diff mbox

[05/24] io-controller: Modify cfq to make use of flat elevator fair queuing

Message ID 1248467274-32073-6-git-send-email-vgoyal@redhat.com (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Vivek Goyal July 24, 2009, 8:27 p.m. UTC
This patch changes cfq to use fair queuing code from elevator layer.

Signed-off-by: Nauman Rafique <nauman@google.com>
Signed-off-by: Fabio Checconi <fabio@gandalf.sssup.it>
Signed-off-by: Paolo Valente <paolo.valente@unimore.it>
Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
 block/Kconfig.iosched |    3 +-
 block/cfq-iosched.c   | 1007 +++++++++++--------------------------------------
 2 files changed, 231 insertions(+), 779 deletions(-)

Comments

Gui Jianfeng July 30, 2009, 6:30 a.m. UTC | #1
Vivek Goyal wrote:
...
>  /*
>   * 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.
> + * no or if we aren't sure, a 1 will cause a preemption attempt.
> + * Some of the preemption logic has been moved to common layer. Only cfq
> + * specific parts are left here.
>   */
>  static int
> -cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
> -		   struct request *rq)
> +cfq_should_preempt(struct request_queue *q, void *new_cfqq, struct request *rq)
>  {
> -	struct cfq_queue *cfqq;
> +	struct cfq_data *cfqd = q->elevator->elevator_data;
> +	struct cfq_queue *cfqq = elv_active_sched_queue(q->elevator);
>  
> -	cfqq = cfqd->active_queue;
>  	if (!cfqq)
>  		return 0;
>  
> -	if (cfq_slice_used(cfqq))
> +	if (elv_ioq_slice_used(cfqq->ioq))
>  		return 1;
>  
>  	if (cfq_class_idle(new_cfqq))
> @@ -2018,13 +1661,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
>  	if (rq_is_meta(rq) && !cfqq->meta_pending)
>  		return 1;
>  
> -	/*
> -	 * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
> -	 */
> -	if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
> -		return 1;
> -
> -	if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
> +	if (!cfqd->active_cic || !elv_ioq_wait_request(cfqq->ioq))
>  		return 0;
>  
>  	/*

Hi Vivek,

cfq_should_preempt() will do the check "if (cfq_rq_close(cfqd, rq)) to see whether
it should preempt the current cfqq. From fairness point of view,  should we also 
check "fairness" value, if it's set fairness == 1, don't allow to preempt the current
cfqq?
Vivek Goyal July 30, 2009, 6:30 p.m. UTC | #2
On Thu, Jul 30, 2009 at 05:42:46PM +0200, Jerome Marchand wrote:
> Vivek Goyal wrote:
> > @@ -1616,11 +1234,12 @@ static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic)
> >  	struct cfq_data *cfqd = cic->key;
> >  	struct cfq_queue *cfqq;
> >  	unsigned long flags;
> > +	struct request_queue *q = cfqd->queue;
> 
> cfqd may be NULL here. We'd better test it before using it.
> 

Thanks Jerome. 

Actually I will drop this chage altogether. This is not required. I don't
know why did I change original code to introduce another local variable. 

Thanks
Vivek

> >  
> >  	if (unlikely(!cfqd))
> >  		return;
> >  
> > -	spin_lock_irqsave(cfqd->queue->queue_lock, flags);
> > +	spin_lock_irqsave(q->queue_lock, flags);
> >  
> >  	cfqq = cic->cfqq[BLK_RW_ASYNC];
> >  	if (cfqq) {
> > @@ -1637,7 +1256,7 @@ static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic)
> >  	if (cfqq)
> >  		cfq_mark_cfqq_prio_changed(cfqq);
> >  
> > -	spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
> > +	spin_unlock_irqrestore(q->queue_lock, flags);
> >  }
> >  
> >  static void cfq_ioc_set_ioprio(struct io_context *ioc)
> 
> 
> --- block/cfq-iosched.c.orig	2009-07-29 10:22:08.000000000 +0200
> +++ block/cfq-iosched.c	2009-07-30 17:25:05.000000000 +0200
> @@ -1271,11 +1271,12 @@ static void changed_ioprio(struct io_con
>  	struct cfq_data *cfqd = cic->key;
>  	struct cfq_queue *cfqq;
>  	unsigned long flags;
> -	struct request_queue *q = cfqd->queue;
> +	struct request_queue *q;
>  
>  	if (unlikely(!cfqd))
>  		return;
>  
> +	q = cfqd->queue;
>  	spin_lock_irqsave(q->queue_lock, flags);
>  
>  	cfqq = cic->cfqq[BLK_RW_ASYNC];

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Vivek Goyal July 31, 2009, 1:18 p.m. UTC | #3
On Thu, Jul 30, 2009 at 02:30:40PM +0800, Gui Jianfeng wrote:
> Vivek Goyal wrote:
> ...
> >  /*
> >   * 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.
> > + * no or if we aren't sure, a 1 will cause a preemption attempt.
> > + * Some of the preemption logic has been moved to common layer. Only cfq
> > + * specific parts are left here.
> >   */
> >  static int
> > -cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
> > -		   struct request *rq)
> > +cfq_should_preempt(struct request_queue *q, void *new_cfqq, struct request *rq)
> >  {
> > -	struct cfq_queue *cfqq;
> > +	struct cfq_data *cfqd = q->elevator->elevator_data;
> > +	struct cfq_queue *cfqq = elv_active_sched_queue(q->elevator);
> >  
> > -	cfqq = cfqd->active_queue;
> >  	if (!cfqq)
> >  		return 0;
> >  
> > -	if (cfq_slice_used(cfqq))
> > +	if (elv_ioq_slice_used(cfqq->ioq))
> >  		return 1;
> >  
> >  	if (cfq_class_idle(new_cfqq))
> > @@ -2018,13 +1661,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
> >  	if (rq_is_meta(rq) && !cfqq->meta_pending)
> >  		return 1;
> >  
> > -	/*
> > -	 * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
> > -	 */
> > -	if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
> > -		return 1;
> > -
> > -	if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
> > +	if (!cfqd->active_cic || !elv_ioq_wait_request(cfqq->ioq))
> >  		return 0;
> >  
> >  	/*
> 
> Hi Vivek,
> 
> cfq_should_preempt() will do the check "if (cfq_rq_close(cfqd, rq)) to see whether
> it should preempt the current cfqq. From fairness point of view,  should we also 
> check "fairness" value, if it's set fairness == 1, don't allow to preempt the current
> cfqq?

Hi Gui,

In V7, fairness=1 means that we try to dispatch request only from one
queue at a time and wait for requests to finish from that queue before
next queue is scheduled in. This helps in better disk time accounting for the
queue.

But currently this is not true for preemption path. So if we decide to
preempt the current queue (either by elevator layer or by cfq), we expire
the queue immediately and bring in the new one. So this is just not
cfq_rq_close() but the whole preemption path.

Currently I will leave it as it is but if we run into significant issues, 
then we can fix it. It will require extra logic of keeping track that
current queue has been preempted. Also keep track who preempted etc and
as soon as last request from queue completes, expire it.

Thanks
Vivek

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diff mbox

Patch

diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index 3398134..dd5224d 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -3,7 +3,7 @@  if BLOCK
 menu "IO Schedulers"
 
 config ELV_FAIR_QUEUING
-	bool "Elevator Fair Queuing Support"
+	bool
 	default n
 	---help---
 	  Traditionally only cfq had notion of multiple queues and it did
@@ -46,6 +46,7 @@  config IOSCHED_DEADLINE
 
 config IOSCHED_CFQ
 	tristate "CFQ I/O scheduler"
+	select ELV_FAIR_QUEUING
 	default y
 	---help---
 	  The CFQ I/O scheduler tries to distribute bandwidth equally
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 5a67ec0..09b56e7 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -12,7 +12,6 @@ 
 #include <linux/rbtree.h>
 #include <linux/ioprio.h>
 #include <linux/blktrace_api.h>
-
 /*
  * tunables
  */
@@ -23,17 +22,10 @@  static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 };
 static const int cfq_back_max = 16 * 1024;
 /* penalty of a backwards seek */
 static const int cfq_back_penalty = 2;
-static const int cfq_slice_sync = HZ / 10;
-static int cfq_slice_async = HZ / 25;
 static const int cfq_slice_async_rq = 2;
 static int cfq_slice_idle = HZ / 125;
 
