6_run_pool, lab6_run_pool);
#else
list_entry_t *le = list_next(&rq->run_list);
while ((le = list_next(le)) != &rq->run_list) {
struct proc_struct *cnt = le2proc(le, run_link);
if (!p || proc_stride_comp_f(&p->lab6_run_pool, &cur->lab6_run_pool))
p = cur;
}
#endif
if (p)
p->lab6_stride += BIG_STRIDE / (p->lab6_priority == 0? 1: p->lab6_priority);
return p;
}
/*
* stride_pick_next pick the element from the ``run-queue'', with the
* minimum value of stride, and returns the corresponding process
* pointer. The process pointer would be calculated by macro le2proc,
* see kern/process/proc.h for definition. Return NULL if
* there is no process in the queue.
*
* When one proc structure is selected, remember to update the stride
* property of the proc. (stride += BIG_STRIDE / priority)
*
* hint: see libs/skew_heap.h for routines of the priority
* queue structures.
*/
static struct proc_struct *
stride_pick_next(struct run_queue *rq) {
/* LAB6: 2012012017
* (1) get a proc_struct pointer p with the minimum value of stride
(1.1) If using skew_heap, we can use le2proc get the p from rq->lab6_run_poll
(1.2) If using list, we have to search list to find the p with minimum stride value
* (2) update p;s stride value: p->lab6_stride
* (3) return p
*/
#if USE_SKEW_HEAP
if (!rq->lab6_run_pool) return NULL;
struct proc_struct *p = le2proc(rq->lab6_run_pool, lab6_run_pool);
#else
list_entry_t *le;
struct proc_struct *p = 0;
for (le = list_next(&rq->run_list); le != &rq->run_list; le = list_next(le)) {
struct proc_struct *q = le2proc(le, run_link);
if (!p || proc_stride_comp_f(&p->lab6_run_pool, &q->lab6_run_pool) == 1) p = q;
}
#endif
if (p) p->lab6_stride += BIG_STRIDE / p->lab6_priority;
return p;
}
