Merge commit 'v2.6.38-rc6' into for-2.6.39/core
[pandora-kernel.git] / block / cfq-iosched.c
index 968455c..f27ff3e 100644 (file)
@@ -87,7 +87,6 @@ struct cfq_rb_root {
        unsigned count;
        unsigned total_weight;
        u64 min_vdisktime;
-       struct rb_node *active;
 };
 #define CFQ_RB_ROOT    (struct cfq_rb_root) { .rb = RB_ROOT, .left = NULL, \
                        .count = 0, .min_vdisktime = 0, }
@@ -97,7 +96,7 @@ struct cfq_rb_root {
  */
 struct cfq_queue {
        /* reference count */
-       atomic_t ref;
+       int ref;
        /* various state flags, see below */
        unsigned int flags;
        /* parent cfq_data */
@@ -180,7 +179,6 @@ struct cfq_group {
        /* group service_tree key */
        u64 vdisktime;
        unsigned int weight;
-       bool on_st;
 
        /* number of cfqq currently on this group */
        int nr_cfqq;
@@ -209,7 +207,7 @@ struct cfq_group {
        struct blkio_group blkg;
 #ifdef CONFIG_CFQ_GROUP_IOSCHED
        struct hlist_node cfqd_node;
-       atomic_t ref;
+       int ref;
 #endif
        /* number of requests that are on the dispatch list or inside driver */
        int dispatched;
@@ -563,11 +561,6 @@ static void update_min_vdisktime(struct cfq_rb_root *st)
        u64 vdisktime = st->min_vdisktime;
        struct cfq_group *cfqg;
 
-       if (st->active) {
-               cfqg = rb_entry_cfqg(st->active);
-               vdisktime = cfqg->vdisktime;
-       }
-
        if (st->left) {
                cfqg = rb_entry_cfqg(st->left);
                vdisktime = min_vdisktime(vdisktime, cfqg->vdisktime);
@@ -605,8 +598,8 @@ cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg)
        return cfq_target_latency * cfqg->weight / st->total_weight;
 }
 
-static inline void
-cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static inline unsigned
+cfq_scaled_cfqq_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
        unsigned slice = cfq_prio_to_slice(cfqd, cfqq);
        if (cfqd->cfq_latency) {
@@ -632,6 +625,14 @@ cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
                                    low_slice);
                }
        }
+       return slice;
+}
+
+static inline void
+cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+       unsigned slice = cfq_scaled_cfqq_slice(cfqd, cfqq);
+
        cfqq->slice_start = jiffies;
        cfqq->slice_end = jiffies + slice;
        cfqq->allocated_slice = slice;
@@ -646,11 +647,11 @@ cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 static inline bool cfq_slice_used(struct cfq_queue *cfqq)
 {
        if (cfq_cfqq_slice_new(cfqq))
-               return 0;
+               return false;
        if (time_before(jiffies, cfqq->slice_end))
-               return 0;
+               return false;
 
-       return 1;
+       return true;
 }
 
 /*
@@ -869,7 +870,7 @@ cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
        struct rb_node *n;
 
        cfqg->nr_cfqq++;
-       if (cfqg->on_st)
+       if (!RB_EMPTY_NODE(&cfqg->rb_node))
                return;
 
        /*
@@ -885,7 +886,6 @@ cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
                cfqg->vdisktime = st->min_vdisktime;
 
        __cfq_group_service_tree_add(st, cfqg);
-       cfqg->on_st = true;
        st->total_weight += cfqg->weight;
 }
 
@@ -894,9 +894,6 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
 {
        struct cfq_rb_root *st = &cfqd->grp_service_tree;
 
-       if (st->active == &cfqg->rb_node)
-               st->active = NULL;
-
        BUG_ON(cfqg->nr_cfqq < 1);
        cfqg->nr_cfqq--;
 
@@ -905,7 +902,6 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
                return;
 
        cfq_log_cfqg(cfqd, cfqg, "del_from_rr group");
-       cfqg->on_st = false;
        st->total_weight -= cfqg->weight;
        if (!RB_EMPTY_NODE(&cfqg->rb_node))
                cfq_rb_erase(&cfqg->rb_node, st);
@@ -1026,11 +1022,11 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
         * elevator which will be dropped by either elevator exit
         * or cgroup deletion path depending on who is exiting first.
         */
-       atomic_set(&cfqg->ref, 1);
+       cfqg->ref = 1;
 
        /*
         * Add group onto cgroup list. It might happen that bdi->dev is
-        * not initiliazed yet. Initialize this new group without major
+        * not initialized yet. Initialize this new group without major
         * and minor info and this info will be filled in once a new thread
         * comes for IO. See code above.
         */
@@ -1071,7 +1067,7 @@ static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create)
 
 static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg)
 {
-       atomic_inc(&cfqg->ref);
+       cfqg->ref++;
        return cfqg;
 }
 
