Commit 80f50691 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  cciss: Add cciss_allow_hpsa module parameter
  cciss: Fix multiple calls to pci_release_regions
  blk-settings: fix function parameter kernel-doc notation
  writeback: kill space in debugfs item name
  writeback: account IO throttling wait as iowait
  elv_iosched_store(): fix strstrip() misuse
  cfq-iosched: avoid probable slice overrun when idling
  cfq-iosched: apply bool value where we return 0/1
  cfq-iosched: fix think time allowed for seekers
  cfq-iosched: fix the slice residual sign
  cfq-iosched: abstract out the 'may this cfqq dispatch' logic
  block: use proper BLK_RW_ASYNC in blk_queue_start_tag()
  block: Seperate read and write statistics of in_flight requests v2
  block: get rid of kblock_schedule_delayed_work()
  cfq-iosched: fix possible problem with jiffies wraparound
  cfq-iosched: fix issue with rq-rq merging and fifo list ordering
parents a3bafbbb 2ec24ff1
...@@ -70,7 +70,7 @@ static void drive_stat_acct(struct request *rq, int new_io) ...@@ -70,7 +70,7 @@ static void drive_stat_acct(struct request *rq, int new_io)
part_stat_inc(cpu, part, merges[rw]); part_stat_inc(cpu, part, merges[rw]);
else { else {
part_round_stats(cpu, part); part_round_stats(cpu, part);
part_inc_in_flight(part); part_inc_in_flight(part, rw);
} }
part_stat_unlock(); part_stat_unlock();
...@@ -1030,9 +1030,9 @@ static void part_round_stats_single(int cpu, struct hd_struct *part, ...@@ -1030,9 +1030,9 @@ static void part_round_stats_single(int cpu, struct hd_struct *part,
if (now == part->stamp) if (now == part->stamp)
return; return;
if (part->in_flight) { if (part_in_flight(part)) {
__part_stat_add(cpu, part, time_in_queue, __part_stat_add(cpu, part, time_in_queue,
part->in_flight * (now - part->stamp)); part_in_flight(part) * (now - part->stamp));
__part_stat_add(cpu, part, io_ticks, (now - part->stamp)); __part_stat_add(cpu, part, io_ticks, (now - part->stamp));
} }
part->stamp = now; part->stamp = now;
...@@ -1739,7 +1739,7 @@ static void blk_account_io_done(struct request *req) ...@@ -1739,7 +1739,7 @@ static void blk_account_io_done(struct request *req)
part_stat_inc(cpu, part, ios[rw]); part_stat_inc(cpu, part, ios[rw]);
part_stat_add(cpu, part, ticks[rw], duration); part_stat_add(cpu, part, ticks[rw], duration);
part_round_stats(cpu, part); part_round_stats(cpu, part);
part_dec_in_flight(part); part_dec_in_flight(part, rw);
part_stat_unlock(); part_stat_unlock();
} }
...@@ -2492,14 +2492,6 @@ int kblockd_schedule_work(struct request_queue *q, struct work_struct *work) ...@@ -2492,14 +2492,6 @@ int kblockd_schedule_work(struct request_queue *q, struct work_struct *work)
} }
EXPORT_SYMBOL(kblockd_schedule_work); EXPORT_SYMBOL(kblockd_schedule_work);
int kblockd_schedule_delayed_work(struct request_queue *q,
struct delayed_work *work,
unsigned long delay)
{
return queue_delayed_work(kblockd_workqueue, work, delay);
}
EXPORT_SYMBOL(kblockd_schedule_delayed_work);
int __init blk_dev_init(void) int __init blk_dev_init(void)
{ {
BUILD_BUG_ON(__REQ_NR_BITS > 8 * BUILD_BUG_ON(__REQ_NR_BITS > 8 *
......
...@@ -351,7 +351,7 @@ static void blk_account_io_merge(struct request *req) ...@@ -351,7 +351,7 @@ static void blk_account_io_merge(struct request *req)
part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req)); part = disk_map_sector_rcu(req->rq_disk, blk_rq_pos(req));
part_round_stats(cpu, part); part_round_stats(cpu, part);
part_dec_in_flight(part); part_dec_in_flight(part, rq_data_dir(req));
part_stat_unlock(); part_stat_unlock();
} }
......
