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[PATCH] CFQ io scheduler updates

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- Adjust slice values

- Instead of one async queue, one is defined per priority level. This
  prevents kernel threads (such as reiserfs/x and others) that run at
  higher io priority from conflicting with others. Previously, it was a
  coin toss what io prio the async queue got, it was defined by who
  first set up the queue.

- Let a time slice only begin, when the previous slice is completely
  done. Previously we could be somewhat unfair to a new sync slice, if
  the previous slice was async and had several ios queued. This might
  need a little tweaking if throughput suffers a little due to this,
  allowing perhaps an overlap of a single request or so.

- Optimize the calling of kblockd_schedule_work() by doing it only when
  it is strictly necessary (no requests in driver and work left to do).

- Correct sync vs async logic. A 'normal' process can be purely async as
  well, and a flusher can be purely sync as well. Sync or async is now a
  property of the class defined and requests pending. Previously writers
  could be considered sync, when they were really async.

- Get rid of the bit fields in cfqq and crq, use flags instead.

- Various other cleanups and fixes

Signed-off-by: Jens Axboe <axboe@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Jens Axboe 2005-06-27 10:56:24 +02:00 committed by Linus Torvalds
parent 3d25f3566b
commit 3b18152c32
2 changed files with 303 additions and 164 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

466
drivers/block/cfq-iosched.c
View File

@ -34,14 +34,15 @@ 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 / 50;
static int cfq_slice_async = HZ / 25;
static int cfq_slice_async_rq = 2;
static int cfq_slice_idle = HZ / 50;
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
@ -96,7 +97,16 @@ static kmem_cache_t *cfq_ioc_pool;
#define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE)
#define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
#define cfq_cfqq_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC)
#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
@ -200,28 +210,15 @@ struct cfq_queue {
unsigned long slice_left;
unsigned long service_last;
/* number of requests that have been handed to the driver */
int in_flight;
/* number of requests that are on the dispatch list */
int on_dispatch[2];
/* io prio of this group */
unsigned short ioprio, org_ioprio;
unsigned short ioprio_class, org_ioprio_class;
/* whether queue is on rr (or empty) list */
unsigned on_rr : 1;
/* idle slice, waiting for new request submission */
unsigned wait_request : 1;
/* set when wait_request gets set, reset on first rq alloc */
unsigned must_alloc : 1;
/* only gets one must_alloc per slice */
unsigned must_alloc_slice : 1;
/* idle slice, request added, now waiting to dispatch it */
unsigned must_dispatch : 1;
/* fifo expire per-slice */
unsigned fifo_expire : 1;
unsigned idle_window : 1;
unsigned prio_changed : 1;
/* various state flags, see below */
unsigned int flags;
};
struct cfq_rq {
@ -233,15 +230,77 @@ struct cfq_rq {
struct cfq_queue *cfq_queue;
struct cfq_io_context *io_context;
unsigned in_flight : 1;
unsigned accounted : 1;
unsigned is_sync : 1;
unsigned requeued : 1;
unsigned int crq_flags;
};
static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int);
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,
};