@@ -1083,7 +1079,7 @@ static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg)
 
        cfqq->cfqg = cfqg;
        /* cfqq reference on cfqg */
-       atomic_inc(&cfqq->cfqg->ref);
+       cfqq->cfqg->ref++;
 }
 
 static void cfq_put_cfqg(struct cfq_group *cfqg)
@@ -1091,11 +1087,12 @@ static void cfq_put_cfqg(struct cfq_group *cfqg)
        struct cfq_rb_root *st;
        int i, j;
 
-       BUG_ON(atomic_read(&cfqg->ref) <= 0);
-       if (!atomic_dec_and_test(&cfqg->ref))
+       BUG_ON(cfqg->ref <= 0);
+       cfqg->ref--;
+       if (cfqg->ref)
                return;
        for_each_cfqg_st(cfqg, i, j, st)
-               BUG_ON(!RB_EMPTY_ROOT(&st->rb) || st->active != NULL);
+               BUG_ON(!RB_EMPTY_ROOT(&st->rb));
        kfree(cfqg);
 }
 
@@ -1200,7 +1197,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                        cfq_group_service_tree_del(cfqd, cfqq->cfqg);
                cfqq->orig_cfqg = cfqq->cfqg;
                cfqq->cfqg = &cfqd->root_group;
-               atomic_inc(&cfqd->root_group.ref);
+               cfqd->root_group.ref++;
                group_changed = 1;
        } else if (!cfqd->cfq_group_isolation
                   && cfqq_type(cfqq) == SYNC_WORKLOAD && cfqq->orig_cfqg) {
@@ -1672,8 +1669,11 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *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;
+       if (timed_out) {
+               if (cfq_cfqq_slice_new(cfqq))
+                       cfqq->slice_resid = cfq_scaled_cfqq_slice(cfqd, cfqq);
+               else
+                       cfqq->slice_resid = cfqq->slice_end - jiffies;
                cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid);
        }
 
@@ -1687,9 +1687,6 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
        if (cfqq == cfqd->active_queue)
                cfqd->active_queue = NULL;
 
-       if (&cfqq->cfqg->rb_node == cfqd->grp_service_tree.active)
-               cfqd->grp_service_tree.active = NULL;
-
        if (cfqd->active_cic) {
                put_io_context(cfqd->active_cic->ioc);
                cfqd->active_cic = NULL;
@@ -1901,10 +1898,10 @@ static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq)
         * in their service tree.
         */
        if (service_tree->count == 1 && cfq_cfqq_sync(cfqq))
-               return 1;
+               return true;
        cfq_log_cfqq(cfqd, cfqq, "Not idling. st->count:%d",
                        service_tree->count);
-       return 0;
+       return false;
 }
 
 static void cfq_arm_slice_timer(struct cfq_data *cfqd)
@@ -2040,7 +2037,7 @@ static int cfqq_process_refs(struct cfq_queue *cfqq)
        int process_refs, io_refs;
 
        io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE];
-       process_refs = atomic_read(&cfqq->ref) - io_refs;
+       process_refs = cfqq->ref - io_refs;
        BUG_ON(process_refs < 0);
        return process_refs;
 }
@@ -2080,10 +2077,10 @@ static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq)
         */
        if (new_process_refs >= process_refs) {
                cfqq->new_cfqq = new_cfqq;
-               atomic_add(process_refs, &new_cfqq->ref);
+               new_cfqq->ref += process_refs;
        } else {
                new_cfqq->new_cfqq = cfqq;
-               atomic_add(new_process_refs, &cfqq->ref);
+               cfqq->ref += new_process_refs;
        }
 }
 
@@ -2116,12 +2113,7 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
        unsigned count;
        struct cfq_rb_root *st;
        unsigned group_slice;
-
-       if (!cfqg) {
-               cfqd->serving_prio = IDLE_WORKLOAD;
-               cfqd->workload_expires = jiffies + 1;
-               return;
-       }
+       enum wl_prio_t original_prio = cfqd->serving_prio;
 
        /* Choose next priority. RT > BE > IDLE */
        if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg))
@@ -2134,6 +2126,9 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
                return;
        }
 
+       if (original_prio != cfqd->serving_prio)
+               goto new_workload;
+
        /*
         * For RT and BE, we have to choose also the type
         * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload
@@ -2148,6 +2143,7 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
        if (count && !time_after(jiffies, cfqd->workload_expires))
                return;
 
+new_workload:
        /* otherwise select new workload type */
        cfqd->serving_type =
                cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio);
@@ -2199,7 +2195,6 @@ static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd)
        if (RB_EMPTY_ROOT(&st->rb))
                return NULL;
        cfqg = cfq_rb_first_group(st);
-       st->active = &cfqg->rb_node;
        update_min_vdisktime(st);
        return cfqg;
 }
@@ -2293,6 +2288,17 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
                goto keep_queue;
        }
 
