static const int cfq_slice_async_rq = 2;
static int cfq_slice_idle = HZ / 125;
+/*
+ * grace period before allowing idle class to get disk access
+ */
#define CFQ_IDLE_GRACE (HZ / 10)
+
+/*
+ * below this threshold, we consider thinktime immediate
+ */
+#define CFQ_MIN_TT (2)
+
#define CFQ_SLICE_SCALE (5)
#define CFQ_KEY_ASYNC (0)
#define ASYNC (0)
#define SYNC (1)
-#define cfq_cfqq_dispatched(cfqq) \
- ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC])
-
-#define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC)
-
-#define cfq_cfqq_sync(cfqq) \
- (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC])
+#define cfq_cfqq_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC)
#define sample_valid(samples) ((samples) > 80)
+/*
+ * Most of our rbtree usage is for sorting with min extraction, so
+ * if we cache the leftmost node we don't have to walk down the tree
+ * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should
+ * move this into the elevator for the rq sorting as well.
+ */
+struct cfq_rb_root {
+ struct rb_root rb;
+ struct rb_node *left;
+};
+#define CFQ_RB_ROOT (struct cfq_rb_root) { RB_ROOT, NULL, }
+
/*
* Per block device queue structure
*/
/*
* rr list of queues with requests and the count of them
*/
- struct list_head rr_list[CFQ_PRIO_LISTS];
- struct list_head busy_rr;
+ struct cfq_rb_root service_tree;
struct list_head cur_rr;
- struct list_head idle_rr;
unsigned int busy_queues;
/*
struct cfq_queue *active_queue;
struct cfq_io_context *active_cic;
- int cur_prio, cur_end_prio;
unsigned int dispatch_slice;
struct timer_list idle_class_timer;
- sector_t last_sector;
+ sector_t last_position;
unsigned long last_end_request;
/*
unsigned int cfq_slice_idle;
struct list_head cic_list;
+
+ sector_t new_seek_mean;
+ u64 new_seek_total;
};
/*
unsigned int key;
/* member of the rr/busy/cur/idle cfqd list */
struct list_head cfq_list;
+ /* service_tree member */
+ struct rb_node rb_node;
+ /* service_tree key */
+ unsigned long rb_key;
/* sorted list of pending requests */
struct rb_root sort_list;
/* if fifo isn't expired, next request to serve */
struct list_head fifo;
unsigned long slice_end;
- unsigned long service_last;
long slice_resid;
- /* number of requests that are on the dispatch list */
- int on_dispatch[2];
+ /* number of requests that are on the dispatch list or inside driver */
+ int dispatched;
/* io prio of this group */
unsigned short ioprio, org_ioprio;
/* various state flags, see below */
unsigned int flags;
+
+ sector_t last_request_pos;
};
enum cfqq_state_flags {
static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short);
static void cfq_dispatch_insert(request_queue_t *, struct request *);
-static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask);
+static struct cfq_queue *cfq_get_queue(struct cfq_data *, unsigned int, struct task_struct *, gfp_t);
/*
* scheduler run of queue, if there are requests pending and no one in the
* if a queue is marked sync and has sync io queued. A sync queue with async
* io only, should not get full sync slice length.
*/
-static inline int
-cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static inline int cfq_prio_slice(struct cfq_data *cfqd, int sync,
+ unsigned short prio)
{
- const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)];
+ const int base_slice = cfqd->cfq_slice[sync];
- WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
+ WARN_ON(prio >= IOPRIO_BE_NR);
- return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio));
+ return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio));
+}
+
+static inline int
+cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+ return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio);
}
static inline void
cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
- cfqq->slice_end += cfqq->slice_resid;
-
- /*
- * Don't carry over residual for more than one slice, we only want
- * to slightly correct the fairness. Carrying over forever would
- * easily introduce oscillations.