 /*
- * offset from end of service tree
- */
-#define CFQ_IDLE_DELAY		(HZ / 5)
-
-/*
  * below this threshold, we consider thinktime immediate
  */
 #define CFQ_MIN_TT		(2)
@@ -43,7 +35,7 @@  static int cfq_slice_idle = HZ / 125;
 
 #define RQ_CIC(rq)		\
 	((struct cfq_io_context *) (rq)->elevator_private)
-#define RQ_CFQQ(rq)		(struct cfq_queue *) ((rq)->elevator_private2)
+#define RQ_CFQQ(rq)	(struct cfq_queue *) (ioq_sched_queue((rq)->ioq))
 
 static struct kmem_cache *cfq_pool;
 static struct kmem_cache *cfq_ioc_pool;
@@ -53,8 +45,6 @@  static struct completion *ioc_gone;
 static DEFINE_SPINLOCK(ioc_gone_lock);
 
 #define CFQ_PRIO_LISTS		IOPRIO_BE_NR
-#define cfq_class_idle(cfqq)	((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
-#define cfq_class_rt(cfqq)	((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
 
 #define sample_valid(samples)	((samples) > 80)
 
@@ -74,16 +64,11 @@  struct cfq_rb_root {
  * Per process-grouping structure
  */
 struct cfq_queue {
-	/* reference count */
-	atomic_t ref;
+	struct io_queue *ioq;
 	/* various state flags, see below */
 	unsigned int flags;
 	/* parent cfq_data */
 	struct cfq_data *cfqd;
-	/* service_tree member */
-	struct rb_node rb_node;
-	/* service_tree key */
-	unsigned long rb_key;
 	/* prio tree member */
 	struct rb_node p_node;
 	/* prio tree root we belong to, if any */
@@ -99,18 +84,13 @@  struct cfq_queue {
 	/* fifo list of requests in sort_list */
 	struct list_head fifo;
 
-	unsigned long slice_end;
-	long slice_resid;
 	unsigned int slice_dispatch;
 
 	/* pending metadata requests */
 	int meta_pending;
-	/* number of requests that are on the dispatch list or inside driver */
-	int dispatched;
 
 	/* io prio of this group */
-	unsigned short ioprio, org_ioprio;
-	unsigned short ioprio_class, org_ioprio_class;
+	unsigned short org_ioprio, org_ioprio_class;
 
 	pid_t pid;
 };
@@ -120,12 +100,6 @@  struct cfq_queue {
  */
 struct cfq_data {
 	struct request_queue *queue;
-
-	/*
-	 * rr list of queues with requests and the count of them
-	 */
-	struct cfq_rb_root service_tree;
-
 	/*
 	 * Each priority tree is sorted by next_request position.  These
 	 * trees are used when determining if two or more queues are
@@ -133,14 +107,6 @@  struct cfq_data {
 	 */
 	struct rb_root prio_trees[CFQ_PRIO_LISTS];
 
-	unsigned int busy_queues;
-	/*
-	 * Used to track any pending rt requests so we can pre-empt current
-	 * non-RT cfqq in service when this value is non-zero.
-	 */
-	unsigned int busy_rt_queues;
-
-	int rq_in_driver;
 	int sync_flight;
 
 	/*
@@ -151,21 +117,8 @@  struct cfq_data {
 	int hw_tag_samples;
 	int rq_in_driver_peak;
 
-	/*
-	 * idle window management
-	 */
-	struct timer_list idle_slice_timer;
-	struct work_struct unplug_work;
-
-	struct cfq_queue *active_queue;
 	struct cfq_io_context *active_cic;
 
-	/*
-	 * async queue for each priority case
-	 */
-	struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR];
-	struct cfq_queue *async_idle_cfqq;
-
 	sector_t last_position;
 
 	/*
@@ -175,7 +128,6 @@  struct cfq_data {
 	unsigned int cfq_fifo_expire[2];
 	unsigned int cfq_back_penalty;
 	unsigned int cfq_back_max;
-	unsigned int cfq_slice[2];
 	unsigned int cfq_slice_async_rq;
 	unsigned int cfq_slice_idle;
 
@@ -188,16 +140,10 @@  struct cfq_data {
 };
 
 enum cfqq_state_flags {
-	CFQ_CFQQ_FLAG_on_rr = 0,	/* on round-robin busy list */
-	CFQ_CFQQ_FLAG_wait_request,	/* waiting for a request */
-	CFQ_CFQQ_FLAG_must_dispatch,	/* must be allowed a dispatch */
 	CFQ_CFQQ_FLAG_must_alloc,	/* must be allowed rq alloc */
 	CFQ_CFQQ_FLAG_must_alloc_slice,	/* per-slice must_alloc flag */
 	CFQ_CFQQ_FLAG_fifo_expire,	/* FIFO checked in this slice */
-	CFQ_CFQQ_FLAG_idle_window,	/* slice idling enabled */
 	CFQ_CFQQ_FLAG_prio_changed,	/* task priority has changed */
-	CFQ_CFQQ_FLAG_slice_new,	/* no requests dispatched in slice */
-	CFQ_CFQQ_FLAG_sync,		/* synchronous queue */
 	CFQ_CFQQ_FLAG_coop,		/* has done a coop jump of the queue */
 };
 
@@ -215,16 +161,10 @@  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_dispatch);
 CFQ_CFQQ_FNS(must_alloc);
 CFQ_CFQQ_FNS(must_alloc_slice);
 CFQ_CFQQ_FNS(fifo_expire);
-CFQ_CFQQ_FNS(idle_window);
 CFQ_CFQQ_FNS(prio_changed);
-CFQ_CFQQ_FNS(slice_new);
-CFQ_CFQQ_FNS(sync);
 CFQ_CFQQ_FNS(coop);
 #undef CFQ_CFQQ_FNS
 
@@ -263,66 +203,27 @@  static inline int cfq_bio_sync(struct bio *bio)
 	return 0;
 }
 
-/*
- * 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->busy_queues) {
-		cfq_log(cfqd, "schedule dispatch");
-		kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work);
-	}
-}
-
-static int cfq_queue_empty(struct request_queue *q)
+static inline struct io_group *cfqq_to_io_group(struct cfq_queue *cfqq)
 {
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-
-	return !cfqd->busy_queues;
+	return ioq_to_io_group(cfqq->ioq);
 }
 
-/*
- * Scale schedule slice based on io priority. Use the sync time slice only
- * if a queue is marked sync and has sync io queued. A sync queue with async
- * io only, should not get full sync slice length.
- */
-static inline int cfq_prio_slice(struct cfq_data *cfqd, int sync,
-				 unsigned short prio)
-{
-	const int base_slice = cfqd->cfq_slice[sync];
-
-	WARN_ON(prio >= IOPRIO_BE_NR);
-
-	return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio));
-}
-
-static inline int
-cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static inline int cfq_class_idle(struct cfq_queue *cfqq)
 {
-	return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio);
+	return elv_ioq_class_idle(cfqq->ioq);
 }
 
-static inline void
-cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static inline int cfq_cfqq_sync(struct cfq_queue *cfqq)
 {
-	cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
-	cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies);
+	return elv_ioq_sync(cfqq->ioq);
 }
 
-/*
- * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end
- * isn't valid until the first request from the dispatch is activated
- * and the slice time set.
- */
-static inline int cfq_slice_used(struct cfq_queue *cfqq)
+static inline int cfqq_is_active_queue(struct cfq_queue *cfqq)
 {
-	if (cfq_cfqq_slice_new(cfqq))
-		return 0;
-	if (time_before(jiffies, cfqq->slice_end))
-		return 0;
+	struct cfq_data *cfqd = cfqq->cfqd;
+	struct elevator_queue *e = cfqd->queue->elevator;
 
-	return 1;
+	return (elv_active_sched_queue(e) == cfqq);
 }
 
 /*
@@ -421,33 +322,6 @@  cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2)
 }
 
