#include <linux/hash.h>
#include <linux/rbtree.h>
#include <linux/mempool.h>
-
-static unsigned long max_elapsed_crq;
-static unsigned long max_elapsed_dispatch;
+#include <linux/ioprio.h>
+#include <linux/writeback.h>
/*
* tunables
*/
static int cfq_quantum = 4; /* max queue in one round of service */
static int cfq_queued = 8; /* minimum rq allocate limit per-queue*/
-static int cfq_service = HZ; /* period over which service is avg */
-static int cfq_fifo_expire_r = HZ / 2; /* fifo timeout for sync requests */
-static int cfq_fifo_expire_w = 5 * HZ; /* fifo timeout for async requests */
-static int cfq_fifo_rate = HZ / 8; /* fifo expiry rate */
+static int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 };
static int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */
static int cfq_back_penalty = 2; /* penalty of a backwards seek */
+static int cfq_slice_sync = HZ / 10;
+static int cfq_slice_async = HZ / 25;
+static int cfq_slice_async_rq = 2;
+static int cfq_slice_idle = HZ / 100;
+
+#define CFQ_IDLE_GRACE (HZ / 10)
+#define CFQ_SLICE_SCALE (5)
+
+#define CFQ_KEY_ASYNC (0)
+#define CFQ_KEY_ANY (0xffff)
+
+/*
+ * disable queueing at the driver/hardware level
+ */
+static int cfq_max_depth = 1;
+
/*
* for the hash of cfqq inside the cfqd
*/
#define list_entry_hash(ptr) hlist_entry((ptr), struct cfq_rq, hash)
#define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list)
+#define list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
#define RQ_DATA(rq) (rq)->elevator_private
#define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node)
#define rq_rb_key(rq) (rq)->sector
-/*
- * threshold for switching off non-tag accounting
- */
-#define CFQ_MAX_TAG (4)
-
-/*
- * sort key types and names
- */
-enum {
- CFQ_KEY_PGID,
- CFQ_KEY_TGID,
- CFQ_KEY_UID,
- CFQ_KEY_GID,
- CFQ_KEY_LAST,
-};
-
-static char *cfq_key_types[] = { "pgid", "tgid", "uid", "gid", NULL };
-
static kmem_cache_t *crq_pool;
static kmem_cache_t *cfq_pool;
static kmem_cache_t *cfq_ioc_pool;
+#define CFQ_PRIO_LISTS IOPRIO_BE_NR
+#define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
+#define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE)
+#define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
+
+#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])
+
+/*
+ * Per block device queue structure
+ */
struct cfq_data {
- struct list_head rr_list;
+ atomic_t ref;
+ request_queue_t *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;
+ unsigned int busy_queues;
+
+ /*
+ * non-ordered list of empty cfqq's
+ */
struct list_head empty_list;
+ /*
+ * cfqq lookup hash
+ */
struct hlist_head *cfq_hash;
- struct hlist_head *crq_hash;
- /* queues on rr_list (ie they have pending requests */
- unsigned int busy_queues;
+ /*
+ * global crq hash for all queues
+ */
+ struct hlist_head *crq_hash;
unsigned int max_queued;
- atomic_t ref;
+ mempool_t *crq_pool;
- int key_type;
+ int rq_in_driver;
- mempool_t *crq_pool;
+ /*
+ * schedule slice state info
+ */
+ /*
+ * idle window management
+ */
+ struct timer_list idle_slice_timer;
+ struct work_struct unplug_work;
- request_queue_t *queue;
+ 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;
+ unsigned long last_end_request;
- int rq_in_driver;
+ unsigned int rq_starved;
/*
* tunables, see top of file
*/
unsigned int cfq_quantum;
unsigned int cfq_queued;
- unsigned int cfq_fifo_expire_r;
- unsigned int cfq_fifo_expire_w;
- unsigned int cfq_fifo_batch_expire;
+ unsigned int cfq_fifo_expire[2];
unsigned int cfq_back_penalty;
unsigned int cfq_back_max;
- unsigned int find_best_crq;
-
- unsigned int cfq_tagged;
+ unsigned int cfq_slice[2];
+ unsigned int cfq_slice_async_rq;
+ unsigned int cfq_slice_idle;
+ unsigned int cfq_max_depth;
};
+/*
+ * Per process-grouping structure
+ */
struct cfq_queue {
/* reference count */
atomic_t ref;
/* parent cfq_data */
struct cfq_data *cfqd;
- /* hash of mergeable requests */
+ /* cfqq lookup hash */
struct hlist_node cfq_hash;
/* hash key */
- unsigned long key;
- /* whether queue is on rr (or empty) list */
- int on_rr;
+ unsigned int key;
/* on either rr or empty list of cfqd */
struct list_head cfq_list;
/* sorted list of pending requests */
/* currently allocated requests */
int allocated[2];
/* fifo list of requests in sort_list */
- struct list_head fifo[2];
- /* last time fifo expired */
- unsigned long last_fifo_expire;
+ struct list_head fifo;
- int key_type;
+ unsigned long slice_start;
+ unsigned long slice_end;
+ unsigned long slice_left;
+ unsigned long service_last;
- unsigned long service_start;
- unsigned long service_used;
+ /* number of requests that are on the dispatch list */
+ int on_dispatch[2];
- unsigned int max_rate;
+ /* io prio of this group */
+ unsigned short ioprio, org_ioprio;
+ unsigned short ioprio_class, org_ioprio_class;
- /* number of requests that have been handed to the driver */
- int in_flight;
- /* number of currently allocated requests */
- int alloc_limit[2];
+ /* various state flags, see below */
+ unsigned int flags;
};
struct cfq_rq {
struct cfq_queue *cfq_queue;
struct cfq_io_context *io_context;
- unsigned long service_start;
- unsigned long queue_start;
+ unsigned int crq_flags;
+};
+
+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_expired,
+};
- unsigned int in_flight : 1;
- unsigned int accounted : 1;
- unsigned int is_sync : 1;
- unsigned int is_write : 1;
+#define CFQ_CFQQ_FNS(name) \
+static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \
+{ \
+ cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \
+} \
+static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \
+{ \
+ cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \
+} \
+static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \
+{ \
+ return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \
+}
+
+CFQ_CFQQ_FNS(on_rr);
+CFQ_CFQQ_FNS(wait_request);
+CFQ_CFQQ_FNS(must_alloc);
+CFQ_CFQQ_FNS(must_alloc_slice);
+CFQ_CFQQ_FNS(must_dispatch);
+CFQ_CFQQ_FNS(fifo_expire);
+CFQ_CFQQ_FNS(idle_window);
+CFQ_CFQQ_FNS(prio_changed);
+CFQ_CFQQ_FNS(expired);
+#undef CFQ_CFQQ_FNS
+
+enum cfq_rq_state_flags {
+ CFQ_CRQ_FLAG_in_flight = 0,
+ CFQ_CRQ_FLAG_in_driver,
+ CFQ_CRQ_FLAG_is_sync,
+ CFQ_CRQ_FLAG_requeued,
};
-static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned long);
+#define CFQ_CRQ_FNS(name) \
+static inline void cfq_mark_crq_##name(struct cfq_rq *crq) \
+{ \
+ crq->crq_flags |= (1 << CFQ_CRQ_FLAG_##name); \
+} \
+static inline void cfq_clear_crq_##name(struct cfq_rq *crq) \
+{ \
+ crq->crq_flags &= ~(1 << CFQ_CRQ_FLAG_##name); \
+} \
+static inline int cfq_crq_##name(const struct cfq_rq *crq) \
+{ \
+ return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \
+}
+
+CFQ_CRQ_FNS(in_flight);
+CFQ_CRQ_FNS(in_driver);
+CFQ_CRQ_FNS(is_sync);
+CFQ_CRQ_FNS(requeued);
+#undef CFQ_CRQ_FNS
+
+static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short);
static void cfq_dispatch_sort(request_queue_t *, struct cfq_rq *);
-static void cfq_update_next_crq(struct cfq_rq *);
static void cfq_put_cfqd(struct cfq_data *cfqd);
-/*
- * what the fairness is based on (ie how processes are grouped and
- * differentiated)
- */
-static inline unsigned long
-cfq_hash_key(struct cfq_data *cfqd, struct task_struct *tsk)
-{
- /*
- * optimize this so that ->key_type is the offset into the struct
- */
- switch (cfqd->key_type) {
- case CFQ_KEY_PGID:
- return process_group(tsk);
- default:
- case CFQ_KEY_TGID:
- return tsk->tgid;
- case CFQ_KEY_UID:
- return tsk->uid;
- case CFQ_KEY_GID:
- return tsk->gid;
- }
-}
+#define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE)
/*
* lots of deadline iosched dupes, can be abstracted later...
if (q->last_merge == crq->request)
q->last_merge = NULL;
-
- cfq_update_next_crq(crq);
}
static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq)
{
const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request));
- BUG_ON(!hlist_unhashed(&crq->hash));
-
hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]);
}
struct cfq_rq *crq = list_entry_hash(entry);
struct request *__rq = crq->request;
- BUG_ON(hlist_unhashed(&crq->hash));
-
if (!rq_mergeable(__rq)) {
cfq_del_crq_hash(crq);
continue;
return NULL;
}
+static inline int cfq_pending_requests(struct cfq_data *cfqd)
+{
+ return !list_empty(&cfqd->queue->queue_head) || cfqd->busy_queues;
+}
+
+/*
+ * scheduler run of queue, if there are requests pending and no one in the
+ * driver that will restart queueing
+ */
+static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
+{
+ if (!cfqd->rq_in_driver && cfq_pending_requests(cfqd))
+ kblockd_schedule_work(&cfqd->unplug_work);
+}
+
+static int cfq_queue_empty(request_queue_t *q)
+{
+ struct cfq_data *cfqd = q->elevator->elevator_data;
+
+ return !cfq_pending_requests(cfqd);
+}
+
/*
* Lifted from AS - choose which of crq1 and crq2 that is best served now.
