2 files changed, 72 insertions, 38 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 15152e2da0d2..67d446de0227 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -26,18 +26,12 @@ 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 / 100;
+static int cfq_slice_idle = HZ / 70;
 
 #define CFQ_IDLE_GRACE          (HZ / 10)
 #define CFQ_SLICE_SCALE         (5)
 
 #define CFQ_KEY_ASYNC           (0)
-#define CFQ_KEY_ANY             (0xffff)
-
-/*
- * disable queueing at the driver/hardware level
- */
-static const int cfq_max_depth = 2;
 
 static DEFINE_RWLOCK(cfq_exit_lock);
 
@@ -102,6 +96,8 @@ static struct completion *ioc_gone;
 #define cfq_cfqq_sync(cfqq)             \
         (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC])
 
+#define sample_valid(samples)   ((samples) > 80)
+
 /*
  * Per block device queue structure
  */
@@ -170,7 +166,6 @@ struct cfq_data {
         unsigned int cfq_slice[2];
         unsigned int cfq_slice_async_rq;
         unsigned int cfq_slice_idle;
-        unsigned int cfq_max_depth;
 
         struct list_head cic_list;
 };
@@ -343,6 +338,14 @@ static int cfq_queue_empty(request_queue_t *q)
         return !cfqd->busy_queues;
 }
 
+static inline pid_t cfq_queue_pid(struct task_struct *task, int rw)
+{
+        if (rw == READ || process_sync(task))
+                return task->pid;
+
+        return CFQ_KEY_ASYNC;
+}
+
 /*
  * Lifted from AS - choose which of crq1 and crq2 that is best served now.
  * We choose the request that is closest to the head right now. Distance
@@ -626,15 +629,20 @@ cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq)
         cfq_add_crq_rb(crq);
 }
 
-static struct request *cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector)
-
+static struct request *
+cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
 {
-        struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, current->pid, CFQ_KEY_ANY);
+        struct task_struct *tsk = current;
+        pid_t key = cfq_queue_pid(tsk, bio_data_dir(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);
@@ -688,7 +696,7 @@ cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
                 goto out;
         }
 
-        __rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio));
+        __rq = cfq_find_rq_fmerge(cfqd, bio);
         if (__rq && elv_rq_merge_ok(__rq, bio)) {
                 ret = ELEVATOR_FRONT_MERGE;
                 goto out;
@@ -891,6 +899,7 @@ static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
 static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 
 {
+        struct cfq_io_context *cic;
         unsigned long sl;
 
         WARN_ON(!RB_EMPTY(&cfqq->sort_list));
@@ -906,13 +915,23 @@ static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
         /*
          * task has exited, don't wait
          */
-        if (cfqd->active_cic && !cfqd->active_cic->ioc->task)
+        cic = cfqd->active_cic;
+        if (!cic || !cic->ioc->task)
                 return 0;
 
         cfq_mark_cfqq_must_dispatch(cfqq);
         cfq_mark_cfqq_wait_request(cfqq);
 
         sl = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle);
+
+        /*
+         * we don't want to idle for seeks, but we do want to allow
+         * 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;
+
         mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
         return 1;
 }
@@ -1129,13 +1148,6 @@ cfq_dispatch_requests(request_queue_t *q, int force)
         if (cfqq) {
                 int max_dispatch;
 
-                /*
-                 * if idle window is disabled, allow queue buildup
-                 */
-                if (!cfq_cfqq_idle_window(cfqq) &&
-                    cfqd->rq_in_driver >= cfqd->cfq_max_depth)
-                        return 0;
-
                 cfq_clear_cfqq_must_dispatch(cfqq);
                 cfq_clear_cfqq_wait_request(cfqq);
                 del_timer(&cfqd->idle_slice_timer);
@@ -1185,13 +1197,13 @@ __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio,
                     const int hashval)
 {
         struct hlist_head *hash_list = &cfqd->cfq_hash[hashval];
-        struct hlist_node *entry, *next;
+        struct hlist_node *entry;
+        struct cfq_queue *__cfqq;
 
-        hlist_for_each_safe(entry, next, hash_list) {
-                struct cfq_queue *__cfqq = list_entry_qhash(entry);
+        hlist_for_each_entry(__cfqq, entry, hash_list, cfq_hash) {
                 const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->org_ioprio_class, __cfqq->org_ioprio);
 
