]> nv-tegra.nvidia Code Review - linux-2.6.git/blobdiff - block/cfq-iosched.c
cfq-iosched: improve continue or break logic in cfq_dispatch
[linux-2.6.git] / block / cfq-iosched.c
index 4c4e9cc3ae26890c0b63a8dcbf6aff3c0caa7d7c..b6491c020f26ec53dedcbed84e20aea0a7aea299 100644 (file)
@@ -4,9 +4,8 @@
  *  Based on ideas from a previously unfinished io
  *  scheduler (round robin per-process disk scheduling) and Andrea Arcangeli.
  *
- *  Copyright (C) 2003 Jens Axboe <axboe@suse.de>
+ *  Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
  */
-#include <linux/config.h>
 #include <linux/module.h>
 #include <linux/blkdev.h>
 #include <linux/elevator.h>
@@ -18,7 +17,6 @@
  * tunables
  */
 static const int cfq_quantum = 4;              /* max queue in one round of service */
-static const int cfq_queued = 8;               /* minimum rq allocate limit per-queue*/
 static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 };
 static const int cfq_back_max = 16 * 1024;     /* maximum backwards seek, in KiB */
 static const int cfq_back_penalty = 2;         /* penalty of a backwards seek */
@@ -26,15 +24,13 @@ static const int cfq_back_penalty = 2;              /* penalty of a backwards seek */
 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 / 70;
+static int cfq_slice_idle = HZ / 125;
 
 #define CFQ_IDLE_GRACE         (HZ / 10)
 #define CFQ_SLICE_SCALE                (5)
 
 #define CFQ_KEY_ASYNC          (0)
 
-static DEFINE_SPINLOCK(cfq_exit_lock);
-
 /*
  * for the hash of cfqq inside the cfqd
  */
@@ -42,42 +38,19 @@ static DEFINE_SPINLOCK(cfq_exit_lock);
 #define CFQ_QHASH_ENTRIES      (1 << CFQ_QHASH_SHIFT)
 #define list_entry_qhash(entry)        hlist_entry((entry), struct cfq_queue, cfq_hash)
 
-/*
- * for the hash of crq inside the cfqq
- */
-#define CFQ_MHASH_SHIFT                6
-#define CFQ_MHASH_BLOCK(sec)   ((sec) >> 3)
-#define CFQ_MHASH_ENTRIES      (1 << CFQ_MHASH_SHIFT)
-#define CFQ_MHASH_FN(sec)      hash_long(CFQ_MHASH_BLOCK(sec), CFQ_MHASH_SHIFT)
-#define rq_hash_key(rq)                ((rq)->sector + (rq)->nr_sectors)
-#define list_entry_hash(ptr)   hlist_entry((ptr), struct cfq_rq, hash)
-
 #define list_entry_cfqq(ptr)   list_entry((ptr), struct cfq_queue, cfq_list)
-#define list_entry_fifo(ptr)   list_entry((ptr), struct request, queuelist)
 
-#define RQ_DATA(rq)            (rq)->elevator_private
+#define RQ_CIC(rq)             ((struct cfq_io_context*)(rq)->elevator_private)
+#define RQ_CFQQ(rq)            ((rq)->elevator_private2)
 
-/*
- * rb-tree defines
- */
-#define RB_EMPTY(node)         ((node)->rb_node == NULL)
-#define RB_CLEAR(node)         do {    \
-               memset(node, 0, sizeof(*node)); \
-} while (0)
-#define RB_CLEAR_ROOT(root)    ((root)->rb_node = NULL)
-#define rb_entry_crq(node)     rb_entry((node), struct cfq_rq, rb_node)
-#define rq_rb_key(rq)          (rq)->sector
-
-static kmem_cache_t *crq_pool;
-static kmem_cache_t *cfq_pool;
-static kmem_cache_t *cfq_ioc_pool;
-
-static atomic_t ioc_count = ATOMIC_INIT(0);
+static struct kmem_cache *cfq_pool;
+static struct kmem_cache *cfq_ioc_pool;
+
+static DEFINE_PER_CPU(unsigned long, ioc_count);
 static struct completion *ioc_gone;
 
 #define CFQ_PRIO_LISTS         IOPRIO_BE_NR
 #define cfq_class_idle(cfqq)   ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
-#define cfq_class_be(cfqq)     ((cfqq)->ioprio_class == IOPRIO_CLASS_BE)
 #define cfq_class_rt(cfqq)     ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
 
 #define ASYNC                  (0)
@@ -108,29 +81,14 @@ struct cfq_data {
        struct list_head idle_rr;
        unsigned int busy_queues;
 
-       /*
-        * non-ordered list of empty cfqq's
-        */
-       struct list_head empty_list;
-
        /*
         * cfqq lookup hash
         */
        struct hlist_head *cfq_hash;
 
-       /*
-        * global crq hash for all queues
-        */
-       struct hlist_head *crq_hash;
-
-       mempool_t *crq_pool;
-
        int rq_in_driver;
        int hw_tag;
 
-       /*
-        * schedule slice state info
-        */
        /*
         * idle window management
         */
@@ -147,13 +105,10 @@ struct cfq_data {
        sector_t last_sector;
        unsigned long last_end_request;
 
-       unsigned int rq_starved;
-
        /*
         * tunables, see top of file
         */
        unsigned int cfq_quantum;
-       unsigned int cfq_queued;
        unsigned int cfq_fifo_expire[2];
        unsigned int cfq_back_penalty;
        unsigned int cfq_back_max;
@@ -176,23 +131,24 @@ struct cfq_queue {
        struct hlist_node cfq_hash;
        /* hash key */
        unsigned int key;
-       /* on either rr or empty list of cfqd */
+       /* member of the rr/busy/cur/idle cfqd list */
        struct list_head cfq_list;
        /* sorted list of pending requests */
        struct rb_root sort_list;
        /* if fifo isn't expired, next request to serve */
-       struct cfq_rq *next_crq;
+       struct request *next_rq;
        /* requests queued in sort_list */
        int queued[2];
        /* currently allocated requests */
        int allocated[2];
+       /* pending metadata requests */
+       int meta_pending;
        /* fifo list of requests in sort_list */
        struct list_head fifo;
 
-       unsigned long slice_start;
        unsigned long slice_end;
-       unsigned long slice_left;
        unsigned long service_last;
+       long slice_resid;
 
        /* number of requests that are on the dispatch list */
        int on_dispatch[2];
@@ -205,27 +161,17 @@ struct cfq_queue {
        unsigned int flags;
 };
 
-struct cfq_rq {
-       struct rb_node rb_node;
-       sector_t rb_key;
-       struct request *request;
-       struct hlist_node hash;
-
-       struct cfq_queue *cfq_queue;
-       struct cfq_io_context *io_context;
-
-       unsigned int crq_flags;
-};
-
 enum cfqq_state_flags {
-       CFQ_CFQQ_FLAG_on_rr = 0,
-       CFQ_CFQQ_FLAG_wait_request,
-       CFQ_CFQQ_FLAG_must_alloc,
-       CFQ_CFQQ_FLAG_must_alloc_slice,
-       CFQ_CFQQ_FLAG_must_dispatch,
-       CFQ_CFQQ_FLAG_fifo_expire,
-       CFQ_CFQQ_FLAG_idle_window,
-       CFQ_CFQQ_FLAG_prio_changed,
+       CFQ_CFQQ_FLAG_on_rr = 0,        /* on round-robin busy list */
+       CFQ_CFQQ_FLAG_wait_request,     /* waiting for a request */
+       CFQ_CFQQ_FLAG_must_alloc,       /* must be allowed rq alloc */
+       CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */
+       CFQ_CFQQ_FLAG_must_dispatch,    /* must dispatch, even if expired */
+       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_queue_new,        /* queue never been serviced */
+       CFQ_CFQQ_FLAG_slice_new,        /* no requests dispatched in slice */
 };
 
 #define CFQ_CFQQ_FNS(name)                                             \
@@ -250,101 +196,93 @@ CFQ_CFQQ_FNS(must_dispatch);
 CFQ_CFQQ_FNS(fifo_expire);
 CFQ_CFQQ_FNS(idle_window);
 CFQ_CFQQ_FNS(prio_changed);
+CFQ_CFQQ_FNS(queue_new);
+CFQ_CFQQ_FNS(slice_new);
 #undef CFQ_CFQQ_FNS
 
-enum cfq_rq_state_flags {
-       CFQ_CRQ_FLAG_is_sync = 0,
-};
-
-#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(is_sync);
-#undef CFQ_CRQ_FNS
-
 static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short);
-static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *);
+static void cfq_dispatch_insert(request_queue_t *, struct request *);
 static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask);
 
 /*
- * lots of deadline iosched dupes, can be abstracted later...
+ * scheduler run of queue, if there are requests pending and no one in the
+ * driver that will restart queueing
  */
-static inline void cfq_del_crq_hash(struct cfq_rq *crq)
+static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
 {
-       hlist_del_init(&crq->hash);
+       if (cfqd->busy_queues)
+               kblockd_schedule_work(&cfqd->unplug_work);
 }
 
-static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq)
+static int cfq_queue_empty(request_queue_t *q)
 {
-       const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request));
+       struct cfq_data *cfqd = q->elevator->elevator_data;
 
-       hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]);
+       return !cfqd->busy_queues;
 }
 