* We choose the request that is closest to the head right now. Distance
return crq2;
if (crq2 == NULL)
return crq1;
+ if (cfq_crq_requeued(crq1))
+ return crq1;
+ if (cfq_crq_requeued(crq2))
+ return crq2;
s1 = crq1->request->sector;
s2 = crq2->request->sector;
last = cfqd->last_sector;
-#if 0
- if (!list_empty(&cfqd->queue->queue_head)) {
- struct list_head *entry = &cfqd->queue->queue_head;
- unsigned long distance = ~0UL;
- struct request *rq;
-
- while ((entry = entry->prev) != &cfqd->queue->queue_head) {
- rq = list_entry_rq(entry);
-
- if (blk_barrier_rq(rq))
- break;
-
- if (distance < abs(s1 - rq->sector + rq->nr_sectors)) {
- distance = abs(s1 - rq->sector +rq->nr_sectors);
- last = rq->sector + rq->nr_sectors;
- }
- if (distance < abs(s2 - rq->sector + rq->nr_sectors)) {
- distance = abs(s2 - rq->sector +rq->nr_sectors);
- last = rq->sector + rq->nr_sectors;
- }
- }
- }
-#endif
-
/*
* by definition, 1KiB is 2 sectors
*/
struct cfq_rq *crq_next = NULL, *crq_prev = NULL;
struct rb_node *rbnext, *rbprev;
- if (!ON_RB(&last->rb_node))
- return NULL;
-
- if ((rbnext = rb_next(&last->rb_node)) == NULL)
+ rbnext = NULL;
+ if (ON_RB(&last->rb_node))
+ rbnext = rb_next(&last->rb_node);
+ if (!rbnext) {
rbnext = rb_first(&cfqq->sort_list);
+ if (rbnext == &last->rb_node)
+ rbnext = NULL;
+ }
rbprev = rb_prev(&last->rb_node);
cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq);
}
-static int cfq_check_sort_rr_list(struct cfq_queue *cfqq)
+static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
{
- struct list_head *head = &cfqq->cfqd->rr_list;
- struct list_head *next, *prev;
-
- /*
- * list might still be ordered
- */
- next = cfqq->cfq_list.next;
- if (next != head) {
- struct cfq_queue *cnext = list_entry_cfqq(next);
+ struct cfq_data *cfqd = cfqq->cfqd;
+ struct list_head *list, *entry;
- if (cfqq->service_used > cnext->service_used)
- return 1;
- }
+ BUG_ON(!cfq_cfqq_on_rr(cfqq));
- prev = cfqq->cfq_list.prev;
- if (prev != head) {
- struct cfq_queue *cprev = list_entry_cfqq(prev);
+ list_del(&cfqq->cfq_list);
- if (cfqq->service_used < cprev->service_used)
- return 1;
+ if (cfq_class_rt(cfqq))
+ list = &cfqd->cur_rr;
+ else if (cfq_class_idle(cfqq))
+ list = &cfqd->idle_rr;
+ else {
+ /*
+ * 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
+ */
+ if (cfq_cfqq_dispatched(cfqq))
+ list = &cfqd->busy_rr;
+ else
+ list = &cfqd->rr_list[cfqq->ioprio];
}
- return 0;
-}
-
-static void cfq_sort_rr_list(struct cfq_queue *cfqq, int new_queue)
-{
- struct list_head *entry = &cfqq->cfqd->rr_list;
-
- if (!cfqq->on_rr)
- return;
- if (!new_queue && !cfq_check_sort_rr_list(cfqq))
+ /*
+ * if queue was preempted, just add to front to be fair. busy_rr
+ * isn't sorted.
+ */
+ if (preempted || list == &cfqd->busy_rr) {
+ list_add(&cfqq->cfq_list, list);
return;
-
- list_del(&cfqq->cfq_list);
+ }
/*
- * sort by our mean service_used, sub-sort by in-flight requests
+ * sort by when queue was last serviced
*/
- while ((entry = entry->prev) != &cfqq->cfqd->rr_list) {
+ entry = list;
+ while ((entry = entry->prev) != list) {
struct cfq_queue *__cfqq = list_entry_cfqq(entry);
- if (cfqq->service_used > __cfqq->service_used)
+ if (!__cfqq->service_last)
+ break;
+ if (time_before(__cfqq->service_last, cfqq->service_last))
break;
- else if (cfqq->service_used == __cfqq->service_used) {
- struct list_head *prv;
-
- while ((prv = entry->prev) != &cfqq->cfqd->rr_list) {
- __cfqq = list_entry_cfqq(prv);
-
- WARN_ON(__cfqq->service_used > cfqq->service_used);
- if (cfqq->service_used != __cfqq->service_used)
- break;
- if (cfqq->in_flight > __cfqq->in_flight)
- break;
-
- entry = prv;
- }
- }
}
list_add(&cfqq->cfq_list, entry);
/*
* add to busy list of queues for service, trying to be fair in ordering
- * the pending list according to requests serviced
+ * the pending list according to last request service
*/
static inline void
-cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq, int requeue)
{
- /*
- * it's currently on the empty list
- */
- cfqq->on_rr = 1;
+ BUG_ON(cfq_cfqq_on_rr(cfqq));
+ cfq_mark_cfqq_on_rr(cfqq);
cfqd->busy_queues++;
- if (time_after(jiffies, cfqq->service_start + cfq_service))
- cfqq->service_used >>= 3;
-
- cfq_sort_rr_list(cfqq, 1);
+ cfq_resort_rr_list(cfqq, requeue);
}
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_move(&cfqq->cfq_list, &cfqd->empty_list);
- cfqq->on_rr = 0;
BUG_ON(!cfqd->busy_queues);
cfqd->busy_queues--;
if (ON_RB(&crq->rb_node)) {
struct cfq_data *cfqd = cfqq->cfqd;
+ const int sync = cfq_crq_is_sync(crq);
- BUG_ON(!cfqq->queued[crq->is_sync]);
+ BUG_ON(!cfqq->queued[sync]);
+ cfqq->queued[sync]--;
cfq_update_next_crq(crq);
- cfqq->queued[crq->is_sync]--;
rb_erase(&crq->rb_node, &cfqq->sort_list);
RB_CLEAR_COLOR(&crq->rb_node);
- if (RB_EMPTY(&cfqq->sort_list) && cfqq->on_rr)
+ if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list))
cfq_del_cfqq_rr(cfqd, cfqq);
}
}
struct cfq_rq *__alias;
crq->rb_key = rq_rb_key(rq);
- cfqq->queued[crq->is_sync]++;
+ cfqq->queued[cfq_crq_is_sync(crq)]++;
/*
* looks a little odd, but the first insert might return an alias.
rb_insert_color(&crq->rb_node, &cfqq->sort_list);
- if (!cfqq->on_rr)
- cfq_add_cfqq_rr(cfqd, cfqq);
+ if (!cfq_cfqq_on_rr(cfqq))
+ cfq_add_cfqq_rr(cfqd, cfqq, cfq_crq_requeued(crq));
/*
* check if this request is a better next-serve candidate
{
if (ON_RB(&crq->rb_node)) {
rb_erase(&crq->rb_node, &cfqq->sort_list);
- cfqq->queued[crq->is_sync]--;
+ cfqq->queued[cfq_crq_is_sync(crq)]--;
}
cfq_add_crq_rb(crq);
}
-static struct request *
-cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector)
+static struct request *cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector)
+
{
- const unsigned long key = cfq_hash_key(cfqd, current);
- struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, key);
+ struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, current->pid, CFQ_KEY_ANY);
struct rb_node *n;
if (!cfqq)
static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
{
+ struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_rq *crq = RQ_DATA(rq);
if (crq) {
struct cfq_queue *cfqq = crq->cfq_queue;
- if (cfqq->cfqd->cfq_tagged) {
- cfqq->service_used--;
- cfq_sort_rr_list(cfqq, 0);
+ if (cfq_crq_in_driver(crq)) {
+ cfq_clear_crq_in_driver(crq);
+ WARN_ON(!cfqd->rq_in_driver);
+ cfqd->rq_in_driver--;
}
+ if (cfq_crq_in_flight(crq)) {
+ const int sync = cfq_crq_is_sync(crq);
- if (crq->accounted) {
- crq->accounted = 0;
- cfqq->cfqd->rq_in_driver--;
+ cfq_clear_crq_in_flight(crq);
+ WARN_ON(!cfqq->on_dispatch[sync]);
+ cfqq->on_dispatch[sync]--;
}
+ cfq_mark_crq_requeued(crq);
}
}
struct cfq_rq *crq = RQ_DATA(rq);
if (crq) {
- cfq_remove_merge_hints(q, crq);
list_del_init(&rq->queuelist);
+ cfq_del_crq_rb(crq);
+ cfq_remove_merge_hints(q, crq);
- if (crq->cfq_queue)
- cfq_del_crq_rb(crq);
}
}
}
__rq = cfq_find_rq_hash(cfqd, bio->bi_sector);
- if (__rq) {
- BUG_ON(__rq->sector + __rq->nr_sectors != bio->bi_sector);
-
- if (elv_rq_merge_ok(__rq, bio)) {
- ret = ELEVATOR_BACK_MERGE;
- goto out;
- }
+ if (__rq && elv_rq_merge_ok(__rq, bio)) {
+ ret = ELEVATOR_BACK_MERGE;
+ goto out;
}
__rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio));
- if (__rq) {
- if (elv_rq_merge_ok(__rq, bio)) {
- ret = ELEVATOR_FRONT_MERGE;
- goto out;
- }
+ if (__rq && elv_rq_merge_ok(__rq, bio)) {
+ ret = ELEVATOR_FRONT_MERGE;
+ goto out;
}
return ELEVATOR_NO_MERGE;
cfq_merged_requests(request_queue_t *q, struct request *rq,
struct request *next)
{
- struct cfq_rq *crq = RQ_DATA(rq);
- struct cfq_rq *cnext = RQ_DATA(next);
-
cfq_merged_request(q, rq);
- if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist)) {
- if (time_before(cnext->queue_start, crq->queue_start)) {
- list_move(&rq->queuelist, &next->queuelist);
- crq->queue_start = cnext->queue_start;
- }
- }
+ /*
+ * reposition in fifo if next is older than rq
+ */
+ if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) &&
+ time_before(next->start_time, rq->start_time))
+ list_move(&rq->queuelist, &next->queuelist);
- cfq_update_next_crq(cnext);
cfq_remove_request(q, next);
}
+static inline void
+__cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+ if (cfqq) {
+ /*
+ * stop potential idle class queues waiting service
+ */
+ 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_clear_cfqq_expired(cfqq);
+ }
+
+ cfqd->active_queue = cfqq;
+}
+
/*
- * we dispatch cfqd->cfq_quantum requests in total from the rr_list queues,
- * this function sector sorts the selected request to minimize seeks. we start
- * at cfqd->last_sector, not 0.
