#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/elevator.h>
-#include <linux/hash.h>
#include <linux/rbtree.h>
#include <linux/ioprio.h>
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)
-#define CFQ_SLICE_SCALE (5)
-
-#define CFQ_KEY_ASYNC (0)
/*
- * for the hash of cfqq inside the cfqd
+ * below this threshold, we consider thinktime immediate
*/
-#define CFQ_QHASH_SHIFT 6
-#define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT)
-#define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash)
+#define CFQ_MIN_TT (2)
-#define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list)
+#define CFQ_SLICE_SCALE (5)
#define RQ_CIC(rq) ((struct cfq_io_context*)(rq)->elevator_private)
#define RQ_CFQQ(rq) ((rq)->elevator_private2)
#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 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
*/
struct cfq_data {
- request_queue_t *queue;
+ struct request_queue *queue;
/*
* 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 list_head cur_rr;
- struct list_head idle_rr;
+ struct cfq_rb_root service_tree;
unsigned int busy_queues;
- /*
- * cfqq lookup hash
- */
- struct hlist_head *cfq_hash;
-
int rq_in_driver;
+ int sync_flight;
int hw_tag;
/*
struct cfq_queue *active_queue;
struct cfq_io_context *active_cic;
- int cur_prio, cur_end_prio;
- unsigned int dispatch_slice;
+
+ /*
+ * async queue for each priority case
+ */
+ struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR];
+ struct cfq_queue *async_idle_cfqq;
struct timer_list idle_class_timer;
- sector_t last_sector;
+ sector_t last_position;
unsigned long last_end_request;
/*
atomic_t ref;
/* parent cfq_data */
struct cfq_data *cfqd;
- /* cfqq lookup hash */
- struct hlist_node cfq_hash;
- /* hash key */
- 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 */
/* fifo list of requests in sort_list */
struct list_head fifo;
- unsigned long slice_start;
unsigned long slice_end;
- unsigned long slice_left;
+ 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;
};
enum cfqq_state_flags {
- CFQ_CFQQ_FLAG_on_rr = 0,
- CFQ_CFQQ_FLAG_wait_request,
- CFQ_CFQQ_FLAG_must_alloc,
- CFQ_CFQQ_FLAG_must_alloc_slice,
- CFQ_CFQQ_FLAG_must_dispatch,
- CFQ_CFQQ_FLAG_fifo_expire,
- CFQ_CFQQ_FLAG_idle_window,
- CFQ_CFQQ_FLAG_prio_changed,
- CFQ_CFQQ_FLAG_queue_new,
+ CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */
+ CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */
+ CFQ_CFQQ_FLAG_must_alloc, /* must be allowed rq alloc */
+ CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */
+ CFQ_CFQQ_FLAG_must_dispatch, /* must dispatch, even if expired */
+ CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */
+ CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */
+ CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */
+ CFQ_CFQQ_FLAG_queue_new, /* queue never been serviced */
+ CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */
+ CFQ_CFQQ_FLAG_sync, /* synchronous queue */
};
#define CFQ_CFQQ_FNS(name) \
CFQ_CFQQ_FNS(idle_window);
CFQ_CFQQ_FNS(prio_changed);
CFQ_CFQQ_FNS(queue_new);
+CFQ_CFQQ_FNS(slice_new);
+CFQ_CFQQ_FNS(sync);
#undef CFQ_CFQQ_FNS
-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 void cfq_dispatch_insert(struct request_queue *, struct request *);
+static struct cfq_queue *cfq_get_queue(struct cfq_data *, int,
+ struct task_struct *, gfp_t);
+static struct cfq_io_context *cfq_cic_rb_lookup(struct cfq_data *,
+ struct io_context *);
+
+static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic,
+ int is_sync)
+{
+ return cic->cfqq[!!is_sync];
+}
+
+static inline void cic_set_cfqq(struct cfq_io_context *cic,
+ struct cfq_queue *cfqq, int is_sync)
+{
+ cic->cfqq[!!is_sync] = cfqq;
+}
+
+/*
+ * We regard a request as SYNC, if it's either a read or has the SYNC bit
+ * set (in which case it could also be direct WRITE).