- */
- cfqq->slice_resid = 0;
}
/*
s1 = rq1->sector;
s2 = rq2->sector;
- last = cfqd->last_sector;
+ last = cfqd->last_position;
/*
* by definition, 1KiB is 2 sectors
}
}
+/*
+ * The below is leftmost cache rbtree addon
+ */
+static struct rb_node *cfq_rb_first(struct cfq_rb_root *root)
+{
+ if (!root->left)
+ root->left = rb_first(&root->rb);
+
+ return root->left;
+}
+
+static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
+{
+ if (root->left == n)
+ root->left = NULL;
+
+ rb_erase(n, &root->rb);
+ RB_CLEAR_NODE(n);
+}
+
/*
* would be nice to take fifo expire time into account as well
*/
return cfq_choose_req(cfqd, next, prev);
}
-static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
+static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
+ struct cfq_queue *cfqq)
{
- struct cfq_data *cfqd = cfqq->cfqd;
- struct list_head *list, *n;
- struct cfq_queue *__cfqq;
-
/*
- * Resorting requires the cfqq to be on the RR list already.
+ * just an approximation, should be ok.
*/
- if (!cfq_cfqq_on_rr(cfqq))
- return;
+ return (cfqd->busy_queues - 1) * (cfq_prio_slice(cfqd, 1, 0) -
+ cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio));
+}
- list_del(&cfqq->cfq_list);
+/*
+ * The cfqd->service_tree holds all pending cfq_queue's that have
+ * requests waiting to be processed. It is sorted in the order that
+ * we will service the queues.
+ */
+static void cfq_service_tree_add(struct cfq_data *cfqd,
+ struct cfq_queue *cfqq)
+{
+ struct rb_node **p = &cfqd->service_tree.rb.rb_node;
+ struct rb_node *parent = NULL;
+ unsigned long rb_key;
+ int left;
- if (cfq_class_rt(cfqq))
- list = &cfqd->cur_rr;
- else if (cfq_class_idle(cfqq))
- list = &cfqd->idle_rr;
- else {
+ rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies;
+ rb_key += cfqq->slice_resid;
+ cfqq->slice_resid = 0;
+
+ if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
/*
- * if cfqq has requests in flight, don't allow it to be
- * found in cfq_set_active_queue before it has finished them.
- * this is done to increase fairness between a process that
- * has lots of io pending vs one that only generates one
- * sporadically or synchronously
+ * same position, nothing more to do
*/
- if (cfq_cfqq_dispatched(cfqq))
- list = &cfqd->busy_rr;
- else
- list = &cfqd->rr_list[cfqq->ioprio];
+ if (rb_key == cfqq->rb_key)
+ return;
+
+ cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
}
- if (preempted || cfq_cfqq_queue_new(cfqq)) {
- /*
- * If this queue was preempted or is new (never been serviced),
- * let it be added first for fairness but beind other new
- * queues.
- */
- n = list;
- while (n->next != list) {
- __cfqq = list_entry_cfqq(n->next);
- if (!cfq_cfqq_queue_new(__cfqq))
- break;
+ left = 1;
+ while (*p) {
+ struct cfq_queue *__cfqq;
+ struct rb_node **n;
+
+ parent = *p;
+ __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
- n = n->next;
- }
- list_add_tail(&cfqq->cfq_list, n);
- } else if (!cfq_cfqq_class_sync(cfqq)) {
- /*
- * async queue always goes to the end. this wont be overly
- * unfair to writes, as the sort of the sync queue wont be
- * allowed to pass the async queue again.
- */
- list_add_tail(&cfqq->cfq_list, list);
- } else {
/*
- * sort by last service, but don't cross a new or async
- * queue. we don't cross a new queue because it hasn't been
- * service before, and we don't cross an async queue because
- * it gets added to the end on expire.
+ * sort RT queues first, we always want to give
+ * preference to them. IDLE queues goes to the back.
+ * after that, sort on the next service time.