+ * 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
*/
-static void cfq_dispatch_sort(request_queue_t *q, struct cfq_rq *crq)
+static int cfq_get_next_prio_level(struct cfq_data *cfqd)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_queue *cfqq = crq->cfq_queue;
- struct list_head *head = &q->queue_head, *entry = head;
- struct request *__rq;
- sector_t last;
-
- cfq_del_crq_rb(crq);
- cfq_remove_merge_hints(q, crq);
- list_del(&crq->request->queuelist);
+ int prio, wrap;
- last = cfqd->last_sector;
- while ((entry = entry->prev) != head) {
- __rq = list_entry_rq(entry);
+ prio = -1;
+ wrap = 0;
+ do {
+ int p;
- if (blk_barrier_rq(crq->request))
- break;
- if (!blk_fs_request(crq->request))
- break;
+ for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) {
+ if (!list_empty(&cfqd->rr_list[p])) {
+ prio = p;
+ break;
+ }
+ }
- if (crq->request->sector > __rq->sector)
- break;
- if (__rq->sector > last && crq->request->sector < last) {
- last = crq->request->sector;
+ 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);
- cfqd->last_sector = last;
- crq->in_flight = 1;
- cfqq->in_flight++;
- list_add(&crq->request->queuelist, entry);
-}
+ if (unlikely(prio == -1))
+ return -1;
-/*
- * return expired entry, or NULL to just start from scratch in rbtree
- */
-static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq)
-{
- struct cfq_data *cfqd = cfqq->cfqd;
- const int reads = !list_empty(&cfqq->fifo[0]);
- const int writes = !list_empty(&cfqq->fifo[1]);
- unsigned long now = jiffies;
- struct cfq_rq *crq;
+ BUG_ON(prio >= CFQ_PRIO_LISTS);
- if (time_before(now, cfqq->last_fifo_expire + cfqd->cfq_fifo_batch_expire))
- return NULL;
+ list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr);
- crq = RQ_DATA(list_entry(cfqq->fifo[0].next, struct request, queuelist));
- if (reads && time_after(now, crq->queue_start + cfqd->cfq_fifo_expire_r)) {
- cfqq->last_fifo_expire = now;
- return crq;
+ cfqd->cur_prio = prio + 1;
+ if (cfqd->cur_prio > cfqd->cur_end_prio) {
+ cfqd->cur_end_prio = cfqd->cur_prio;
+ cfqd->cur_prio = 0;
}
-
- crq = RQ_DATA(list_entry(cfqq->fifo[1].next, struct request, queuelist));
- if (writes && time_after(now, crq->queue_start + cfqd->cfq_fifo_expire_w)) {
- cfqq->last_fifo_expire = now;
- return crq;
+ if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) {
+ cfqd->cur_prio = 0;
+ cfqd->cur_end_prio = 0;
}
- return NULL;
+ return prio;
}
-/*
- * dispatch a single request from given queue
- */
-static inline void
-cfq_dispatch_request(request_queue_t *q, struct cfq_data *cfqd,
- struct cfq_queue *cfqq)
+static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
{
- struct cfq_rq *crq;
+ struct cfq_queue *cfqq;
/*
- * follow expired path, else get first next available
+ * if current queue is expired but not done with its requests yet,
+ * wait for that to happen
*/
- if ((crq = cfq_check_fifo(cfqq)) == NULL) {
- if (cfqd->find_best_crq)
- crq = cfqq->next_crq;
- else
- crq = rb_entry_crq(rb_first(&cfqq->sort_list));
+ if ((cfqq = cfqd->active_queue) != NULL) {
+ if (cfq_cfqq_expired(cfqq) && cfq_cfqq_dispatched(cfqq))
+ return NULL;
}
- cfqd->last_sector = crq->request->sector + crq->request->nr_sectors;
+ /*
+ * 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
+ */
+ if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1)
+ cfqq = list_entry_cfqq(cfqd->cur_rr.next);
/*
- * finally, insert request into driver list
+ * 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
*/
- cfq_dispatch_sort(q, crq);
+ if (!cfqq && !list_empty(&cfqd->idle_rr)) {
+ 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);
+ }
+
+ __cfq_set_active_queue(cfqd, cfqq);
+ return cfqq;
}
-static int cfq_dispatch_requests(request_queue_t *q, int max_dispatch)
+/*
+ * current cfqq expired its slice (or was too idle), select new one
+ */
+static void
+__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
+ int preempted)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_queue *cfqq;
- struct list_head *entry, *tmp;
- int queued, busy_queues, first_round;
-
- if (list_empty(&cfqd->rr_list))
- return 0;
+ unsigned long now = jiffies;
- queued = 0;
- first_round = 1;
-restart:
- busy_queues = 0;
- list_for_each_safe(entry, tmp, &cfqd->rr_list) {
- cfqq = list_entry_cfqq(entry);
+ if (cfq_cfqq_wait_request(cfqq))
+ del_timer(&cfqd->idle_slice_timer);
- BUG_ON(RB_EMPTY(&cfqq->sort_list));
+ if (!preempted && !cfq_cfqq_dispatched(cfqq))
+ cfqq->service_last = now;
- /*
- * first round of queueing, only select from queues that
- * don't already have io in-flight
- */
- if (first_round && cfqq->in_flight)
- continue;
+ cfq_clear_cfqq_must_dispatch(cfqq);
+ cfq_clear_cfqq_wait_request(cfqq);
- cfq_dispatch_request(q, cfqd, cfqq);
+ /*
+ * store what was left of this slice, if the queue idled out
+ * or was preempted
+ */
+ if (time_after(now, cfqq->slice_end))
+ cfqq->slice_left = now - cfqq->slice_end;
+ else
+ cfqq->slice_left = 0;
- if (!RB_EMPTY(&cfqq->sort_list))
- busy_queues++;
+ if (cfq_cfqq_on_rr(cfqq))
+ cfq_resort_rr_list(cfqq, preempted);
- queued++;
- }
+ if (cfqq == cfqd->active_queue)
+ cfqd->active_queue = NULL;
- if ((queued < max_dispatch) && (busy_queues || first_round)) {
- first_round = 0;
- goto restart;
+ if (cfqd->active_cic) {
+ put_io_context(cfqd->active_cic->ioc);
+ cfqd->active_cic = NULL;
}
- return queued;
+ cfqd->dispatch_slice = 0;
}
-static inline void cfq_account_dispatch(struct cfq_rq *crq)
+static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted)
{
- struct cfq_queue *cfqq = crq->cfq_queue;
- struct cfq_data *cfqd = cfqq->cfqd;
- unsigned long now, elapsed;
+ struct cfq_queue *cfqq = cfqd->active_queue;
- if (!blk_fs_request(crq->request))
- return;
+ if (cfqq) {
+ /*
+ * use deferred expiry, if there are requests in progress as
+ * not to disturb the slice of the next queue
+ */
+ if (cfq_cfqq_dispatched(cfqq))
+ cfq_mark_cfqq_expired(cfqq);
+ else
+ __cfq_slice_expired(cfqd, cfqq, preempted);
+ }
+}
- /*
- * accounted bit is necessary since some drivers will call
- * elv_next_request() many times for the same request (eg ide)
- */
- if (crq->accounted)
- return;
+static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
- now = jiffies;
- if (cfqq->service_start == ~0UL)
- cfqq->service_start = now;
+{
+ WARN_ON(!RB_EMPTY(&cfqq->sort_list));
+ WARN_ON(cfqq != cfqd->active_queue);
/*
- * on drives with tagged command queueing, command turn-around time
- * doesn't necessarily reflect the time spent processing this very
- * command inside the drive. so do the accounting differently there,
- * by just sorting on the number of requests
+ * idle is disabled, either manually or by past process history
*/
- if (cfqd->cfq_tagged) {
- if (time_after(now, cfqq->service_start + cfq_service)) {
- cfqq->service_start = now;
- cfqq->service_used /= 10;
- }
-
- cfqq->service_used++;
- cfq_sort_rr_list(cfqq, 0);
- }
+ if (!cfqd->cfq_slice_idle)
+ return 0;
+ if (!cfq_cfqq_idle_window(cfqq))
+ return 0;
+ /*
+ * task has exited, don't wait
+ */
+ if (cfqd->active_cic && !cfqd->active_cic->ioc->task)
+ return 0;
- elapsed = now - crq->queue_start;
- if (elapsed > max_elapsed_dispatch)
- max_elapsed_dispatch = elapsed;
+ cfq_mark_cfqq_must_dispatch(cfqq);
+ cfq_mark_cfqq_wait_request(cfqq);
- crq->accounted = 1;
- crq->service_start = now;
+ if (!timer_pending(&cfqd->idle_slice_timer)) {
+ unsigned long slice_left = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle);
- if (++cfqd->rq_in_driver >= CFQ_MAX_TAG && !cfqd->cfq_tagged) {
- cfqq->cfqd->cfq_tagged = 1;
- printk("cfq: depth %d reached, tagging now on\n", CFQ_MAX_TAG);
+ cfqd->idle_slice_timer.expires = jiffies + slice_left;
+ add_timer(&cfqd->idle_slice_timer);
}
+
+ return 1;
}
-static inline void
-cfq_account_completion(struct cfq_queue *cfqq, struct cfq_rq *crq)
+/*
+ * we dispatch cfqd->cfq_quantum requests in total from the rr_list queues,
+ * this function sector sorts the selected request to minimize seeks. we start
+ * at cfqd->last_sector, not 0.