...@@ -242,7 +242,7 @@ EXPORT_SYMBOL(blk_queue_max_hw_sectors); ...@@ -242,7 +242,7 @@ EXPORT_SYMBOL(blk_queue_max_hw_sectors);
/** /**
* blk_queue_max_discard_sectors - set max sectors for a single discard * blk_queue_max_discard_sectors - set max sectors for a single discard
* @q: the request queue for the device * @q: the request queue for the device
* @max_discard: maximum number of sectors to discard * @max_discard_sectors: maximum number of sectors to discard
**/ **/
void blk_queue_max_discard_sectors(struct request_queue *q, void blk_queue_max_discard_sectors(struct request_queue *q,
unsigned int max_discard_sectors) unsigned int max_discard_sectors)
......
...@@ -359,7 +359,7 @@ int blk_queue_start_tag(struct request_queue *q, struct request *rq) ...@@ -359,7 +359,7 @@ int blk_queue_start_tag(struct request_queue *q, struct request *rq)
max_depth -= 2; max_depth -= 2;
if (!max_depth) if (!max_depth)
max_depth = 1; max_depth = 1;
if (q->in_flight[0] > max_depth) if (q->in_flight[BLK_RW_ASYNC] > max_depth)
return 1; return 1;
} }
......
...@@ -150,7 +150,7 @@ struct cfq_data { ...@@ -150,7 +150,7 @@ struct cfq_data {
* idle window management * idle window management
*/ */
struct timer_list idle_slice_timer; struct timer_list idle_slice_timer;
struct delayed_work unplug_work; struct work_struct unplug_work;
struct cfq_queue *active_queue; struct cfq_queue *active_queue;
struct cfq_io_context *active_cic; struct cfq_io_context *active_cic;
...@@ -230,7 +230,7 @@ CFQ_CFQQ_FNS(coop); ...@@ -230,7 +230,7 @@ CFQ_CFQQ_FNS(coop);
blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args) blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
static void cfq_dispatch_insert(struct request_queue *, struct request *); static void cfq_dispatch_insert(struct request_queue *, struct request *);
static struct cfq_queue *cfq_get_queue(struct cfq_data *, int, static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool,
struct io_context *, gfp_t); struct io_context *, gfp_t);
static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *, static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *,
struct io_context *); struct io_context *);
...@@ -241,40 +241,35 @@ static inline int rq_in_driver(struct cfq_data *cfqd) ...@@ -241,40 +241,35 @@ static inline int rq_in_driver(struct cfq_data *cfqd)
} }
static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic, static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic,
int is_sync) bool is_sync)
{ {
return cic->cfqq[!!is_sync]; return cic->cfqq[is_sync];
} }
static inline void cic_set_cfqq(struct cfq_io_context *cic, static inline void cic_set_cfqq(struct cfq_io_context *cic,
struct cfq_queue *cfqq, int is_sync) struct cfq_queue *cfqq, bool is_sync)
{ {
cic->cfqq[!!is_sync] = cfqq; cic->cfqq[is_sync] = cfqq;
} }
/* /*
* We regard a request as SYNC, if it's either a read or has the SYNC bit * 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). * set (in which case it could also be direct WRITE).
*/ */
static inline int cfq_bio_sync(struct bio *bio) static inline bool cfq_bio_sync(struct bio *bio)
{ {
if (bio_data_dir(bio) == READ || bio_rw_flagged(bio, BIO_RW_SYNCIO)) return bio_data_dir(bio) == READ || bio_rw_flagged(bio, BIO_RW_SYNCIO);
return 1;
return 0;
} }
/* /*
* scheduler run of queue, if there are requests pending and no one in the * scheduler run of queue, if there are requests pending and no one in the
* driver that will restart queueing * driver that will restart queueing
*/ */
static inline void cfq_schedule_dispatch(struct cfq_data *cfqd, static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
unsigned long delay)
{ {
if (cfqd->busy_queues) { if (cfqd->busy_queues) {
cfq_log(cfqd, "schedule dispatch"); cfq_log(cfqd, "schedule dispatch");
kblockd_schedule_delayed_work(cfqd->queue, &cfqd->unplug_work, kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work);
delay);
} }
} }
...@@ -290,7 +285,7 @@ static int cfq_queue_empty(struct request_queue *q) ...@@ -290,7 +285,7 @@ static int cfq_queue_empty(struct request_queue *q)
* if a queue is marked sync and has sync io queued. A sync queue with async * 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. * io only, should not get full sync slice length.