*/
- n = list;
- while ((n = n->prev) != list) {
- struct cfq_queue *__cfqq = list_entry_cfqq(n);
+ if (cfq_class_rt(cfqq) > cfq_class_rt(__cfqq))
+ n = &(*p)->rb_left;
+ else if (cfq_class_rt(cfqq) < cfq_class_rt(__cfqq))
+ n = &(*p)->rb_right;
+ else if (cfq_class_idle(cfqq) < cfq_class_idle(__cfqq))
+ n = &(*p)->rb_left;
+ else if (cfq_class_idle(cfqq) > cfq_class_idle(__cfqq))
+ n = &(*p)->rb_right;
+ else if (rb_key < __cfqq->rb_key)
+ n = &(*p)->rb_left;
+ else
+ n = &(*p)->rb_right;
- if (!cfq_cfqq_class_sync(cfqq) || !__cfqq->service_last)
- break;
- if (time_before(__cfqq->service_last, cfqq->service_last))
- break;
- }
- list_add(&cfqq->cfq_list, n);
+ if (n == &(*p)->rb_right)
+ left = 0;
+
+ p = n;
}
+
+ if (left)
+ cfqd->service_tree.left = &cfqq->rb_node;
+
+ cfqq->rb_key = rb_key;
+ rb_link_node(&cfqq->rb_node, parent, p);
+ rb_insert_color(&cfqq->rb_node, &cfqd->service_tree.rb);
+}
+
+/*
+ * Update cfqq's position in the service tree.
+ */
+static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
+{
+ /*
+ * Resorting requires the cfqq to be on the RR list already.
+ */
+ if (cfq_cfqq_on_rr(cfqq))
+ cfq_service_tree_add(cfqq->cfqd, cfqq);
}
/*
cfq_resort_rr_list(cfqq, 0);
}
+/*
+ * Called when the cfqq no longer has requests pending, remove it from
+ * the service tree.
+ */
static inline void
cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
cfq_clear_cfqq_on_rr(cfqq);
list_del_init(&cfqq->cfq_list);
+ if (!RB_EMPTY_NODE(&cfqq->rb_node))
+ cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
+
BUG_ON(!cfqd->busy_queues);
cfqd->busy_queues--;
}
*/
if (!cfqd->hw_tag && cfqd->rq_in_driver > 4)
cfqd->hw_tag = 1;
+
+ cfqd->last_position = rq->hard_sector + rq->hard_nr_sectors;
}
static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
}
}
-static int
-cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
+static int cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct request *__rq;
cfq_clear_cfqq_must_alloc_slice(cfqq);
cfq_clear_cfqq_fifo_expire(cfqq);
cfq_mark_cfqq_slice_new(cfqq);
+ cfq_clear_cfqq_queue_new(cfqq);
}
cfqd->active_queue = cfqq;
cfq_clear_cfqq_must_dispatch(cfqq);
cfq_clear_cfqq_wait_request(cfqq);
- cfq_clear_cfqq_queue_new(cfqq);
/*
* store what was left of this slice, if the queue idled out
}
/*
- * 0
- * 0,1
- * 0,1,2
- * 0,1,2,3
- * 0,1,2,3,4
- * 0,1,2,3,4,5
- * 0,1,2,3,4,5,6
- * 0,1,2,3,4,5,6,7
+ * Get next queue for service. Unless we have a queue preemption,
+ * we'll simply select the first cfqq in the service tree.
*/
-static int cfq_get_next_prio_level(struct cfq_data *cfqd)
+static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
{
- int prio, wrap;
+ struct cfq_queue *cfqq = NULL;
- prio = -1;
- wrap = 0;
- do {
- int p;
+ if (!list_empty(&cfqd->cur_rr)) {
+ /*
+ * if current list is non-empty, grab first entry.
+ */
+ cfqq = list_entry_cfqq(cfqd->cur_rr.next);
+ } else if (!RB_EMPTY_ROOT(&cfqd->service_tree.rb)) {
+ struct rb_node *n = cfq_rb_first(&cfqd->service_tree);
- for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) {
- if (!list_empty(&cfqd->rr_list[p])) {
- prio = p;
- break;
- }
- }
+ cfqq = rb_entry(n, struct cfq_queue, rb_node);
+ if (cfq_class_idle(cfqq)) {
+ unsigned long end;
- if (prio != -1)
- break;
- cfqd->cur_prio = 0;
- if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) {
- cfqd->cur_end_prio = 0;
- if (wrap)
- break;
- wrap = 1;
+ /*
+ * if we have idle queues and no rt or be queues had
+ * pending requests, either allow immediate service if
+ * the grace period has passed or arm the idle grace
+ * timer
+ */
+ end = cfqd->last_end_request + CFQ_IDLE_GRACE;
+ if (time_before(jiffies, end)) {
+ mod_timer(&cfqd->idle_class_timer, end);
+ cfqq = NULL;
+ }
}
- } while (1);
-
- if (unlikely(prio == -1))
- return -1;
+ }
- BUG_ON(prio >= CFQ_PRIO_LISTS);
+ return cfqq;
+}
- list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr);
+/*
+ * Get and set a new active queue for service.