+ */
+static void cfq_dispatch_sort(request_queue_t *q, struct cfq_rq *crq)
+{
+ struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_queue *cfqq = crq->cfq_queue;
+ struct list_head *head = &q->queue_head, *entry = head;
+ struct request *__rq;
+ sector_t last;
+
+ list_del(&crq->request->queuelist);
+
+ last = cfqd->last_sector;
+ list_for_each_entry_reverse(__rq, head, queuelist) {
+ struct cfq_rq *__crq = RQ_DATA(__rq);
+
+ if (blk_barrier_rq(__rq))
+ break;
+ if (!blk_fs_request(__rq))
+ break;
+ if (cfq_crq_requeued(__crq))
+ break;
+
+ if (__rq->sector <= crq->request->sector)
+ break;
+ if (__rq->sector > last && crq->request->sector < last) {
+ last = crq->request->sector + crq->request->nr_sectors;
+ break;
+ }
+ entry = &__rq->queuelist;
+ }
+
+ cfqd->last_sector = last;
+
+ cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq);
+
+ cfq_del_crq_rb(crq);
+ cfq_remove_merge_hints(q, crq);
+
+ cfq_mark_crq_in_flight(crq);
+ cfq_clear_crq_requeued(crq);
+
+ cfqq->on_dispatch[cfq_crq_is_sync(crq)]++;
+ list_add_tail(&crq->request->queuelist, entry);
+}
+
+/*
+ * return expired entry, or NULL to just start from scratch in rbtree
+ */
+static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq)
{
struct cfq_data *cfqd = cfqq->cfqd;
+ struct request *rq;
+ struct cfq_rq *crq;
- if (!crq->accounted)
+ if (cfq_cfqq_fifo_expire(cfqq))
+ return NULL;
+
+ if (!list_empty(&cfqq->fifo)) {
+ int fifo = cfq_cfqq_class_sync(cfqq);
+
+ crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next));
+ rq = crq->request;
+ if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) {
+ cfq_mark_cfqq_fifo_expire(cfqq);
+ return crq;
+ }
+ }
+
+ 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);
+
+ 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;
+}
+
+static inline int
+cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+ const int base_rq = cfqd->cfq_slice_async_rq;
+
+ WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
+
+ return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio));
+}
+
+/*
+ * get next queue for service
+ */
+static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd, int force)
+{
+ unsigned long now = jiffies;
+ struct cfq_queue *cfqq;
+
+ cfqq = cfqd->active_queue;
+ if (!cfqq)
+ goto new_queue;
+
+ if (cfq_cfqq_expired(cfqq))
+ goto new_queue;
+
+ /*
+ * slice has expired
+ */
+ if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end))
+ goto expire;
+
+ /*
+ * if queue has requests, dispatch one. if not, check if
+ * enough slice is left to wait for one
+ */
+ if (!RB_EMPTY(&cfqq->sort_list))
+ goto keep_queue;
+ else if (!force && cfq_cfqq_class_sync(cfqq) &&
+ time_before(now, cfqq->slice_end)) {
+ if (cfq_arm_slice_timer(cfqd, cfqq))
+ return NULL;
+ }
+
+expire:
+ cfq_slice_expired(cfqd, 0);
+new_queue:
+ cfqq = cfq_set_active_queue(cfqd);
+keep_queue:
+ return cfqq;
+}
+
+static int
+__cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
+ int max_dispatch)
+{
+ int dispatched = 0;
+
+ BUG_ON(RB_EMPTY(&cfqq->sort_list));
+
+ do {
+ struct cfq_rq *crq;
+
+ /*
+ * follow expired path, else get first next available
+ */
+ if ((crq = cfq_check_fifo(cfqq)) == NULL)
+ crq = cfqq->next_crq;
+
+ /*
+ * finally, insert request into driver dispatch list
+ */
+ cfq_dispatch_sort(cfqd->queue, crq);
+
+ cfqd->dispatch_slice++;
+ dispatched++;
+
+ if (!cfqd->active_cic) {
+ atomic_inc(&crq->io_context->ioc->refcount);
+ cfqd->active_cic = crq->io_context;
+ }
+
+ if (RB_EMPTY(&cfqq->sort_list))
+ break;
+
+ } while (dispatched < max_dispatch);
+
+ /*
+ * if slice end isn't set yet, set it. if at least one request was
+ * sync, use the sync time slice value
+ */
+ 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_slice_expired(cfqd, 0);
+
+ return dispatched;
+}
+
+static int
+cfq_dispatch_requests(request_queue_t *q, int max_dispatch, int force)
+{
+ struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_queue *cfqq;
+
+ if (!cfqd->busy_queues)
+ return 0;
+
+ cfqq = cfq_select_queue(cfqd, force);
+ if (cfqq) {
+ cfq_clear_cfqq_must_dispatch(cfqq);
+ cfq_clear_cfqq_wait_request(cfqq);
+ del_timer(&cfqd->idle_slice_timer);
+
+ if (cfq_class_idle(cfqq))
+ max_dispatch = 1;
+
+ return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
+ }
+
+ return 0;
+}
+
+static inline void cfq_account_dispatch(struct cfq_rq *crq)
+{
+ struct cfq_queue *cfqq = crq->cfq_queue;
+ struct cfq_data *cfqd = cfqq->cfqd;
+
+ if (unlikely(!blk_fs_request(crq->request)))
+ return;
+
+ /*
+ * accounted bit is necessary since some drivers will call
+ * elv_next_request() many times for the same request (eg ide)
+ */
+ if (cfq_crq_in_driver(crq))
+ return;
+
+ cfq_mark_crq_in_driver(crq);
+ cfqd->rq_in_driver++;
+}
+
+static inline void
+cfq_account_completion(struct cfq_queue *cfqq, struct cfq_rq *crq)
+{
+ struct cfq_data *cfqd = cfqq->cfqd;
+ unsigned long now;
+
+ if (!cfq_crq_in_driver(crq))
return;
+ now = jiffies;
+
WARN_ON(!cfqd->rq_in_driver);
cfqd->rq_in_driver--;
- if (!cfqd->cfq_tagged) {
- unsigned long now = jiffies;
- unsigned long duration = now - crq->service_start;
+ if (!cfq_class_idle(cfqq))
+ cfqd->last_end_request = now;
- if (time_after(now, cfqq->service_start + cfq_service)) {
- cfqq->service_start = now;
- cfqq->service_used >>= 3;
+ if (!cfq_cfqq_dispatched(cfqq)) {
+ if (cfq_cfqq_on_rr(cfqq)) {
+ cfqq->service_last = now;
+ cfq_resort_rr_list(cfqq, 0);
+ }
+ if (cfq_cfqq_expired(cfqq)) {
+ __cfq_slice_expired(cfqd, cfqq, 0);
+ cfq_schedule_dispatch(cfqd);
}
-
- cfqq->service_used += duration;
- cfq_sort_rr_list(cfqq, 0);
-
- if (duration > max_elapsed_crq)
- max_elapsed_crq = duration;
}
+
+ if (cfq_crq_is_sync(crq))
+ crq->io_context->last_end_request = now;
}
static struct request *cfq_next_request(request_queue_t *q)
dispatch:
rq = list_entry_rq(q->queue_head.next);
- if ((crq = RQ_DATA(rq)) != NULL) {
+ crq = RQ_DATA(rq);
+ if (crq) {
+ struct cfq_queue *cfqq = crq->cfq_queue;
+
+ /*
+ * if idle window is disabled, allow queue buildup
+ */
+ if (!cfq_crq_in_driver(crq) &&
+ !cfq_cfqq_idle_window(cfqq) &&
+ cfqd->rq_in_driver >= cfqd->cfq_max_depth)
+ return NULL;
+
cfq_remove_merge_hints(q, crq);
cfq_account_dispatch(crq);
}
return rq;
}
- if (cfq_dispatch_requests(q, cfqd->cfq_quantum))
+ if (cfq_dispatch_requests(q, cfqd->cfq_quantum, 0))
goto dispatch;
return NULL;
*/
static void cfq_put_queue(struct cfq_queue *cfqq)
{
- BUG_ON(!atomic_read(&cfqq->ref));
+ struct cfq_data *cfqd = cfqq->cfqd;
+
+ BUG_ON(atomic_read(&cfqq->ref) <= 0);
if (!atomic_dec_and_test(&cfqq->ref))
return;
BUG_ON(rb_first(&cfqq->sort_list));
- BUG_ON(cfqq->on_rr);
+ BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]);
+ BUG_ON(cfq_cfqq_on_rr(cfqq));
+
+ if (unlikely(cfqd->active_queue == cfqq)) {
+ __cfq_slice_expired(cfqd, cfqq, 0);
+ cfq_schedule_dispatch(cfqd);
+ }
cfq_put_cfqd(cfqq->cfqd);
}
static inline struct cfq_queue *
-__cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned long key, const int hashval)
+__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, *next;
hlist_for_each_safe(entry, next, hash_list) {
struct cfq_queue *__cfqq = list_entry_qhash(entry);
+ const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->ioprio_class, __cfqq->ioprio);
- if (__cfqq->key == key)
+ if (__cfqq->key == key && (__p == prio || prio == CFQ_KEY_ANY))
return __cfqq;
}
}
static struct cfq_queue *
-cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned long key)
+cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio)
{
- return __cfq_find_cfq_hash(cfqd, key, hash_long(key, CFQ_QHASH_SHIFT));
+ return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT));
}
-static inline void
-cfq_rehash_cfqq(struct cfq_data *cfqd, struct cfq_queue **cfqq,
- struct cfq_io_context *cic)
+static void cfq_free_io_context(struct cfq_io_context *cic)
{
- unsigned long hashkey = cfq_hash_key(cfqd, current);
- unsigned long hashval = hash_long(hashkey, CFQ_QHASH_SHIFT);
- struct cfq_queue *__cfqq;
- unsigned long flags;
-
- spin_lock_irqsave(cfqd->queue->queue_lock, flags);
-
- hlist_del(&(*cfqq)->cfq_hash);
+ struct cfq_io_context *__cic;
+ struct list_head *entry, *next;
- __cfqq = __cfq_find_cfq_hash(cfqd, hashkey, hashval);
- if (!__cfqq || __cfqq == *cfqq) {
- __cfqq = *cfqq;
- hlist_add_head(&__cfqq->cfq_hash, &cfqd->cfq_hash[hashval]);
- __cfqq->key_type = cfqd->key_type;
- } else {
- atomic_inc(&__cfqq->ref);
- cic->cfqq = __cfqq;
- cfq_put_queue(*cfqq);
- *cfqq = __cfqq;
+ list_for_each_safe(entry, next, &cic->list) {
+ __cic = list_entry(entry, struct cfq_io_context, list);
+ kmem_cache_free(cfq_ioc_pool, __cic);
}
- cic->cfqq = __cfqq;
- spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
+ kmem_cache_free(cfq_ioc_pool, cic);
}
-static void cfq_free_io_context(struct cfq_io_context *cic)
+/*
+ * Called with interrupts disabled
+ */
+static void cfq_exit_single_io_context(struct cfq_io_context *cic)
{
- kmem_cache_free(cfq_ioc_pool, cic);
+ struct cfq_data *cfqd = cic->cfqq->cfqd;
+ request_queue_t *q = cfqd->queue;
+
+ WARN_ON(!irqs_disabled());
+
+ spin_lock(q->queue_lock);
+
+ if (unlikely(cic->cfqq == cfqd->active_queue)) {