-static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset)
+static inline pid_t cfq_queue_pid(struct task_struct *task, int rw, int is_sync)
 {
-       struct hlist_head *hash_list = &cfqd->crq_hash[CFQ_MHASH_FN(offset)];
-       struct hlist_node *entry, *next;
-
-       hlist_for_each_safe(entry, next, hash_list) {
-               struct cfq_rq *crq = list_entry_hash(entry);
-               struct request *__rq = crq->request;
-
-               if (!rq_mergeable(__rq)) {
-                       cfq_del_crq_hash(crq);
-                       continue;
-               }
-
-               if (rq_hash_key(__rq) == offset)
-                       return __rq;
-       }
+       /*
+        * Use the per-process queue, for read requests and syncronous writes
+        */
+       if (!(rw & REQ_RW) || is_sync)
+               return task->pid;
 
-       return NULL;
+       return CFQ_KEY_ASYNC;
 }
 
 /*
- * scheduler run of queue, if there are requests pending and no one in the
- * driver that will restart queueing
+ * 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 void cfq_schedule_dispatch(struct cfq_data *cfqd)
+static inline int
+cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
-       if (cfqd->busy_queues)
-               kblockd_schedule_work(&cfqd->unplug_work);
+       const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)];
+
+       WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
+
+       return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio));
 }
 
-static int cfq_queue_empty(request_queue_t *q)
+static inline void
+cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
-       struct cfq_data *cfqd = q->elevator->elevator_data;
+       cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
+       cfqq->slice_end += cfqq->slice_resid;
 
-       return !cfqd->busy_queues;
+       /*
+        * Don't carry over residual for more than one slice, we only want
+        * to slightly correct the fairness. Carrying over forever would
+        * easily introduce oscillations.
+        */
+       cfqq->slice_resid = 0;
 }
 
-static inline pid_t cfq_queue_pid(struct task_struct *task, int rw)
+/*
+ * 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)
 {
-       if (rw == READ || rw == WRITE_SYNC)
-               return task->pid;
+       if (cfq_cfqq_slice_new(cfqq))
+               return 0;
+       if (time_before(jiffies, cfqq->slice_end))
+               return 0;
 
-       return CFQ_KEY_ASYNC;
+       return 1;
 }
 
 /*
- * Lifted from AS - choose which of crq1 and crq2 that is best served now.
+ * Lifted from AS - choose which of rq1 and rq2 that is best served now.
  * We choose the request that is closest to the head right now. Distance
  * behind the head is penalized and only allowed to a certain extent.
  */
-static struct cfq_rq *
-cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2)
+static struct request *
+cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2)
 {
        sector_t last, s1, s2, d1 = 0, d2 = 0;
        unsigned long back_max;
@@ -352,18 +290,22 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2)
 #define CFQ_RQ2_WRAP   0x02 /* request 2 wraps */
        unsigned wrap = 0; /* bit mask: requests behind the disk head? */
 
-       if (crq1 == NULL || crq1 == crq2)
-               return crq2;
-       if (crq2 == NULL)
-               return crq1;
+       if (rq1 == NULL || rq1 == rq2)
+               return rq2;
+       if (rq2 == NULL)
+               return rq1;
 
-       if (cfq_crq_is_sync(crq1) && !cfq_crq_is_sync(crq2))
-               return crq1;
-       else if (cfq_crq_is_sync(crq2) && !cfq_crq_is_sync(crq1))
-               return crq2;
+       if (rq_is_sync(rq1) && !rq_is_sync(rq2))
+               return rq1;
+       else if (rq_is_sync(rq2) && !rq_is_sync(rq1))
+               return rq2;
+       if (rq_is_meta(rq1) && !rq_is_meta(rq2))
+               return rq1;
+       else if (rq_is_meta(rq2) && !rq_is_meta(rq1))
+               return rq2;
 
-       s1 = crq1->request->sector;
-       s2 = crq2->request->sector;
+       s1 = rq1->sector;
+       s2 = rq2->sector;
 
        last = cfqd->last_sector;
 
@@ -398,23 +340,23 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2)
         * check two variables for all permutations: --> faster!
         */
        switch (wrap) {
-       case 0: /* common case for CFQ: crq1 and crq2 not wrapped */
+       case 0: /* common case for CFQ: rq1 and rq2 not wrapped */
                if (d1 < d2)
-                       return crq1;
+                       return rq1;
                else if (d2 < d1)
-                       return crq2;
+                       return rq2;
                else {
                        if (s1 >= s2)
-                               return crq1;
+                               return rq1;
                        else
-                               return crq2;
+                               return rq2;
                }
 
        case CFQ_RQ2_WRAP:
-               return crq1;
+               return rq1;
        case CFQ_RQ1_WRAP:
-               return crq2;
-       case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both crqs wrapped */
+               return rq2;
+       case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */
        default:
                /*
                 * Since both rqs are wrapped,
@@ -423,52 +365,50 @@ cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2)
                 * since back seek takes more time than forward.
                 */
                if (s1 <= s2)
-                       return crq1;
+                       return rq1;
                else
-                       return crq2;
+                       return rq2;
        }
 }
 
 /*
  * would be nice to take fifo expire time into account as well
  */
-static struct cfq_rq *
-cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-                 struct cfq_rq *last)
+static struct request *
+cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
+                 struct request *last)
 {
-       struct cfq_rq *crq_next = NULL, *crq_prev = NULL;
-       struct rb_node *rbnext, *rbprev;
+       struct rb_node *rbnext = rb_next(&last->rb_node);
+       struct rb_node *rbprev = rb_prev(&last->rb_node);
+       struct request *next = NULL, *prev = NULL;
 
-       if (!(rbnext = rb_next(&last->rb_node))) {
-               rbnext = rb_first(&cfqq->sort_list);
-               if (rbnext == &last->rb_node)
-                       rbnext = NULL;
-       }
-
-       rbprev = rb_prev(&last->rb_node);
+       BUG_ON(RB_EMPTY_NODE(&last->rb_node));
 
        if (rbprev)
-               crq_prev = rb_entry_crq(rbprev);
-       if (rbnext)
-               crq_next = rb_entry_crq(rbnext);
+               prev = rb_entry_rq(rbprev);
 
-       return cfq_choose_req(cfqd, crq_next, crq_prev);
-}
-
-static void cfq_update_next_crq(struct cfq_rq *crq)
-{
-       struct cfq_queue *cfqq = crq->cfq_queue;
+       if (rbnext)
+               next = rb_entry_rq(rbnext);
+       else {
+               rbnext = rb_first(&cfqq->sort_list);
+               if (rbnext && rbnext != &last->rb_node)
+                       next = rb_entry_rq(rbnext);
+       }
 
-       if (cfqq->next_crq == crq)
-               cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq);
+       return cfq_choose_req(cfqd, next, prev);
 }
 
 static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
 {
        struct cfq_data *cfqd = cfqq->cfqd;
-       struct list_head *list, *entry;
+       struct list_head *list, *n;
+       struct cfq_queue *__cfqq;
 
-       BUG_ON(!cfq_cfqq_on_rr(cfqq));
+       /*
+        * Resorting requires the cfqq to be on the RR list already.
+        */
+       if (!cfq_cfqq_on_rr(cfqq))
+               return;
 
        list_del(&cfqq->cfq_list);
 
@@ -490,32 +430,46 @@ static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
                        list = &cfqd->rr_list[cfqq->ioprio];
        }
 
-       /*
-        * if queue was preempted, just add to front to be fair. busy_rr
-        * isn't sorted, but insert at the back for fairness.
-        */
-       if (preempted || list == &cfqd->busy_rr) {
-               if (preempted)
-                       list = list->prev;
+       if (preempted || cfq_cfqq_queue_new(cfqq)) {
+               /*
+                * If this queue was preempted or is new (never been serviced),
+                * let it be added first for fairness but beind other new
+                * queues.
+                */
+               n = list;
+               while (n->next != list) {
+                       __cfqq = list_entry_cfqq(n->next);
+                       if (!cfq_cfqq_queue_new(__cfqq))
+                               break;
 
+                       n = n->next;
+               }
+               list_add_tail(&cfqq->cfq_list, n);
+       } else if (!cfq_cfqq_class_sync(cfqq)) {
+               /*
+                * async queue always goes to the end. this wont be overly
+                * unfair to writes, as the sort of the sync queue wont be
+                * allowed to pass the async queue again.
+                */
                list_add_tail(&cfqq->cfq_list, list);
-               return;
-       }
-
-       /*
-        * sort by when queue was last serviced
-        */
-       entry = list;
-       while ((entry = entry->prev) != list) {
-               struct cfq_queue *__cfqq = list_entry_cfqq(entry);
+       } else {
+               /*
+                * sort by last service, but don't cross a new or async
+                * queue. we don't cross a new queue because it hasn't been
+                * service before, and we don't cross an async queue because
+                * it gets added to the end on expire.
+                */
+               n = list;
+               while ((n = n->prev) != list) {
+                       struct cfq_queue *__cfqq = list_entry_cfqq(n);
 
-               if (!__cfqq->service_last)
-                       break;
-               if (time_before(__cfqq->service_last, cfqq->service_last))
-                       break;
+                       if (!cfq_cfqq_class_sync(cfqq) || !__cfqq->service_last)
+                               break;
+                       if (time_before(__cfqq->service_last, cfqq->service_last))
+                               break;
+               }
+               list_add(&cfqq->cfq_list, n);
        }
-
-       list_add(&cfqq->cfq_list, entry);
 }
 
 /*
@@ -537,7 +491,7 @@ cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
        BUG_ON(!cfq_cfqq_on_rr(cfqq));
        cfq_clear_cfqq_on_rr(cfqq);
-       list_move(&cfqq->cfq_list, &cfqd->empty_list);
+       list_del_init(&cfqq->cfq_list);
 