 /*
- * The below is leftmost cache rbtree addon
- */
-static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root)
-{
-	if (!root->left)
-		root->left = rb_first(&root->rb);
-
-	if (root->left)
-		return rb_entry(root->left, struct cfq_queue, rb_node);
-
-	return NULL;
-}
-
-static void rb_erase_init(struct rb_node *n, struct rb_root *root)
-{
-	rb_erase(n, root);
-	RB_CLEAR_NODE(n);
-}
-
-static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
-{
-	if (root->left == n)
-		root->left = NULL;
-	rb_erase_init(n, &root->rb);
-}
-
-/*
  * would be nice to take fifo expire time into account as well
  */
 static struct request *
@@ -460,10 +334,10 @@  cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 
 	BUG_ON(RB_EMPTY_NODE(&last->rb_node));
 
-	if (rbprev)
+	if (rbprev != NULL)
 		prev = rb_entry_rq(rbprev);
 
-	if (rbnext)
+	if (rbnext != NULL)
 		next = rb_entry_rq(rbnext);
 	else {
 		rbnext = rb_first(&cfqq->sort_list);
@@ -474,95 +348,6 @@  cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	return cfq_choose_req(cfqd, next, prev);
 }
 
-static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
-				      struct cfq_queue *cfqq)
-{
-	/*
-	 * just an approximation, should be ok.
-	 */
-	return (cfqd->busy_queues - 1) * (cfq_prio_slice(cfqd, 1, 0) -
-		       cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio));
-}
-
-/*
- * The cfqd->service_tree holds all pending cfq_queue's that have
- * requests waiting to be processed. It is sorted in the order that
- * we will service the queues.
- */
-static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-				 int add_front)
-{
-	struct rb_node **p, *parent;
-	struct cfq_queue *__cfqq;
-	unsigned long rb_key;
-	int left;
-
-	if (cfq_class_idle(cfqq)) {
-		rb_key = CFQ_IDLE_DELAY;
-		parent = rb_last(&cfqd->service_tree.rb);
-		if (parent && parent != &cfqq->rb_node) {
-			__cfqq = rb_entry(parent, struct cfq_queue, rb_node);
-			rb_key += __cfqq->rb_key;
-		} else
-			rb_key += jiffies;
-	} else if (!add_front) {
-		rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies;
-		rb_key += cfqq->slice_resid;
-		cfqq->slice_resid = 0;
-	} else
-		rb_key = 0;
-
-	if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
-		/*
-		 * same position, nothing more to do
-		 */
-		if (rb_key == cfqq->rb_key)
-			return;
-
-		cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
-	}
-
-	left = 1;
-	parent = NULL;
-	p = &cfqd->service_tree.rb.rb_node;
-	while (*p) {
-		struct rb_node **n;
-
-		parent = *p;
-		__cfqq = rb_entry(parent, struct cfq_queue, rb_node);
-
-		/*
-		 * sort RT queues first, we always want to give
-		 * preference to them. IDLE queues goes to the back.
-		 * after that, sort on the next service time.
-		 */
-		if (cfq_class_rt(cfqq) > cfq_class_rt(__cfqq))
-			n = &(*p)->rb_left;
-		else if (cfq_class_rt(cfqq) < cfq_class_rt(__cfqq))
-			n = &(*p)->rb_right;
-		else if (cfq_class_idle(cfqq) < cfq_class_idle(__cfqq))
-			n = &(*p)->rb_left;
-		else if (cfq_class_idle(cfqq) > cfq_class_idle(__cfqq))
-			n = &(*p)->rb_right;
-		else if (rb_key < __cfqq->rb_key)
-			n = &(*p)->rb_left;
-		else
-			n = &(*p)->rb_right;
-
-		if (n == &(*p)->rb_right)
-			left = 0;
-
-		p = n;
-	}
-
-	if (left)
-		cfqd->service_tree.left = &cfqq->rb_node;
-
-	cfqq->rb_key = rb_key;
-	rb_link_node(&cfqq->rb_node, parent, p);
-	rb_insert_color(&cfqq->rb_node, &cfqd->service_tree.rb);
-}
-
 static struct cfq_queue *
 cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root,
 		     sector_t sector, struct rb_node **ret_parent,
@@ -624,57 +409,43 @@  static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 		cfqq->p_root = NULL;
 }
 
-/*
- * Update cfqq's position in the service tree.
- */
-static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+/* An active ioq is being reset. A chance to do cic related stuff. */
+static void cfq_active_ioq_reset(struct request_queue *q, void *sched_queue)
 {
-	/*
-	 * Resorting requires the cfqq to be on the RR list already.
-	 */
-	if (cfq_cfqq_on_rr(cfqq)) {
-		cfq_service_tree_add(cfqd, cfqq, 0);
-		cfq_prio_tree_add(cfqd, cfqq);
-	}
-}
+	struct cfq_data *cfqd = q->elevator->elevator_data;
+	struct cfq_queue *cfqq = sched_queue;
 
-/*
- * add to busy list of queues for service, trying to be fair in ordering
- * the pending list according to last request service
- */
-static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	cfq_log_cfqq(cfqd, cfqq, "add_to_rr");
-	BUG_ON(cfq_cfqq_on_rr(cfqq));
-	cfq_mark_cfqq_on_rr(cfqq);
-	cfqd->busy_queues++;
-	if (cfq_class_rt(cfqq))
-		cfqd->busy_rt_queues++;
+	if (cfqd->active_cic) {
+		put_io_context(cfqd->active_cic->ioc);
+		cfqd->active_cic = NULL;
+	}
 
-	cfq_resort_rr_list(cfqd, cfqq);
+	/* Resort the cfqq in prio tree */
+	if (cfqq)
+		cfq_prio_tree_add(cfqd, cfqq);
 }
 
-/*
- * Called when the cfqq no longer has requests pending, remove it from
- * the service tree.
- */
-static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+/* An ioq has been set as active one. */
+static void cfq_active_ioq_set(struct request_queue *q, void *sched_queue,
+				int coop)
 {
-	cfq_log_cfqq(cfqd, cfqq, "del_from_rr");
-	BUG_ON(!cfq_cfqq_on_rr(cfqq));
-	cfq_clear_cfqq_on_rr(cfqq);
+	struct cfq_queue *cfqq = sched_queue;
 
-	if (!RB_EMPTY_NODE(&cfqq->rb_node))
-		cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
-	if (cfqq->p_root) {
-		rb_erase(&cfqq->p_node, cfqq->p_root);
-		cfqq->p_root = NULL;
-	}
+	cfqq->slice_dispatch = 0;
+
+	cfq_clear_cfqq_must_alloc_slice(cfqq);
+	cfq_clear_cfqq_fifo_expire(cfqq);
 
-	BUG_ON(!cfqd->busy_queues);
-	cfqd->busy_queues--;
-	if (cfq_class_rt(cfqq))
-		cfqd->busy_rt_queues--;
+	/*
+	 * If queue was selected because it was a close cooperator, then
+	 * mark it so that it is not selected again and again. Otherwise
+	 * clear the coop flag so that it becomes eligible to get selected
+	 * again.
+	 */
+	if (coop)
+		cfq_mark_cfqq_coop(cfqq);
+	else
+		cfq_clear_cfqq_coop(cfqq);
 }
 
 /*
@@ -683,7 +454,6 @@  static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 static void cfq_del_rq_rb(struct request *rq)
 {
 	struct cfq_queue *cfqq = RQ_CFQQ(rq);
-	struct cfq_data *cfqd = cfqq->cfqd;
 	const int sync = rq_is_sync(rq);
 
 	BUG_ON(!cfqq->queued[sync]);
@@ -691,8 +461,17 @@  static void cfq_del_rq_rb(struct request *rq)
 
 	elv_rb_del(&cfqq->sort_list, rq);
 
-	if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list))
-		cfq_del_cfqq_rr(cfqd, cfqq);
+	/*
+	 * If this was last request in the queue, remove this queue from
+	 * prio trees. For last request nr_queued count will still be 1 as
+	 * elevator fair queuing layer is yet to do the accounting.
+	 */
+	if (elv_ioq_nr_queued(cfqq->ioq) == 1) {
+		if (cfqq->p_root) {
+			rb_erase(&cfqq->p_node, cfqq->p_root);
+			cfqq->p_root = NULL;
+		}
+	}
 }
 
 static void cfq_add_rq_rb(struct request *rq)
@@ -710,9 +489,6 @@  static void cfq_add_rq_rb(struct request *rq)
 	while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL)
 		cfq_dispatch_insert(cfqd->queue, __alias);
 