+ __cfq_slice_expired(cfqd, cic->cfqq, 0);
+ cfq_schedule_dispatch(cfqd);
+ }
+
+ cfq_put_queue(cic->cfqq);
+ cic->cfqq = NULL;
+ spin_unlock(q->queue_lock);
}
/*
- * locking hierarchy is: io_context lock -> queue locks
+ * Another task may update the task cic list, if it is doing a queue lookup
+ * on its behalf. cfq_cic_lock excludes such concurrent updates
*/
static void cfq_exit_io_context(struct cfq_io_context *cic)
{
- struct cfq_queue *cfqq = cic->cfqq;
- struct list_head *entry = &cic->list;
- request_queue_t *q;
+ struct cfq_io_context *__cic;
+ struct list_head *entry;
unsigned long flags;
+ local_irq_save(flags);
+
/*
* put the reference this task is holding to the various queues
*/
- spin_lock_irqsave(&cic->ioc->lock, flags);
- while ((entry = cic->list.next) != &cic->list) {
- struct cfq_io_context *__cic;
-
+ list_for_each(entry, &cic->list) {
__cic = list_entry(entry, struct cfq_io_context, list);
- list_del(entry);
-
- q = __cic->cfqq->cfqd->queue;
- spin_lock(q->queue_lock);
- cfq_put_queue(__cic->cfqq);
- spin_unlock(q->queue_lock);
+ cfq_exit_single_io_context(__cic);
}
- q = cfqq->cfqd->queue;
- spin_lock(q->queue_lock);
- cfq_put_queue(cfqq);
- spin_unlock(q->queue_lock);
-
- cic->cfqq = NULL;
- spin_unlock_irqrestore(&cic->ioc->lock, flags);
+ cfq_exit_single_io_context(cic);
+ local_irq_restore(flags);
}
-static struct cfq_io_context *cfq_alloc_io_context(int gfp_flags)
+static struct cfq_io_context *
+cfq_alloc_io_context(struct cfq_data *cfqd, int gfp_mask)
{
- struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_flags);
+ struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask);
if (cic) {
- cic->dtor = cfq_free_io_context;
- cic->exit = cfq_exit_io_context;
INIT_LIST_HEAD(&cic->list);
cic->cfqq = NULL;
+ cic->key = NULL;
+ cic->last_end_request = jiffies;
+ cic->ttime_total = 0;
+ cic->ttime_samples = 0;
+ cic->ttime_mean = 0;
+ cic->dtor = cfq_free_io_context;
+ cic->exit = cfq_exit_io_context;
}
return cic;
}
+static void cfq_init_prio_data(struct cfq_queue *cfqq)
+{
+ struct task_struct *tsk = current;
+ int ioprio_class;
+
+ if (!cfq_cfqq_prio_changed(cfqq))
+ return;
+
+ ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio);
+ switch (ioprio_class) {
+ default:
+ printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class);
+ case IOPRIO_CLASS_NONE:
+ /*
+ * no prio set, place us in the middle of the BE classes
+ */
+ cfqq->ioprio = task_nice_ioprio(tsk);
+ cfqq->ioprio_class = IOPRIO_CLASS_BE;
+ break;
+ case IOPRIO_CLASS_RT:
+ cfqq->ioprio = task_ioprio(tsk);
+ cfqq->ioprio_class = IOPRIO_CLASS_RT;
+ break;
+ case IOPRIO_CLASS_BE:
+ cfqq->ioprio = task_ioprio(tsk);
+ cfqq->ioprio_class = IOPRIO_CLASS_BE;
+ break;
+ case IOPRIO_CLASS_IDLE:
+ cfqq->ioprio_class = IOPRIO_CLASS_IDLE;
+ cfqq->ioprio = 7;
+ cfq_clear_cfqq_idle_window(cfqq);
+ break;
+ }
+
+ /*
+ * keep track of original prio settings in case we have to temporarily
+ * elevate the priority of this queue
+ */
+ 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);
+}
+
+static inline void changed_ioprio(struct cfq_queue *cfqq)
+{
+ if (cfqq) {
+ struct cfq_data *cfqd = cfqq->cfqd;
+
+ spin_lock(cfqd->queue->queue_lock);
+ cfq_mark_cfqq_prio_changed(cfqq);
+ cfq_init_prio_data(cfqq);
+ spin_unlock(cfqd->queue->queue_lock);
+ }
+}
+
+/*
+ * callback from sys_ioprio_set, irqs are disabled
+ */
+static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio)
+{
+ struct cfq_io_context *cic = ioc->cic;
+
+ changed_ioprio(cic->cfqq);
+
+ list_for_each_entry(cic, &cic->list, list)
+ changed_ioprio(cic->cfqq);
+
+ return 0;
+}
+
+static struct cfq_queue *
+cfq_get_queue(struct cfq_data *cfqd, unsigned int key, unsigned short ioprio,
+ int gfp_mask)
+{
+ const int hashval = hash_long(key, CFQ_QHASH_SHIFT);
+ struct cfq_queue *cfqq, *new_cfqq = NULL;
+
+retry:
+ cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval);
+
+ if (!cfqq) {
+ if (new_cfqq) {
+ cfqq = new_cfqq;
+ new_cfqq = NULL;
+ } else if (gfp_mask & __GFP_WAIT) {
+ spin_unlock_irq(cfqd->queue->queue_lock);
+ new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask);
+ spin_lock_irq(cfqd->queue->queue_lock);
+ goto retry;
+ } else {
+ cfqq = kmem_cache_alloc(cfq_pool, gfp_mask);
+ if (!cfqq)
+ goto out;
+ }
+
+ memset(cfqq, 0, sizeof(*cfqq));
+
+ INIT_HLIST_NODE(&cfqq->cfq_hash);
+ INIT_LIST_HEAD(&cfqq->cfq_list);
+ RB_CLEAR_ROOT(&cfqq->sort_list);
+ 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;
+ atomic_inc(&cfqd->ref);
+ cfqq->service_last = 0;
+ /*
+ * set ->slice_left to allow preemption for a new process
+ */
+ cfqq->slice_left = 2 * cfqd->cfq_slice_idle;
+ cfq_mark_cfqq_idle_window(cfqq);
+ cfq_mark_cfqq_prio_changed(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;
+}
+
/*
* Setup general io context and cfq io context. There can be several cfq
* io contexts per general io context, if this process is doing io to more
* cfqq, so we don't need to worry about it disappearing
*/
static struct cfq_io_context *
-cfq_get_io_context(struct cfq_queue **cfqq, int gfp_flags)
+cfq_get_io_context(struct cfq_data *cfqd, pid_t pid, int gfp_mask)
{
- struct cfq_data *cfqd = (*cfqq)->cfqd;
- struct cfq_queue *__cfqq = *cfqq;
+ struct io_context *ioc = NULL;
struct cfq_io_context *cic;
- struct io_context *ioc;
- might_sleep_if(gfp_flags & __GFP_WAIT);
+ might_sleep_if(gfp_mask & __GFP_WAIT);
- ioc = get_io_context(gfp_flags);
+ ioc = get_io_context(gfp_mask);
if (!ioc)
return NULL;
if ((cic = ioc->cic) == NULL) {
- cic = cfq_alloc_io_context(gfp_flags);
+ cic = cfq_alloc_io_context(cfqd, gfp_mask);
if (cic == NULL)
goto err;
+ /*
+ * manually increment generic io_context usage count, it
+ * cannot go away since we are already holding one ref to it
+ */
ioc->cic = cic;
+ ioc->set_ioprio = cfq_ioc_set_ioprio;
cic->ioc = ioc;
- cic->cfqq = __cfqq;
- atomic_inc(&__cfqq->ref);
+ cic->key = cfqd;
+ atomic_inc(&cfqd->ref);
} else {
struct cfq_io_context *__cic;
- unsigned long flags;
/*
- * since the first cic on the list is actually the head
- * itself, need to check this here or we'll duplicate an
- * cic per ioc for no reason
+ * the first cic on the list is actually the head itself
*/
- if (cic->cfqq == __cfqq)
+ if (cic->key == cfqd)
goto out;
/*
* should be ok here, the list will usually not be more than
* 1 or a few entries long
*/
- spin_lock_irqsave(&ioc->lock, flags);
list_for_each_entry(__cic, &cic->list, list) {
/*
* this process is already holding a reference to
* this queue, so no need to get one more
*/
- if (__cic->cfqq == __cfqq) {
+ if (__cic->key == cfqd) {
cic = __cic;
- spin_unlock_irqrestore(&ioc->lock, flags);
goto out;
}
}
- spin_unlock_irqrestore(&ioc->lock, flags);
/*
* nope, process doesn't have a cic assoicated with this
* cfqq yet. get a new one and add to list
*/
- __cic = cfq_alloc_io_context(gfp_flags);
+ __cic = cfq_alloc_io_context(cfqd, gfp_mask);
if (__cic == NULL)
goto err;
__cic->ioc = ioc;
- __cic->cfqq = __cfqq;
- atomic_inc(&__cfqq->ref);
- spin_lock_irqsave(&ioc->lock, flags);
+ __cic->key = cfqd;
+ atomic_inc(&cfqd->ref);
list_add(&__cic->list, &cic->list);
- spin_unlock_irqrestore(&ioc->lock, flags);
-
cic = __cic;
- *cfqq = __cfqq;
}
-out:
- /*
- * if key_type has been changed on the fly, we lazily rehash
- * each queue at lookup time
- */
- if ((*cfqq)->key_type != cfqd->key_type)
- cfq_rehash_cfqq(cfqd, cfqq, cic);
+out:
+ return cic;
+err:
+ put_io_context(ioc);
+ return NULL;
+}
+
+static void
+cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic)
+{
+ unsigned long elapsed, ttime;
+
+ /*
+ * if this context already has stuff queued, thinktime is from
+ * last queue not last end
+ */
+#if 0
+ if (time_after(cic->last_end_request, cic->last_queue))
+ elapsed = jiffies - cic->last_end_request;
+ else
+ elapsed = jiffies - cic->last_queue;
+#else
+ elapsed = jiffies - cic->last_end_request;
+#endif
+
+ ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle);
+
+ cic->ttime_samples = (7*cic->ttime_samples + 256) / 8;
+ cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8;
+ cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples;
+}
+
+#define sample_valid(samples) ((samples) > 80)
+
+/*
+ * Disable idle window if the process thinks too long or seeks so much that
+ * it doesn't matter
+ */
+static void
+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);
+
+ if (!cic->ioc->task || !cfqd->cfq_slice_idle)
+ enable_idle = 0;
+ else if (sample_valid(cic->ttime_samples)) {
+ if (cic->ttime_mean > cfqd->cfq_slice_idle)
+ enable_idle = 0;
+ else
+ enable_idle = 1;
+ }
+
+ if (enable_idle)
+ cfq_mark_cfqq_idle_window(cfqq);
+ else
+ 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.
+ */
+static int
+cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
+ struct cfq_rq *crq)
+{
+ struct cfq_queue *cfqq = cfqd->active_queue;
+
+ if (cfq_class_idle(new_cfqq))
+ return 0;
+
+ if (!cfqq)
+ return 1;
+
+ 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 (cfq_crq_is_sync(crq) && !cfq_cfqq_sync(cfqq))
+ return 1;
+
+ return 0;
+}
+
+/*
+ * cfqq preempts the active queue. if we allowed preempt with no slice left,
+ * let it have half of its nominal slice.