        BUG_ON(!cfqd->busy_queues);
        cfqd->busy_queues--;
@@ -546,110 +500,62 @@ cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 /*
  * rb tree support functions
  */
-static inline void cfq_del_crq_rb(struct cfq_rq *crq)
+static inline void cfq_del_rq_rb(struct request *rq)
 {
-       struct cfq_queue *cfqq = crq->cfq_queue;
+       struct cfq_queue *cfqq = RQ_CFQQ(rq);
        struct cfq_data *cfqd = cfqq->cfqd;
-       const int sync = cfq_crq_is_sync(crq);
+       const int sync = rq_is_sync(rq);
 
        BUG_ON(!cfqq->queued[sync]);
        cfqq->queued[sync]--;
 
-       cfq_update_next_crq(crq);
-
-       rb_erase(&crq->rb_node, &cfqq->sort_list);
+       elv_rb_del(&cfqq->sort_list, rq);
 
-       if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list))
+       if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list))
                cfq_del_cfqq_rr(cfqd, cfqq);
 }
 
-static struct cfq_rq *
-__cfq_add_crq_rb(struct cfq_rq *crq)
-{
-       struct rb_node **p = &crq->cfq_queue->sort_list.rb_node;
-       struct rb_node *parent = NULL;
-       struct cfq_rq *__crq;
-
-       while (*p) {
-               parent = *p;
-               __crq = rb_entry_crq(parent);
-
-               if (crq->rb_key < __crq->rb_key)
-                       p = &(*p)->rb_left;
-               else if (crq->rb_key > __crq->rb_key)
-                       p = &(*p)->rb_right;
-               else
-                       return __crq;
-       }
-
-       rb_link_node(&crq->rb_node, parent, p);
-       return NULL;
-}
-
-static void cfq_add_crq_rb(struct cfq_rq *crq)
+static void cfq_add_rq_rb(struct request *rq)
 {
-       struct cfq_queue *cfqq = crq->cfq_queue;
+       struct cfq_queue *cfqq = RQ_CFQQ(rq);
        struct cfq_data *cfqd = cfqq->cfqd;
-       struct request *rq = crq->request;
-       struct cfq_rq *__alias;
+       struct request *__alias;
 
-       crq->rb_key = rq_rb_key(rq);
-       cfqq->queued[cfq_crq_is_sync(crq)]++;
+       cfqq->queued[rq_is_sync(rq)]++;
 
        /*
         * looks a little odd, but the first insert might return an alias.
         * if that happens, put the alias on the dispatch list
         */
-       while ((__alias = __cfq_add_crq_rb(crq)) != NULL)
+       while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL)
                cfq_dispatch_insert(cfqd->queue, __alias);
 
-       rb_insert_color(&crq->rb_node, &cfqq->sort_list);
-
        if (!cfq_cfqq_on_rr(cfqq))
                cfq_add_cfqq_rr(cfqd, cfqq);
-
-       /*
-        * check if this request is a better next-serve candidate
-        */
-       cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
 }
 
 static inline void
-cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq)
+cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq)
 {
-       rb_erase(&crq->rb_node, &cfqq->sort_list);
-       cfqq->queued[cfq_crq_is_sync(crq)]--;
-
-       cfq_add_crq_rb(crq);
+       elv_rb_del(&cfqq->sort_list, rq);
+       cfqq->queued[rq_is_sync(rq)]--;
+       cfq_add_rq_rb(rq);
 }
 
 static struct request *
 cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
 {
        struct task_struct *tsk = current;
-       pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio));
+       pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio), bio_sync(bio));
        struct cfq_queue *cfqq;
-       struct rb_node *n;
-       sector_t sector;
 
        cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
-       if (!cfqq)
-               goto out;
-
-       sector = bio->bi_sector + bio_sectors(bio);
-       n = cfqq->sort_list.rb_node;
-       while (n) {
-               struct cfq_rq *crq = rb_entry_crq(n);
+       if (cfqq) {
+               sector_t sector = bio->bi_sector + bio_sectors(bio);
 
-               if (sector < crq->rb_key)
-                       n = n->rb_left;
-               else if (sector > crq->rb_key)
-                       n = n->rb_right;
-               else
-                       return crq->request;
+               return elv_rb_find(&cfqq->sort_list, sector);
        }
 
-out:
        return NULL;
 }
 
@@ -679,11 +585,18 @@ static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
 
 static void cfq_remove_request(struct request *rq)
 {
-       struct cfq_rq *crq = RQ_DATA(rq);
+       struct cfq_queue *cfqq = RQ_CFQQ(rq);
+
+       if (cfqq->next_rq == rq)
+               cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq);
 
        list_del_init(&rq->queuelist);
-       cfq_del_crq_rb(crq);
-       cfq_del_crq_hash(crq);
+       cfq_del_rq_rb(rq);
+
+       if (rq_is_meta(rq)) {
+               WARN_ON(!cfqq->meta_pending);
+               cfqq->meta_pending--;
+       }
 }
 
 static int
@@ -691,39 +604,23 @@ cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
 {
        struct cfq_data *cfqd = q->elevator->elevator_data;
        struct request *__rq;
-       int ret;
-
-       __rq = cfq_find_rq_hash(cfqd, bio->bi_sector);
-       if (__rq && elv_rq_merge_ok(__rq, bio)) {
-               ret = ELEVATOR_BACK_MERGE;
-               goto out;
-       }
 
        __rq = cfq_find_rq_fmerge(cfqd, bio);
        if (__rq && elv_rq_merge_ok(__rq, bio)) {
-               ret = ELEVATOR_FRONT_MERGE;
-               goto out;
+               *req = __rq;
+               return ELEVATOR_FRONT_MERGE;
        }
 
        return ELEVATOR_NO_MERGE;
-out:
-       *req = __rq;
-       return ret;
 }
 
-static void cfq_merged_request(request_queue_t *q, struct request *req)
+static void cfq_merged_request(request_queue_t *q, struct request *req,
+                              int type)
 {
-       struct cfq_data *cfqd = q->elevator->elevator_data;
-       struct cfq_rq *crq = RQ_DATA(req);
-
-       cfq_del_crq_hash(crq);
-       cfq_add_crq_hash(cfqd, crq);
-
-       if (rq_rb_key(req) != crq->rb_key) {
-               struct cfq_queue *cfqq = crq->cfq_queue;
+       if (type == ELEVATOR_FRONT_MERGE) {
+               struct cfq_queue *cfqq = RQ_CFQQ(req);
 
-               cfq_update_next_crq(crq);
-               cfq_reposition_crq_rb(cfqq, crq);
+               cfq_reposition_rq_rb(cfqq, req);
        }
 }
 
@@ -731,8 +628,6 @@ static void
 cfq_merged_requests(request_queue_t *q, struct request *rq,
                    struct request *next)
 {
-       cfq_merged_request(q, rq);
-
        /*
         * reposition in fifo if next is older than rq
         */
@@ -743,6 +638,33 @@ cfq_merged_requests(request_queue_t *q, struct request *rq,
        cfq_remove_request(next);
 }
 
+static int cfq_allow_merge(request_queue_t *q, struct request *rq,
+                          struct bio *bio)
+{
+       struct cfq_data *cfqd = q->elevator->elevator_data;
+       const int rw = bio_data_dir(bio);
+       struct cfq_queue *cfqq;
+       pid_t key;
+
+       /*
+        * Disallow merge of a sync bio into an async request.
+        */
+       if ((bio_data_dir(bio) == READ || bio_sync(bio)) && !rq_is_sync(rq))
+               return 0;
+
+       /*
+        * Lookup the cfqq that this bio will be queued with. Allow
+        * merge only if rq is queued there.
+        */
+       key = cfq_queue_pid(current, rw, bio_sync(bio));
+       cfqq = cfq_find_cfq_hash(cfqd, key, current->ioprio);
+
+       if (cfqq == RQ_CFQQ(rq))
+               return 1;
+
+       return 0;
+}
+
 static inline void
 __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
@@ -752,11 +674,10 @@ __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
                 */
                del_timer(&cfqd->idle_class_timer);
 
-               cfqq->slice_start = jiffies;
                cfqq->slice_end = 0;
-               cfqq->slice_left = 0;
                cfq_clear_cfqq_must_alloc_slice(cfqq);
                cfq_clear_cfqq_fifo_expire(cfqq);
+               cfq_mark_cfqq_slice_new(cfqq);
        }
 
        cfqd->active_queue = cfqq;
@@ -767,32 +688,23 @@ __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
  */
 static void
 __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-                   int preempted)
+                   int preempted, int timed_out)
 {
-       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_schedule_dispatch(cfqd);
-       }
-
        cfq_clear_cfqq_must_dispatch(cfqq);
        cfq_clear_cfqq_wait_request(cfqq);
+       cfq_clear_cfqq_queue_new(cfqq);
 
        /*
         * store what was left of this slice, if the queue idled out
         * or was preempted
         */
-       if (time_after(cfqq->slice_end, now))
-               cfqq->slice_left = cfqq->slice_end - now;
-       else
-               cfqq->slice_left = 0;
+       if (timed_out && !cfq_cfqq_slice_new(cfqq))
+               cfqq->slice_resid = cfqq->slice_end - jiffies;
 
-       if (cfq_cfqq_on_rr(cfqq))
-               cfq_resort_rr_list(cfqq, preempted);
+       cfq_resort_rr_list(cfqq, preempted);
 
        if (cfqq == cfqd->active_queue)
                cfqd->active_queue = NULL;
@@ -805,12 +717,13 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
        cfqd->dispatch_slice = 0;
 }
 