-	if (!cfq_cfqq_on_rr(cfqq))
-		cfq_add_cfqq_rr(cfqd, cfqq);
-
 	/*
 	 * check if this request is a better next-serve candidate
 	 */
@@ -760,23 +536,9 @@  static void cfq_activate_request(struct request_queue *q, struct request *rq)
 {
 	struct cfq_data *cfqd = q->elevator->elevator_data;
 
-	cfqd->rq_in_driver++;
-	cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d",
-						cfqd->rq_in_driver);
-
 	cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq);
 }
 
-static void cfq_deactivate_request(struct request_queue *q, struct request *rq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-
-	WARN_ON(!cfqd->rq_in_driver);
-	cfqd->rq_in_driver--;
-	cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d",
-						cfqd->rq_in_driver);
-}
-
 static void cfq_remove_request(struct request *rq)
 {
 	struct cfq_queue *cfqq = RQ_CFQQ(rq);
@@ -861,93 +623,21 @@  static int cfq_allow_merge(struct request_queue *q, struct request *rq,
 	return 0;
 }
 
-static void __cfq_set_active_queue(struct cfq_data *cfqd,
-				   struct cfq_queue *cfqq)
-{
-	if (cfqq) {
-		cfq_log_cfqq(cfqd, cfqq, "set_active");
-		cfqq->slice_end = 0;
-		cfqq->slice_dispatch = 0;
-
-		cfq_clear_cfqq_wait_request(cfqq);
-		cfq_clear_cfqq_must_dispatch(cfqq);
-		cfq_clear_cfqq_must_alloc_slice(cfqq);
-		cfq_clear_cfqq_fifo_expire(cfqq);
-		cfq_mark_cfqq_slice_new(cfqq);
-
-		del_timer(&cfqd->idle_slice_timer);
-	}
-
-	cfqd->active_queue = 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 timed_out)
+__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
-	cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out);
-
-	if (cfq_cfqq_wait_request(cfqq))
-		del_timer(&cfqd->idle_slice_timer);
-
-	cfq_clear_cfqq_wait_request(cfqq);
-
-	/*
-	 * store what was left of this slice, if the queue idled/timed out
-	 */
-	if (timed_out && !cfq_cfqq_slice_new(cfqq)) {
-		cfqq->slice_resid = cfqq->slice_end - jiffies;
-		cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid);
-	}
-
-	cfq_resort_rr_list(cfqd, cfqq);
-
-	if (cfqq == cfqd->active_queue)
-		cfqd->active_queue = NULL;
-
-	if (cfqd->active_cic) {
-		put_io_context(cfqd->active_cic->ioc);
-		cfqd->active_cic = NULL;
-	}
+	__elv_ioq_slice_expired(cfqd->queue, cfqq->ioq);
 }
 
-static inline void cfq_slice_expired(struct cfq_data *cfqd, int timed_out)
+static inline void cfq_slice_expired(struct cfq_data *cfqd)
 {
-	struct cfq_queue *cfqq = cfqd->active_queue;
+	struct cfq_queue *cfqq = elv_active_sched_queue(cfqd->queue->elevator);
 
 	if (cfqq)
-		__cfq_slice_expired(cfqd, cfqq, timed_out);
-}
-
-/*
- * Get next queue for service. Unless we have a queue preemption,
- * we'll simply select the first cfqq in the service tree.
- */
-static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
-{
-	if (RB_EMPTY_ROOT(&cfqd->service_tree.rb))
-		return NULL;
-
-	return cfq_rb_first(&cfqd->service_tree);
-}
-
-/*
- * Get and set a new active queue for service.
- */
-static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd,
-					      struct cfq_queue *cfqq)
-{
-	if (!cfqq) {
-		cfqq = cfq_get_next_queue(cfqd);
-		if (cfqq)
-			cfq_clear_cfqq_coop(cfqq);
-	}
-
-	__cfq_set_active_queue(cfqd, cfqq);
-	return cfqq;
+		__cfq_slice_expired(cfqd, cfqq);
 }
 
 static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd,
@@ -1024,11 +714,11 @@  static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
  * associated with the I/O issued by cur_cfqq.  I'm not sure this is a valid
  * assumption.
  */
-static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
-					      struct cfq_queue *cur_cfqq,
-					      int probe)
+static struct io_queue *cfq_close_cooperator(struct request_queue *q,
+					      void *cur_sched_queue)
 {
-	struct cfq_queue *cfqq;
+	struct cfq_queue *cur_cfqq = cur_sched_queue, *cfqq;
+	struct cfq_data *cfqd = q->elevator->elevator_data;
 
 	/*
 	 * A valid cfq_io_context is necessary to compare requests against
@@ -1049,14 +739,13 @@  static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
 	if (cfq_cfqq_coop(cfqq))
 		return NULL;
 
-	if (!probe)
-		cfq_mark_cfqq_coop(cfqq);
-	return cfqq;
+	return cfqq->ioq;
 }
 
-static void cfq_arm_slice_timer(struct cfq_data *cfqd)
+static void cfq_arm_slice_timer(struct request_queue *q, void *sched_queue)
 {
-	struct cfq_queue *cfqq = cfqd->active_queue;
+	struct cfq_data *cfqd = q->elevator->elevator_data;
+	struct cfq_queue *cfqq = sched_queue;
 	struct cfq_io_context *cic;
 	unsigned long sl;
 
@@ -1069,18 +758,18 @@  static void cfq_arm_slice_timer(struct cfq_data *cfqd)
 		return;
 
 	WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
-	WARN_ON(cfq_cfqq_slice_new(cfqq));
+	WARN_ON(elv_ioq_slice_new(cfqq->ioq));
 
 	/*
 	 * idle is disabled, either manually or by past process history
 	 */
-	if (!cfqd->cfq_slice_idle || !cfq_cfqq_idle_window(cfqq))
+	if (!cfqd->cfq_slice_idle || !elv_ioq_idle_window(cfqq->ioq))
 		return;
 
 	/*
 	 * still requests with the driver, don't idle
 	 */
-	if (cfqd->rq_in_driver)
+	if (elv_rq_in_driver(q->elevator))
 		return;
 
 	/*
@@ -1090,7 +779,7 @@  static void cfq_arm_slice_timer(struct cfq_data *cfqd)
 	if (!cic || !atomic_read(&cic->ioc->nr_tasks))
 		return;
 
-	cfq_mark_cfqq_wait_request(cfqq);
+	elv_mark_ioq_wait_request(cfqq->ioq);
 
 	/*
 	 * we don't want to idle for seeks, but we do want to allow
@@ -1101,7 +790,7 @@  static void cfq_arm_slice_timer(struct cfq_data *cfqd)
 	if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
 		sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT));
 
-	mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
+	elv_mod_idle_slice_timer(q->elevator, jiffies + sl);
 	cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl);
 }
 
@@ -1110,13 +799,12 @@  static void cfq_arm_slice_timer(struct cfq_data *cfqd)
  */
 static void cfq_dispatch_insert(struct request_queue *q, struct request *rq)
 {
-	struct cfq_data *cfqd = q->elevator->elevator_data;
 	struct cfq_queue *cfqq = RQ_CFQQ(rq);
+	struct cfq_data *cfqd = q->elevator->elevator_data;
 
-	cfq_log_cfqq(cfqd, cfqq, "dispatch_insert");
+	cfq_log_cfqq(cfqd, cfqq, "dispatch_insert sect=%d", blk_rq_sectors(rq));
 
 	cfq_remove_request(rq);
-	cfqq->dispatched++;
 	elv_dispatch_sort(q, rq);
 
 	if (cfq_cfqq_sync(cfqq))
@@ -1154,78 +842,11 @@  static inline int
 cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
 	const int base_rq = cfqd->cfq_slice_async_rq;
+	unsigned short ioprio = elv_ioq_ioprio(cfqq->ioq);
 
-	WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
+	WARN_ON(ioprio >= IOPRIO_BE_NR);
 