+ */
+static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+ struct cfq_queue *__cfqq, *next;
+
+ list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list)
+ cfq_resort_rr_list(__cfqq, 1);
- return cic;
-err:
- put_io_context(ioc);
- return NULL;
+ if (!cfqq->slice_left)
+ cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2;
+
+ cfqq->slice_end = cfqq->slice_left + jiffies;
+ __cfq_slice_expired(cfqd, cfqq, 1);
+ __cfq_set_active_queue(cfqd, cfqq);
}
-static struct cfq_queue *
-__cfq_get_queue(struct cfq_data *cfqd, unsigned long key, int gfp_mask)
+/*
+ * should really be a ll_rw_blk.c helper
+ */
+static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
- const int hashval = hash_long(key, CFQ_QHASH_SHIFT);
- struct cfq_queue *cfqq, *new_cfqq = NULL;
-
-retry:
- cfqq = __cfq_find_cfq_hash(cfqd, key, hashval);
+ request_queue_t *q = cfqd->queue;
- if (!cfqq) {
- if (new_cfqq) {
- cfqq = new_cfqq;
- new_cfqq = NULL;
- } else {
- spin_unlock_irq(cfqd->queue->queue_lock);
- new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask);
- spin_lock_irq(cfqd->queue->queue_lock);
+ if (!blk_queue_plugged(q))
+ q->request_fn(q);
+ else
+ __generic_unplug_device(q);
+}
- if (!new_cfqq && !(gfp_mask & __GFP_WAIT))
- goto out;
+/*
+ * Called when a new fs request (crq) is added (to cfqq). Check if there's
+ * something we should do about it
+ */
+static void
+cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
+ struct cfq_rq *crq)
+{
+ const int sync = cfq_crq_is_sync(crq);
- goto retry;
- }
+ cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
- memset(cfqq, 0, sizeof(*cfqq));
+ if (sync) {
+ struct cfq_io_context *cic = crq->io_context;
- INIT_HLIST_NODE(&cfqq->cfq_hash);
- INIT_LIST_HEAD(&cfqq->cfq_list);
- RB_CLEAR_ROOT(&cfqq->sort_list);
- INIT_LIST_HEAD(&cfqq->fifo[0]);
- INIT_LIST_HEAD(&cfqq->fifo[1]);
+ cfq_update_io_thinktime(cfqd, cic);
+ cfq_update_idle_window(cfqd, cfqq, cic);
- cfqq->key = key;
- hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]);
- atomic_set(&cfqq->ref, 0);
- cfqq->cfqd = cfqd;
- atomic_inc(&cfqd->ref);
- cfqq->key_type = cfqd->key_type;
- cfqq->service_start = ~0UL;
+ cic->last_queue = jiffies;
}
- if (new_cfqq)
- kmem_cache_free(cfq_pool, new_cfqq);
-
- atomic_inc(&cfqq->ref);
-out:
- WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq);
- return cfqq;
+ if (cfqq == cfqd->active_queue) {
+ /*
+ * if we are waiting for a request for this queue, let it rip
+ * immediately and flag that we must not expire this queue
+ * just now
+ */
+ if (cfq_cfqq_wait_request(cfqq)) {
+ cfq_mark_cfqq_must_dispatch(cfqq);
+ del_timer(&cfqd->idle_slice_timer);
+ cfq_start_queueing(cfqd, cfqq);
+ }
+ } else if (cfq_should_preempt(cfqd, cfqq, crq)) {
+ /*
+ * not the active queue - expire current slice if it is
+ * idle and has expired it's mean thinktime or this new queue
+ * has some old slice time left and is of higher priority
+ */
+ cfq_preempt_queue(cfqd, cfqq);
+ cfq_mark_cfqq_must_dispatch(cfqq);
+ cfq_start_queueing(cfqd, cfqq);
+ }
}
-static void cfq_enqueue(struct cfq_data *cfqd, struct cfq_rq *crq)
+static void cfq_enqueue(struct cfq_data *cfqd, struct request *rq)
{
- crq->is_sync = 0;
- if (rq_data_dir(crq->request) == READ || current->flags & PF_SYNCWRITE)
- crq->is_sync = 1;
+ struct cfq_rq *crq = RQ_DATA(rq);
+ struct cfq_queue *cfqq = crq->cfq_queue;
+
+ cfq_init_prio_data(cfqq);
cfq_add_crq_rb(crq);
- crq->queue_start = jiffies;
- list_add_tail(&crq->request->queuelist, &crq->cfq_queue->fifo[crq->is_sync]);
+ list_add_tail(&rq->queuelist, &cfqq->fifo);
+
+ if (rq_mergeable(rq)) {
+ cfq_add_crq_hash(cfqd, crq);
+
+ if (!cfqd->queue->last_merge)
+ cfqd->queue->last_merge = rq;
+ }
+
+ cfq_crq_enqueued(cfqd, cfqq, crq);
}
static void
cfq_insert_request(request_queue_t *q, struct request *rq, int where)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_rq *crq = RQ_DATA(rq);
switch (where) {
case ELEVATOR_INSERT_BACK:
- while (cfq_dispatch_requests(q, cfqd->cfq_quantum))
+ while (cfq_dispatch_requests(q, INT_MAX, 1))
;
list_add_tail(&rq->queuelist, &q->queue_head);
+ /*
+ * If we were idling with pending requests on
+ * inactive cfqqs, force dispatching will
+ * remove the idle timer and the queue won't
+ * be kicked by __make_request() afterward.
+ * Kick it here.
+ */
+ cfq_schedule_dispatch(cfqd);
break;
case ELEVATOR_INSERT_FRONT:
list_add(&rq->queuelist, &q->queue_head);
break;
case ELEVATOR_INSERT_SORT:
BUG_ON(!blk_fs_request(rq));
- cfq_enqueue(cfqd, crq);
+ cfq_enqueue(cfqd, rq);
break;
default:
printk("%s: bad insert point %d\n", __FUNCTION__,where);
return;
}
-
- if (rq_mergeable(rq)) {
- cfq_add_crq_hash(cfqd, crq);
-
- if (!q->last_merge)
- q->last_merge = rq;
- }
-}
-
-static int cfq_queue_empty(request_queue_t *q)
-{
- struct cfq_data *cfqd = q->elevator->elevator_data;
-
- return list_empty(&q->queue_head) && list_empty(&cfqd->rr_list);
}
static void cfq_completed_request(request_queue_t *q, struct request *rq)
cfqq = crq->cfq_queue;
- if (crq->in_flight) {
- WARN_ON(!cfqq->in_flight);
- cfqq->in_flight--;
+ if (cfq_crq_in_flight(crq)) {
+ const int sync = cfq_crq_is_sync(crq);
+
+ WARN_ON(!cfqq->on_dispatch[sync]);
+ cfqq->on_dispatch[sync]--;
}
cfq_account_completion(cfqq, crq);
return NULL;
}
-static int cfq_may_queue(request_queue_t *q, int rw)
+/*
+ * we temporarily boost lower priority queues if they are holding fs exclusive
+ * resources. they are boosted to normal prio (CLASS_BE/4)
+ */
+static void cfq_prio_boost(struct cfq_queue *cfqq)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_queue *cfqq;
- int ret = ELV_MQUEUE_MAY;
+ const int ioprio_class = cfqq->ioprio_class;
+ const int ioprio = cfqq->ioprio;
- if (current->flags & PF_MEMALLOC)
- return ELV_MQUEUE_MAY;
+ if (has_fs_excl()) {
+ /*
+ * boost idle prio on transactions that would lock out other
+ * users of the filesystem
+ */
+ if (cfq_class_idle(cfqq))
+ cfqq->ioprio_class = IOPRIO_CLASS_BE;
+ if (cfqq->ioprio > IOPRIO_NORM)
+ cfqq->ioprio = IOPRIO_NORM;
+ } else {
+ /*
+ * check if we need to unboost the queue
+ */
+ if (cfqq->ioprio_class != cfqq->org_ioprio_class)
+ cfqq->ioprio_class = cfqq->org_ioprio_class;
+ if (cfqq->ioprio != cfqq->org_ioprio)
+ cfqq->ioprio = cfqq->org_ioprio;
+ }
- cfqq = cfq_find_cfq_hash(cfqd, cfq_hash_key(cfqd, current));
- if (cfqq) {
- int limit = cfqd->max_queued;
+ /*
+ * 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);
+}
- if (cfqq->allocated[rw] < cfqd->cfq_queued)
- return ELV_MQUEUE_MUST;
+static inline pid_t cfq_queue_pid(struct task_struct *task, int rw)
+{
+ if (rw == READ || process_sync(task))
+ return task->pid;
- if (cfqd->busy_queues)
- limit = q->nr_requests / cfqd->busy_queues;
+ return CFQ_KEY_ASYNC;
+}
- if (limit < cfqd->cfq_queued)
- limit = cfqd->cfq_queued;
- else if (limit > cfqd->max_queued)
- limit = cfqd->max_queued;
+static inline int
+__cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq,
+ struct task_struct *task, int rw)
+{
+#if 1
+ if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) &&
+ !cfq_cfqq_must_alloc_slice(cfqq)) {
+ cfq_mark_cfqq_must_alloc_slice(cfqq);
+ return ELV_MQUEUE_MUST;
+ }
- if (cfqq->allocated[rw] >= limit) {
- if (limit > cfqq->alloc_limit[rw])
- cfqq->alloc_limit[rw] = limit;
+ return ELV_MQUEUE_MAY;
+#else
+ if (!cfqq || task->flags & PF_MEMALLOC)
+ return ELV_MQUEUE_MAY;
+ if (!cfqq->allocated[rw] || cfq_cfqq_must_alloc(cfqq)) {
+ if (cfq_cfqq_wait_request(cfqq))
+ return ELV_MQUEUE_MUST;
- ret = ELV_MQUEUE_NO;
+ /*
+ * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we
+ * can quickly flood the queue with writes from a single task
+ */
+ if (rw == READ || !cfq_cfqq_must_alloc_slice(cfqq)) {
+ cfq_mark_cfqq_must_alloc_slice(cfqq);
+ return ELV_MQUEUE_MUST;
}
+
+ return ELV_MQUEUE_MAY;
}
+ if (cfq_class_idle(cfqq))
+ return ELV_MQUEUE_NO;
+ if (cfqq->allocated[rw] >= cfqd->max_queued) {
+ struct io_context *ioc = get_io_context(GFP_ATOMIC);
+ int ret = ELV_MQUEUE_NO;
- return ret;
+ if (ioc && ioc->nr_batch_requests)
+ ret = ELV_MQUEUE_MAY;
+
+ put_io_context(ioc);
+ return ret;
+ }
+
+ return ELV_MQUEUE_MAY;
+#endif
+}
+
+static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio)
+{
+ struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct task_struct *tsk = current;
+ struct cfq_queue *cfqq;
+
+ /*
+ * don't force setup of a queue from here, as a call to may_queue
+ * does not necessarily imply that a request actually will be queued.