-static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted)
+static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted,
+                                    int timed_out)
 {
        struct cfq_queue *cfqq = cfqd->active_queue;
 
        if (cfqq)
-               __cfq_slice_expired(cfqd, cfqq, preempted);
+               __cfq_slice_expired(cfqd, cfqq, preempted, timed_out);
 }
 
 /*
@@ -874,26 +787,25 @@ static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
 {
        struct cfq_queue *cfqq = NULL;
 
-       /*
-        * if current list is non-empty, grab first entry. if it is empty,
-        * get next prio level and grab first entry then if any are spliced
-        */
-       if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1)
+       if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) {
+               /*
+                * if current list is non-empty, grab first entry. if it is
+                * empty, get next prio level and grab first entry then if any
+                * are spliced
+                */
                cfqq = list_entry_cfqq(cfqd->cur_rr.next);
-
-       /*
-        * If no new queues are available, check if the busy list has some
-        * before falling back to idle io.
-        */
-       if (!cfqq && !list_empty(&cfqd->busy_rr))
+       } else if (!list_empty(&cfqd->busy_rr)) {
+               /*
+                * If no new queues are available, check if the busy list has
+                * some before falling back to idle io.
+                */
                cfqq = list_entry_cfqq(cfqd->busy_rr.next);
-
-       /*
-        * if we have idle queues and no rt or be queues had pending
-        * requests, either allow immediate service if the grace period
-        * has passed or arm the idle grace timer
-        */
-       if (!cfqq && !list_empty(&cfqd->idle_rr)) {
+       } else if (!list_empty(&cfqd->idle_rr)) {
+               /*
+                * if we have idle queues and no rt or be queues had pending
+                * requests, either allow immediate service if the grace period
+                * has passed or arm the idle grace timer
+                */
                unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE;
 
                if (time_after_eq(jiffies, end))
@@ -906,14 +818,15 @@ static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
        return cfqq;
 }
 
-static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+#define CIC_SEEKY(cic) ((cic)->seek_mean > (128 * 1024))
 
+static int cfq_arm_slice_timer(struct cfq_data *cfqd)
 {
+       struct cfq_queue *cfqq = cfqd->active_queue;
        struct cfq_io_context *cic;
        unsigned long sl;
 
-       WARN_ON(!RB_EMPTY(&cfqq->sort_list));
-       WARN_ON(cfqq != cfqd->active_queue);
+       WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
 
        /*
         * idle is disabled, either manually or by past process history
@@ -939,69 +852,50 @@ static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
         * fair distribution of slice time for a process doing back-to-back
         * seeks. so allow a little bit of time for him to submit a new rq
         */
-       if (sample_valid(cic->seek_samples) && cic->seek_mean > 131072)
-               sl = 2;
+       if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
+               sl = min(sl, msecs_to_jiffies(2));
 
        mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
        return 1;
 }
 
-static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq)
+static void cfq_dispatch_insert(request_queue_t *q, struct request *rq)
 {
        struct cfq_data *cfqd = q->elevator->elevator_data;
-       struct cfq_queue *cfqq = crq->cfq_queue;
+       struct cfq_queue *cfqq = RQ_CFQQ(rq);
+
+       cfq_remove_request(rq);
+       cfqq->on_dispatch[rq_is_sync(rq)]++;
+       elv_dispatch_sort(q, rq);
 
-       cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq);
-       cfq_remove_request(crq->request);
-       cfqq->on_dispatch[cfq_crq_is_sync(crq)]++;
-       elv_dispatch_sort(q, crq->request);
+       rq = list_entry(q->queue_head.prev, struct request, queuelist);
+       cfqd->last_sector = rq->sector + rq->nr_sectors;
 }
 
 /*
  * return expired entry, or NULL to just start from scratch in rbtree
  */
-static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq)
+static inline struct request *cfq_check_fifo(struct cfq_queue *cfqq)
 {
        struct cfq_data *cfqd = cfqq->cfqd;
        struct request *rq;
-       struct cfq_rq *crq;
+       int fifo;
 
        if (cfq_cfqq_fifo_expire(cfqq))
                return NULL;
 
-       if (!list_empty(&cfqq->fifo)) {
-               int fifo = cfq_cfqq_class_sync(cfqq);
+       cfq_mark_cfqq_fifo_expire(cfqq);
 
-               crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next));
-               rq = crq->request;
-               if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) {
-                       cfq_mark_cfqq_fifo_expire(cfqq);
-                       return crq;
-               }
-       }
-
-       return NULL;
-}
-
-/*
- * Scale schedule slice based on io priority. Use the sync time slice only
- * if a queue is marked sync and has sync io queued. A sync queue with async
- * io only, should not get full sync slice length.
- */
-static inline int
-cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-       const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)];
+       if (list_empty(&cfqq->fifo))
+               return NULL;
 
-       WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
+       fifo = cfq_cfqq_class_sync(cfqq);
+       rq = rq_entry_fifo(cfqq->fifo.next);
 
-       return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio));
-}
+       if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo]))
+               return rq;
 
-static inline void
-cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-       cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
+       return NULL;
 }
 
 static inline int
@@ -1019,7 +913,6 @@ cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
  */
 static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
 {
-       unsigned long now = jiffies;
        struct cfq_queue *cfqq;
 
        cfqq = cfqd->active_queue;
@@ -1029,23 +922,25 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
        /*
         * slice has expired
         */
-       if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end))
+       if (!cfq_cfqq_must_dispatch(cfqq) && cfq_slice_used(cfqq))
                goto expire;
 
        /*
         * if queue has requests, dispatch one. if not, check if
         * enough slice is left to wait for one
         */
-       if (!RB_EMPTY(&cfqq->sort_list))
+       if (!RB_EMPTY_ROOT(&cfqq->sort_list))
                goto keep_queue;
-       else if (cfq_cfqq_class_sync(cfqq) &&
-                time_before(now, cfqq->slice_end)) {
-               if (cfq_arm_slice_timer(cfqd, cfqq))
+       else if (cfq_cfqq_slice_new(cfqq) || cfq_cfqq_dispatched(cfqq)) {
+               cfqq = NULL;
+               goto keep_queue;
+       } else if (cfq_cfqq_class_sync(cfqq)) {
+               if (cfq_arm_slice_timer(cfqd))
                        return NULL;
        }
 
 expire:
-       cfq_slice_expired(cfqd, 0);
+       cfq_slice_expired(cfqd, 0, 0);
 new_queue:
        cfqq = cfq_set_active_queue(cfqd);
 keep_queue:
@@ -1058,50 +953,45 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 {
        int dispatched = 0;
 
-       BUG_ON(RB_EMPTY(&cfqq->sort_list));
+       BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
 
        do {
-               struct cfq_rq *crq;
+               struct request *rq;
 
                /*
                 * follow expired path, else get first next available
                 */
-               if ((crq = cfq_check_fifo(cfqq)) == NULL)
-                       crq = cfqq->next_crq;
+               if ((rq = cfq_check_fifo(cfqq)) == NULL)
+                       rq = cfqq->next_rq;
 
                /*
                 * finally, insert request into driver dispatch list
                 */
-               cfq_dispatch_insert(cfqd->queue, crq);
+               cfq_dispatch_insert(cfqd->queue, rq);
 
                cfqd->dispatch_slice++;
                dispatched++;
 
                if (!cfqd->active_cic) {
-                       atomic_inc(&crq->io_context->ioc->refcount);
-                       cfqd->active_cic = crq->io_context;
+                       atomic_inc(&RQ_CIC(rq)->ioc->refcount);
+                       cfqd->active_cic = RQ_CIC(rq);
                }
 
-               if (RB_EMPTY(&cfqq->sort_list))
+               if (RB_EMPTY_ROOT(&cfqq->sort_list))
                        break;
 
        } while (dispatched < max_dispatch);
 
-       /*
-        * if slice end isn't set yet, set it. if at least one request was
-        * sync, use the sync time slice value
-        */
-       if (!cfqq->slice_end)
-               cfq_set_prio_slice(cfqd, cfqq);
-
        /*
         * expire an async queue immediately if it has used up its slice. idle
         * queue always expire after 1 dispatch round.
         */
        if ((!cfq_cfqq_sync(cfqq) &&
            cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
-           cfq_class_idle(cfqq))
-               cfq_slice_expired(cfqd, 0);
+           cfq_class_idle(cfqq)) {
+               cfqq->slice_end = jiffies + 1;
+               cfq_slice_expired(cfqd, 0, 0);
+       }
 
        return dispatched;
 }
@@ -1109,17 +999,18 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 static int
 cfq_forced_dispatch_cfqqs(struct list_head *list)
 {
-       int dispatched = 0;
        struct cfq_queue *cfqq, *next;
-       struct cfq_rq *crq;
+       int dispatched;
 
+       dispatched = 0;
        list_for_each_entry_safe(cfqq, next, list, cfq_list) {
-               while ((crq = cfqq->next_crq)) {
-                       cfq_dispatch_insert(cfqq->cfqd->queue, crq);
+               while (cfqq->next_rq) {
+                       cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq);
                        dispatched++;
                }
                BUG_ON(!list_empty(&cfqq->fifo));
        }
+
        return dispatched;
 }
 
@@ -1135,7 +1026,7 @@ cfq_forced_dispatch(struct cfq_data *cfqd)
        dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr);
        dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr);
 
-       cfq_slice_expired(cfqd, 0);
+       cfq_slice_expired(cfqd, 0, 0);
 