+ */
+static inline int cfq_bio_sync(struct bio *bio)
+{
+ if (bio_data_dir(bio) == READ || bio_sync(bio))
+ return 1;
+
+ return 0;
+}
/*
* scheduler run of queue, if there are requests pending and no one in the
kblockd_schedule_work(&cfqd->unplug_work);
}
-static int cfq_queue_empty(request_queue_t *q)
+static int cfq_queue_empty(struct request_queue *q)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
return !cfqd->busy_queues;
}
-static inline pid_t cfq_queue_pid(struct task_struct *task, int rw, int is_sync)
+/*
+ * Scale schedule slice based on io priority. Use the sync time slice only
+ * 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_slice(struct cfq_data *cfqd, int sync,
+ unsigned short prio)
{
- /*
- * Use the per-process queue, for read requests and syncronous writes
- */
- if (!(rw & REQ_RW) || is_sync)
- return task->pid;
+ const int base_slice = cfqd->cfq_slice[sync];
+
+ WARN_ON(prio >= IOPRIO_BE_NR);
+
+ return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio));
+}
- return CFQ_KEY_ASYNC;
+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;
+}
+
+/*
+ * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end
+ * isn't valid until the first request from the dispatch is activated
+ * and the slice time set.
+ */
+static inline int cfq_slice_used(struct cfq_queue *cfqq)
+{
+ if (cfq_cfqq_slice_new(cfqq))
+ return 0;
+ if (time_before(jiffies, cfqq->slice_end))
+ return 0;
+
+ return 1;
}
/*
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;
-
- BUG_ON(!cfq_cfqq_on_rr(cfqq));
+ /*
+ * just an approximation, should be ok.
+ */
+ 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, int add_front)
+{
+ struct rb_node **p = &cfqd->service_tree.rb.rb_node;
+ struct rb_node *parent = NULL;
+ unsigned long rb_key;
+ int left;
+
+ if (!add_front) {
+ rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies;
+ rb_key += cfqq->slice_resid;
+ cfqq->slice_resid = 0;
+ } else
+ rb_key = 0;
- if (cfq_class_rt(cfqq))
- list = &cfqd->cur_rr;
- else if (cfq_class_idle(cfqq))
- list = &cfqd->idle_rr;
- else {
+ 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 this queue was preempted or is new (never been serviced), let
- * it be added first for fairness but beind other new queues.
- * Otherwise, just add to the back of the list.
- */
- if (preempted || cfq_cfqq_queue_new(cfqq)) {
- struct list_head *n = list;
+ left = 1;
+ while (*p) {
struct cfq_queue *__cfqq;
+ struct rb_node **n;
- while (n->next != list) {
- __cfqq = list_entry_cfqq(n->next);
- if (!cfq_cfqq_queue_new(__cfqq))
- break;
+ parent = *p;
+ __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
- n = n->next;
- }
+ /*
+ * 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.
+ */
+ 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;
- list = n;
+ if (n == &(*p)->rb_right)
+ left = 0;
+
+ p = n;
}
- list_add_tail(&cfqq->cfq_list, list);
+ 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_data *cfqd, struct cfq_queue *cfqq)
+{
+ /*
+ * Resorting requires the cfqq to be on the RR list already.
+ */
+ if (cfq_cfqq_on_rr(cfqq))
+ cfq_service_tree_add(cfqd, cfqq, 0);
}
/*
cfq_mark_cfqq_on_rr(cfqq);
cfqd->busy_queues++;
- cfq_resort_rr_list(cfqq, 0);
+ cfq_resort_rr_list(cfqd, cfqq);
}
+/*
+ * 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)
{
BUG_ON(!cfq_cfqq_on_rr(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 (!cfq_cfqq_on_rr(cfqq))
cfq_add_cfqq_rr(cfqd, cfqq);
+
+ /*
+ * check if this request is a better next-serve candidate
+ */
+ cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
+ BUG_ON(!cfqq->next_rq);
}
static inline void
cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
{
struct task_struct *tsk = current;
- pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio), bio_sync(bio));
+ struct cfq_io_context *cic;
struct cfq_queue *cfqq;
- cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
+ cic = cfq_cic_rb_lookup(cfqd, tsk->io_context);
+ if (!cic)
+ return NULL;
+
+ cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
if (cfqq) {
sector_t sector = bio->bi_sector + bio_sectors(bio);
return NULL;
}
-static void cfq_activate_request(request_queue_t *q, struct request *rq)
+static void cfq_activate_request(struct request_queue *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
*/
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 void cfq_deactivate_request(struct request_queue *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
}
}
-static int
-cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
+static int cfq_merge(struct request_queue *q, struct request **req,
+ struct bio *bio)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct request *__rq;
return ELEVATOR_NO_MERGE;
}
-static void cfq_merged_request(request_queue_t *q, struct request *req,
+static void cfq_merged_request(struct request_queue *q, struct request *req,
int type)
{
if (type == ELEVATOR_FRONT_MERGE) {
}
static void
-cfq_merged_requests(request_queue_t *q, struct request *rq,
+cfq_merged_requests(struct request_queue *q, struct request *rq,
struct request *next)
{
/*
cfq_remove_request(next);
}
-static int cfq_allow_merge(request_queue_t *q, struct request *rq,
+static int cfq_allow_merge(struct request_queue *q, struct request *rq,
struct bio *bio)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- const int rw = bio_data_dir(bio);
+ struct cfq_io_context *cic;
struct cfq_queue *cfqq;
- pid_t key;
/*
* Disallow merge of a sync bio into an async request.