+ * so just lookup a possibly existing queue, or return 'may queue'
+ * if that fails
+ */
+ cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio);
+ if (cfqq) {
+ cfq_init_prio_data(cfqq);
+ cfq_prio_boost(cfqq);
+
+ return __cfq_may_queue(cfqd, cfqq, tsk, rw);
+ }
+
+ return ELV_MQUEUE_MAY;
}
static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq)
{
+ struct cfq_data *cfqd = q->elevator->elevator_data;
struct request_list *rl = &q->rq;
- const int write = waitqueue_active(&rl->wait[WRITE]);
- const int read = waitqueue_active(&rl->wait[READ]);
- if (read && cfqq->allocated[READ] < cfqq->alloc_limit[READ])
- wake_up(&rl->wait[READ]);
- if (write && cfqq->allocated[WRITE] < cfqq->alloc_limit[WRITE])
- wake_up(&rl->wait[WRITE]);
+ if (cfqq->allocated[READ] <= cfqd->max_queued || cfqd->rq_starved) {
+ smp_mb();
+ if (waitqueue_active(&rl->wait[READ]))
+ wake_up(&rl->wait[READ]);
+ }
+
+ if (cfqq->allocated[WRITE] <= cfqd->max_queued || cfqd->rq_starved) {
+ smp_mb();
+ if (waitqueue_active(&rl->wait[WRITE]))
+ wake_up(&rl->wait[WRITE]);
+ }
}
/*
if (crq) {
struct cfq_queue *cfqq = crq->cfq_queue;
+ const int rw = rq_data_dir(rq);
- BUG_ON(q->last_merge == rq);
- BUG_ON(!hlist_unhashed(&crq->hash));
+ BUG_ON(!cfqq->allocated[rw]);
+ cfqq->allocated[rw]--;
- if (crq->io_context)
- put_io_context(crq->io_context->ioc);
-
- BUG_ON(!cfqq->allocated[crq->is_write]);
- cfqq->allocated[crq->is_write]--;
+ put_io_context(crq->io_context->ioc);
mempool_free(crq, cfqd->crq_pool);
rq->elevator_private = NULL;
- smp_mb();
cfq_check_waiters(q, cfqq);
cfq_put_queue(cfqq);
}
}
/*
- * Allocate cfq data structures associated with this request. A queue and
+ * Allocate cfq data structures associated with this request.
*/
-static int cfq_set_request(request_queue_t *q, struct request *rq, int gfp_mask)
+static int
+cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
+ int 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);
- struct cfq_queue *cfqq, *saved_cfqq;
+ pid_t key = cfq_queue_pid(tsk, rw);
+ struct cfq_queue *cfqq;
struct cfq_rq *crq;
unsigned long flags;
might_sleep_if(gfp_mask & __GFP_WAIT);
+ cic = cfq_get_io_context(cfqd, key, gfp_mask);
+
spin_lock_irqsave(q->queue_lock, flags);
- cfqq = __cfq_get_queue(cfqd, cfq_hash_key(cfqd, current), gfp_mask);
- if (!cfqq)
- goto out_lock;
+ if (!cic)
+ goto queue_fail;
+
+ if (!cic->cfqq) {
+ cfqq = cfq_get_queue(cfqd, key, tsk->ioprio, gfp_mask);
+ if (!cfqq)
+ goto queue_fail;
-repeat:
- if (cfqq->allocated[rw] >= cfqd->max_queued)
- goto out_lock;
+ cic->cfqq = cfqq;
+ } else
+ cfqq = cic->cfqq;
cfqq->allocated[rw]++;
+ cfq_clear_cfqq_must_alloc(cfqq);
+ cfqd->rq_starved = 0;
+ atomic_inc(&cfqq->ref);
spin_unlock_irqrestore(q->queue_lock, flags);
- /*
- * if hashing type has changed, the cfq_queue might change here.
- */
- saved_cfqq = cfqq;
- cic = cfq_get_io_context(&cfqq, gfp_mask);
- if (!cic)
- goto err;
-
- /*
- * repeat allocation checks on queue change
- */
- if (unlikely(saved_cfqq != cfqq)) {
- spin_lock_irqsave(q->queue_lock, flags);
- saved_cfqq->allocated[rw]--;
- goto repeat;
- }
-
crq = mempool_alloc(cfqd->crq_pool, gfp_mask);
if (crq) {
RB_CLEAR(&crq->rb_node);
INIT_HLIST_NODE(&crq->hash);
crq->cfq_queue = cfqq;
crq->io_context = cic;
- crq->service_start = crq->queue_start = 0;
- crq->in_flight = crq->accounted = crq->is_sync = 0;
- crq->is_write = rw;
+ cfq_clear_crq_in_flight(crq);
+ cfq_clear_crq_in_driver(crq);
+ cfq_clear_crq_requeued(crq);
+
+ if (rw == READ || process_sync(tsk))
+ cfq_mark_crq_is_sync(crq);
+ else
+ cfq_clear_crq_is_sync(crq);
+
rq->elevator_private = crq;
- cfqq->alloc_limit[rw] = 0;
return 0;
}
- put_io_context(cic->ioc);
-err:
spin_lock_irqsave(q->queue_lock, flags);
cfqq->allocated[rw]--;
+ if (!(cfqq->allocated[0] + cfqq->allocated[1]))
+ cfq_mark_cfqq_must_alloc(cfqq);
cfq_put_queue(cfqq);
-out_lock:
+queue_fail:
+ if (cic)
+ put_io_context(cic->ioc);
+ /*
+ * mark us rq allocation starved. we need to kickstart the process
+ * ourselves if there are no pending requests that can do it for us.
+ * that would be an extremely rare OOM situation
+ */
+ cfqd->rq_starved = 1;
+ cfq_schedule_dispatch(cfqd);
spin_unlock_irqrestore(q->queue_lock, flags);
return 1;
}
+static void cfq_kick_queue(void *data)
+{
+ request_queue_t *q = data;
+ struct cfq_data *cfqd = q->elevator->elevator_data;
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+
+ if (cfqd->rq_starved) {
+ struct request_list *rl = &q->rq;
+
+ /*
+ * we aren't guaranteed to get a request after this, but we
+ * have to be opportunistic
+ */
+ smp_mb();
+ if (waitqueue_active(&rl->wait[READ]))
+ wake_up(&rl->wait[READ]);
+ if (waitqueue_active(&rl->wait[WRITE]))
+ wake_up(&rl->wait[WRITE]);
+ }
+
+ blk_remove_plug(q);
+ q->request_fn(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+/*
+ * Timer running if the active_queue is currently idling inside its time slice
+ */
+static void cfq_idle_slice_timer(unsigned long data)
+{
+ struct cfq_data *cfqd = (struct cfq_data *) data;
+ struct cfq_queue *cfqq;
+ unsigned long flags;
+
+ spin_lock_irqsave(cfqd->queue->queue_lock, flags);
+
+ if ((cfqq = cfqd->active_queue) != NULL) {
+ unsigned long now = jiffies;
+
+ /*
+ * expired
+ */
+ if (time_after(now, cfqq->slice_end))
+ goto expire;
+
+ /*
+ * only expire and reinvoke request handler, if there are
+ * other queues with pending requests
+ */
+ if (!cfq_pending_requests(cfqd)) {
+ cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end);
+ add_timer(&cfqd->idle_slice_timer);
+ goto out_cont;
+ }
+
+ /*
+ * not expired and it has a request pending, let it dispatch
+ */
+ if (!RB_EMPTY(&cfqq->sort_list)) {
+ cfq_mark_cfqq_must_dispatch(cfqq);
+ goto out_kick;
+ }
+ }
+expire:
+ cfq_slice_expired(cfqd, 0);
+out_kick:
+ cfq_schedule_dispatch(cfqd);
+out_cont:
+ spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
+}
+
+/*
+ * Timer running if an idle class queue is waiting for service
+ */
+static void cfq_idle_class_timer(unsigned long data)
+{
+ struct cfq_data *cfqd = (struct cfq_data *) data;
+ unsigned long flags, end;
+
+ spin_lock_irqsave(cfqd->queue->queue_lock, flags);
+
+ /*
+ * race with a non-idle queue, reset timer
+ */
+ end = cfqd->last_end_request + CFQ_IDLE_GRACE;
+ if (!time_after_eq(jiffies, end)) {
+ cfqd->idle_class_timer.expires = end;
+ add_timer(&cfqd->idle_class_timer);
+ } else
+ cfq_schedule_dispatch(cfqd);
+
+ spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
+}
+
+static void cfq_shutdown_timer_wq(struct cfq_data *cfqd)
+{
+ del_timer_sync(&cfqd->idle_slice_timer);
+ del_timer_sync(&cfqd->idle_class_timer);
+ blk_sync_queue(cfqd->queue);
+}
+
static void cfq_put_cfqd(struct cfq_data *cfqd)
{
request_queue_t *q = cfqd->queue;
blk_put_queue(q);
+ cfq_shutdown_timer_wq(cfqd);
+ q->elevator->elevator_data = NULL;
+
mempool_destroy(cfqd->crq_pool);
kfree(cfqd->crq_hash);
kfree(cfqd->cfq_hash);
static void cfq_exit_queue(elevator_t *e)
{
- cfq_put_cfqd(e->elevator_data);
+ struct cfq_data *cfqd = e->elevator_data;
+
+ cfq_shutdown_timer_wq(cfqd);
+ cfq_put_cfqd(cfqd);
}
static int cfq_init_queue(request_queue_t *q, elevator_t *e)
return -ENOMEM;
memset(cfqd, 0, sizeof(*cfqd));
- INIT_LIST_HEAD(&cfqd->rr_list);
+
+ 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);
INIT_LIST_HEAD(&cfqd->empty_list);
cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL);
cfqd->queue = q;
atomic_inc(&q->refcnt);
- /*
- * just set it to some high value, we want anyone to be able to queue
- * some requests. fairness is handled differently
- */
- q->nr_requests = 1024;
- cfqd->max_queued = q->nr_requests / 16;
+ cfqd->max_queued = q->nr_requests / 4;
q->nr_batching = cfq_queued;
- cfqd->key_type = CFQ_KEY_TGID;
- cfqd->find_best_crq = 1;
+
+ init_timer(&cfqd->idle_slice_timer);
+ cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
+ cfqd->idle_slice_timer.data = (unsigned long) cfqd;
+
+ init_timer(&cfqd->idle_class_timer);
+ cfqd->idle_class_timer.function = cfq_idle_class_timer;
+ cfqd->idle_class_timer.data = (unsigned long) cfqd;
+
+ INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q);
+
atomic_set(&cfqd->ref, 1);
cfqd->cfq_queued = cfq_queued;