#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,
};
#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_put_cfqd(struct cfq_data *cfqd);
static inline int cfq_pending_requests(struct cfq_data *cfqd);
#define process_sync(tsk) ((tsk)->flags & PF_SYNCWRITE)
@ -305,9 +364,9 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2)
return crq2;
if (crq2 == NULL)
return crq1;
if (crq1->requeued)
if (cfq_crq_requeued(crq1))
return crq1;
if (crq2->requeued)
if (cfq_crq_requeued(crq2))
return crq2;
s1 = crq1->request->sector;
@ -407,7 +466,7 @@ static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
struct cfq_data *cfqd = cfqq->cfqd;
struct list_head *list, *entry;
BUG_ON(!cfqq->on_rr);
BUG_ON(!cfq_cfqq_on_rr(cfqq));
list_del(&cfqq->cfq_list);
@ -423,7 +482,7 @@ static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
* has lots of io pending vs one that only generates one
* sporadically or synchronously
*/
if (cfqq->in_flight)
if (cfq_cfqq_dispatched(cfqq))
list = &cfqd->busy_rr;
else
list = &cfqd->rr_list[cfqq->ioprio];
@ -461,8 +520,8 @@ static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
static inline void
cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq, int requeue)
{
BUG_ON(cfqq->on_rr);
cfqq->on_rr = 1;
BUG_ON(cfq_cfqq_on_rr(cfqq));
cfq_mark_cfqq_on_rr(cfqq);
cfqd->busy_queues++;
cfq_resort_rr_list(cfqq, requeue);
@ -471,8 +530,8 @@ cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq, int requeue)
static inline void
cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
BUG_ON(!cfqq->on_rr);
cfqq->on_rr = 0;
BUG_ON(!cfq_cfqq_on_rr(cfqq));
cfq_clear_cfqq_on_rr(cfqq);
list_move(&cfqq->cfq_list, &cfqd->empty_list);
BUG_ON(!cfqd->busy_queues);
@ -488,7 +547,7 @@ static inline void cfq_del_crq_rb(struct cfq_rq *crq)
if (ON_RB(&crq->rb_node)) {
struct cfq_data *cfqd = cfqq->cfqd;
const int sync = crq->is_sync;
const int sync = cfq_crq_is_sync(crq);
BUG_ON(!cfqq->queued[sync]);
cfqq->queued[sync]--;
@ -498,7 +557,7 @@ static inline void cfq_del_crq_rb(struct cfq_rq *crq)
rb_erase(&crq->rb_node, &cfqq->sort_list);
RB_CLEAR_COLOR(&crq->rb_node);
if (cfqq->on_rr && RB_EMPTY(&cfqq->sort_list))
if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list))
cfq_del_cfqq_rr(cfqd, cfqq);
}
}
@ -534,7 +593,7 @@ static void cfq_add_crq_rb(struct cfq_rq *crq)
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.
@ -545,8 +604,8 @@ static void cfq_add_crq_rb(struct cfq_rq *crq)
rb_insert_color(&crq->rb_node, &cfqq->sort_list);
if (!cfqq->on_rr)
cfq_add_cfqq_rr(cfqd, cfqq, crq->requeued);
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
@ -559,7 +618,7 @@ cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq)
{
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);
@ -568,7 +627,7 @@ cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq)
static struct request *cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector)
{
struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, current->pid);
struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, current->pid, CFQ_KEY_ANY);
struct rb_node *n;
if (!cfqq)
@ -598,17 +657,19 @@ static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
if (crq) {
struct cfq_queue *cfqq = crq->cfq_queue;
if (crq->accounted) {
crq->accounted = 0;
if (cfq_crq_in_driver(crq)) {
cfq_clear_crq_in_driver(crq);
WARN_ON(!cfqd->rq_in_driver);
cfqd->rq_in_driver--;
}
if (crq->in_flight) {
crq->in_flight = 0;
WARN_ON(!cfqq->in_flight);
cfqq->in_flight--;
if (cfq_crq_in_flight(crq)) {
const int sync = cfq_crq_is_sync(crq);