*/
- if ((bio_data_dir(bio) == READ || bio_sync(bio)) && !rq_is_sync(rq))
+ if (cfq_bio_sync(bio) && !rq_is_sync(rq))
return 0;
/*
* Lookup the cfqq that this bio will be queued with. Allow
* merge only if rq is queued there.
*/
- key = cfq_queue_pid(current, rw, bio_sync(bio));
- cfqq = cfq_find_cfq_hash(cfqd, key, current->ioprio);
+ cic = cfq_cic_rb_lookup(cfqd, current->io_context);
+ if (!cic)
+ return 0;
+ cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
if (cfqq == RQ_CFQQ(rq))
return 1;
*/
del_timer(&cfqd->idle_class_timer);
- cfqq->slice_start = jiffies;
cfqq->slice_end = 0;
- cfqq->slice_left = 0;
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;
*/
static void
__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- int preempted)
+ int timed_out)
{
- unsigned long now = jiffies;
-
if (cfq_cfqq_wait_request(cfqq))
del_timer(&cfqd->idle_slice_timer);
- if (!preempted && !cfq_cfqq_dispatched(cfqq))
- cfq_schedule_dispatch(cfqd);
-
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
- * or was preempted
+ * store what was left of this slice, if the queue idled/timed out
*/
- if (time_after(cfqq->slice_end, now))
- cfqq->slice_left = cfqq->slice_end - now;
- else
- cfqq->slice_left = 0;
+ if (timed_out && !cfq_cfqq_slice_new(cfqq))
+ cfqq->slice_resid = cfqq->slice_end - jiffies;
- if (cfq_cfqq_on_rr(cfqq))
- cfq_resort_rr_list(cfqq, preempted);
+ cfq_resort_rr_list(cfqd, cfqq);
if (cfqq == cfqd->active_queue)
cfqd->active_queue = NULL;
put_io_context(cfqd->active_cic->ioc);
cfqd->active_cic = NULL;
}
-
- cfqd->dispatch_slice = 0;
}
-static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted)
+static inline void cfq_slice_expired(struct cfq_data *cfqd, int timed_out)
{
struct cfq_queue *cfqq = cfqd->active_queue;
if (cfqq)
- __cfq_slice_expired(cfqd, cfqq, preempted);
+ __cfq_slice_expired(cfqd, cfqq, timed_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;
-
- prio = -1;
- wrap = 0;
- do {
- int p;
-
- for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) {
- if (!list_empty(&cfqd->rr_list[p])) {
- prio = p;
- break;
- }
- }
-
- 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;
- }
- } while (1);
+ struct cfq_queue *cfqq;
+ struct rb_node *n;
- if (unlikely(prio == -1))
- return -1;
+ if (RB_EMPTY_ROOT(&cfqd->service_tree.rb))
+ return NULL;
- BUG_ON(prio >= CFQ_PRIO_LISTS);
+ n = cfq_rb_first(&cfqd->service_tree);
+ cfqq = rb_entry(n, struct cfq_queue, rb_node);
- list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr);
+ if (cfq_class_idle(cfqq)) {
+ unsigned long end;
- 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;
+ /*
+ * 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;
+ }
}
- return prio;
+ return cfqq;
}
+/*
+ * 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 = NULL;
-
- 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 (time_after_eq(jiffies, end))
- cfqq = list_entry_cfqq(cfqd->idle_rr.next);
- else
- mod_timer(&cfqd->idle_class_timer, end);
- }
+ struct cfq_queue *cfqq;
+ cfqq = cfq_get_next_queue(cfqd);
__cfq_set_active_queue(cfqd, cfqq);
return cfqq;
}
-#define CIC_SEEKY(cic) ((cic)->seek_mean > (128 * 1024))
+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 int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static inline int cfq_rq_close(struct cfq_data *cfqd, struct request *rq)
+{
+ struct cfq_io_context *cic = cfqd->active_cic;
+
+ if (!sample_valid(cic->seek_samples))
+ return 0;
+ return cfq_dist_from_last(cfqd, rq) <= cic->seek_mean;
+}
+
+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 > (8 * 1024))
+
+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(cfqq != cfqd->active_queue);
+ 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;
}
-static void cfq_dispatch_insert(request_queue_t *q, struct request *rq)
+/*
+ * Move request from internal lists to the request queue dispatch list.
