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- #include <defs.h>
- #include <list.h>
- #include <proc.h>
- #include <assert.h>
- #include <default_sched.h>
-
- #define USE_SKEW_HEAP 1
-
- /* You should define the BigStride constant here*/
- /* LAB6: YOUR CODE */
- #define BIG_STRIDE 0x7FFFFFFF /* ??? */
-
- /* The compare function for two skew_heap_node_t's and the
- * corresponding procs*/
- static int
- proc_stride_comp_f(void *a, void *b)
- {
- struct proc_struct *p = le2proc(a, lab6_run_pool);
- struct proc_struct *q = le2proc(b, lab6_run_pool);
- int32_t c = p->lab6_stride - q->lab6_stride;
- if (c > 0) return 1;
- else if (c == 0) return 0;
- else return -1;
- }
-
- /*
- * stride_init initializes the run-queue rq with correct assignment for
- * member variables, including:
- *
- * - run_list: should be a empty list after initialization.
- * - lab6_run_pool: NULL
- * - proc_num: 0
- * - max_time_slice: no need here, the variable would be assigned by the caller.
- *
- * hint: see proj13.1/libs/list.h for routines of the list structures.
- */
- static void
- stride_init(struct run_queue *rq) {
- /* LAB6: YOUR CODE */
- list_init(&(rq->run_list));
- rq->lab6_run_pool = NULL;
- rq->proc_num = 0;
- }
-
- /*
- * stride_enqueue inserts the process ``proc'' into the run-queue
- * ``rq''. The procedure should verify/initialize the relevant members
- * of ``proc'', and then put the ``lab6_run_pool'' node into the
- * queue(since we use priority queue here). The procedure should also
- * update the meta date in ``rq'' structure.
- *
- * proc->time_slice denotes the time slices allocation for the
- * process, which should set to rq->max_time_slice.
- *
- * hint: see proj13.1/libs/skew_heap.h for routines of the priority
- * queue structures.
- */
- static void
- stride_enqueue(struct run_queue *rq, struct proc_struct *proc) {
- /* LAB6: YOUR CODE */
- #if USE_SKEW_HEAP
- rq->lab6_run_pool =
- skew_heap_insert(rq->lab6_run_pool, &(proc->lab6_run_pool), proc_stride_comp_f);
- #else
- assert(list_empty(&(proc->run_link)));
- list_add_before(&(rq->run_list), &(proc->run_link));
- #endif
- if (proc->time_slice == 0 || proc->time_slice > rq->max_time_slice) {
- proc->time_slice = rq->max_time_slice;
- }
- proc->rq = rq;
- rq->proc_num ++;
- }
-
- /*
- * stride_dequeue removes the process ``proc'' from the run-queue
- * ``rq'', the operation would be finished by the skew_heap_remove
- * operations. Remember to update the ``rq'' structure.
- *
- * hint: see proj13.1/libs/skew_heap.h for routines of the priority
- * queue structures.
- */
- static void
- stride_dequeue(struct run_queue *rq, struct proc_struct *proc) {
- /* LAB6: YOUR CODE */
- #if USE_SKEW_HEAP
- rq->lab6_run_pool =
- skew_heap_remove(rq->lab6_run_pool, &(proc->lab6_run_pool), proc_stride_comp_f);
- #else
- assert(!list_empty(&(proc->run_link)) && proc->rq == rq);
- list_del_init(&(proc->run_link));
- #endif
- rq->proc_num --;
- }
- /*
- * 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 proj13.1/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 proj13.1/libs/skew_heap.h for routines of the priority
- * queue structures.
- */
- static struct proc_struct *
- stride_pick_next(struct run_queue *rq) {
- /* LAB6: YOUR CODE */
- #if USE_SKEW_HEAP
- if (rq->lab6_run_pool == NULL) return NULL;
- struct proc_struct *p = le2proc(rq->lab6_run_pool, lab6_run_pool);
- #else
- list_entry_t *le = list_next(&(rq->run_list));
-
- if (le == &rq->run_list)
- return NULL;
-
- struct proc_struct *p = le2proc(le, run_link);
- le = list_next(le);
- while (le != &rq->run_list)
- {
- struct proc_struct *q = le2proc(le, run_link);
- if ((int32_t)(p->lab6_stride - q->lab6_stride) > 0)
- p = q;
- le = list_next(le);
- }
- #endif
- if (p->lab6_priority == 0)
- p->lab6_stride += BIG_STRIDE;
- else p->lab6_stride += BIG_STRIDE / p->lab6_priority;
- return p;
- }
-
- /*
- * stride_proc_tick works with the tick event of current process. You
- * should check whether the time slices for current process is
- * exhausted and update the proc struct ``proc''. proc->time_slice
- * denotes the time slices left for current
- * process. proc->need_resched is the flag variable for process
- * switching.
- */
- static void
- stride_proc_tick(struct run_queue *rq, struct proc_struct *proc) {
- /* LAB6: YOUR CODE */
- if (proc->time_slice > 0) {
- proc->time_slice --;
- }
- if (proc->time_slice == 0) {
- proc->need_resched = 1;
- }
- }
-
- struct sched_class default_sched_class = {
- .name = "stride_scheduler",
- .init = stride_init,
- .enqueue = stride_enqueue,
- .dequeue = stride_dequeue,
- .pick_next = stride_pick_next,
- .proc_tick = stride_proc_tick,
- };
-
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