        BUG_ON(cfqd->busy_queues);
 
@@ -1146,7 +1037,8 @@ static int
 cfq_dispatch_requests(request_queue_t *q, int force)
 {
        struct cfq_data *cfqd = q->elevator->elevator_data;
-       struct cfq_queue *cfqq;
+       struct cfq_queue *cfqq, *prev_cfqq;
+       int dispatched;
 
        if (!cfqd->busy_queues)
                return 0;
@@ -1154,10 +1046,25 @@ cfq_dispatch_requests(request_queue_t *q, int force)
        if (unlikely(force))
                return cfq_forced_dispatch(cfqd);
 
-       cfqq = cfq_select_queue(cfqd);
-       if (cfqq) {
+       dispatched = 0;
+       prev_cfqq = NULL;
+       while ((cfqq = cfq_select_queue(cfqd)) != NULL) {
                int max_dispatch;
 
+               /*
+                * Don't repeat dispatch from the previous queue.
+                */
+               if (prev_cfqq == cfqq)
+                       break;
+
+               /*
+                * So we have dispatched before in this round, if the
+                * next queue has idling enabled (must be sync), don't
+                * allow it service until the previous have continued.
+                */
+               if (cfqd->rq_in_driver && cfq_cfqq_idle_window(cfqq))
+                       break;
+
                cfq_clear_cfqq_must_dispatch(cfqq);
                cfq_clear_cfqq_wait_request(cfqq);
                del_timer(&cfqd->idle_slice_timer);
@@ -1166,15 +1073,16 @@ cfq_dispatch_requests(request_queue_t *q, int force)
                if (cfq_class_idle(cfqq))
                        max_dispatch = 1;
 
-               return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
+               dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
+               prev_cfqq = cfqq;
        }
 
-       return 0;
+       return dispatched;
 }
 
 /*
- * task holds one reference to the queue, dropped when task exits. each crq
- * in-flight on this queue also holds a reference, dropped when crq is freed.
+ * 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.
  */
@@ -1191,8 +1099,10 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
        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);
+       if (unlikely(cfqd->active_queue == cfqq)) {
+               __cfq_slice_expired(cfqd, cfqq, 0, 0);
+               cfq_schedule_dispatch(cfqd);
+       }
 
        /*
         * it's on the empty list and still hashed
@@ -1202,7 +1112,7 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
        kmem_cache_free(cfq_pool, cfqq);
 }
 
-static inline struct cfq_queue *
+static struct cfq_queue *
 __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio,
                    const int hashval)
 {
@@ -1239,62 +1149,65 @@ static void cfq_free_io_context(struct io_context *ioc)
                freed++;
        }
 
-       if (atomic_sub_and_test(freed, &ioc_count) && ioc_gone)
+       elv_ioc_count_mod(ioc_count, -freed);
+
+       if (ioc_gone && !elv_ioc_count_read(ioc_count))
                complete(ioc_gone);
 }
 
-static void cfq_trim(struct io_context *ioc)
+static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
-       ioc->set_ioprio = NULL;
-       cfq_free_io_context(ioc);
+       if (unlikely(cfqq == cfqd->active_queue)) {
+               __cfq_slice_expired(cfqd, cfqq, 0, 0);
+               cfq_schedule_dispatch(cfqd);
+       }
+
+       cfq_put_queue(cfqq);
 }
 
-/*
- * Called with interrupts disabled
- */
-static void cfq_exit_single_io_context(struct cfq_io_context *cic)
+static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
+                                        struct cfq_io_context *cic)
 {
-       struct cfq_data *cfqd = cic->key;
-       request_queue_t *q;
-
-       if (!cfqd)
-               return;
-
-       q = cfqd->queue;
-
-       WARN_ON(!irqs_disabled());
-
-       spin_lock(q->queue_lock);
+       list_del_init(&cic->queue_list);
+       smp_wmb();
+       cic->key = NULL;
 
        if (cic->cfqq[ASYNC]) {
-               if (unlikely(cic->cfqq[ASYNC] == cfqd->active_queue))
-                       __cfq_slice_expired(cfqd, cic->cfqq[ASYNC], 0);
-               cfq_put_queue(cic->cfqq[ASYNC]);
+               cfq_exit_cfqq(cfqd, cic->cfqq[ASYNC]);
                cic->cfqq[ASYNC] = NULL;
        }
 
        if (cic->cfqq[SYNC]) {
-               if (unlikely(cic->cfqq[SYNC] == cfqd->active_queue))
-                       __cfq_slice_expired(cfqd, cic->cfqq[SYNC], 0);
-               cfq_put_queue(cic->cfqq[SYNC]);
+               cfq_exit_cfqq(cfqd, cic->cfqq[SYNC]);
                cic->cfqq[SYNC] = NULL;
        }
+}
 
-       cic->key = NULL;
-       list_del_init(&cic->queue_list);
-       spin_unlock(q->queue_lock);
+
+/*
+ * Called with interrupts disabled
+ */
+static void cfq_exit_single_io_context(struct cfq_io_context *cic)
+{
+       struct cfq_data *cfqd = cic->key;
+
+       if (cfqd) {
+               request_queue_t *q = cfqd->queue;
+
+               spin_lock_irq(q->queue_lock);
+               __cfq_exit_single_io_context(cfqd, cic);
+               spin_unlock_irq(q->queue_lock);
+       }
 }
 
 static void cfq_exit_io_context(struct io_context *ioc)
 {
        struct cfq_io_context *__cic;
-       unsigned long flags;
        struct rb_node *n;
 
        /*
         * put the reference this task is holding to the various queues
         */
-       spin_lock_irqsave(&cfq_exit_lock, flags);
 
        n = rb_first(&ioc->cic_root);
        while (n != NULL) {
@@ -1303,22 +1216,21 @@ static void cfq_exit_io_context(struct io_context *ioc)
                cfq_exit_single_io_context(__cic);
                n = rb_next(n);
        }
-
-       spin_unlock_irqrestore(&cfq_exit_lock, flags);
 }
 
 static struct cfq_io_context *
 cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
 {
-       struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask);
+       struct cfq_io_context *cic;
 
+       cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask, cfqd->queue->node);
        if (cic) {
                memset(cic, 0, sizeof(*cic));
                cic->last_end_request = jiffies;
                INIT_LIST_HEAD(&cic->queue_list);
                cic->dtor = cfq_free_io_context;
                cic->exit = cfq_exit_io_context;
-               atomic_inc(&ioc_count);
+               elv_ioc_count_inc(ioc_count);
        }
 
        return cic;
@@ -1365,9 +1277,7 @@ static void cfq_init_prio_data(struct cfq_queue *cfqq)
        cfqq->org_ioprio = cfqq->ioprio;
        cfqq->org_ioprio_class = cfqq->ioprio_class;
 
-       if (cfq_cfqq_on_rr(cfqq))
-               cfq_resort_rr_list(cfqq, 0);
-
+       cfq_resort_rr_list(cfqq, 0);
        cfq_clear_cfqq_prio_changed(cfqq);
 }
 
@@ -1375,36 +1285,37 @@ static inline void changed_ioprio(struct cfq_io_context *cic)
 {
        struct cfq_data *cfqd = cic->key;
        struct cfq_queue *cfqq;
-       if (cfqd) {
-               spin_lock(cfqd->queue->queue_lock);
-               cfqq = cic->cfqq[ASYNC];
-               if (cfqq) {
-                       struct cfq_queue *new_cfqq;
-                       new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC,
-                                               cic->ioc->task, GFP_ATOMIC);
-                       if (new_cfqq) {
-                               cic->cfqq[ASYNC] = new_cfqq;
-                               cfq_put_queue(cfqq);
-                       }
-               }
-               cfqq = cic->cfqq[SYNC];
-               if (cfqq) {
-                       cfq_mark_cfqq_prio_changed(cfqq);
-                       cfq_init_prio_data(cfqq);
+       unsigned long flags;
+
+       if (unlikely(!cfqd))
+               return;
+
+       spin_lock_irqsave(cfqd->queue->queue_lock, flags);
+
+       cfqq = cic->cfqq[ASYNC];
+       if (cfqq) {
+               struct cfq_queue *new_cfqq;
+               new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC, cic->ioc->task,
+                                        GFP_ATOMIC);
+               if (new_cfqq) {
+                       cic->cfqq[ASYNC] = new_cfqq;
+                       cfq_put_queue(cfqq);
                }
-               spin_unlock(cfqd->queue->queue_lock);
        }
+
+       cfqq = cic->cfqq[SYNC];
+       if (cfqq)
+               cfq_mark_cfqq_prio_changed(cfqq);
+
+       spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
 }
 
-/*
- * callback from sys_ioprio_set, irqs are disabled
- */
-static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio)
+static void cfq_ioc_set_ioprio(struct io_context *ioc)
 {
        struct cfq_io_context *cic;
        struct rb_node *n;
 