+ */
+static void cfq_dispatch_insert(struct request_queue *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
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);
- rq = list_entry(q->queue_head.prev, struct request, queuelist);
- cfqd->last_sector = rq->sector + rq->nr_sectors;
+ if (cfq_cfqq_sync(cfqq))
+ cfqd->sync_flight++;
}
/*
if (cfq_cfqq_fifo_expire(cfqq))
return NULL;
+
+ cfq_mark_cfqq_fifo_expire(cfqq);
+
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])) {
- cfq_mark_cfqq_fifo_expire(cfqq);
- return rq;
- }
-
- return NULL;
-}
-
-/*
- * Scale schedule slice based on io priority. Use the sync time slice only
- * 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)
-{
- const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)];
-
- WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
+ if (time_before(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo]))
+ return NULL;
- return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - 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;
+ 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)
{
- unsigned long now = jiffies;
struct cfq_queue *cfqq;
cfqq = cfqd->active_queue;
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) && time_after(now, cfqq->slice_end))
+ 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_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 (timer_pending(&cfqd->idle_slice_timer) ||
+ (cfqq->dispatched && cfq_cfqq_idle_window(cfqq))) {
cfqq = NULL;
goto keep_queue;
- } else if (cfq_cfqq_class_sync(cfqq)) {
- if (cfq_arm_slice_timer(cfqd, cfqq))
- 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)
*/
cfq_dispatch_insert(cfqd->queue, rq);
- cfqd->dispatch_slice++;
dispatched++;
if (!cfqd->active_cic) {
} while (dispatched < max_dispatch);
- /*
- * if slice end isn't set yet, set it.
- */
- if (!cfqq->slice_end)
- cfq_set_prio_slice(cfqd, cfqq);
-
/*
* expire an async queue immediately if it has used up its slice. idle
* queue always expire after 1 dispatch round.
*/
- if ((!cfq_cfqq_sync(cfqq) &&
- cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
- cfq_class_idle(cfqq) ||
- !cfq_cfqq_idle_window(cfqq))
+ if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) &&
+ dispatched >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
+ cfq_class_idle(cfqq))) {
+ cfqq->slice_end = jiffies + 1;
cfq_slice_expired(cfqd, 0);
+ }
return dispatched;
}
-static int
-cfq_forced_dispatch_cfqqs(struct list_head *list)
+static inline int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq)
{
- struct cfq_queue *cfqq, *next;
- int dispatched;
+ int dispatched = 0;
- 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));
+ 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(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_cfqqs(&cfqd->busy_rr);
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr);
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr);
+ dispatched += __cfq_forced_dispatch_cfqq(cfqq);
+ }
cfq_slice_expired(cfqd, 0);
return dispatched;
}
-static int
-cfq_dispatch_requests(request_queue_t *q, int force)
+static int cfq_dispatch_requests(struct request_queue *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;
- /*
- * Don't repeat dispatch from the previous queue.
- */
- if (prev_cfqq == cfqq)
- break;
-
- cfq_clear_cfqq_must_dispatch(cfqq);
- cfq_clear_cfqq_wait_request(cfqq);
- del_timer(&cfqd->idle_slice_timer);
-
max_dispatch = cfqd->cfq_quantum;
if (cfq_class_idle(cfqq))
max_dispatch = 1;
- dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
+ if (cfqq->dispatched >= max_dispatch) {
+ if (cfqd->busy_queues > 1)
+ break;
+ if (cfqq->dispatched >= 4 * max_dispatch)
+ break;
+ }
- /*
- * If the dispatch cfqq has idling enabled and is still
- * the active queue, break out.
