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Commit 3b18152c authored by Jens Axboe's avatar Jens Axboe Committed by Linus Torvalds
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[PATCH] CFQ io scheduler updates 



- 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: default avatarJens Axboe <axboe@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 3d25f356

drivers/block/cfq-iosched.c

+299 −161
Original line number Diff line number Diff line
@@ -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,
@@ -802,26 +873,26 @@ 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 inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted)

static void

__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,

		    int preempted)

{

	struct cfq_queue *cfqq = cfqd->active_queue;



	if (cfqq) {

	unsigned long now = jiffies;



		if (cfqq->wait_request)

	if (cfq_cfqq_wait_request(cfqq))

		del_timer(&cfqd->idle_slice_timer);



		if (!preempted && !cfqq->in_flight)

	if (!preempted && !cfq_cfqq_dispatched(cfqq))

		cfqq->service_last = now;



		cfqq->must_dispatch = 0;

		cfqq->wait_request = 0;

	cfq_clear_cfqq_must_dispatch(cfqq);

	cfq_clear_cfqq_wait_request(cfqq);



	/*

	 * store what was left of this slice, if the queue idled out
@@ -832,20 +903,36 @@ static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted) 
	else

		cfqq->slice_left = 0;



		if (cfqq->on_rr)

	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) {

		/*

		 * 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);

	}

}



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) {

	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 @@ static struct request *cfq_next_request(request_queue_t *q) 


		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 @@ cfq_get_queue(struct cfq_data *cfqd, unsigned int key, int gfp_mask) 
		 * 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 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio, 
	 * 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,

include/linux/ioprio.h

+1 −0
Original line number Diff line number Diff line
@@ -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)