-       spin_lock(&cfq_exit_lock);
+       ioc->ioprio_changed = 0;
 
        n = rb_first(&ioc->cic_root);
        while (n != NULL) {
@@ -1413,10 +1324,6 @@ static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio)
                changed_ioprio(cic);
                n = rb_next(n);
        }
-
-       spin_unlock(&cfq_exit_lock);
-
-       return 0;
 }
 
 static struct cfq_queue *
@@ -1436,12 +1343,18 @@ retry:
                        cfqq = new_cfqq;
                        new_cfqq = NULL;
                } else if (gfp_mask & __GFP_WAIT) {
+                       /*
+                        * Inform the allocator of the fact that we will
+                        * just repeat this allocation if it fails, to allow
+                        * the allocator to do whatever it needs to attempt to
+                        * free memory.
+                        */
                        spin_unlock_irq(cfqd->queue->queue_lock);
-                       new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask);
+                       new_cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask|__GFP_NOFAIL, cfqd->queue->node);
                        spin_lock_irq(cfqd->queue->queue_lock);
                        goto retry;
                } else {
-                       cfqq = kmem_cache_alloc(cfq_pool, gfp_mask);
+                       cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask, cfqd->queue->node);
                        if (!cfqq)
                                goto out;
                }
@@ -1450,21 +1363,16 @@ retry:
 
                INIT_HLIST_NODE(&cfqq->cfq_hash);
                INIT_LIST_HEAD(&cfqq->cfq_list);
-               RB_CLEAR_ROOT(&cfqq->sort_list);
                INIT_LIST_HEAD(&cfqq->fifo);
 
                cfqq->key = key;
                hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]);
                atomic_set(&cfqq->ref, 0);
                cfqq->cfqd = cfqd;
-               cfqq->service_last = 0;
-               /*
-                * set ->slice_left to allow preemption for a new process
-                */
-               cfqq->slice_left = 2 * cfqd->cfq_slice_idle;
-               if (!cfqd->hw_tag)
-                       cfq_mark_cfqq_idle_window(cfqq);
+
+               cfq_mark_cfqq_idle_window(cfqq);
                cfq_mark_cfqq_prio_changed(cfqq);
+               cfq_mark_cfqq_queue_new(cfqq);
                cfq_init_prio_data(cfqq);
        }
 
@@ -1480,12 +1388,10 @@ out:
 static void
 cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic)
 {
-       spin_lock(&cfq_exit_lock);
+       WARN_ON(!list_empty(&cic->queue_list));
        rb_erase(&cic->rb_node, &ioc->cic_root);
-       list_del_init(&cic->queue_list);
-       spin_unlock(&cfq_exit_lock);
        kmem_cache_free(cfq_ioc_pool, cic);
-       atomic_dec(&ioc_count);
+       elv_ioc_count_dec(ioc_count);
 }
 
 static struct cfq_io_context *
@@ -1524,12 +1430,12 @@ cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
        struct rb_node **p;
        struct rb_node *parent;
        struct cfq_io_context *__cic;
+       unsigned long flags;
        void *k;
 
        cic->ioc = ioc;
        cic->key = cfqd;
 
-       ioc->set_ioprio = cfq_ioc_set_ioprio;
 restart:
        parent = NULL;
        p = &ioc->cic_root.rb_node;
@@ -1539,7 +1445,7 @@ restart:
                /* ->key must be copied to avoid race with cfq_exit_queue() */
                k = __cic->key;
                if (unlikely(!k)) {
-                       cfq_drop_dead_cic(ioc, cic);
+                       cfq_drop_dead_cic(ioc, __cic);
                        goto restart;
                }
 
@@ -1551,11 +1457,12 @@ restart:
                        BUG();
        }
 
-       spin_lock(&cfq_exit_lock);
        rb_link_node(&cic->rb_node, parent, p);
        rb_insert_color(&cic->rb_node, &ioc->cic_root);
+
+       spin_lock_irqsave(cfqd->queue->queue_lock, flags);
        list_add(&cic->queue_list, &cfqd->cic_list);
-       spin_unlock(&cfq_exit_lock);
+       spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
 }
 
 /*
@@ -1571,7 +1478,7 @@ cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
 
        might_sleep_if(gfp_mask & __GFP_WAIT);
 
-       ioc = get_io_context(gfp_mask);
+       ioc = get_io_context(gfp_mask, cfqd->queue->node);
        if (!ioc)
                return NULL;
 
@@ -1585,6 +1492,10 @@ cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
 
        cfq_cic_link(cfqd, ioc, cic);
 out:
+       smp_read_barrier_depends();
+       if (unlikely(ioc->ioprio_changed))
+               cfq_ioc_set_ioprio(ioc);
+
        return cic;
 err:
        put_io_context(ioc);
@@ -1594,22 +1505,8 @@ err:
 static void
 cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic)
 {
-       unsigned long elapsed, ttime;
-
-       /*
-        * if this context already has stuff queued, thinktime is from
-        * last queue not last end
-        */
-#if 0
-       if (time_after(cic->last_end_request, cic->last_queue))
-               elapsed = jiffies - cic->last_end_request;
-       else
-               elapsed = jiffies - cic->last_queue;
-#else
-               elapsed = jiffies - cic->last_end_request;
-#endif
-
-       ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle);
+       unsigned long elapsed = jiffies - cic->last_end_request;
+       unsigned long ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle);
 
        cic->ttime_samples = (7*cic->ttime_samples + 256) / 8;
        cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8;
@@ -1617,16 +1514,15 @@ cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic)
 }
 
 static void
-cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic,
-                      struct cfq_rq *crq)
+cfq_update_io_seektime(struct cfq_io_context *cic, struct request *rq)
 {
        sector_t sdist;
        u64 total;
 
-       if (cic->last_request_pos < crq->request->sector)
-               sdist = crq->request->sector - cic->last_request_pos;
+       if (cic->last_request_pos < rq->sector)
+               sdist = rq->sector - cic->last_request_pos;
        else
-               sdist = cic->last_request_pos - crq->request->sector;
+               sdist = cic->last_request_pos - rq->sector;
 
        /*
         * Don't allow the seek distance to get too large from the
@@ -1654,7 +1550,8 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 {
        int enable_idle = cfq_cfqq_idle_window(cfqq);
 
-       if (!cic->ioc->task || !cfqd->cfq_slice_idle || cfqd->hw_tag)
+       if (!cic->ioc->task || !cfqd->cfq_slice_idle ||
+           (cfqd->hw_tag && CIC_SEEKY(cic)))
                enable_idle = 0;
        else if (sample_valid(cic->ttime_samples)) {
                if (cic->ttime_mean > cfqd->cfq_slice_idle)
@@ -1669,14 +1566,13 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                cfq_clear_cfqq_idle_window(cfqq);
 }
 
-
 /*
  * Check if new_cfqq should preempt the currently active queue. Return 0 for
  * no or if we aren't sure, a 1 will cause a preempt.
  */
 static int
 cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
-                  struct cfq_rq *crq)
+                  struct request *rq)
 {
        struct cfq_queue *cfqq = cfqd->active_queue;
 
@@ -1684,18 +1580,23 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
                return 0;
 
        if (!cfqq)
-               return 1;
+               return 0;
 
        if (cfq_class_idle(cfqq))
                return 1;
        if (!cfq_cfqq_wait_request(new_cfqq))
                return 0;
        /*
-        * if it doesn't have slice left, forget it
+        * if the new request is sync, but the currently running queue is
+        * not, let the sync request have priority.
         */
-       if (new_cfqq->slice_left < cfqd->cfq_slice_idle)
-               return 0;
-       if (cfq_crq_is_sync(crq) && !cfq_cfqq_sync(cfqq))
+       if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq))
+               return 1;
+       /*
+        * So both queues are sync. Let the new request get disk time if
+        * it's a metadata request and the current queue is doing regular IO.
+        */
+       if (rq_is_meta(rq) && !cfqq->meta_pending)
                return 1;
 
        return 0;
@@ -1707,69 +1608,60 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
  */
 static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
-       struct cfq_queue *__cfqq, *next;
+       cfq_slice_expired(cfqd, 1, 1);
 
-       list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list)
-               cfq_resort_rr_list(__cfqq, 1);
-
-       if (!cfqq->slice_left)
-               cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2;
-
-       cfqq->slice_end = cfqq->slice_left + jiffies;
-       __cfq_slice_expired(cfqd, cfqq, 1);
-       __cfq_set_active_queue(cfqd, cfqq);
-}
-
-/*
- * should really be a ll_rw_blk.c helper
- */
-static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-       request_queue_t *q = cfqd->queue;
+       /*
+        * 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));
+       list_move(&cfqq->cfq_list, &cfqd->cur_rr);
 
-       if (!blk_queue_plugged(q))
-               q->request_fn(q);
-       else
-               __generic_unplug_device(q);
+       cfqq->slice_end = 0;
+       cfq_mark_cfqq_slice_new(cfqq);
 }
 
 /*
- * Called when a new fs request (crq) is added (to cfqq). Check if there's
+ * Called when a new fs request (rq) is added (to cfqq). Check if there's
  * something we should do about it
  */
 static void
-cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-                struct cfq_rq *crq)
+cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
+               struct request *rq)
 {
-       struct cfq_io_context *cic;
+       struct cfq_io_context *cic = RQ_CIC(rq);
 
-       cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
+       if (rq_is_meta(rq))
+               cfqq->meta_pending++;
 
-       cic = crq->io_context;
+       /*
+        * check if this request is a better next-serve candidate)) {
+        */
+       cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
+       BUG_ON(!cfqq->next_rq);
 
        /*
         * we never wait for an async request and we don't allow preemption
         * of an async request. so just return early
         */
-       if (!cfq_crq_is_sync(crq)) {
+       if (!rq_is_sync(rq)) {
                /*
                 * sync process issued an async request, if it's waiting
                 * then expire it and kick rq handling.
                 */
                if (cic == cfqd->active_cic &&
                    del_timer(&cfqd->idle_slice_timer)) {
-                       cfq_slice_expired(cfqd, 0);
-                       cfq_start_queueing(cfqd, cfqq);
+                       cfq_slice_expired(cfqd, 0, 0);
+                       blk_start_queueing(cfqd->queue);
                }
                return;
        }
 
        cfq_update_io_thinktime(cfqd, cic);
-       cfq_update_io_seektime(cfqd, cic, crq);
+       cfq_update_io_seektime(cic, rq);
        cfq_update_idle_window(cfqd, cfqq, cic);
 