- */
- if (cfq_cfqq_idle_window(cfqq) && cfqd->active_queue)
+ if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq))
break;
- prev_cfqq = cfqq;
+ cfq_clear_cfqq_must_dispatch(cfqq);
+ cfq_clear_cfqq_wait_request(cfqq);
+ del_timer(&cfqd->idle_slice_timer);
+
+ dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
}
return dispatched;
BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]);
BUG_ON(cfq_cfqq_on_rr(cfqq));
- if (unlikely(cfqd->active_queue == cfqq))
+ if (unlikely(cfqd->active_queue == cfqq)) {
__cfq_slice_expired(cfqd, cfqq, 0);
-
- /*
- * 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);
-}
-
-static struct cfq_queue *
-__cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio,
- const int hashval)
-{
- struct hlist_head *hash_list = &cfqd->cfq_hash[hashval];
- struct hlist_node *entry;
- struct cfq_queue *__cfqq;
-
- hlist_for_each_entry(__cfqq, entry, hash_list, cfq_hash) {
- const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->org_ioprio_class, __cfqq->org_ioprio);
-
- if (__cfqq->key == key && (__p == prio || !prio))
- return __cfqq;
+ cfq_schedule_dispatch(cfqd);
}
- return NULL;
-}
-
-static struct cfq_queue *
-cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio)
-{
- return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT));
+ kmem_cache_free(cfq_pool, cfqq);
}
static void cfq_free_io_context(struct io_context *ioc)
struct rb_node *n;
int freed = 0;
+ ioc->ioc_data = NULL;
+
while ((n = rb_first(&ioc->cic_root)) != NULL) {
__cic = rb_entry(n, struct cfq_io_context, rb_node);
rb_erase(&__cic->rb_node, &ioc->cic_root);
static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
- if (unlikely(cfqq == cfqd->active_queue))
+ if (unlikely(cfqq == cfqd->active_queue)) {
__cfq_slice_expired(cfqd, cfqq, 0);
+ cfq_schedule_dispatch(cfqd);
+ }
cfq_put_queue(cfqq);
}
}
}
-
-/*
- * Called with interrupts disabled
- */
static void cfq_exit_single_io_context(struct cfq_io_context *cic)
{
struct cfq_data *cfqd = cic->key;
if (cfqd) {
- request_queue_t *q = cfqd->queue;
+ struct request_queue *q = cfqd->queue;
spin_lock_irq(q->queue_lock);
__cfq_exit_single_io_context(cfqd, cic);
}
}
+/*
+ * 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;
struct rb_node *n;
+ ioc->ioc_data = NULL;
+
/*
* put the reference this task is holding to the various queues
*/
-
n = rb_first(&ioc->cic_root);
while (n != NULL) {
__cic = rb_entry(n, struct cfq_io_context, rb_node);
{
struct cfq_io_context *cic;
- cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask, cfqd->queue->node);
+ cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO,
+ cfqd->queue->node);
if (cic) {
- memset(cic, 0, sizeof(*cic));
cic->last_end_request = jiffies;
INIT_LIST_HEAD(&cic->queue_list);
cic->dtor = cfq_free_io_context;
*/
cfqq->org_ioprio = cfqq->ioprio;
cfqq->org_ioprio_class = cfqq->ioprio_class;
-
- if (cfq_cfqq_on_rr(cfqq))
- cfq_resort_rr_list(cfqq, 0);
-
cfq_clear_cfqq_prio_changed(cfqq);
}
cfqq = cic->cfqq[ASYNC];
if (cfqq) {
struct cfq_queue *new_cfqq;
- new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC, cic->ioc->task,
+ new_cfqq = cfq_get_queue(cfqd, ASYNC, cic->ioc->task,
GFP_ATOMIC);
if (new_cfqq) {
cic->cfqq[ASYNC] = new_cfqq;
}
static struct cfq_queue *
-cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk,
- gfp_t gfp_mask)
+cfq_find_alloc_queue(struct cfq_data *cfqd, int is_sync,
+ struct task_struct *tsk, gfp_t gfp_mask)
{
- const int hashval = hash_long(key, CFQ_QHASH_SHIFT);
struct cfq_queue *cfqq, *new_cfqq = NULL;
- unsigned short ioprio;
+ struct cfq_io_context *cic;
retry:
- ioprio = tsk->ioprio;
- cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval);
+ cic = cfq_cic_rb_lookup(cfqd, tsk->io_context);
+ /* cic always exists here */
+ cfqq = cic_to_cfqq(cic, is_sync);
if (!cfqq) {
if (new_cfqq) {
* free memory.