-	return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio));
-}
-
-/*
- * Select a queue for service. If we have a current active queue,
- * check whether to continue servicing it, or retrieve and set a new one.
- */
-static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
-{
-	struct cfq_queue *cfqq, *new_cfqq = NULL;
-
-	cfqq = cfqd->active_queue;
-	if (!cfqq)
-		goto new_queue;
-
-	/*
-	 * The active queue has run out of time, expire it and select new.
-	 */
-	if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq))
-		goto expire;
-
-	/*
-	 * If we have a RT cfqq waiting, then we pre-empt the current non-rt
-	 * cfqq.
-	 */
-	if (!cfq_class_rt(cfqq) && cfqd->busy_rt_queues) {
-		/*
-		 * We simulate this as cfqq timed out so that it gets to bank
-		 * the remaining of its time slice.
-		 */
-		cfq_log_cfqq(cfqd, cfqq, "preempt");
-		cfq_slice_expired(cfqd, 1);
-		goto new_queue;
-	}
-
-	/*
-	 * The active queue has requests and isn't expired, allow it to
-	 * dispatch.
-	 */
-	if (!RB_EMPTY_ROOT(&cfqq->sort_list))
-		goto keep_queue;
-
-	/*
-	 * If another queue has a request waiting within our mean seek
-	 * distance, let it run.  The expire code will check for close
-	 * cooperators and put the close queue at the front of the service
-	 * tree.
-	 */
-	new_cfqq = cfq_close_cooperator(cfqd, cfqq, 0);
-	if (new_cfqq)
-		goto expire;
-
-	/*
-	 * No requests pending. If the active queue still has requests in
-	 * flight or is idling for a new request, allow either of these
-	 * conditions to happen (or time out) before selecting a new queue.
-	 */
-	if (timer_pending(&cfqd->idle_slice_timer) ||
-	    (cfqq->dispatched && cfq_cfqq_idle_window(cfqq))) {
-		cfqq = NULL;
-		goto keep_queue;
-	}
-
-expire:
-	cfq_slice_expired(cfqd, 0);
-new_queue:
-	cfqq = cfq_set_active_queue(cfqd, new_cfqq);
-keep_queue:
-	return cfqq;
+	return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - ioprio));
 }
 
 static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq)
@@ -1250,12 +871,14 @@  static int cfq_forced_dispatch(struct cfq_data *cfqd)
 	struct cfq_queue *cfqq;
 	int dispatched = 0;
 
-	while ((cfqq = cfq_rb_first(&cfqd->service_tree)) != NULL)
+	while ((cfqq = elv_select_sched_queue(cfqd->queue, 1)) != NULL)
 		dispatched += __cfq_forced_dispatch_cfqq(cfqq);
 
-	cfq_slice_expired(cfqd, 0);
+	/* This probably is redundant now. above loop will should make sure
+	 * that all the busy queues have expired */
+	cfq_slice_expired(cfqd);
 
-	BUG_ON(cfqd->busy_queues);
+	BUG_ON(elv_nr_busy_ioq(cfqd->queue->elevator));
 
 	cfq_log(cfqd, "forced_dispatch=%d", dispatched);
 	return dispatched;
@@ -1301,13 +924,10 @@  static int cfq_dispatch_requests(struct request_queue *q, int force)
 	struct cfq_queue *cfqq;
 	unsigned int max_dispatch;
 
-	if (!cfqd->busy_queues)
-		return 0;
-
 	if (unlikely(force))
 		return cfq_forced_dispatch(cfqd);
 
-	cfqq = cfq_select_queue(cfqd);
+	cfqq = elv_select_sched_queue(q, 0);
 	if (!cfqq)
 		return 0;
 
@@ -1324,7 +944,7 @@  static int cfq_dispatch_requests(struct request_queue *q, int force)
 	/*
 	 * Does this cfqq already have too much IO in flight?
 	 */
-	if (cfqq->dispatched >= max_dispatch) {
+	if (elv_ioq_nr_dispatched(cfqq->ioq) >= max_dispatch) {
 		/*
 		 * idle queue must always only have a single IO in flight
 		 */
@@ -1334,13 +954,13 @@  static int cfq_dispatch_requests(struct request_queue *q, int force)
 		/*
 		 * We have other queues, don't allow more IO from this one
 		 */
-		if (cfqd->busy_queues > 1)
+		if (elv_nr_busy_ioq(q->elevator) > 1)
 			return 0;
 
 		/*
 		 * we are the only queue, allow up to 4 times of 'quantum'
 		 */
-		if (cfqq->dispatched >= 4 * max_dispatch)
+		if (elv_ioq_nr_dispatched(cfqq->ioq) >= 4 * max_dispatch)
 			return 0;
 	}
 
@@ -1349,51 +969,45 @@  static int cfq_dispatch_requests(struct request_queue *q, int force)
 	 */
 	cfq_dispatch_request(cfqd, cfqq);
 	cfqq->slice_dispatch++;
-	cfq_clear_cfqq_must_dispatch(cfqq);
 
 	/*
 	 * expire an async queue immediately if it has used up its slice. idle
 	 * queue always expire after 1 dispatch round.
 	 */
-	if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) &&
+	if (elv_nr_busy_ioq(q->elevator) > 1 && ((!cfq_cfqq_sync(cfqq) &&
 	    cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
 	    cfq_class_idle(cfqq))) {
-		cfqq->slice_end = jiffies + 1;
-		cfq_slice_expired(cfqd, 0);
+		cfq_slice_expired(cfqd);
 	}
 
 	cfq_log(cfqd, "dispatched a request");
 	return 1;
 }
 
-/*
- * task holds one reference to the queue, dropped when task exits. each rq
- * in-flight on this queue also holds a reference, dropped when rq is freed.
- *
- * queue lock must be held here.
- */
-static void cfq_put_queue(struct cfq_queue *cfqq)
+static void cfq_free_cfq_queue(struct elevator_queue *e, void *sched_queue)
 {
+	struct cfq_queue *cfqq = sched_queue;
 	struct cfq_data *cfqd = cfqq->cfqd;
 
-	BUG_ON(atomic_read(&cfqq->ref) <= 0);
+	BUG_ON(!cfqq);
 
-	if (!atomic_dec_and_test(&cfqq->ref))
-		return;
-
-	cfq_log_cfqq(cfqd, cfqq, "put_queue");
+	cfq_log_cfqq(cfqd, cfqq, "free_queue");
 	BUG_ON(rb_first(&cfqq->sort_list));
 	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);
+	if (unlikely(cfqq_is_active_queue(cfqq))) {
+		__cfq_slice_expired(cfqd, cfqq);
+		elv_schedule_dispatch(cfqd->queue);
 	}
 
 	kmem_cache_free(cfq_pool, cfqq);
 }
 
+static inline void cfq_put_queue(struct cfq_queue *cfqq)
+{
+	elv_put_ioq(cfqq->ioq);
+}
+
 /*
  * Must always be called with the rcu_read_lock() held
  */
@@ -1481,9 +1095,9 @@  static void cfq_free_io_context(struct io_context *ioc)
 
 static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
-	if (unlikely(cfqq == cfqd->active_queue)) {
-		__cfq_slice_expired(cfqd, cfqq, 0);
-		cfq_schedule_dispatch(cfqd);
+	if (unlikely(cfqq == elv_active_sched_queue(cfqd->queue->elevator))) {
+		__cfq_slice_expired(cfqd, cfqq);
+		elv_schedule_dispatch(cfqd->queue);
 	}
 
 	cfq_put_queue(cfqq);
@@ -1553,9 +1167,10 @@  static struct cfq_io_context *
 cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
 {
 	struct cfq_io_context *cic;
+	struct request_queue *q = cfqd->queue;
 
 	cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO,
-							cfqd->queue->node);
+							q->node);
 	if (cic) {
 		cic->last_end_request = jiffies;
 		INIT_LIST_HEAD(&cic->queue_list);
@@ -1571,7 +1186,7 @@  cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
 static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
 {
 	struct task_struct *tsk = current;
-	int ioprio_class;
+	int ioprio_class, ioprio;
 
 	if (!cfq_cfqq_prio_changed(cfqq))
 		return;
@@ -1584,30 +1199,33 @@  static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
 		/*
 		 * no prio set, inherit CPU scheduling settings
 		 */
-		cfqq->ioprio = task_nice_ioprio(tsk);
-		cfqq->ioprio_class = task_nice_ioclass(tsk);
+		ioprio = task_nice_ioprio(tsk);
+		ioprio_class = task_nice_ioclass(tsk);
 		break;
 	case IOPRIO_CLASS_RT:
-		cfqq->ioprio = task_ioprio(ioc);
-		cfqq->ioprio_class = IOPRIO_CLASS_RT;
+		ioprio = task_ioprio(ioc);
+		ioprio_class = IOPRIO_CLASS_RT;
 		break;
 	case IOPRIO_CLASS_BE:
-		cfqq->ioprio = task_ioprio(ioc);
-		cfqq->ioprio_class = IOPRIO_CLASS_BE;
+		ioprio = task_ioprio(ioc);
+		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);
+		ioprio_class = IOPRIO_CLASS_IDLE;
+		ioprio = 7;
+		elv_clear_ioq_idle_window(cfqq->ioq);
 		break;
 	}
 