cfq_clear_crq_in_flight(crq);
WARN_ON(!cfqq->on_dispatch[sync]);
cfqq->on_dispatch[sync]--;
}
crq->requeued = 1;
cfq_mark_crq_requeued(crq);
}
}
@ -712,8 +773,9 @@ __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
cfqq->slice_start = jiffies;
cfqq->slice_end = 0;
cfqq->slice_left = 0;
cfqq->must_alloc_slice = 0;
cfqq->fifo_expire = 0;
cfq_clear_cfqq_must_alloc_slice(cfqq);
cfq_clear_cfqq_fifo_expire(cfqq);
cfq_clear_cfqq_expired(cfqq);
}
cfqd->active_queue = cfqq;
@ -776,9 +838,18 @@ static int cfq_get_next_prio_level(struct cfq_data *cfqd)
return prio;
}
static void cfq_set_active_queue(struct cfq_data *cfqd)
static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
{
struct cfq_queue *cfqq = NULL;
struct cfq_queue *cfqq;
/*
* if current queue is expired but not done with its requests yet,
* wait for that to happen
*/
if ((cfqq = cfqd->active_queue) != NULL) {
if (cfq_cfqq_expired(cfqq) && cfq_cfqq_dispatched(cfqq))
return NULL;
}
/*
* if current list is non-empty, grab first entry. if it is empty,
@ -802,48 +873,64 @@ static void cfq_set_active_queue(struct cfq_data *cfqd)
}
__cfq_set_active_queue(cfqd, cfqq);
return cfqq;
}
/*
* 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)
{
unsigned long now = jiffies;
if (cfq_cfqq_wait_request(cfqq))
del_timer(&cfqd->idle_slice_timer);
if (!preempted && !cfq_cfqq_dispatched(cfqq))
cfqq->service_last = now;
cfq_clear_cfqq_must_dispatch(cfqq);
cfq_clear_cfqq_wait_request(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 (cfq_cfqq_on_rr(cfqq))
cfq_resort_rr_list(cfqq, preempted);
if (cfqq == cfqd->active_queue)
cfqd->active_queue = NULL;
if (cfqd->active_cic) {
put_io_context(cfqd->active_cic->ioc);
cfqd->active_cic = NULL;
}
cfqd->dispatch_slice = 0;
}
static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted)
{
struct cfq_queue *cfqq = cfqd->active_queue;
if (cfqq) {
unsigned long now = jiffies;
if (cfqq->wait_request)
del_timer(&cfqd->idle_slice_timer);
if (!preempted && !cfqq->in_flight)
cfqq->service_last = now;
cfqq->must_dispatch = 0;
cfqq->wait_request = 0;
/*
* store what was left of this slice, if the queue idled out
* or was preempted
* use deferred expiry, if there are requests in progress as
* not to disturb the slice of the next queue
*/
if (time_after(now, cfqq->slice_end))
cfqq->slice_left = now - cfqq->slice_end;
if (cfq_cfqq_dispatched(cfqq))
cfq_mark_cfqq_expired(cfqq);
else
cfqq->slice_left = 0;
if (cfqq->on_rr)
cfq_resort_rr_list(cfqq, preempted);
cfqd->active_queue = NULL;
if (cfqd->active_cic) {
put_io_context(cfqd->active_cic->ioc);
cfqd->active_cic = NULL;
}
__cfq_slice_expired(cfqd, cfqq, preempted);
}
cfqd->dispatch_slice = 0;
}
static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
@ -857,7 +944,7 @@ static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
*/
if (!cfqd->cfq_slice_idle)
return 0;
if (!cfqq->idle_window)
if (!cfq_cfqq_idle_window(cfqq))
return 0;
/*
* task has exited, don't wait
@ -865,13 +952,13 @@ static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
if (cfqd->active_cic && !cfqd->active_cic->ioc->task)
return 0;
cfqq->wait_request = 1;
cfqq->must_alloc = 1;
cfq_mark_cfqq_must_dispatch(cfqq);
cfq_mark_cfqq_wait_request(cfqq);
if (!timer_pending(&cfqd->idle_slice_timer)) {
unsigned long slice_left = cfqq->slice_end - 1;
unsigned long slice_left = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle);
cfqd->idle_slice_timer.expires = min(jiffies + cfqd->cfq_slice_idle, slice_left);