*/
spin_unlock_irq(cfqd->queue->queue_lock);
- new_cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask|__GFP_NOFAIL, cfqd->queue->node);
+ new_cfqq = kmem_cache_alloc_node(cfq_pool,
+ gfp_mask | __GFP_NOFAIL | __GFP_ZERO,
+ cfqd->queue->node);
spin_lock_irq(cfqd->queue->queue_lock);
goto retry;
} else {
- cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask, cfqd->queue->node);
+ cfqq = kmem_cache_alloc_node(cfq_pool,
+ gfp_mask | __GFP_ZERO,
+ cfqd->queue->node);
if (!cfqq)
goto out;
}
- memset(cfqq, 0, sizeof(*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;
- hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]);
atomic_set(&cfqq->ref, 0);
cfqq->cfqd = cfqd;
- /*
- * set ->slice_left to allow preemption for a new process
- */
- cfqq->slice_left = 2 * cfqd->cfq_slice_idle;
- cfq_mark_cfqq_idle_window(cfqq);
+
+ if (is_sync) {
+ cfq_mark_cfqq_idle_window(cfqq);
+ cfq_mark_cfqq_sync(cfqq);
+ }
+
cfq_mark_cfqq_prio_changed(cfqq);
cfq_mark_cfqq_queue_new(cfqq);
+
cfq_init_prio_data(cfqq);
}
if (new_cfqq)
kmem_cache_free(cfq_pool, new_cfqq);
- atomic_inc(&cfqq->ref);
out:
WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq);
return cfqq;
}
+static struct cfq_queue **
+cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio)
+{
+ switch(ioprio_class) {
+ case IOPRIO_CLASS_RT:
+ return &cfqd->async_cfqq[0][ioprio];
+ case IOPRIO_CLASS_BE:
+ return &cfqd->async_cfqq[1][ioprio];
+ case IOPRIO_CLASS_IDLE:
+ return &cfqd->async_idle_cfqq;
+ default:
+ BUG();
+ }
+}
+
+static struct cfq_queue *
+cfq_get_queue(struct cfq_data *cfqd, int is_sync, struct task_struct *tsk,
+ gfp_t gfp_mask)
+{
+ const int ioprio = task_ioprio(tsk);
+ const int ioprio_class = task_ioprio_class(tsk);
+ struct cfq_queue **async_cfqq = NULL;
+ struct cfq_queue *cfqq = NULL;
+
+ if (!is_sync) {
+ async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio);
+ cfqq = *async_cfqq;
+ }
+
+ if (!cfqq)
+ cfqq = cfq_find_alloc_queue(cfqd, is_sync, tsk, gfp_mask);
+
+ /*
+ * pin the queue now that it's allocated, scheduler exit will prune it
+ */
+ if (!is_sync && !(*async_cfqq)) {
+ atomic_inc(&cfqq->ref);
+ *async_cfqq = cfqq;
+ }
+
+ atomic_inc(&cfqq->ref);
+ 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)
{
WARN_ON(!list_empty(&cic->queue_list));
+
+ if (ioc->ioc_data == cic)
+ ioc->ioc_data = NULL;
+
rb_erase(&cic->rb_node, &ioc->cic_root);
kmem_cache_free(cfq_ioc_pool, cic);
elv_ioc_count_dec(ioc_count);
struct cfq_io_context *cic;
void *k, *key = cfqd;
+ if (unlikely(!ioc))
+ return NULL;
+
+ /*
+ * we maintain a last-hit cache, to avoid browsing over the tree
+ */
+ cic = ioc->ioc_data;
+ if (cic && cic->key == cfqd)
+ return cic;
+
restart:
n = ioc->cic_root.rb_node;
while (n) {
n = n->rb_left;
else if (key > k)
n = n->rb_right;
- else
+ else {
+ ioc->ioc_data = cic;
return cic;
+ }
}
return NULL;
}
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;
cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct cfq_io_context *cic)
{
- int enable_idle = cfq_cfqq_idle_window(cfqq);
+ int enable_idle;
+
+ if (!cfq_cfqq_sync(cfqq))
+ return;
+
+ enable_idle = cfq_cfqq_idle_window(cfqq);
if (!cic->ioc->task || !cfqd->cfq_slice_idle ||
(cfqd->hw_tag && CIC_SEEKY(cic)))
cfq_clear_cfqq_idle_window(cfqq);
}
-
/*
* Check if new_cfqq should preempt the currently active queue. Return 0 for
* no or if we aren't sure, a 1 will cause a preempt.
cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
struct request *rq)
{
- struct cfq_queue *cfqq = cfqd->active_queue;
+ 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))
return 1;
- if (!cfq_cfqq_wait_request(new_cfqq))
- return 0;
- /*
- * if it doesn't have slice left, forget it
- */
- if (new_cfqq->slice_left < cfqd->cfq_slice_idle)
- return 0;
+
/*
* if the new request is sync, but the currently running queue is
* not, let the sync request have priority.