+	elv_ioq_set_ioprio_class(cfqq->ioq, ioprio_class);
+	elv_ioq_set_ioprio(cfqq->ioq, ioprio);
+
 	/*
 	 * 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;
+	cfqq->org_ioprio = ioprio;
+	cfqq->org_ioprio_class = ioprio_class;
 	cfq_clear_cfqq_prio_changed(cfqq);
 }
 
@@ -1616,11 +1234,12 @@  static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic)
 	struct cfq_data *cfqd = cic->key;
 	struct cfq_queue *cfqq;
 	unsigned long flags;
+	struct request_queue *q = cfqd->queue;
 
 	if (unlikely(!cfqd))
 		return;
 
-	spin_lock_irqsave(cfqd->queue->queue_lock, flags);
+	spin_lock_irqsave(q->queue_lock, flags);
 
 	cfqq = cic->cfqq[BLK_RW_ASYNC];
 	if (cfqq) {
@@ -1637,7 +1256,7 @@  static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic)
 	if (cfqq)
 		cfq_mark_cfqq_prio_changed(cfqq);
 
-	spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
+	spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
 static void cfq_ioc_set_ioprio(struct io_context *ioc)
@@ -1649,19 +1268,17 @@  static void cfq_ioc_set_ioprio(struct io_context *ioc)
 static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 			  pid_t pid, int is_sync)
 {
-	RB_CLEAR_NODE(&cfqq->rb_node);
 	RB_CLEAR_NODE(&cfqq->p_node);
 	INIT_LIST_HEAD(&cfqq->fifo);
 
-	atomic_set(&cfqq->ref, 0);
 	cfqq->cfqd = cfqd;
 
 	cfq_mark_cfqq_prio_changed(cfqq);
 
 	if (is_sync) {
 		if (!cfq_class_idle(cfqq))
-			cfq_mark_cfqq_idle_window(cfqq);
-		cfq_mark_cfqq_sync(cfqq);
+			elv_mark_ioq_idle_window(cfqq->ioq);
+		elv_mark_ioq_sync(cfqq->ioq);
 	}
 	cfqq->pid = pid;
 }
@@ -1672,8 +1289,13 @@  cfq_find_alloc_queue(struct cfq_data *cfqd, int is_sync,
 {
 	struct cfq_queue *cfqq, *new_cfqq = NULL;
 	struct cfq_io_context *cic;
+	struct request_queue *q = cfqd->queue;
+	struct io_queue *ioq = NULL, *new_ioq = NULL;
+	struct io_group *iog = NULL;
 
 retry:
+	iog = io_get_io_group(q);
+
 	cic = cfq_cic_lookup(cfqd, ioc);
 	/* cic always exists here */
 	cfqq = cic_to_cfqq(cic, is_sync);
@@ -1683,8 +1305,29 @@  retry:
 	 * originally, since it should just be a temporary situation.
 	 */
 	if (!cfqq || cfqq == &cfqd->oom_cfqq) {
+		/* Allocate ioq object first and then cfqq */
+		if (new_ioq) {
+			goto alloc_cfqq;
+		} else if (gfp_mask & __GFP_WAIT) {
+			spin_unlock_irq(cfqd->queue->queue_lock);
+			new_ioq = elv_alloc_ioq(q, gfp_mask | __GFP_ZERO);
+			spin_lock_irq(cfqd->queue->queue_lock);
+			if (new_ioq)
+				goto retry;
+		} else
+			ioq = elv_alloc_ioq(q, gfp_mask | __GFP_ZERO);
+
+alloc_cfqq:
+		if (!ioq && !new_ioq) {
+			/* ioq allocation failed. Deafult to oom_cfqq */
+			cfqq = &cfqd->oom_cfqq;
+			goto out;
+		}
+
 		cfqq = NULL;
 		if (new_cfqq) {
+			ioq = new_ioq;
+			new_ioq = NULL;
 			cfqq = new_cfqq;
 			new_cfqq = NULL;
 		} else if (gfp_mask & __GFP_WAIT) {
@@ -1702,60 +1345,58 @@  retry:
 		}
 
 		if (cfqq) {
+			elv_init_ioq(q->elevator, ioq, current->pid, is_sync);
+			elv_init_ioq_io_group(q->elevator, ioq, iog);
+			elv_init_ioq_prio_data(q->elevator, ioq,
+						IOPRIO_CLASS_BE, IOPRIO_NORM);
+			elv_init_ioq_sched_queue(q->elevator, ioq, cfqq);
+
+			cfqq->ioq = ioq;
 			cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync);
 			cfq_init_prio_data(cfqq, ioc);
 			cfq_log_cfqq(cfqd, cfqq, "alloced");
-		} else
+		} else {
 			cfqq = &cfqd->oom_cfqq;
+			/* If ioq allocation was successful, free it up */
+			if (ioq)
+				elv_free_ioq(ioq);
+		}
 	}
 
+	if (new_ioq)
+		elv_free_ioq(new_ioq);
+
 	if (new_cfqq)
 		kmem_cache_free(cfq_pool, new_cfqq);
 
+out:
 	return cfqq;
 }
 
-static struct cfq_queue **
-cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio)
-{
-	switch (ioprio_class) {
-	case IOPRIO_CLASS_RT:
-		return &cfqd->async_cfqq[0][ioprio];
-	case IOPRIO_CLASS_BE:
-		return &cfqd->async_cfqq[1][ioprio];
-	case IOPRIO_CLASS_IDLE:
-		return &cfqd->async_idle_cfqq;
-	default:
-		BUG();
-	}
-}
-
 static struct cfq_queue *
 cfq_get_queue(struct cfq_data *cfqd, int is_sync, struct io_context *ioc,
 	      gfp_t gfp_mask)
 {
 	const int ioprio = task_ioprio(ioc);
 	const int ioprio_class = task_ioprio_class(ioc);
-	struct cfq_queue **async_cfqq = NULL;
+	struct cfq_queue *async_cfqq = NULL;
 	struct cfq_queue *cfqq = NULL;
+	struct io_group *iog = io_get_io_group(cfqd->queue);
 
 	if (!is_sync) {
-		async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio);
-		cfqq = *async_cfqq;
+		async_cfqq = io_group_async_queue_prio(iog, ioprio_class,
+								ioprio);
+		cfqq = async_cfqq;
 	}
 
 	if (!cfqq)
 		cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask);
 
-	/*
-	 * pin the queue now that it's allocated, scheduler exit will prune it
-	 */
-	if (!is_sync && !(*async_cfqq)) {
-		atomic_inc(&cfqq->ref);
-		*async_cfqq = cfqq;
-	}
+	if (!is_sync && !async_cfqq)
+		io_group_set_async_queue(iog, ioprio_class, ioprio, cfqq->ioq);
 
-	atomic_inc(&cfqq->ref);
+	/* ioc reference */
+	elv_get_ioq(cfqq->ioq);
 	return cfqq;
 }
 
@@ -1834,6 +1475,7 @@  static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
 {
 	unsigned long flags;
 	int ret;
+	struct request_queue *q = cfqd->queue;
 
 	ret = radix_tree_preload(gfp_mask);
 	if (!ret) {
@@ -1850,9 +1492,9 @@  static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
 		radix_tree_preload_end();
 
 		if (!ret) {
-			spin_lock_irqsave(cfqd->queue->queue_lock, flags);
+			spin_lock_irqsave(q->queue_lock, flags);
 			list_add(&cic->queue_list, &cfqd->cic_list);
-			spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
+			spin_unlock_irqrestore(q->queue_lock, flags);
 		}
 	}
 
@@ -1872,10 +1514,11 @@  cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
 {
 	struct io_context *ioc = NULL;
 	struct cfq_io_context *cic;
+	struct request_queue *q = cfqd->queue;
 
 	might_sleep_if(gfp_mask & __GFP_WAIT);
 
-	ioc = get_io_context(gfp_mask, cfqd->queue->node);
+	ioc = get_io_context(gfp_mask, q->node);
 	if (!ioc)
 		return NULL;
 