-                if (__cfqq->key == key && (__p == prio || prio == CFQ_KEY_ANY))
+                if (__cfqq->key == key && (__p == prio || !prio))
                         return __cfqq;
         }
 
@@ -1572,7 +1584,33 @@ cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic)
         cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples;
 }
 
-#define sample_valid(samples)   ((samples) > 80)
+static void
+cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic,
+                       struct cfq_rq *crq)
+{
+        sector_t sdist;
+        u64 total;
+
+        if (cic->last_request_pos < crq->request->sector)
+                sdist = crq->request->sector - cic->last_request_pos;
+        else
+                sdist = cic->last_request_pos - crq->request->sector;
+
+        /*
+         * Don't allow the seek distance to get too large from the
+         * odd fragment, pagein, etc
+         */
+        if (cic->seek_samples <= 60) /* second&third seek */
+                sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*1024);
+        else
+                sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*64);
+
+        cic->seek_samples = (7*cic->seek_samples + 256) / 8;
+        cic->seek_total = (7*cic->seek_total + (u64)256*sdist) / 8;
+        total = cic->seek_total + (cic->seek_samples/2);
+        do_div(total, cic->seek_samples);
+        cic->seek_mean = (sector_t)total;
+}
 
 /*
  * Disable idle window if the process thinks too long or seeks so much that
@@ -1685,9 +1723,11 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
         cic = crq->io_context;
 
         cfq_update_io_thinktime(cfqd, cic);
+        cfq_update_io_seektime(cfqd, cic, crq);
         cfq_update_idle_window(cfqd, cfqq, cic);
 
         cic->last_queue = jiffies;
+        cic->last_request_pos = crq->request->sector + crq->request->nr_sectors;
 
         if (cfqq == cfqd->active_queue) {
                 /*
@@ -1820,14 +1860,6 @@ static void cfq_prio_boost(struct cfq_queue *cfqq)
                 cfq_resort_rr_list(cfqq, 0);
 }
 
-static inline pid_t cfq_queue_pid(struct task_struct *task, int rw)
-{
-        if (rw == READ || process_sync(task))
-                return task->pid;
-
-        return CFQ_KEY_ASYNC;
-}
-
 static inline int
 __cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                 struct task_struct *task, int rw)
@@ -2226,7 +2258,6 @@ static int cfq_init_queue(request_queue_t *q, elevator_t *e)
         cfqd->cfq_slice[1] = cfq_slice_sync;
         cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
         cfqd->cfq_slice_idle = cfq_slice_idle;
-        cfqd->cfq_max_depth = cfq_max_depth;
 
         return 0;
 out_crqpool:
@@ -2309,7 +2340,6 @@ SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1);
 SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1);
 SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1);
 SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0);
-SHOW_FUNCTION(cfq_max_depth_show, cfqd->cfq_max_depth, 0);
 #undef SHOW_FUNCTION
 
 #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV)                 \
@@ -2338,7 +2368,6 @@ STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1);
 STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1);
 STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1);
 STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0);
-STORE_FUNCTION(cfq_max_depth_store, &cfqd->cfq_max_depth, 1, UINT_MAX, 0);
 #undef STORE_FUNCTION
 
 #define CFQ_ATTR(name) \
@@ -2355,7 +2384,6 @@ static struct elv_fs_entry cfq_attrs[] = {
         CFQ_ATTR(slice_async),
         CFQ_ATTR(slice_async_rq),
         CFQ_ATTR(slice_idle),
-        CFQ_ATTR(max_depth),
         __ATTR_NULL
 };
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ed0ffa673568..d0cac8b58de7 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -63,11 +63,17 @@ struct cfq_io_context {
         struct io_context *ioc;
 
         unsigned long last_end_request;
-        unsigned long last_queue;
+        sector_t last_request_pos;
+        unsigned long last_queue;
+
         unsigned long ttime_total;
         unsigned long ttime_samples;
         unsigned long ttime_mean;
 
+        unsigned int seek_samples;
+        u64 seek_total;
+        sector_t seek_mean;
+
         struct list_head queue_list;
 
         void (*dtor)(struct io_context *); /* destructor */