*/
if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq))
return 1;
+
/*
* So both queues are sync. Let the new request get disk time if
* it's a metadata request and the current queue is doing regular IO.
if (rq_is_meta(rq) && !cfqq->meta_pending)
return 1;
+ if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
+ return 0;
+
+ /*
+ * if this request is as-good as one we would expect from the
+ * current cfqq, let it preempt
+ */
+ if (cfq_rq_close(cfqd, rq))
+ return 1;
+
return 0;
}
{
cfq_slice_expired(cfqd, 1);
- if (!cfqq->slice_left)
- cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2;
-
/*
* Put the new queue at the front of the of the current list,
* so we know that it will be selected next.
*/
BUG_ON(!cfq_cfqq_on_rr(cfqq));
- list_move(&cfqq->cfq_list, &cfqd->cur_rr);
- cfqq->slice_end = cfqq->slice_left + jiffies;
+ cfq_service_tree_add(cfqd, cfqq, 1);
+
+ cfqq->slice_end = 0;
+ cfq_mark_cfqq_slice_new(cfqq);
}
/*
if (rq_is_meta(rq))
cfqq->meta_pending++;
- /*
- * check if this request is a better next-serve candidate)) {
- */
- cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
- BUG_ON(!cfqq->next_rq);
-
- /*
- * 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);
- 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;
}
}
-static void cfq_insert_request(request_queue_t *q, struct request *rq)
+static void cfq_insert_request(struct request_queue *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq = RQ_CFQQ(rq);
cfq_rq_enqueued(cfqd, cfqq, rq);
}
-static void cfq_completed_request(request_queue_t *q, struct request *rq)
+static void cfq_completed_request(struct request_queue *q, struct request *rq)
{
struct cfq_queue *cfqq = RQ_CFQQ(rq);
struct cfq_data *cfqd = cfqq->cfqd;
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->dispatched--;
+
+ if (cfq_cfqq_sync(cfqq))
+ cfqd->sync_flight--;
if (!cfq_class_idle(cfqq))
cfqd->last_end_request = now;
- if (!cfq_cfqq_dispatched(cfqq) && cfq_cfqq_on_rr(cfqq))
- cfq_resort_rr_list(cfqq, 0);
-
if (sync)
RQ_CIC(rq)->last_end_request = now;
* or if we want to idle in case it has no pending requests.
*/
if (cfqd->active_queue == cfqq) {
- if (time_after(now, cfqq->slice_end))
- cfq_slice_expired(cfqd, 0);
- else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) {
- if (!cfq_arm_slice_timer(cfqd, cfqq))
- cfq_schedule_dispatch(cfqd);
+ if (cfq_cfqq_slice_new(cfqq)) {
+ cfq_set_prio_slice(cfqd, cfqq);
+ cfq_clear_cfqq_slice_new(cfqq);
}
+ if (cfq_slice_used(cfqq))
+ cfq_slice_expired(cfqd, 1);
+ 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_cfqq_on_rr(cfqq))
- cfq_resort_rr_list(cfqq, 0);
}
static inline int __cfq_may_queue(struct cfq_queue *cfqq)
return ELV_MQUEUE_MAY;
}
-static int cfq_may_queue(request_queue_t *q, int rw)
+static int cfq_may_queue(struct request_queue *q, int rw)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct task_struct *tsk = current;
+ struct cfq_io_context *cic;
struct cfq_queue *cfqq;
- unsigned int key;
-
- key = cfq_queue_pid(tsk, rw, rw & REQ_RW_SYNC);
/*
* don't force setup of a queue from here, as a call to may_queue
* so just lookup a possibly existing queue, or return 'may queue'
* if that fails
*/
- cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
+ cic = cfq_cic_rb_lookup(cfqd, tsk->io_context);
+ if (!cic)
+ return ELV_MQUEUE_MAY;
+
+ cfqq = cic_to_cfqq(cic, rw & REQ_RW_SYNC);
if (cfqq) {
cfq_init_prio_data(cfqq);
cfq_prio_boost(cfqq);
* Allocate cfq data structures associated with this request.