-       cic->last_queue = jiffies;
-       cic->last_request_pos = crq->request->sector + crq->request->nr_sectors;
+       cic->last_request_pos = rq->sector + rq->nr_sectors;
 
        if (cfqq == cfqd->active_queue) {
                /*
@@ -1780,9 +1672,9 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                if (cfq_cfqq_wait_request(cfqq)) {
                        cfq_mark_cfqq_must_dispatch(cfqq);
                        del_timer(&cfqd->idle_slice_timer);
-                       cfq_start_queueing(cfqd, cfqq);
+                       blk_start_queueing(cfqd->queue);
                }
-       } else if (cfq_should_preempt(cfqd, cfqq, crq)) {
+       } 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
@@ -1790,34 +1682,29 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                 */
                cfq_preempt_queue(cfqd, cfqq);
                cfq_mark_cfqq_must_dispatch(cfqq);
-               cfq_start_queueing(cfqd, cfqq);
+               blk_start_queueing(cfqd->queue);
        }
 }
 
 static void cfq_insert_request(request_queue_t *q, struct request *rq)
 {
        struct cfq_data *cfqd = q->elevator->elevator_data;
-       struct cfq_rq *crq = RQ_DATA(rq);
-       struct cfq_queue *cfqq = crq->cfq_queue;
+       struct cfq_queue *cfqq = RQ_CFQQ(rq);
 
        cfq_init_prio_data(cfqq);
 
-       cfq_add_crq_rb(crq);
+       cfq_add_rq_rb(rq);
 
        list_add_tail(&rq->queuelist, &cfqq->fifo);
 
-       if (rq_mergeable(rq))
-               cfq_add_crq_hash(cfqd, crq);
-
-       cfq_crq_enqueued(cfqd, cfqq, crq);
+       cfq_rq_enqueued(cfqd, cfqq, rq);
 }
 
 static void cfq_completed_request(request_queue_t *q, struct request *rq)
 {
-       struct cfq_rq *crq = RQ_DATA(rq);
-       struct cfq_queue *cfqq = crq->cfq_queue;
+       struct cfq_queue *cfqq = RQ_CFQQ(rq);
        struct cfq_data *cfqd = cfqq->cfqd;
-       const int sync = cfq_crq_is_sync(crq);
+       const int sync = rq_is_sync(rq);
        unsigned long now;
 
        now = jiffies;
@@ -1826,44 +1713,32 @@ static void cfq_completed_request(request_queue_t *q, struct request *rq)
        WARN_ON(!cfqq->on_dispatch[sync]);
        cfqd->rq_in_driver--;
        cfqq->on_dispatch[sync]--;
+       cfqq->service_last = now;
 
        if (!cfq_class_idle(cfqq))
                cfqd->last_end_request = now;
 
-       if (!cfq_cfqq_dispatched(cfqq)) {
-               if (cfq_cfqq_on_rr(cfqq)) {
-                       cfqq->service_last = now;
-                       cfq_resort_rr_list(cfqq, 0);
-               }
-               cfq_schedule_dispatch(cfqd);
-       }
-
-       if (cfq_crq_is_sync(crq))
-               crq->io_context->last_end_request = now;
-}
-
-static struct request *
-cfq_former_request(request_queue_t *q, struct request *rq)
-{
-       struct cfq_rq *crq = RQ_DATA(rq);
-       struct rb_node *rbprev = rb_prev(&crq->rb_node);
-
-       if (rbprev)
-               return rb_entry_crq(rbprev)->request;
-
-       return NULL;
-}
-
-static struct request *
-cfq_latter_request(request_queue_t *q, struct request *rq)
-{
-       struct cfq_rq *crq = RQ_DATA(rq);
-       struct rb_node *rbnext = rb_next(&crq->rb_node);
+       cfq_resort_rr_list(cfqq, 0);
 
-       if (rbnext)
-               return rb_entry_crq(rbnext)->request;
+       if (sync)
+               RQ_CIC(rq)->last_end_request = now;
 
-       return NULL;
+       /*
+        * 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) {
+               if (cfq_cfqq_slice_new(cfqq)) {
+                       cfq_set_prio_slice(cfqd, cfqq);
+                       cfq_clear_cfqq_slice_new(cfqq);
+               }
+               if (cfq_slice_used(cfqq))
+                       cfq_slice_expired(cfqd, 0, 1);
+               else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) {
+                       if (!cfq_arm_slice_timer(cfqd))
+                               cfq_schedule_dispatch(cfqd);
+               }
+       }
 }
 
 /*
@@ -1897,14 +1772,11 @@ 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) &&
-           cfq_cfqq_on_rr(cfqq))
+       if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio))
                cfq_resort_rr_list(cfqq, 0);
 }
 
-static inline int
-__cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-               struct task_struct *task, int rw)
+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)) {
@@ -1915,11 +1787,14 @@ __cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq,
        return ELV_MQUEUE_MAY;
 }
 
-static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio)
+static int cfq_may_queue(request_queue_t *q, int rw)
 {
        struct cfq_data *cfqd = q->elevator->elevator_data;
        struct task_struct *tsk = current;
        struct cfq_queue *cfqq;
+       unsigned int key;
+
+       key = cfq_queue_pid(tsk, rw, rw & REQ_RW_SYNC);
 
        /*
         * don't force setup of a queue from here, as a call to may_queue
@@ -1927,53 +1802,35 @@ 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), tsk->ioprio);
+       cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
        if (cfqq) {
                cfq_init_prio_data(cfqq);
                cfq_prio_boost(cfqq);
 
-               return __cfq_may_queue(cfqd, cfqq, tsk, rw);
+               return __cfq_may_queue(cfqq);
        }
 
        return ELV_MQUEUE_MAY;
 }
 
-static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq)
-{
-       struct cfq_data *cfqd = q->elevator->elevator_data;
-
-       if (unlikely(cfqd->rq_starved)) {
-               struct request_list *rl = &q->rq;
-
-               smp_mb();
-               if (waitqueue_active(&rl->wait[READ]))
-                       wake_up(&rl->wait[READ]);
-               if (waitqueue_active(&rl->wait[WRITE]))
-                       wake_up(&rl->wait[WRITE]);
-       }
-}
-
 /*
  * queue lock held here
  */
-static void cfq_put_request(request_queue_t *q, struct request *rq)
+static void cfq_put_request(struct request *rq)
 {
-       struct cfq_data *cfqd = q->elevator->elevator_data;
-       struct cfq_rq *crq = RQ_DATA(rq);
+       struct cfq_queue *cfqq = RQ_CFQQ(rq);
 
-       if (crq) {
-               struct cfq_queue *cfqq = crq->cfq_queue;
+       if (cfqq) {
                const int rw = rq_data_dir(rq);
 
                BUG_ON(!cfqq->allocated[rw]);
                cfqq->allocated[rw]--;
 
-               put_io_context(crq->io_context->ioc);
+               put_io_context(RQ_CIC(rq)->ioc);
 
-               mempool_free(crq, cfqd->crq_pool);
                rq->elevator_private = NULL;
+               rq->elevator_private2 = NULL;
 
-               cfq_check_waiters(q, cfqq);
                cfq_put_queue(cfqq);
        }
 }
@@ -1982,18 +1839,16 @@ static void cfq_put_request(request_queue_t *q, struct request *rq)
  * Allocate cfq data structures associated with this request.
  */
 static int
-cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
-               gfp_t gfp_mask)
+cfq_set_request(request_queue_t *q, struct request *rq, gfp_t 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);
+       const int is_sync = rq_is_sync(rq);
+       pid_t key = cfq_queue_pid(tsk, rw, is_sync);
        struct cfq_queue *cfqq;
-       struct cfq_rq *crq;
        unsigned long flags;
-       int is_sync = key != CFQ_KEY_ASYNC;
 
        might_sleep_if(gfp_mask & __GFP_WAIT);
 
@@ -2015,71 +1870,32 @@ cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
 
        cfqq->allocated[rw]++;
        cfq_clear_cfqq_must_alloc(cfqq);
-       cfqd->rq_starved = 0;
        atomic_inc(&cfqq->ref);
-       spin_unlock_irqrestore(q->queue_lock, flags);
 
-       crq = mempool_alloc(cfqd->crq_pool, gfp_mask);
-       if (crq) {
-               RB_CLEAR(&crq->rb_node);
-               crq->rb_key = 0;
-               crq->request = rq;
-               INIT_HLIST_NODE(&crq->hash);
-               crq->cfq_queue = cfqq;
-               crq->io_context = cic;
-
-               if (is_sync)
-                       cfq_mark_crq_is_sync(crq);
-               else
-                       cfq_clear_crq_is_sync(crq);
+       spin_unlock_irqrestore(q->queue_lock, flags);
 
-               rq->elevator_private = crq;
-               return 0;
-       }
+       rq->elevator_private = cic;
+       rq->elevator_private2 = cfqq;
+       return 0;
 