+ */
+static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
+{
+ struct cfq_queue *cfqq;
- cfqd->cur_prio = prio + 1;
- if (cfqd->cur_prio > cfqd->cur_end_prio) {
- cfqd->cur_end_prio = cfqd->cur_prio;
- cfqd->cur_prio = 0;
- }
- if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) {
- cfqd->cur_prio = 0;
- cfqd->cur_end_prio = 0;
- }
+ cfqq = cfq_get_next_queue(cfqd);
+ __cfq_set_active_queue(cfqd, cfqq);
+ return cfqq;
+}
- return prio;
+static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd,
+ struct request *rq)
+{
+ if (rq->sector >= cfqd->last_position)
+ return rq->sector - cfqd->last_position;
+ else
+ return cfqd->last_position - rq->sector;
}
-static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
+static inline int cfq_rq_close(struct cfq_data *cfqd, struct request *rq)
{
- struct cfq_queue *cfqq = NULL;
+ struct cfq_io_context *cic = cfqd->active_cic;
- if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) {
- /*
- * if current list is non-empty, grab first entry. if it is
- * empty, get next prio level and grab first entry then if any
- * are spliced
- */
- cfqq = list_entry_cfqq(cfqd->cur_rr.next);
- } else if (!list_empty(&cfqd->busy_rr)) {
- /*
- * If no new queues are available, check if the busy list has
- * some before falling back to idle io.
- */
- cfqq = list_entry_cfqq(cfqd->busy_rr.next);
- } else if (!list_empty(&cfqd->idle_rr)) {
- /*
- * if we have idle queues and no rt or be queues had pending
- * requests, either allow immediate service if the grace period
- * has passed or arm the idle grace timer
- */
- unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE;
+ if (!sample_valid(cic->seek_samples))
+ return 0;
- if (time_after_eq(jiffies, end))
- cfqq = list_entry_cfqq(cfqd->idle_rr.next);
- else
- mod_timer(&cfqd->idle_class_timer, end);
- }
+ return cfq_dist_from_last(cfqd, rq) <= cic->seek_mean;
+}
- __cfq_set_active_queue(cfqd, cfqq);
- return cfqq;
+static int cfq_close_cooperator(struct cfq_data *cfq_data,
+ struct cfq_queue *cfqq)
+{
+ /*
+ * We should notice if some of the queues are cooperating, eg
+ * working closely on the same area of the disk. In that case,
+ * we can group them together and don't waste time idling.
+ */
+ return 0;
}
-#define CIC_SEEKY(cic) ((cic)->seek_mean > (128 * 1024))
+#define CIC_SEEKY(cic) ((cic)->seek_mean > (8 * 1024))
-static int cfq_arm_slice_timer(struct cfq_data *cfqd)
+static void cfq_arm_slice_timer(struct cfq_data *cfqd)
{
struct cfq_queue *cfqq = cfqd->active_queue;
struct cfq_io_context *cic;
unsigned long sl;
WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
+ WARN_ON(cfq_cfqq_slice_new(cfqq));
/*
* idle is disabled, either manually or by past process history
*/
- if (!cfqd->cfq_slice_idle)
- return 0;
- if (!cfq_cfqq_idle_window(cfqq))
- return 0;
+ if (!cfqd->cfq_slice_idle || !cfq_cfqq_idle_window(cfqq))
+ return;
+
/*
* task has exited, don't wait
*/
cic = cfqd->active_cic;
if (!cic || !cic->ioc->task)
- return 0;
+ return;
+
+ /*
+ * See if this prio level has a good candidate
+ */
+ if (cfq_close_cooperator(cfqd, cfqq) &&
+ (sample_valid(cic->ttime_samples) && cic->ttime_mean > 2))
+ return;
cfq_mark_cfqq_must_dispatch(cfqq);
cfq_mark_cfqq_wait_request(cfqq);
- sl = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle);
-
/*
* we don't want to idle for seeks, but we do want to allow
* fair distribution of slice time for a process doing back-to-back
* seeks. so allow a little bit of time for him to submit a new rq
*/
+ sl = cfqd->cfq_slice_idle;
if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
- sl = min(sl, msecs_to_jiffies(2));
+ sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT));
mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
- return 1;
}
+/*
+ * Move request from internal lists to the request queue dispatch list.