cfqd->idle_slice_timer.expires = jiffies + slice_left;
add_timer(&cfqd->idle_slice_timer);
}
@ -901,7 +988,7 @@ static void cfq_dispatch_sort(request_queue_t *q, struct cfq_rq *crq)
break;
if (!blk_fs_request(__rq))
break;
if (__crq->requeued)
if (cfq_crq_requeued(__crq))
break;
if (__rq->sector <= crq->request->sector)
@ -920,9 +1007,10 @@ static void cfq_dispatch_sort(request_queue_t *q, struct cfq_rq *crq)
cfq_del_crq_rb(crq);
cfq_remove_merge_hints(q, crq);
crq->in_flight = 1;
crq->requeued = 0;
cfqq->in_flight++;
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);
}
@ -935,16 +1023,16 @@ static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq)
struct request *rq;
struct cfq_rq *crq;
if (cfqq->fifo_expire)
if (cfq_cfqq_fifo_expire(cfqq))
return NULL;
if (!list_empty(&cfqq->fifo)) {
int fifo = cfq_cfqq_sync(cfqq);
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])) {
cfqq->fifo_expire = 1;
cfq_mark_cfqq_fifo_expire(cfqq);
return crq;
}
}
@ -953,7 +1041,9 @@ static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq)
}
/*
* Scale schedule slice based on io priority
* 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)
@ -981,6 +1071,16 @@ cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio));
}
/*
* 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);
}
/*
* get next queue for service
*/
@ -993,11 +1093,14 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd, int force)
if (!cfqq)
goto new_queue;
if (cfq_cfqq_expired(cfqq))
goto new_queue;
/*
* slice has expired
*/
if (!cfqq->must_dispatch && time_after(jiffies, cfqq->slice_end))
goto new_queue;
if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end))
goto expire;
/*
* if queue has requests, dispatch one. if not, check if
@ -1005,17 +1108,18 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd, int force)
*/
if (!RB_EMPTY(&cfqq->sort_list))
goto keep_queue;
else if (!force && cfq_cfqq_sync(cfqq) &&
else if (!force && cfq_cfqq_class_sync(cfqq) &&
time_before(now, cfqq->slice_end)) {
if (cfq_arm_slice_timer(cfqd, cfqq))
return NULL;
}
new_queue:
expire:
cfq_slice_expired(cfqd, 0);
cfq_set_active_queue(cfqd);
new_queue:
cfqq = cfq_set_active_queue(cfqd);
keep_queue:
return cfqd->active_queue;
return cfqq;
}
static int
@ -1083,8 +1187,8 @@ cfq_dispatch_requests(request_queue_t *q, int max_dispatch, int force)
cfqq = cfq_select_queue(cfqd, force);
if (cfqq) {
cfqq->wait_request = 0;
cfqq->must_dispatch = 0;
cfq_clear_cfqq_must_dispatch(cfqq);
cfq_clear_cfqq_wait_request(cfqq);
del_timer(&cfqd->idle_slice_timer);
if (cfq_class_idle(cfqq))
@ -1108,10 +1212,10 @@ static inline void cfq_account_dispatch(struct cfq_rq *crq)
* accounted bit is necessary since some drivers will call
* elv_next_request() many times for the same request (eg ide)
*/
if (crq->accounted)
if (cfq_crq_in_driver(crq))
return;
crq->accounted = 1;
cfq_mark_crq_in_driver(crq);
cfqd->rq_in_driver++;
}
@ -1121,7 +1225,7 @@ cfq_account_completion(struct cfq_queue *cfqq, struct cfq_rq *crq)
struct cfq_data *cfqd = cfqq->cfqd;
unsigned long now;
if (!crq->accounted)
if (!cfq_crq_in_driver(crq))
return;
now = jiffies;
@ -1132,12 +1236,18 @@ cfq_account_completion(struct cfq_queue *cfqq, struct cfq_rq *crq)
if (!cfq_class_idle(cfqq))
cfqd->last_end_request = now;
if (!cfqq->in_flight && cfqq->on_rr) {
cfqq->service_last = now;
cfq_resort_rr_list(cfqq, 0);
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);
}
}
if (crq->is_sync)
if (cfq_crq_is_sync(crq))
crq->io_context->last_end_request = now;
}