@@ -1894,7 +1537,6 @@  out:
 	smp_read_barrier_depends();
 	if (unlikely(ioc->ioprio_changed))
 		cfq_ioc_set_ioprio(ioc);
-
 	return cic;
 err_free:
 	cfq_cic_free(cic);
@@ -1960,7 +1602,7 @@  cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq))
 		return;
 
-	enable_idle = old_idle = cfq_cfqq_idle_window(cfqq);
+	enable_idle = old_idle = elv_ioq_idle_window(cfqq->ioq);
 
 	if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
 	    (cfqd->hw_tag && CIC_SEEKY(cic)))
@@ -1975,27 +1617,28 @@  cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	if (old_idle != enable_idle) {
 		cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle);
 		if (enable_idle)
-			cfq_mark_cfqq_idle_window(cfqq);
+			elv_mark_ioq_idle_window(cfqq->ioq);
 		else
-			cfq_clear_cfqq_idle_window(cfqq);
+			elv_clear_ioq_idle_window(cfqq->ioq);
 	}
 }
 
 /*
  * 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.
+ * no or if we aren't sure, a 1 will cause a preemption attempt.
+ * Some of the preemption logic has been moved to common layer. Only cfq
+ * specific parts are left here.
  */
 static int
-cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
-		   struct request *rq)
+cfq_should_preempt(struct request_queue *q, void *new_cfqq, struct request *rq)
 {
-	struct cfq_queue *cfqq;
+	struct cfq_data *cfqd = q->elevator->elevator_data;
+	struct cfq_queue *cfqq = elv_active_sched_queue(q->elevator);
 
-	cfqq = cfqd->active_queue;
 	if (!cfqq)
 		return 0;
 
-	if (cfq_slice_used(cfqq))
+	if (elv_ioq_slice_used(cfqq->ioq))
 		return 1;
 
 	if (cfq_class_idle(new_cfqq))
@@ -2018,13 +1661,7 @@  cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
 	if (rq_is_meta(rq) && !cfqq->meta_pending)
 		return 1;
 
-	/*
-	 * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
-	 */
-	if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
-		return 1;
-
-	if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
+	if (!cfqd->active_cic || !elv_ioq_wait_request(cfqq->ioq))
 		return 0;
 
 	/*
@@ -2038,29 +1675,10 @@  cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
 }
 
 /*
- * 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)
-{
-	cfq_log_cfqq(cfqd, cfqq, "preempt");
-	cfq_slice_expired(cfqd, 1);
-
-	/*
-	 * Put the new queue at the front of the of the current list,
-	 * so we know that it will be selected next.
-	 */
-	BUG_ON(!cfq_cfqq_on_rr(cfqq));
-
-	cfq_service_tree_add(cfqd, cfqq, 1);
-
-	cfqq->slice_end = 0;
-	cfq_mark_cfqq_slice_new(cfqq);
-}
-
-/*
  * Called when a new fs request (rq) is added (to cfqq). Check if there's
  * something we should do about it
+ * After enqueuing the request whether queue should be preempted or kicked
+ * decision is taken by common layer.
  */
 static void
 cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
@@ -2077,36 +1695,6 @@  cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	cfq_update_idle_window(cfqd, cfqq, cic);
 
 	cic->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq);
-
-	if (cfqq == cfqd->active_queue) {
-		/*
-		 * Remember that we saw a request from this process, but
-		 * don't start queuing just yet. Otherwise we risk seeing lots
-		 * of tiny requests, because we disrupt the normal plugging
-		 * and merging. If the request is already larger than a single
-		 * page, let it rip immediately. For that case we assume that
-		 * merging is already done. Ditto for a busy system that
-		 * has other work pending, don't risk delaying until the
-		 * idle timer unplug to continue working.
-		 */
-		if (cfq_cfqq_wait_request(cfqq)) {
-			if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE ||
-			    cfqd->busy_queues > 1) {
-				del_timer(&cfqd->idle_slice_timer);
-			__blk_run_queue(cfqd->queue);
-			}
-			cfq_mark_cfqq_must_dispatch(cfqq);
-		}
-	} else if (cfq_should_preempt(cfqd, cfqq, rq)) {
-		/*
-		 * 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 or
-		 * this new queue is RT and the current one is BE
-		 */
-		cfq_preempt_queue(cfqd, cfqq);
-		__blk_run_queue(cfqd->queue);
-	}
 }
 
 static void cfq_insert_request(struct request_queue *q, struct request *rq)
@@ -2130,11 +1718,13 @@  static void cfq_insert_request(struct request_queue *q, struct request *rq)
  */
 static void cfq_update_hw_tag(struct cfq_data *cfqd)
 {
-	if (cfqd->rq_in_driver > cfqd->rq_in_driver_peak)
-		cfqd->rq_in_driver_peak = cfqd->rq_in_driver;
+	struct elevator_queue *eq = cfqd->queue->elevator;
+
+	if (elv_rq_in_driver(eq) > cfqd->rq_in_driver_peak)
+		cfqd->rq_in_driver_peak = elv_rq_in_driver(eq);
 
 	if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN &&
-	    cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN)
+	    elv_rq_in_driver(eq) <= CFQ_HW_QUEUE_MIN)
 		return;
 
 	if (cfqd->hw_tag_samples++ < 50)
@@ -2161,44 +1751,10 @@  static void cfq_completed_request(struct request_queue *q, struct request *rq)
 
 	cfq_update_hw_tag(cfqd);
 
-	WARN_ON(!cfqd->rq_in_driver);
-	WARN_ON(!cfqq->dispatched);
-	cfqd->rq_in_driver--;
-	cfqq->dispatched--;
-
 	if (cfq_cfqq_sync(cfqq))
 		cfqd->sync_flight--;
-
 	if (sync)
 		RQ_CIC(rq)->last_end_request = now;
-
-	/*
-	 * If this is the active queue, check if it needs to be expired,
-	 * or if we want to idle in case it has no pending requests.
-	 */
-	if (cfqd->active_queue == cfqq) {
-		const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list);
-
-		if (cfq_cfqq_slice_new(cfqq)) {
-			cfq_set_prio_slice(cfqd, cfqq);
-			cfq_clear_cfqq_slice_new(cfqq);
-		}
-		/*
-		 * If there are no requests waiting in this queue, and
-		 * there are other queues ready to issue requests, AND
-		 * those other queues are issuing requests within our
-		 * mean seek distance, give them a chance to run instead
-		 * of idling.
-		 */
-		if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq))
-			cfq_slice_expired(cfqd, 1);
-		else if (cfqq_empty && !cfq_close_cooperator(cfqd, cfqq, 1) &&
-			 sync && !rq_noidle(rq))
-			cfq_arm_slice_timer(cfqd);
-	}
-
-	if (!cfqd->rq_in_driver)
-		cfq_schedule_dispatch(cfqd);
 }
 
 /*
@@ -2207,30 +1763,33 @@  static void cfq_completed_request(struct request_queue *q, struct request *rq)
  */
 static void cfq_prio_boost(struct cfq_queue *cfqq)
 {
+	struct io_queue *ioq = cfqq->ioq;
+
 	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;
+			elv_ioq_set_ioprio_class(ioq, IOPRIO_CLASS_BE);
+		if (elv_ioq_ioprio(ioq) > IOPRIO_NORM)
+			elv_ioq_set_ioprio(ioq, 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;
+		if (elv_ioq_ioprio_class(ioq) != cfqq->org_ioprio_class)
+			elv_ioq_set_ioprio_class(ioq, cfqq->org_ioprio_class);
+		if (elv_ioq_ioprio(ioq) != cfqq->org_ioprio)
+			elv_ioq_set_ioprio(ioq, cfqq->org_ioprio);
 	}
 }
 
 static inline int __cfq_may_queue(struct cfq_queue *cfqq)
 {
-	if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) &&
-	    !cfq_cfqq_must_alloc_slice(cfqq)) {
+	if ((elv_ioq_wait_request(cfqq->ioq) ||
+	   cfq_cfqq_must_alloc(cfqq)) && !cfq_cfqq_must_alloc_slice(cfqq)) {
 		cfq_mark_cfqq_must_alloc_slice(cfqq);
 		return ELV_MQUEUE_MUST;
 	}
@@ -2282,7 +1841,7 @@  static void cfq_put_request(struct request *rq)
 		put_io_context(RQ_CIC(rq)->ioc);
 
 		rq->elevator_private = NULL;
-		rq->elevator_private2 = NULL;
+		rq->ioq = NULL;
 
 		cfq_put_queue(cfqq);
 	}
@@ -2318,119 +1877,31 @@  cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
 
 	cfqq->allocated[rw]++;
 	cfq_clear_cfqq_must_alloc(cfqq);
-	atomic_inc(&cfqq->ref);
+	elv_get_ioq(cfqq->ioq);
 
 	spin_unlock_irqrestore(q->queue_lock, flags);
 
 	rq->elevator_private = cic;
-	rq->elevator_private2 = cfqq;
+	rq->ioq = cfqq->ioq;
 	return 0;
 
 queue_fail:
 	if (cic)
 		put_io_context(cic->ioc);
 