+ */
static void cfq_dispatch_insert(request_queue_t *q, struct request *rq)
{
struct cfq_queue *cfqq = RQ_CFQQ(rq);
cfq_remove_request(rq);
- cfqq->on_dispatch[rq_is_sync(rq)]++;
+ cfqq->dispatched++;
elv_dispatch_sort(q, rq);
}
if (list_empty(&cfqq->fifo))
return NULL;
- fifo = cfq_cfqq_class_sync(cfqq);
+ fifo = cfq_cfqq_sync(cfqq);
rq = rq_entry_fifo(cfqq->fifo.next);
- if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo]))
- return rq;
+ if (time_before(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo]))
+ return NULL;
- return NULL;
+ return rq;
}
static inline int
}
/*
- * get next queue for service
+ * Select a queue for service. If we have a current active queue,
+ * check whether to continue servicing it, or retrieve and set a new one.
*/
static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
{
goto new_queue;
/*
- * slice has expired
+ * The active queue has run out of time, expire it and select new.
*/
- if (!cfq_cfqq_must_dispatch(cfqq) && cfq_slice_used(cfqq))
+ if (cfq_slice_used(cfqq))
goto expire;
/*
- * if queue has requests, dispatch one. if not, check if
- * enough slice is left to wait for one
+ * The active queue has requests and isn't expired, allow it to
+ * dispatch.
*/
if (!RB_EMPTY_ROOT(&cfqq->sort_list))
goto keep_queue;
- else if (cfq_cfqq_slice_new(cfqq) || cfq_cfqq_dispatched(cfqq)) {
+
+ /*
+ * No requests pending. If the active queue still has requests in
+ * flight or is idling for a new request, allow either of these
+ * conditions to happen (or time out) before selecting a new queue.
+ */
+ if (cfqq->dispatched || timer_pending(&cfqd->idle_slice_timer)) {
cfqq = NULL;
goto keep_queue;
- } else if (cfq_cfqq_class_sync(cfqq)) {
- if (cfq_arm_slice_timer(cfqd))
- return NULL;
}
expire:
return cfqq;
}
+/*
+ * Dispatch some requests from cfqq, moving them to the request queue
+ * dispatch list.
+ */
static int
__cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
int max_dispatch)
return dispatched;
}
-static int
-cfq_forced_dispatch_cfqqs(struct list_head *list)
+static inline int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq)
+{
+ int dispatched = 0;
+
+ while (cfqq->next_rq) {
+ cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq);
+ dispatched++;
+ }
+
+ BUG_ON(!list_empty(&cfqq->fifo));
+ return dispatched;
+}
+
+static int cfq_forced_dispatch_cfqqs(struct list_head *list)
{
struct cfq_queue *cfqq, *next;
int dispatched;
dispatched = 0;
- list_for_each_entry_safe(cfqq, next, list, cfq_list) {
- while (cfqq->next_rq) {
- cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq);
- dispatched++;
- }
- BUG_ON(!list_empty(&cfqq->fifo));
- }
+ list_for_each_entry_safe(cfqq, next, list, cfq_list)
+ dispatched += __cfq_forced_dispatch_cfqq(cfqq);
return dispatched;
}
-static int
-cfq_forced_dispatch(struct cfq_data *cfqd)
+/*
+ * Drain our current requests. Used for barriers and when switching
+ * io schedulers on-the-fly.