+       /*
+        * This is a deep seek queue, but the device is much faster than
+        * the queue can deliver, don't idle
+        **/
+       if (CFQQ_SEEKY(cfqq) && cfq_cfqq_idle_window(cfqq) &&
+           (cfq_cfqq_slice_new(cfqq) ||
+           (cfqq->slice_end - jiffies > jiffies - cfqq->slice_start))) {
+               cfq_clear_cfqq_deep(cfqq);
+               cfq_clear_cfqq_idle_window(cfqq);
+       }
+
        if (cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) {
                cfqq = NULL;
                goto keep_queue;
@@ -2367,12 +2373,12 @@ static inline bool cfq_slice_used_soon(struct cfq_data *cfqd,
 {
        /* the queue hasn't finished any request, can't estimate */
        if (cfq_cfqq_slice_new(cfqq))
-               return 1;
+               return true;
        if (time_after(jiffies + cfqd->cfq_slice_idle * cfqq->dispatched,
                cfqq->slice_end))
-               return 1;
+               return true;
 
-       return 0;
+       return false;
 }
 
 static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq)
@@ -2538,9 +2544,10 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
        struct cfq_data *cfqd = cfqq->cfqd;
        struct cfq_group *cfqg, *orig_cfqg;
 
-       BUG_ON(atomic_read(&cfqq->ref) <= 0);
+       BUG_ON(cfqq->ref <= 0);
 
-       if (!atomic_dec_and_test(&cfqq->ref))
+       cfqq->ref--;
+       if (cfqq->ref)
                return;
 
        cfq_log_cfqq(cfqd, cfqq, "put_queue");
@@ -2843,7 +2850,7 @@ static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
        RB_CLEAR_NODE(&cfqq->p_node);
        INIT_LIST_HEAD(&cfqq->fifo);
 
-       atomic_set(&cfqq->ref, 0);
+       cfqq->ref = 0;
        cfqq->cfqd = cfqd;
 
        cfq_mark_cfqq_prio_changed(cfqq);
@@ -2979,11 +2986,11 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc,
         * pin the queue now that it's allocated, scheduler exit will prune it
         */
        if (!is_sync && !(*async_cfqq)) {
-               atomic_inc(&cfqq->ref);
+               cfqq->ref++;
                *async_cfqq = cfqq;
        }
 
-       atomic_inc(&cfqq->ref);
+       cfqq->ref++;
        return cfqq;
 }
 
@@ -3265,6 +3272,10 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
        if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
                return true;
 
+       /* An idle queue should not be idle now for some reason */
+       if (RB_EMPTY_ROOT(&cfqq->sort_list) && !cfq_should_idle(cfqd, cfqq))
+               return true;
+
        if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
                return false;
 
@@ -3284,9 +3295,18 @@ 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 *old_cfqq = cfqd->active_queue;
+
        cfq_log_cfqq(cfqd, cfqq, "preempt");
        cfq_slice_expired(cfqd, 1);
 
+       /*
+        * workload type is changed, don't save slice, otherwise preempt
+        * doesn't happen
+        */
+       if (cfqq_type(old_cfqq) != cfqq_type(cfqq))
+               cfqq->cfqg->saved_workload_slice = 0;
+
        /*
         * Put the new queue at the front of the of the current list,
         * so we know that it will be selected next.
@@ -3412,6 +3432,10 @@ static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
        struct cfq_io_context *cic = cfqd->active_cic;
 
+       /* If the queue already has requests, don't wait */
+       if (!RB_EMPTY_ROOT(&cfqq->sort_list))
+               return false;
+
        /* If there are other queues in the group, don't wait */
        if (cfqq->cfqg->nr_cfqq > 1)
                return false;
@@ -3681,10 +3705,10 @@ new_queue:
        }
 
        cfqq->allocated[rw]++;
-       atomic_inc(&cfqq->ref);
 
        spin_unlock_irqrestore(q->queue_lock, flags);
 
+       cfqq->ref++;
        rq->elevator_private[0] = cic;
        rq->elevator_private[1] = cfqq;
        rq->elevator_private[2] = cfq_ref_get_cfqg(cfqq->cfqg);
@@ -3862,6 +3886,10 @@ static void *cfq_init_queue(struct request_queue *q)
        if (!cfqd)
                return NULL;
 
+       /*
+        * Don't need take queue_lock in the routine, since we are
+        * initializing the ioscheduler, and nobody is using cfqd
+        */
        cfqd->cic_index = i;
 
        /* Init root service tree */
@@ -3881,7 +3909,7 @@ static void *cfq_init_queue(struct request_queue *q)
         * Take a reference to root group which we never drop. This is just
         * to make sure that cfq_put_cfqg() does not try to kfree root group
         */
-       atomic_set(&cfqg->ref, 1);
+       cfqg->ref = 1;
        rcu_read_lock();
        cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg,
                                        (void *)cfqd, 0);
@@ -3901,7 +3929,7 @@ static void *cfq_init_queue(struct request_queue *q)
         * will not attempt to free it.
         */
        cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0);
-       atomic_inc(&cfqd->oom_cfqq.ref);
+       cfqd->oom_cfqq.ref++;
        cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group);
 
        INIT_LIST_HEAD(&cfqd->cic_list);