@ -1153,10 +1263,13 @@ dispatch:
crq = RQ_DATA(rq);
if (crq) {
struct cfq_queue *cfqq = crq->cfq_queue;
/*
* if idle window is disabled, allow queue buildup
*/
if (!crq->in_flight && !crq->cfq_queue->idle_window &&
if (!cfq_crq_in_driver(crq) &&
!cfq_cfqq_idle_window(cfqq) &&
cfqd->rq_in_driver >= cfqd->cfq_max_depth)
return NULL;
@ -1190,11 +1303,11 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
BUG_ON(rb_first(&cfqq->sort_list));
BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]);
BUG_ON(cfqq->on_rr);
BUG_ON(cfq_cfqq_on_rr(cfqq));
if (unlikely(cfqd->active_queue == cfqq)) {
cfq_slice_expired(cfqd, 0);
kblockd_schedule_work(&cfqd->unplug_work);
__cfq_slice_expired(cfqd, cfqq, 0);
cfq_schedule_dispatch(cfqd);
}
cfq_put_cfqd(cfqq->cfqd);
@ -1208,15 +1321,17 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
}
static inline struct cfq_queue *
__cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int 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;
}
@ -1224,9 +1339,9 @@ __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, const int hashval)
}
static struct cfq_queue *
cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int 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 void cfq_free_io_context(struct cfq_io_context *cic)
@ -1255,8 +1370,8 @@ static void cfq_exit_single_io_context(struct cfq_io_context *cic)
spin_lock(q->queue_lock);
if (unlikely(cic->cfqq == cfqd->active_queue)) {
cfq_slice_expired(cfqd, 0);
kblockd_schedule_work(&cfqd->unplug_work);
__cfq_slice_expired(cfqd, cic->cfqq, 0);
cfq_schedule_dispatch(cfqd);
}
cfq_put_queue(cic->cfqq);
@ -1313,7 +1428,7 @@ static void cfq_init_prio_data(struct cfq_queue *cfqq)
struct task_struct *tsk = current;
int ioprio_class;
if (!cfqq->prio_changed)
if (!cfq_cfqq_prio_changed(cfqq))
return;
ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio);
@ -1338,7 +1453,7 @@ static void cfq_init_prio_data(struct cfq_queue *cfqq)
case IOPRIO_CLASS_IDLE:
cfqq->ioprio_class = IOPRIO_CLASS_IDLE;
cfqq->ioprio = 7;
cfqq->idle_window = 0;
cfq_clear_cfqq_idle_window(cfqq);
break;
}
@ -1349,10 +1464,10 @@ static void cfq_init_prio_data(struct cfq_queue *cfqq)
cfqq->org_ioprio = cfqq->ioprio;
cfqq->org_ioprio_class = cfqq->ioprio_class;
if (cfqq->on_rr)
if (cfq_cfqq_on_rr(cfqq))
cfq_resort_rr_list(cfqq, 0);
cfqq->prio_changed = 0;
cfq_clear_cfqq_prio_changed(cfqq);
}
static inline void changed_ioprio(struct cfq_queue *cfqq)
@ -1361,7 +1476,7 @@ static inline void changed_ioprio(struct cfq_queue *cfqq)
struct cfq_data *cfqd = cfqq->cfqd;
spin_lock(cfqd->queue->queue_lock);
cfqq->prio_changed = 1;
cfq_mark_cfqq_prio_changed(cfqq);
cfq_init_prio_data(cfqq);
spin_unlock(cfqd->queue->queue_lock);
}
@ -1383,13 +1498,14 @@ static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio)
}
static struct cfq_queue *
cfq_get_queue(struct cfq_data *cfqd, unsigned int key, int gfp_mask)
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, hashval);
cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval);
if (!cfqq) {
if (new_cfqq) {
@ -1423,10 +1539,9 @@ retry:
* set ->slice_left to allow preemption for a new process
*/
cfqq->slice_left = 2 * cfqd->cfq_slice_idle;
cfqq->idle_window = 1;
cfqq->ioprio = -1;
cfqq->ioprio_class = -1;
cfqq->prio_changed = 1;
cfq_mark_cfqq_idle_window(cfqq);
cfq_mark_cfqq_prio_changed(cfqq);
cfq_init_prio_data(cfqq);
}
if (new_cfqq)
@ -1553,7 +1668,7 @@ static void
cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct cfq_io_context *cic)
{
int enable_idle = cfqq->idle_window;