-	cfq_schedule_dispatch(cfqd);
+	elv_schedule_dispatch(cfqd->queue);
 	spin_unlock_irqrestore(q->queue_lock, flags);
 	cfq_log(cfqd, "set_request fail");
 	return 1;
 }
 
-static void cfq_kick_queue(struct work_struct *work)
-{
-	struct cfq_data *cfqd =
-		container_of(work, struct cfq_data, unplug_work);
-	struct request_queue *q = cfqd->queue;
-
-	spin_lock_irq(q->queue_lock);
-	__blk_run_queue(cfqd->queue);
-	spin_unlock_irq(q->queue_lock);
-}
-
-/*
- * 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;
-	int timed_out = 1;
-
-	cfq_log(cfqd, "idle timer fired");
-
-	spin_lock_irqsave(cfqd->queue->queue_lock, flags);
-
-	cfqq = cfqd->active_queue;
-	if (cfqq) {
-		timed_out = 0;
-
-		/*
-		 * We saw a request before the queue expired, let it through
-		 */
-		if (cfq_cfqq_must_dispatch(cfqq))
-			goto out_kick;
-
-		/*
-		 * expired
-		 */
-		if (cfq_slice_used(cfqq))
-			goto expire;
-
-		/*
-		 * only expire and reinvoke request handler, if there are
-		 * other queues with pending requests
-		 */
-		if (!cfqd->busy_queues)
-			goto out_cont;
-
-		/*
-		 * not expired and it has a request pending, let it dispatch
-		 */
-		if (!RB_EMPTY_ROOT(&cfqq->sort_list))
-			goto out_kick;
-	}
-expire:
-	cfq_slice_expired(cfqd, timed_out);
-out_kick:
-	cfq_schedule_dispatch(cfqd);
-out_cont:
-	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);
-	cancel_work_sync(&cfqd->unplug_work);
-}
-
-static void cfq_put_async_queues(struct cfq_data *cfqd)
-{
-	int i;
-
-	for (i = 0; i < IOPRIO_BE_NR; i++) {
-		if (cfqd->async_cfqq[0][i])
-			cfq_put_queue(cfqd->async_cfqq[0][i]);
-		if (cfqd->async_cfqq[1][i])
-			cfq_put_queue(cfqd->async_cfqq[1][i]);
-	}
-
-	if (cfqd->async_idle_cfqq)
-		cfq_put_queue(cfqd->async_idle_cfqq);
-}
-
 static void cfq_exit_queue(struct elevator_queue *e)
 {
 	struct cfq_data *cfqd = e->elevator_data;
 	struct request_queue *q = cfqd->queue;
 
-	cfq_shutdown_timer_wq(cfqd);
-
 	spin_lock_irq(q->queue_lock);
 
-	if (cfqd->active_queue)
-		__cfq_slice_expired(cfqd, cfqd->active_queue, 0);
-
 	while (!list_empty(&cfqd->cic_list)) {
 		struct cfq_io_context *cic = list_entry(cfqd->cic_list.next,
 							struct cfq_io_context,
@@ -2439,12 +1910,7 @@  static void cfq_exit_queue(struct elevator_queue *e)
 		__cfq_exit_single_io_context(cfqd, cic);
 	}
 
-	cfq_put_async_queues(cfqd);
-
 	spin_unlock_irq(q->queue_lock);
-
-	cfq_shutdown_timer_wq(cfqd);
-
 	kfree(cfqd);
 }
 
@@ -2457,8 +1923,6 @@  static void *cfq_init_queue(struct request_queue *q, struct elevator_queue *eq)
 	if (!cfqd)
 		return NULL;
 
-	cfqd->service_tree = CFQ_RB_ROOT;
-
 	/*
 	 * Not strictly needed (since RB_ROOT just clears the node and we
 	 * zeroed cfqd on alloc), but better be safe in case someone decides
@@ -2473,28 +1937,22 @@  static void *cfq_init_queue(struct request_queue *q, struct elevator_queue *eq)
 	 * will not attempt to free it.
 	 */
 	cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0);
-	atomic_inc(&cfqd->oom_cfqq.ref);
+
+	/* Link up oom_ioq and oom_cfqq */
+	cfqd->oom_cfqq.ioq = elv_get_oom_ioq(eq);
+	elv_init_ioq_sched_queue(eq, elv_get_oom_ioq(eq), &cfqd->oom_cfqq);
 
 	INIT_LIST_HEAD(&cfqd->cic_list);
 
 	cfqd->queue = q;
 
-	init_timer(&cfqd->idle_slice_timer);
-	cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
-	cfqd->idle_slice_timer.data = (unsigned long) cfqd;
-
-	INIT_WORK(&cfqd->unplug_work, cfq_kick_queue);
-
 	cfqd->cfq_quantum = cfq_quantum;
 	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->hw_tag = 1;
 
 	return cfqd;
 }
@@ -2560,8 +2018,6 @@  SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1);
 SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0);
 SHOW_FUNCTION(cfq_back_seek_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);
 #undef SHOW_FUNCTION
 
@@ -2590,8 +2046,6 @@  STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0);
 STORE_FUNCTION(cfq_back_seek_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);
 #undef STORE_FUNCTION
@@ -2605,10 +2059,10 @@  static struct elv_fs_entry cfq_attrs[] = {
 	CFQ_ATTR(fifo_expire_async),
 	CFQ_ATTR(back_seek_max),
 	CFQ_ATTR(back_seek_penalty),
-	CFQ_ATTR(slice_sync),
-	CFQ_ATTR(slice_async),
 	CFQ_ATTR(slice_async_rq),
 	CFQ_ATTR(slice_idle),
+	ELV_ATTR(slice_sync),
+	ELV_ATTR(slice_async),
 	__ATTR_NULL
 };
 
@@ -2621,8 +2075,6 @@  static struct elevator_type iosched_cfq = {
 		.elevator_dispatch_fn =		cfq_dispatch_requests,
 		.elevator_add_req_fn =		cfq_insert_request,
 		.elevator_activate_req_fn =	cfq_activate_request,
-		.elevator_deactivate_req_fn =	cfq_deactivate_request,
-		.elevator_queue_empty_fn =	cfq_queue_empty,
 		.elevator_completed_req_fn =	cfq_completed_request,
 		.elevator_former_req_fn =	elv_rb_former_request,
 		.elevator_latter_req_fn =	elv_rb_latter_request,
@@ -2632,7 +2084,14 @@  static struct elevator_type iosched_cfq = {
 		.elevator_init_fn =		cfq_init_queue,
 		.elevator_exit_fn =		cfq_exit_queue,
 		.trim =				cfq_free_io_context,
+		.elevator_free_sched_queue_fn =	cfq_free_cfq_queue,
+		.elevator_active_ioq_set_fn = 	cfq_active_ioq_set,
+		.elevator_active_ioq_reset_fn =	cfq_active_ioq_reset,
+		.elevator_arm_slice_timer_fn = 	cfq_arm_slice_timer,
+		.elevator_should_preempt_fn = 	cfq_should_preempt,
+		.elevator_close_cooperator_fn = cfq_close_cooperator,
 	},
+	.elevator_features =    ELV_IOSCHED_NEED_FQ,
 	.elevator_attrs =	cfq_attrs,
 	.elevator_name =	"cfq",
 	.elevator_owner =	THIS_MODULE,
@@ -2640,14 +2099,6 @@  static struct elevator_type iosched_cfq = {
 
 static int __init cfq_init(void)
 {
-	/*
-	 * 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;