*/
static int
-cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask)
+cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct task_struct *tsk = current;
struct cfq_io_context *cic;
const int rw = rq_data_dir(rq);
const int is_sync = rq_is_sync(rq);
- pid_t key = cfq_queue_pid(tsk, rw, is_sync);
struct cfq_queue *cfqq;
unsigned long flags;
if (!cic)
goto queue_fail;
- if (!cic->cfqq[is_sync]) {
- cfqq = cfq_get_queue(cfqd, key, tsk, gfp_mask);
+ cfqq = cic_to_cfqq(cic, is_sync);
+ if (!cfqq) {
+ cfqq = cfq_get_queue(cfqd, is_sync, tsk, gfp_mask);
+
if (!cfqq)
goto queue_fail;
- cic->cfqq[is_sync] = cfqq;
- } else
- cfqq = cic->cfqq[is_sync];
+ cic_set_cfqq(cic, cfqq, is_sync);
+ }
cfqq->allocated[rw]++;
cfq_clear_cfqq_must_alloc(cfqq);
{
struct cfq_data *cfqd =
container_of(work, struct cfq_data, unplug_work);
- request_queue_t *q = cfqd->queue;
+ struct request_queue *q = cfqd->queue;
unsigned long flags;
spin_lock_irqsave(q->queue_lock, flags);
struct cfq_data *cfqd = (struct cfq_data *) data;
struct cfq_queue *cfqq;
unsigned long flags;
+ int timed_out = 1;
spin_lock_irqsave(cfqd->queue->queue_lock, flags);
if ((cfqq = cfqd->active_queue) != NULL) {
- unsigned long now = jiffies;
+ timed_out = 0;
/*
* expired
*/
- if (time_after(now, cfqq->slice_end))
+ if (cfq_slice_used(cfqq))
goto expire;
/*
}
}
expire:
- cfq_slice_expired(cfqd, 0);
+ cfq_slice_expired(cfqd, timed_out);
out_kick:
cfq_schedule_dispatch(cfqd);
out_cont:
blk_sync_queue(cfqd->queue);
}
+static void cfq_put_async_queues(struct cfq_data *cfqd)
+{
+ int i;
+
+ for (i = 0; i < IOPRIO_BE_NR; i++) {
+ if (cfqd->async_cfqq[0][i])
+ cfq_put_queue(cfqd->async_cfqq[0][i]);
+ if (cfqd->async_cfqq[1][i])
+ cfq_put_queue(cfqd->async_cfqq[1][i]);
+ if (cfqd->async_idle_cfqq)
+ cfq_put_queue(cfqd->async_idle_cfqq);
+ }
+}
+
static void cfq_exit_queue(elevator_t *e)
{
struct cfq_data *cfqd = e->elevator_data;
- request_queue_t *q = cfqd->queue;
+ struct request_queue *q = cfqd->queue;
cfq_shutdown_timer_wq(cfqd);
__cfq_exit_single_io_context(cfqd, cic);
}
+ cfq_put_async_queues(cfqd);
+
spin_unlock_irq(q->queue_lock);
cfq_shutdown_timer_wq(cfqd);
- kfree(cfqd->cfq_hash);
kfree(cfqd);
}
-static void *cfq_init_queue(request_queue_t *q)
+static void *cfq_init_queue(struct request_queue *q)
{
struct cfq_data *cfqd;
- int i;
- cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL, q->node);
+ cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node);
if (!cfqd)
return NULL;
- 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);
- INIT_LIST_HEAD(&cfqd->cur_rr);
- INIT_LIST_HEAD(&cfqd->idle_rr);
+ cfqd->service_tree = CFQ_RB_ROOT;
INIT_LIST_HEAD(&cfqd->cic_list);
- cfqd->cfq_hash = kmalloc_node(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL, q->node);
- if (!cfqd->cfq_hash)
- goto out_free;
-
- for (i = 0; i < CFQ_QHASH_ENTRIES; i++)
- INIT_HLIST_HEAD(&cfqd->cfq_hash[i]);
-
cfqd->queue = q;
init_timer(&cfqd->idle_slice_timer);
cfqd->cfq_slice_idle = cfq_slice_idle;
return cfqd;
-out_free:
- kfree(cfqd);
- return NULL;
}
static void cfq_slab_kill(void)
static int __init cfq_slab_setup(void)
{
- cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0,
- NULL, NULL);
+ cfq_pool = KMEM_CACHE(cfq_queue, 0);
if (!cfq_pool)
goto fail;
- cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool",
- sizeof(struct cfq_io_context), 0, 0, NULL, NULL);
+ cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0);
if (!cfq_ioc_pool)
goto fail;
/*
* sysfs parts below -->
*/
-
static ssize_t
cfq_var_show(unsigned int var, char *page)
{
Code Review / linux-2.6.git / blobdiff