-       spin_lock_irqsave(q->queue_lock, flags);
-       cfqq->allocated[rw]--;
-       if (!(cfqq->allocated[0] + cfqq->allocated[1]))
-               cfq_mark_cfqq_must_alloc(cfqq);
-       cfq_put_queue(cfqq);
 queue_fail:
        if (cic)
                put_io_context(cic->ioc);
-       /*
-        * mark us rq allocation starved. we need to kickstart the process
-        * ourselves if there are no pending requests that can do it for us.
-        * that would be an extremely rare OOM situation
-        */
-       cfqd->rq_starved = 1;
+
        cfq_schedule_dispatch(cfqd);
        spin_unlock_irqrestore(q->queue_lock, flags);
        return 1;
 }
 
-static void cfq_kick_queue(void *data)
+static void cfq_kick_queue(struct work_struct *work)
 {
-       request_queue_t *q = data;
-       struct cfq_data *cfqd = q->elevator->elevator_data;
+       struct cfq_data *cfqd =
+               container_of(work, struct cfq_data, unplug_work);
+       request_queue_t *q = cfqd->queue;
        unsigned long flags;
 
        spin_lock_irqsave(q->queue_lock, flags);
-
-       if (cfqd->rq_starved) {
-               struct request_list *rl = &q->rq;
-
-               /*
-                * we aren't guaranteed to get a request after this, but we
-                * have to be opportunistic
-                */
-               smp_mb();
-               if (waitqueue_active(&rl->wait[READ]))
-                       wake_up(&rl->wait[READ]);
-               if (waitqueue_active(&rl->wait[WRITE]))
-                       wake_up(&rl->wait[WRITE]);
-       }
-
-       blk_remove_plug(q);
-       q->request_fn(q);
+       blk_start_queueing(q);
        spin_unlock_irqrestore(q->queue_lock, flags);
 }
 
@@ -2091,38 +1907,36 @@ 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;
 
        spin_lock_irqsave(cfqd->queue->queue_lock, flags);
 
        if ((cfqq = cfqd->active_queue) != NULL) {
-               unsigned long now = jiffies;
+               timed_out = 0;
 
                /*
                 * expired
                 */
-               if (time_after(now, cfqq->slice_end))
+               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) {
-                       cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end);
-                       add_timer(&cfqd->idle_slice_timer);
+               if (!cfqd->busy_queues)
                        goto out_cont;
-               }
 
                /*
                 * not expired and it has a request pending, let it dispatch
                 */
-               if (!RB_EMPTY(&cfqq->sort_list)) {
+               if (!RB_EMPTY_ROOT(&cfqq->sort_list)) {
                        cfq_mark_cfqq_must_dispatch(cfqq);
                        goto out_kick;
                }
        }
 expire:
-       cfq_slice_expired(cfqd, 0);
+       cfq_slice_expired(cfqd, 0, timed_out);
 out_kick:
        cfq_schedule_dispatch(cfqd);
 out_cont:
@@ -2165,45 +1979,33 @@ static void cfq_exit_queue(elevator_t *e)
 
        cfq_shutdown_timer_wq(cfqd);
 
-       spin_lock(&cfq_exit_lock);
        spin_lock_irq(q->queue_lock);
 
        if (cfqd->active_queue)
-               __cfq_slice_expired(cfqd, cfqd->active_queue, 0);
+               __cfq_slice_expired(cfqd, cfqd->active_queue, 0, 0);
 
        while (!list_empty(&cfqd->cic_list)) {
                struct cfq_io_context *cic = list_entry(cfqd->cic_list.next,
                                                        struct cfq_io_context,
                                                        queue_list);
-               if (cic->cfqq[ASYNC]) {
-                       cfq_put_queue(cic->cfqq[ASYNC]);
-                       cic->cfqq[ASYNC] = NULL;
-               }
-               if (cic->cfqq[SYNC]) {
-                       cfq_put_queue(cic->cfqq[SYNC]);
-                       cic->cfqq[SYNC] = NULL;
-               }
-               cic->key = NULL;
-               list_del_init(&cic->queue_list);
+
+               __cfq_exit_single_io_context(cfqd, cic);
        }
 
        spin_unlock_irq(q->queue_lock);
-       spin_unlock(&cfq_exit_lock);
 
        cfq_shutdown_timer_wq(cfqd);
 
-       mempool_destroy(cfqd->crq_pool);
-       kfree(cfqd->crq_hash);
        kfree(cfqd->cfq_hash);
        kfree(cfqd);
 }
 
-static void *cfq_init_queue(request_queue_t *q, elevator_t *e)
+static void *cfq_init_queue(request_queue_t *q)
 {
        struct cfq_data *cfqd;
        int i;
 
-       cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL);
+       cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL, q->node);
        if (!cfqd)
                return NULL;
 
@@ -2215,23 +2017,12 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e)
        INIT_LIST_HEAD(&cfqd->busy_rr);
        INIT_LIST_HEAD(&cfqd->cur_rr);
        INIT_LIST_HEAD(&cfqd->idle_rr);
-       INIT_LIST_HEAD(&cfqd->empty_list);
        INIT_LIST_HEAD(&cfqd->cic_list);
 
-       cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL);
-       if (!cfqd->crq_hash)
-               goto out_crqhash;
-
-       cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL);
+       cfqd->cfq_hash = kmalloc_node(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL, q->node);
        if (!cfqd->cfq_hash)
-               goto out_cfqhash;
-
-       cfqd->crq_pool = mempool_create_slab_pool(BLKDEV_MIN_RQ, crq_pool);
-       if (!cfqd->crq_pool)
-               goto out_crqpool;
+               goto out_free;
 
-       for (i = 0; i < CFQ_MHASH_ENTRIES; i++)
-               INIT_HLIST_HEAD(&cfqd->crq_hash[i]);
        for (i = 0; i < CFQ_QHASH_ENTRIES; i++)
                INIT_HLIST_HEAD(&cfqd->cfq_hash[i]);
 
@@ -2245,9 +2036,8 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e)
        cfqd->idle_class_timer.function = cfq_idle_class_timer;
        cfqd->idle_class_timer.data = (unsigned long) cfqd;
 
-       INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q);
+       INIT_WORK(&cfqd->unplug_work, cfq_kick_queue);
 
-       cfqd->cfq_queued = cfq_queued;
        cfqd->cfq_quantum = cfq_quantum;
        cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0];
        cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1];
@@ -2259,19 +2049,13 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e)
        cfqd->cfq_slice_idle = cfq_slice_idle;
 
        return cfqd;
-out_crqpool:
-       kfree(cfqd->cfq_hash);
-out_cfqhash:
-       kfree(cfqd->crq_hash);
-out_crqhash:
+out_free:
        kfree(cfqd);
        return NULL;
 }
 
 static void cfq_slab_kill(void)
 {
-       if (crq_pool)
-               kmem_cache_destroy(crq_pool);
        if (cfq_pool)
                kmem_cache_destroy(cfq_pool);
        if (cfq_ioc_pool)
@@ -2280,11 +2064,6 @@ static void cfq_slab_kill(void)
 
 static int __init cfq_slab_setup(void)
 {
-       crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0,
-                                       NULL, NULL);
-       if (!crq_pool)
-               goto fail;
-
        cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0,
                                        NULL, NULL);
        if (!cfq_pool)
@@ -2330,7 +2109,6 @@ static ssize_t __FUNC(elevator_t *e, char *page)                  \
        return cfq_var_show(__data, (page));                            \
 }
 SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0);
-SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0);
 SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1);
 SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1);
 SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0);
@@ -2358,7 +2136,6 @@ static ssize_t __FUNC(elevator_t *e, const char *page, size_t count)      \
        return ret;                                                     \
 }
 STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0);
-STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0);
 STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1);
 STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1);
 STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0);
@@ -2374,7 +2151,6 @@ STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX,
 
 static struct elv_fs_entry cfq_attrs[] = {
        CFQ_ATTR(quantum),
-       CFQ_ATTR(queued),
        CFQ_ATTR(fifo_expire_sync),
        CFQ_ATTR(fifo_expire_async),
        CFQ_ATTR(back_seek_max),
@@ -2391,20 +2167,21 @@ static struct elevator_type iosched_cfq = {
                .elevator_merge_fn =            cfq_merge,
                .elevator_merged_fn =           cfq_merged_request,
                .elevator_merge_req_fn =        cfq_merged_requests,
+               .elevator_allow_merge_fn =      cfq_allow_merge,
                .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 =       cfq_former_request,
-               .elevator_latter_req_fn =       cfq_latter_request,
+               .elevator_former_req_fn =       elv_rb_former_request,
+               .elevator_latter_req_fn =       elv_rb_latter_request,
                .elevator_set_req_fn =          cfq_set_request,
                .elevator_put_req_fn =          cfq_put_request,
                .elevator_may_queue_fn =        cfq_may_queue,
                .elevator_init_fn =             cfq_init_queue,
                .elevator_exit_fn =             cfq_exit_queue,
-               .trim =                         cfq_trim,
+               .trim =                         cfq_free_io_context,
        },
        .elevator_attrs =       cfq_attrs,
        .elevator_name =        "cfq",
@@ -2435,12 +2212,12 @@ static int __init cfq_init(void)
 
 static void __exit cfq_exit(void)
 {
-       DECLARE_COMPLETION(all_gone);
+       DECLARE_COMPLETION_ONSTACK(all_gone);
        elv_unregister(&iosched_cfq);
        ioc_gone = &all_gone;
        /* ioc_gone's update must be visible before reading ioc_count */
        smp_wmb();
-       if (atomic_read(&ioc_count))
+       if (elv_ioc_count_read(ioc_count))
                wait_for_completion(ioc_gone);
        synchronize_rcu();
        cfq_slab_kill();