*/ */
static inline int cfq_prio_slice(struct cfq_data *cfqd, int sync, static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync,
unsigned short prio) unsigned short prio)
{ {
const int base_slice = cfqd->cfq_slice[sync]; const int base_slice = cfqd->cfq_slice[sync];
...@@ -318,7 +313,7 @@ cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq) ...@@ -318,7 +313,7 @@ cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
* isn't valid until the first request from the dispatch is activated * isn't valid until the first request from the dispatch is activated
* and the slice time set. * and the slice time set.
*/ */
static inline int cfq_slice_used(struct cfq_queue *cfqq) static inline bool cfq_slice_used(struct cfq_queue *cfqq)
{ {
if (cfq_cfqq_slice_new(cfqq)) if (cfq_cfqq_slice_new(cfqq))
return 0; return 0;
...@@ -493,7 +488,7 @@ static unsigned long cfq_slice_offset(struct cfq_data *cfqd, ...@@ -493,7 +488,7 @@ static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
* we will service the queues. * we will service the queues.
*/ */
static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
int add_front) bool add_front)
{ {
struct rb_node **p, *parent; struct rb_node **p, *parent;
struct cfq_queue *__cfqq; struct cfq_queue *__cfqq;
...@@ -509,11 +504,20 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, ...@@ -509,11 +504,20 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
} else } else
rb_key += jiffies; rb_key += jiffies;
} else if (!add_front) { } else if (!add_front) {
/*
* Get our rb key offset. Subtract any residual slice
* value carried from last service. A negative resid
* count indicates slice overrun, and this should position
* the next service time further away in the tree.
*/
rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies;
rb_key += cfqq->slice_resid; rb_key -= cfqq->slice_resid;
cfqq->slice_resid = 0; cfqq->slice_resid = 0;
} else } else {
rb_key = 0; rb_key = -HZ;
__cfqq = cfq_rb_first(&cfqd->service_tree);
rb_key += __cfqq ? __cfqq->rb_key : jiffies;
}
if (!RB_EMPTY_NODE(&cfqq->rb_node)) { if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
/* /*
...@@ -547,7 +551,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, ...@@ -547,7 +551,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
n = &(*p)->rb_left; n = &(*p)->rb_left;
else if (cfq_class_idle(cfqq) > cfq_class_idle(__cfqq)) else if (cfq_class_idle(cfqq) > cfq_class_idle(__cfqq))
n = &(*p)->rb_right; n = &(*p)->rb_right;
else if (rb_key < __cfqq->rb_key) else if (time_before(rb_key, __cfqq->rb_key))
n = &(*p)->rb_left; n = &(*p)->rb_left;
else else
n = &(*p)->rb_right; n = &(*p)->rb_right;
...@@ -827,8 +831,10 @@ cfq_merged_requests(struct request_queue *q, struct request *rq, ...@@ -827,8 +831,10 @@ cfq_merged_requests(struct request_queue *q, struct request *rq,
* reposition in fifo if next is older than rq * reposition in fifo if next is older than rq
*/ */
if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) && if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) &&
time_before(next->start_time, rq->start_time)) time_before(rq_fifo_time(next), rq_fifo_time(rq))) {
list_move(&rq->queuelist, &next->queuelist); list_move(&rq->queuelist, &next->queuelist);
rq_set_fifo_time(rq, rq_fifo_time(next));
}
cfq_remove_request(next); cfq_remove_request(next);
} }
...@@ -844,7 +850,7 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq, ...@@ -844,7 +850,7 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq,
* Disallow merge of a sync bio into an async request. * Disallow merge of a sync bio into an async request.