int enable_idle = cfq_cfqq_idle_window(cfqq);
if (!cic->ioc->task || !cfqd->cfq_slice_idle)
enable_idle = 0;
@ -1564,7 +1679,10 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
enable_idle = 1;
}
cfqq->idle_window = enable_idle;
if (enable_idle)
cfq_mark_cfqq_idle_window(cfqq);
else
cfq_clear_cfqq_idle_window(cfqq);
}
@ -1586,14 +1704,14 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
if (cfq_class_idle(cfqq))
return 1;
if (!new_cfqq->wait_request)
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 (crq->is_sync && !cfq_cfqq_sync(cfqq))
if (cfq_crq_is_sync(crq) && !cfq_cfqq_sync(cfqq))
return 1;
return 0;
@ -1614,7 +1732,7 @@ static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2;
cfqq->slice_end = cfqq->slice_left + jiffies;
cfq_slice_expired(cfqd, 1);
__cfq_slice_expired(cfqd, cfqq, 1);
__cfq_set_active_queue(cfqd, cfqq);
}
@ -1639,7 +1757,7 @@ static void
cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct cfq_rq *crq)
{
const int sync = crq->is_sync;
const int sync = cfq_crq_is_sync(crq);
cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
@ -1658,8 +1776,8 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
* immediately and flag that we must not expire this queue
* just now
*/
if (cfqq->wait_request) {
cfqq->must_dispatch = 1;
if (cfq_cfqq_wait_request(cfqq)) {
cfq_mark_cfqq_must_dispatch(cfqq);
del_timer(&cfqd->idle_slice_timer);
cfq_start_queueing(cfqd, cfqq);
}
@ -1670,7 +1788,7 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
* has some old slice time left and is of higher priority
*/
cfq_preempt_queue(cfqd, cfqq);
cfqq->must_dispatch = 1;
cfq_mark_cfqq_must_dispatch(cfqq);
cfq_start_queueing(cfqd, cfqq);
}
}
@ -1713,7 +1831,7 @@ cfq_insert_request(request_queue_t *q, struct request *rq, int where)
* be kicked by __make_request() afterward.
* Kick it here.
*/
kblockd_schedule_work(&cfqd->unplug_work);
cfq_schedule_dispatch(cfqd);
break;
case ELEVATOR_INSERT_FRONT:
list_add(&rq->queuelist, &q->queue_head);
@ -1750,9 +1868,11 @@ 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);
@ -1814,7 +1934,7 @@ static void cfq_prio_boost(struct cfq_queue *cfqq)
* refile between round-robin lists if we moved the priority class
*/
if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) &&
cfqq->on_rr)
cfq_cfqq_on_rr(cfqq))
cfq_resort_rr_list(cfqq, 0);
}
@ -1830,23 +1950,27 @@ static inline int
__cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct task_struct *task, int rw)
{
if (cfqq->wait_request && cfqq->must_alloc)
#if 1
if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) &&
!cfq_cfqq_must_alloc_slice) {
cfq_mark_cfqq_must_alloc_slice(cfqq);
return ELV_MQUEUE_MUST;
}
return ELV_MQUEUE_MAY;
#if 0
#else
if (!cfqq || task->flags & PF_MEMALLOC)
return ELV_MQUEUE_MAY;
if (!cfqq->allocated[rw] || cfqq->must_alloc) {
if (cfqq->wait_request)
if (!cfqq->allocated[rw] || cfq_cfqq_must_alloc(cfqq)) {
if (cfq_cfqq_wait_request(cfqq))
return ELV_MQUEUE_MUST;
/*
* only allow 1 ELV_MQUEUE_MUST per slice, otherwise we
* can quickly flood the queue with writes from a single task
*/
if (rw == READ || !cfqq->must_alloc_slice) {
cfqq->must_alloc_slice = 1;
if (rw == READ || !cfq_cfqq_must_alloc_slice) {
cfq_mark_cfqq_must_alloc_slice(cfqq);
return ELV_MQUEUE_MUST;
}
@ -1881,7 +2005,7 @@ static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio)
* 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));
cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio);
if (cfqq) {
cfq_init_prio_data(cfqq);