cfqd->cfq_quantum = cfq_quantum;
- cfqd->cfq_fifo_expire_r = cfq_fifo_expire_r;
- cfqd->cfq_fifo_expire_w = cfq_fifo_expire_w;
- cfqd->cfq_fifo_batch_expire = cfq_fifo_rate;
+ cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0];
+ cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1];
cfqd->cfq_back_max = cfq_back_max;
cfqd->cfq_back_penalty = cfq_back_penalty;
+ cfqd->cfq_slice[0] = cfq_slice_async;
+ cfqd->cfq_slice[1] = cfq_slice_sync;
+ cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
+ cfqd->cfq_slice_idle = cfq_slice_idle;
+ cfqd->cfq_max_depth = cfq_max_depth;
return 0;
out_crqpool:
return -ENOMEM;
}
-
/*
* sysfs parts below -->
*/
return count;
}
-static ssize_t
-cfq_clear_elapsed(struct cfq_data *cfqd, const char *page, size_t count)
-{
- max_elapsed_dispatch = max_elapsed_crq = 0;
- return count;
-}
-
-static ssize_t
-cfq_set_key_type(struct cfq_data *cfqd, const char *page, size_t count)
-{
- spin_lock_irq(cfqd->queue->queue_lock);
- if (!strncmp(page, "pgid", 4))
- cfqd->key_type = CFQ_KEY_PGID;
- else if (!strncmp(page, "tgid", 4))
- cfqd->key_type = CFQ_KEY_TGID;
- else if (!strncmp(page, "uid", 3))
- cfqd->key_type = CFQ_KEY_UID;
- else if (!strncmp(page, "gid", 3))
- cfqd->key_type = CFQ_KEY_GID;
- spin_unlock_irq(cfqd->queue->queue_lock);
- return count;
-}
-
-static ssize_t
-cfq_read_key_type(struct cfq_data *cfqd, char *page)
-{
- ssize_t len = 0;
- int i;
-
- for (i = CFQ_KEY_PGID; i < CFQ_KEY_LAST; i++) {
- if (cfqd->key_type == i)
- len += sprintf(page+len, "[%s] ", cfq_key_types[i]);
- else
- len += sprintf(page+len, "%s ", cfq_key_types[i]);
- }
- len += sprintf(page+len, "\n");
- return len;
-}
-
#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
static ssize_t __FUNC(struct cfq_data *cfqd, char *page) \
{ \
}
SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0);
SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0);
-SHOW_FUNCTION(cfq_fifo_expire_r_show, cfqd->cfq_fifo_expire_r, 1);
-SHOW_FUNCTION(cfq_fifo_expire_w_show, cfqd->cfq_fifo_expire_w, 1);
-SHOW_FUNCTION(cfq_fifo_batch_expire_show, cfqd->cfq_fifo_batch_expire, 1);
-SHOW_FUNCTION(cfq_find_best_show, cfqd->find_best_crq, 0);
+SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1);
+SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1);
SHOW_FUNCTION(cfq_back_max_show, cfqd->cfq_back_max, 0);
SHOW_FUNCTION(cfq_back_penalty_show, cfqd->cfq_back_penalty, 0);
+SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1);
+SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1);
+SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1);
+SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0);
+SHOW_FUNCTION(cfq_max_depth_show, cfqd->cfq_max_depth, 0);
#undef SHOW_FUNCTION
#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
}
STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0);
STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0);
-STORE_FUNCTION(cfq_fifo_expire_r_store, &cfqd->cfq_fifo_expire_r, 1, UINT_MAX, 1);
-STORE_FUNCTION(cfq_fifo_expire_w_store, &cfqd->cfq_fifo_expire_w, 1, UINT_MAX, 1);
-STORE_FUNCTION(cfq_fifo_batch_expire_store, &cfqd->cfq_fifo_batch_expire, 0, UINT_MAX, 1);
-STORE_FUNCTION(cfq_find_best_store, &cfqd->find_best_crq, 0, 1, 0);
+STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1);
+STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1);
STORE_FUNCTION(cfq_back_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0);
STORE_FUNCTION(cfq_back_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0);
+STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1);
+STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1);
+STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1);
+STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0);
+STORE_FUNCTION(cfq_max_depth_store, &cfqd->cfq_max_depth, 1, UINT_MAX, 0);
#undef STORE_FUNCTION
static struct cfq_fs_entry cfq_quantum_entry = {
.show = cfq_queued_show,
.store = cfq_queued_store,
};
-static struct cfq_fs_entry cfq_fifo_expire_r_entry = {
+static struct cfq_fs_entry cfq_fifo_expire_sync_entry = {
.attr = {.name = "fifo_expire_sync", .mode = S_IRUGO | S_IWUSR },
- .show = cfq_fifo_expire_r_show,
- .store = cfq_fifo_expire_r_store,
+ .show = cfq_fifo_expire_sync_show,
+ .store = cfq_fifo_expire_sync_store,
};
-static struct cfq_fs_entry cfq_fifo_expire_w_entry = {
+static struct cfq_fs_entry cfq_fifo_expire_async_entry = {
.attr = {.name = "fifo_expire_async", .mode = S_IRUGO | S_IWUSR },
- .show = cfq_fifo_expire_w_show,
- .store = cfq_fifo_expire_w_store,
-};
-static struct cfq_fs_entry cfq_fifo_batch_expire_entry = {
- .attr = {.name = "fifo_batch_expire", .mode = S_IRUGO | S_IWUSR },
- .show = cfq_fifo_batch_expire_show,
- .store = cfq_fifo_batch_expire_store,
-};
-static struct cfq_fs_entry cfq_find_best_entry = {
- .attr = {.name = "find_best_crq", .mode = S_IRUGO | S_IWUSR },
- .show = cfq_find_best_show,
- .store = cfq_find_best_store,
+ .show = cfq_fifo_expire_async_show,
+ .store = cfq_fifo_expire_async_store,
};
static struct cfq_fs_entry cfq_back_max_entry = {
.attr = {.name = "back_seek_max", .mode = S_IRUGO | S_IWUSR },
.show = cfq_back_penalty_show,
.store = cfq_back_penalty_store,
};
-static struct cfq_fs_entry cfq_clear_elapsed_entry = {
- .attr = {.name = "clear_elapsed", .mode = S_IWUSR },
- .store = cfq_clear_elapsed,
+static struct cfq_fs_entry cfq_slice_sync_entry = {
+ .attr = {.name = "slice_sync", .mode = S_IRUGO | S_IWUSR },
+ .show = cfq_slice_sync_show,
+ .store = cfq_slice_sync_store,
+};
+static struct cfq_fs_entry cfq_slice_async_entry = {
+ .attr = {.name = "slice_async", .mode = S_IRUGO | S_IWUSR },
+ .show = cfq_slice_async_show,
+ .store = cfq_slice_async_store,
+};
+static struct cfq_fs_entry cfq_slice_async_rq_entry = {
+ .attr = {.name = "slice_async_rq", .mode = S_IRUGO | S_IWUSR },
+ .show = cfq_slice_async_rq_show,
+ .store = cfq_slice_async_rq_store,
+};
+static struct cfq_fs_entry cfq_slice_idle_entry = {
+ .attr = {.name = "slice_idle", .mode = S_IRUGO | S_IWUSR },
+ .show = cfq_slice_idle_show,
+ .store = cfq_slice_idle_store,
};
-static struct cfq_fs_entry cfq_key_type_entry = {
- .attr = {.name = "key_type", .mode = S_IRUGO | S_IWUSR },
- .show = cfq_read_key_type,
- .store = cfq_set_key_type,
+static struct cfq_fs_entry cfq_max_depth_entry = {
+ .attr = {.name = "max_depth", .mode = S_IRUGO | S_IWUSR },
+ .show = cfq_max_depth_show,
+ .store = cfq_max_depth_store,
};
static struct attribute *default_attrs[] = {
&cfq_quantum_entry.attr,
&cfq_queued_entry.attr,
- &cfq_fifo_expire_r_entry.attr,
- &cfq_fifo_expire_w_entry.attr,
- &cfq_fifo_batch_expire_entry.attr,
- &cfq_key_type_entry.attr,
- &cfq_find_best_entry.attr,
+ &cfq_fifo_expire_sync_entry.attr,
+ &cfq_fifo_expire_async_entry.attr,
&cfq_back_max_entry.attr,
&cfq_back_penalty_entry.attr,
- &cfq_clear_elapsed_entry.attr,
+ &cfq_slice_sync_entry.attr,
+ &cfq_slice_async_entry.attr,
+ &cfq_slice_async_rq_entry.attr,
+ &cfq_slice_idle_entry.attr,
+ &cfq_max_depth_entry.attr,
NULL,
};
struct cfq_fs_entry *entry = to_cfq(attr);
if (!entry->show)
- return 0;
+ return -EIO;
return entry->show(e->elevator_data, page);
}
struct cfq_fs_entry *entry = to_cfq(attr);
if (!entry->store)
- return -EINVAL;
+ return -EIO;
return entry->store(e->elevator_data, page, length);
}
{
int ret;
+ /*
+ * could be 0 on HZ < 1000 setups
+ */
+ if (!cfq_slice_async)
+ cfq_slice_async = 1;
+ if (!cfq_slice_idle)
+ cfq_slice_idle = 1;
+
if (cfq_slab_setup())
return -ENOMEM;
ret = elv_register(&iosched_cfq);
- if (!ret) {
- __module_get(THIS_MODULE);
- return 0;
- }
+ if (ret)
+ cfq_slab_kill();
- cfq_slab_kill();
return ret;
}
static void __exit cfq_exit(void)
{
+ struct task_struct *g, *p;
+ unsigned long flags;
+
+ read_lock_irqsave(&tasklist_lock, flags);
+
+ /*
+ * iterate each process in the system, removing our io_context
+ */
+ do_each_thread(g, p) {
+ struct io_context *ioc = p->io_context;
+
+ if (ioc && ioc->cic) {
+ ioc->cic->exit(ioc->cic);
+ cfq_free_io_context(ioc->cic);
+ ioc->cic = NULL;
+ }
+ } while_each_thread(g, p);
+
+ read_unlock_irqrestore(&tasklist_lock, flags);
+
cfq_slab_kill();
elv_unregister(&iosched_cfq);
}
projects / linux-2.6 / blobdiff