*/ */
if (cfq_bio_sync(bio) && !rq_is_sync(rq)) if (cfq_bio_sync(bio) && !rq_is_sync(rq))
return 0; return false;
/* /*
* Lookup the cfqq that this bio will be queued with. Allow * Lookup the cfqq that this bio will be queued with. Allow
...@@ -852,13 +858,10 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq, ...@@ -852,13 +858,10 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq,
*/ */
cic = cfq_cic_lookup(cfqd, current->io_context); cic = cfq_cic_lookup(cfqd, current->io_context);
if (!cic) if (!cic)
return 0; return false;
cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio)); cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
if (cfqq == RQ_CFQQ(rq)) return cfqq == RQ_CFQQ(rq);
return 1;
return 0;
} }
static void __cfq_set_active_queue(struct cfq_data *cfqd, static void __cfq_set_active_queue(struct cfq_data *cfqd,
...@@ -886,7 +889,7 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd, ...@@ -886,7 +889,7 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd,
*/ */
static void static void
__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
int timed_out) bool timed_out)
{ {
cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out); cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out);
...@@ -914,7 +917,7 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, ...@@ -914,7 +917,7 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
} }
} }
static inline void cfq_slice_expired(struct cfq_data *cfqd, int timed_out) static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out)
{ {
struct cfq_queue *cfqq = cfqd->active_queue; struct cfq_queue *cfqq = cfqd->active_queue;
...@@ -1026,7 +1029,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, ...@@ -1026,7 +1029,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
*/ */
static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
struct cfq_queue *cur_cfqq, struct cfq_queue *cur_cfqq,
int probe) bool probe)
{ {
struct cfq_queue *cfqq; struct cfq_queue *cfqq;
...@@ -1090,6 +1093,15 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd) ...@@ -1090,6 +1093,15 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
if (!cic || !atomic_read(&cic->ioc->nr_tasks)) if (!cic || !atomic_read(&cic->ioc->nr_tasks))
return; return;
/*
* If our average think time is larger than the remaining time
* slice, then don't idle. This avoids overrunning the allotted
* time slice.
*/
if (sample_valid(cic->ttime_samples) &&
(cfqq->slice_end - jiffies < cic->ttime_mean))
return;
cfq_mark_cfqq_wait_request(cfqq); cfq_mark_cfqq_wait_request(cfqq);
/* /*
...@@ -1129,9 +1141,7 @@ static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) ...@@ -1129,9 +1141,7 @@ static void cfq_dispatch_insert(struct request_queue *q, struct request *rq)
*/ */
static struct request *cfq_check_fifo(struct cfq_queue *cfqq) static struct request *cfq_check_fifo(struct cfq_queue *cfqq)
{ {
struct cfq_data *cfqd = cfqq->cfqd; struct request *rq = NULL;
struct request *rq;
int fifo;
if (cfq_cfqq_fifo_expire(cfqq)) if (cfq_cfqq_fifo_expire(cfqq))
return NULL; return NULL;
...@@ -1141,13 +1151,11 @@ static struct request *cfq_check_fifo(struct cfq_queue *cfqq) ...@@ -1141,13 +1151,11 @@ static struct request *cfq_check_fifo(struct cfq_queue *cfqq)
if (list_empty(&cfqq->fifo)) if (list_empty(&cfqq->fifo))
return NULL; return NULL;
fifo = cfq_cfqq_sync(cfqq);
rq = rq_entry_fifo(cfqq->fifo.next); rq = rq_entry_fifo(cfqq->fifo.next);
if (time_before(jiffies, rq_fifo_time(rq)))
if (time_before(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo]))
rq = NULL; rq = NULL;
cfq_log_cfqq(cfqd, cfqq, "fifo=%p", rq); cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq);
return rq; return rq;
} }
...@@ -1248,67 +1256,21 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd) ...@@ -1248,67 +1256,21 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd)
return dispatched; return dispatched;
} }
/* static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq)
* Dispatch a request from cfqq, moving them to the request queue
* dispatch list.