cfq_prio_boost(cfqq);
@ -1943,15 +2067,17 @@ 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);
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, cfq_queue_pid(current, rw), gfp_mask);
cic = cfq_get_io_context(cfqd, key, gfp_mask);
spin_lock_irqsave(q->queue_lock, flags);
@ -1959,7 +2085,7 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
goto queue_fail;
if (!cic->cfqq) {
cfqq = cfq_get_queue(cfqd, current->pid, gfp_mask);
cfqq = cfq_get_queue(cfqd, key, tsk->ioprio, gfp_mask);
if (!cfqq)
goto queue_fail;
@ -1968,7 +2094,7 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
cfqq = cic->cfqq;
cfqq->allocated[rw]++;
cfqq->must_alloc = 0;
cfq_clear_cfqq_must_alloc(cfqq);
cfqd->rq_starved = 0;
atomic_inc(&cfqq->ref);
spin_unlock_irqrestore(q->queue_lock, flags);
@ -1981,9 +2107,15 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
INIT_HLIST_NODE(&crq->hash);
crq->cfq_queue = cfqq;
crq->io_context = cic;
crq->in_flight = crq->accounted = 0;
crq->is_sync = (rw == READ || process_sync(current));
crq->requeued = 0;
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;
return 0;
}
@ -1991,7 +2123,7 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
spin_lock_irqsave(q->queue_lock, flags);
cfqq->allocated[rw]--;
if (!(cfqq->allocated[0] + cfqq->allocated[1]))
cfqq->must_alloc = 1;
cfq_mark_cfqq_must_alloc(cfqq);
cfq_put_queue(cfqq);
queue_fail:
if (cic)
@ -2002,7 +2134,7 @@ queue_fail:
* that would be an extremely rare OOM situation
*/
cfqd->rq_starved = 1;
kblockd_schedule_work(&cfqd->unplug_work);
cfq_schedule_dispatch(cfqd);
spin_unlock_irqrestore(q->queue_lock, flags);
return 1;
}
@ -2068,15 +2200,14 @@ static void cfq_idle_slice_timer(unsigned long data)
* not expired and it has a request pending, let it dispatch
*/
if (!RB_EMPTY(&cfqq->sort_list)) {
cfqq->must_dispatch = 1;
cfq_mark_cfqq_must_dispatch(cfqq);
goto out_kick;
}
}
expire:
cfq_slice_expired(cfqd, 0);
out_kick:
if (cfq_pending_requests(cfqd))
kblockd_schedule_work(&cfqd->unplug_work);
cfq_schedule_dispatch(cfqd);
out_cont:
spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
}
@ -2099,11 +2230,17 @@ static void cfq_idle_class_timer(unsigned long data)
cfqd->idle_class_timer.expires = end;
add_timer(&cfqd->idle_class_timer);
} else
kblockd_schedule_work(&cfqd->unplug_work);
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)
{
@ -2112,7 +2249,7 @@ static void cfq_put_cfqd(struct cfq_data *cfqd)
if (!atomic_dec_and_test(&cfqd->ref))
return;
blk_sync_queue(q);
cfq_shutdown_timer_wq(cfqd);
blk_put_queue(q);
@ -2126,8 +2263,7 @@ static void cfq_exit_queue(elevator_t *e)
{
struct cfq_data *cfqd = e->elevator_data;
del_timer_sync(&cfqd->idle_slice_timer);
del_timer_sync(&cfqd->idle_class_timer);
cfq_shutdown_timer_wq(cfqd);
cfq_put_cfqd(cfqd);
}
@ -2198,6 +2334,7 @@ static int cfq_init_queue(request_queue_t *q, elevator_t *e)
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:
kfree(cfqd->cfq_hash);
@ -2369,6 +2506,7 @@ static struct cfq_fs_entry cfq_max_depth_entry = {
.show = cfq_max_depth_show,
.store = cfq_max_depth_store,
};
static struct attribute *default_attrs[] = {
&cfq_quantum_entry.attr,
&cfq_queued_entry.attr,

1
include/linux/ioprio.h
View File

@ -12,6 +12,7 @@
#define IOPRIO_PRIO_CLASS(mask) ((mask) >> IOPRIO_CLASS_SHIFT)
#define IOPRIO_PRIO_DATA(mask) ((mask) & IOPRIO_PRIO_MASK)
#define IOPRIO_PRIO_VALUE(class, data) (((class) << IOPRIO_CLASS_SHIFT) | data)
#define ioprio_valid(mask) (IOPRIO_PRIO_CLASS((mask)) != IOPRIO_CLASS_NONE)