+ */
+static int cfq_forced_dispatch(struct cfq_data *cfqd)
{
- int i, dispatched = 0;
+ int dispatched = 0;
+ struct rb_node *n;
- for (i = 0; i < CFQ_PRIO_LISTS; i++)
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->rr_list[i]);
+ while ((n = cfq_rb_first(&cfqd->service_tree)) != NULL) {
+ struct cfq_queue *cfqq = rb_entry(n, struct cfq_queue, rb_node);
+
+ dispatched += __cfq_forced_dispatch_cfqq(cfqq);
+ }
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->busy_rr);
dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr);
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr);
cfq_slice_expired(cfqd, 0, 0);
return dispatched;
}
-static int
-cfq_dispatch_requests(request_queue_t *q, int force)
+static int cfq_dispatch_requests(request_queue_t *q, int force)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_queue *cfqq, *prev_cfqq;
+ struct cfq_queue *cfqq;
int dispatched;
if (!cfqd->busy_queues)
return cfq_forced_dispatch(cfqd);
dispatched = 0;
- prev_cfqq = NULL;
while ((cfqq = cfq_select_queue(cfqd)) != NULL) {
int max_dispatch;
if (cfqd->busy_queues > 1) {
- /*
- * Don't repeat dispatch from the previous queue.
- */
- if (prev_cfqq == cfqq)
- break;
-
/*
* So we have dispatched before in this round, if the
* next queue has idling enabled (must be sync), don't
- * allow it service until the previous have continued.
+ * allow it service until the previous have completed.
*/
- if (cfqd->rq_in_driver && cfq_cfqq_idle_window(cfqq))
+ if (cfqd->rq_in_driver && cfq_cfqq_idle_window(cfqq) &&
+ dispatched)
+ break;
+ if (cfqq->dispatched >= cfqd->cfq_quantum)
break;
}
max_dispatch = 1;
dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
- prev_cfqq = cfqq;
}
return dispatched;
/*
* it's on the empty list and still hashed
*/
- list_del(&cfqq->cfq_list);
hlist_del(&cfqq->cfq_hash);
kmem_cache_free(cfq_pool, cfqq);
}
}
}
-
-/*
- * Called with interrupts disabled
- */
static void cfq_exit_single_io_context(struct cfq_io_context *cic)
{
struct cfq_data *cfqd = cic->key;
}
}
+/*
+ * The process that ioc belongs to has exited, we need to clean up
+ * and put the internal structures we have that belongs to that process.
+ */
static void cfq_exit_io_context(struct io_context *ioc)
{
struct cfq_io_context *__cic;
*/
cfqq->org_ioprio = cfqq->ioprio;
cfqq->org_ioprio_class = cfqq->ioprio_class;
-
- cfq_resort_rr_list(cfqq, 0);
cfq_clear_cfqq_prio_changed(cfqq);
}
INIT_HLIST_NODE(&cfqq->cfq_hash);
INIT_LIST_HEAD(&cfqq->cfq_list);
+ RB_CLEAR_NODE(&cfqq->rb_node);
INIT_LIST_HEAD(&cfqq->fifo);
cfqq->key = key;
return cfqq;
}
+/*
+ * We drop cfq io contexts lazily, so we may find a dead one.
+ */
static void
cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic)
{
}
static void
-cfq_update_io_seektime(struct cfq_io_context *cic, struct request *rq)
+cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic,
+ struct request *rq)
{
sector_t sdist;
u64 total;
else
sdist = cic->last_request_pos - rq->sector;
+ if (!cic->seek_samples) {
+ cfqd->new_seek_total = (7*cic->seek_total + (u64)256*sdist) / 8;
+ cfqd->new_seek_mean = cfqd->new_seek_total / 256;
+ }
+
/*
* Don't allow the seek distance to get too large from the
* odd fragment, pagein, etc
cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
struct request *rq)
{
- struct cfq_queue *cfqq = cfqd->active_queue;
- sector_t dist;
+ struct cfq_queue *cfqq;
- if (cfq_class_idle(new_cfqq))
+ cfqq = cfqd->active_queue;
+ if (!cfqq)
return 0;
- if (!cfqq)
+ if (cfq_slice_used(cfqq))
+ return 1;
+
+ if (cfq_class_idle(new_cfqq))
return 0;
if (cfq_class_idle(cfqq))
* if this request is as-good as one we would expect from the
* current cfqq, let it preempt
*/
- if (rq->sector > cfqd->last_sector)
- dist = rq->sector - cfqd->last_sector;
- else
- dist = cfqd->last_sector - rq->sector;
-
- if (dist <= cfqd->active_cic->seek_mean)
+ if (cfq_rq_close(cfqd, rq))
return 1;
return 0;
* so we know that it will be selected next.