*/
static void cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{ {
struct request *rq;
BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
/*
* follow expired path, else get first next available
*/
rq = cfq_check_fifo(cfqq);
if (!rq)
rq = cfqq->next_rq;
/*
* insert request into driver dispatch list
*/
cfq_dispatch_insert(cfqd->queue, rq);
if (!cfqd->active_cic) {
struct cfq_io_context *cic = RQ_CIC(rq);
atomic_long_inc(&cic->ioc->refcount);
cfqd->active_cic = cic;
}
}
/*
* Find the cfqq that we need to service and move a request from that to the
* dispatch list
*/
static int cfq_dispatch_requests(struct request_queue *q, int force)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq;
unsigned int max_dispatch; unsigned int max_dispatch;
if (!cfqd->busy_queues)
return 0;
if (unlikely(force))
return cfq_forced_dispatch(cfqd);
cfqq = cfq_select_queue(cfqd);
if (!cfqq)
return 0;
/* /*
* Drain async requests before we start sync IO * Drain async requests before we start sync IO
*/ */
if (cfq_cfqq_idle_window(cfqq) && cfqd->rq_in_driver[BLK_RW_ASYNC]) if (cfq_cfqq_idle_window(cfqq) && cfqd->rq_in_driver[BLK_RW_ASYNC])
return 0; return false;
/* /*
* If this is an async queue and we have sync IO in flight, let it wait * If this is an async queue and we have sync IO in flight, let it wait
*/ */
if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq)) if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq))
return 0; return false;
max_dispatch = cfqd->cfq_quantum; max_dispatch = cfqd->cfq_quantum;
if (cfq_class_idle(cfqq)) if (cfq_class_idle(cfqq))
...@@ -1322,13 +1284,13 @@ static int cfq_dispatch_requests(struct request_queue *q, int force) ...@@ -1322,13 +1284,13 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
* idle queue must always only have a single IO in flight * idle queue must always only have a single IO in flight
*/ */
if (cfq_class_idle(cfqq)) if (cfq_class_idle(cfqq))
return 0; return false;
/* /*
* We have other queues, don't allow more IO from this one * We have other queues, don't allow more IO from this one
*/ */
if (cfqd->busy_queues > 1) if (cfqd->busy_queues > 1)
return 0; return false;
/* /*
* Sole queue user, allow bigger slice * Sole queue user, allow bigger slice
...@@ -1352,13 +1314,72 @@ static int cfq_dispatch_requests(struct request_queue *q, int force) ...@@ -1352,13 +1314,72 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
max_dispatch = depth; max_dispatch = depth;
} }
if (cfqq->dispatched >= max_dispatch) /*
* If we're below the current max, allow a dispatch
*/
return cfqq->dispatched < max_dispatch;
}
/*
* Dispatch a request from cfqq, moving them to the request queue
* dispatch list.
*/
static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
struct request *rq;
BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
if (!cfq_may_dispatch(cfqd, cfqq))
return false;
/*
* follow expired path, else get first next available
*/
rq = cfq_check_fifo(cfqq);
if (!rq)
rq = cfqq->next_rq;
/*
* insert request into driver dispatch list
*/
cfq_dispatch_insert(cfqd->queue, rq);
if (!cfqd->active_cic) {
struct cfq_io_context *cic = RQ_CIC(rq);
atomic_long_inc(&cic->ioc->refcount);
cfqd->active_cic = cic;
}
return true;
}
/*
* Find the cfqq that we need to service and move a request from that to the
* dispatch list
*/
static int cfq_dispatch_requests(struct request_queue *q, int force)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq;
if (!cfqd->busy_queues)
return 0;
if (unlikely(force))
return cfq_forced_dispatch(cfqd);
cfqq = cfq_select_queue(cfqd);
if (!cfqq)
return 0; return 0;
/* /*
* Dispatch a request from this cfqq * Dispatch a request from this cfqq, if it is allowed
*/ */
cfq_dispatch_request(cfqd, cfqq); if (!cfq_dispatch_request(cfqd, cfqq))
return 0;
cfqq->slice_dispatch++;