*/
BUG_ON(!cfq_cfqq_on_rr(cfqq));
- list_move(&cfqq->cfq_list, &cfqd->cur_rr);
+ list_del_init(&cfqq->cfq_list);
+ list_add(&cfqq->cfq_list, &cfqd->cur_rr);
cfqq->slice_end = 0;
cfq_mark_cfqq_slice_new(cfqq);
if (rq_is_meta(rq))
cfqq->meta_pending++;
- /*
- * we never wait for an async request and we don't allow preemption
- * of an async request. so just return early
- */
- if (!rq_is_sync(rq)) {
- /*
- * sync process issued an async request, if it's waiting
- * then expire it and kick rq handling.
- */
- if (cic == cfqd->active_cic &&
- del_timer(&cfqd->idle_slice_timer)) {
- cfq_slice_expired(cfqd, 0, 0);
- blk_start_queueing(cfqd->queue);
- }
- return;
- }
-
cfq_update_io_thinktime(cfqd, cic);
- cfq_update_io_seektime(cic, rq);
+ cfq_update_io_seektime(cfqd, cic, rq);
cfq_update_idle_window(cfqd, cfqq, cic);
cic->last_request_pos = rq->sector + rq->nr_sectors;
+ cfqq->last_request_pos = cic->last_request_pos;
if (cfqq == cfqd->active_queue) {
/*
now = jiffies;
WARN_ON(!cfqd->rq_in_driver);
- WARN_ON(!cfqq->on_dispatch[sync]);
+ WARN_ON(!cfqq->dispatched);
cfqd->rq_in_driver--;
- cfqq->on_dispatch[sync]--;
- cfqq->service_last = now;
-
- cfqd->last_sector = rq->hard_sector + rq->hard_nr_sectors;
+ cfqq->dispatched--;
if (!cfq_class_idle(cfqq))
cfqd->last_end_request = now;
- cfq_resort_rr_list(cfqq, 0);
-
if (sync)
RQ_CIC(rq)->last_end_request = now;
}
if (cfq_slice_used(cfqq))
cfq_slice_expired(cfqd, 0, 1);
- else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) {
- if (!cfq_arm_slice_timer(cfqd))
- cfq_schedule_dispatch(cfqd);
- }
+ else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list))
+ cfq_arm_slice_timer(cfqd);
}
+
+ if (!cfqd->rq_in_driver)
+ cfq_schedule_dispatch(cfqd);
}
/*
*/
static void cfq_prio_boost(struct cfq_queue *cfqq)
{
- const int ioprio_class = cfqq->ioprio_class;
- const int ioprio = cfqq->ioprio;
-
if (has_fs_excl()) {
/*
* boost idle prio on transactions that would lock out other
if (cfqq->ioprio != cfqq->org_ioprio)
cfqq->ioprio = cfqq->org_ioprio;
}
-
- /*
- * refile between round-robin lists if we moved the priority class
- */
- if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio))
- cfq_resort_rr_list(cfqq, 0);
}
static inline int __cfq_may_queue(struct cfq_queue *cfqq)
memset(cfqd, 0, sizeof(*cfqd));
- for (i = 0; i < CFQ_PRIO_LISTS; i++)
- INIT_LIST_HEAD(&cfqd->rr_list[i]);
-
- INIT_LIST_HEAD(&cfqd->busy_rr);
+ cfqd->service_tree = CFQ_RB_ROOT;
INIT_LIST_HEAD(&cfqd->cur_rr);
- INIT_LIST_HEAD(&cfqd->idle_rr);
INIT_LIST_HEAD(&cfqd->cic_list);
cfqd->cfq_hash = kmalloc_node(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL, q->node);
/*
* sysfs parts below -->
*/
-
static ssize_t
cfq_var_show(unsigned int var, char *page)
{
projects / powerpc.git / blobdiff