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-rw-r--r--block/as-iosched.c13
-rw-r--r--block/cfq-iosched.c98
-rw-r--r--block/deadline-iosched.c13
-rw-r--r--block/elevator.c63
-rw-r--r--block/ll_rw_blk.c26
-rw-r--r--block/noop-iosched.c7
6 files changed, 139 insertions, 81 deletions
diff --git a/block/as-iosched.c b/block/as-iosched.c
index ed336ab453ba..0c750393be4a 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -1647,17 +1647,17 @@ static void as_exit_queue(elevator_t *e)
* initialize elevator private data (as_data), and alloc a arq for
* each request on the free lists
*/
-static int as_init_queue(request_queue_t *q, elevator_t *e)
+static void *as_init_queue(request_queue_t *q, elevator_t *e)
{
struct as_data *ad;
int i;
if (!arq_pool)
- return -ENOMEM;
+ return NULL;
ad = kmalloc_node(sizeof(*ad), GFP_KERNEL, q->node);
if (!ad)
- return -ENOMEM;
+ return NULL;
memset(ad, 0, sizeof(*ad));
ad->q = q; /* Identify what queue the data belongs to */
@@ -1666,7 +1666,7 @@ static int as_init_queue(request_queue_t *q, elevator_t *e)
GFP_KERNEL, q->node);
if (!ad->hash) {
kfree(ad);
- return -ENOMEM;
+ return NULL;
}
ad->arq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
@@ -1674,7 +1674,7 @@ static int as_init_queue(request_queue_t *q, elevator_t *e)
if (!ad->arq_pool) {
kfree(ad->hash);
kfree(ad);
- return -ENOMEM;
+ return NULL;
}
/* anticipatory scheduling helpers */
@@ -1695,14 +1695,13 @@ static int as_init_queue(request_queue_t *q, elevator_t *e)
ad->antic_expire = default_antic_expire;
ad->batch_expire[REQ_SYNC] = default_read_batch_expire;
ad->batch_expire[REQ_ASYNC] = default_write_batch_expire;
- e->elevator_data = ad;
ad->current_batch_expires = jiffies + ad->batch_expire[REQ_SYNC];
ad->write_batch_count = ad->batch_expire[REQ_ASYNC] / 10;
if (ad->write_batch_count < 2)
ad->write_batch_count = 2;
- return 0;
+ return ad;
}
/*
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 01c416ba8437..6200d9b9af28 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -33,7 +33,7 @@ static int cfq_slice_idle = HZ / 70;
#define CFQ_KEY_ASYNC (0)
-static DEFINE_RWLOCK(cfq_exit_lock);
+static DEFINE_SPINLOCK(cfq_exit_lock);
/*
* for the hash of cfqq inside the cfqd
@@ -128,6 +128,7 @@ struct cfq_data {
mempool_t *crq_pool;
int rq_in_driver;
+ int hw_tag;
/*
* schedule slice state info
@@ -495,10 +496,13 @@ static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
/*
* if queue was preempted, just add to front to be fair. busy_rr
- * isn't sorted.
+ * isn't sorted, but insert at the back for fairness.
*/
if (preempted || list == &cfqd->busy_rr) {
- list_add(&cfqq->cfq_list, list);
+ if (preempted)
+ list = list->prev;
+
+ list_add_tail(&cfqq->cfq_list, list);
return;
}
@@ -658,6 +662,15 @@ static void cfq_activate_request(request_queue_t *q, struct request *rq)
struct cfq_data *cfqd = q->elevator->elevator_data;
cfqd->rq_in_driver++;
+
+ /*
+ * If the depth is larger 1, it really could be queueing. But lets
+ * make the mark a little higher - idling could still be good for
+ * low queueing, and a low queueing number could also just indicate
+ * a SCSI mid layer like behaviour where limit+1 is often seen.
+ */
+ if (!cfqd->hw_tag && cfqd->rq_in_driver > 4)
+ cfqd->hw_tag = 1;
}
static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
@@ -873,6 +886,13 @@ static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
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))
+ 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
@@ -1278,7 +1298,7 @@ static void cfq_exit_io_context(struct io_context *ioc)
/*
* put the reference this task is holding to the various queues
*/
- read_lock_irqsave(&cfq_exit_lock, flags);
+ spin_lock_irqsave(&cfq_exit_lock, flags);
n = rb_first(&ioc->cic_root);
while (n != NULL) {
@@ -1288,7 +1308,7 @@ static void cfq_exit_io_context(struct io_context *ioc)
n = rb_next(n);
}
- read_unlock_irqrestore(&cfq_exit_lock, flags);
+ spin_unlock_irqrestore(&cfq_exit_lock, flags);
}
static struct cfq_io_context *
@@ -1297,17 +1317,12 @@ 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);
if (cic) {
- RB_CLEAR(&cic->rb_node);
- cic->key = NULL;
- cic->cfqq[ASYNC] = NULL;
- cic->cfqq[SYNC] = NULL;
+ memset(cic, 0, sizeof(*cic));
+ RB_CLEAR_COLOR(&cic->rb_node);
cic->last_end_request = jiffies;
- cic->ttime_total = 0;
- cic->ttime_samples = 0;
- cic->ttime_mean = 0;
+ INIT_LIST_HEAD(&cic->queue_list);
cic->dtor = cfq_free_io_context;
cic->exit = cfq_exit_io_context;
- INIT_LIST_HEAD(&cic->queue_list);
atomic_inc(&ioc_count);
}
@@ -1394,17 +1409,17 @@ static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio)
struct cfq_io_context *cic;
struct rb_node *n;
- write_lock(&cfq_exit_lock);
+ spin_lock(&cfq_exit_lock);
n = rb_first(&ioc->cic_root);
while (n != NULL) {
cic = rb_entry(n, struct cfq_io_context, rb_node);
-
+
changed_ioprio(cic);
n = rb_next(n);
}
- write_unlock(&cfq_exit_lock);
+ spin_unlock(&cfq_exit_lock);
return 0;
}
@@ -1452,7 +1467,8 @@ retry:
* set ->slice_left to allow preemption for a new process
*/
cfqq->slice_left = 2 * cfqd->cfq_slice_idle;
- cfq_mark_cfqq_idle_window(cfqq);
+ if (!cfqd->hw_tag)
+ cfq_mark_cfqq_idle_window(cfqq);
cfq_mark_cfqq_prio_changed(cfqq);
cfq_init_prio_data(cfqq);
}
@@ -1469,9 +1485,10 @@ out:
static void
cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic)
{
- read_lock(&cfq_exit_lock);
+ spin_lock(&cfq_exit_lock);
rb_erase(&cic->rb_node, &ioc->cic_root);
- read_unlock(&cfq_exit_lock);
+ list_del_init(&cic->queue_list);
+ spin_unlock(&cfq_exit_lock);
kmem_cache_free(cfq_ioc_pool, cic);
atomic_dec(&ioc_count);
}
@@ -1539,11 +1556,11 @@ restart:
BUG();
}
- read_lock(&cfq_exit_lock);
+ spin_lock(&cfq_exit_lock);
rb_link_node(&cic->rb_node, parent, p);
rb_insert_color(&cic->rb_node, &ioc->cic_root);
list_add(&cic->queue_list, &cfqd->cic_list);
- read_unlock(&cfq_exit_lock);
+ spin_unlock(&cfq_exit_lock);
}
/*
@@ -1642,7 +1659,7 @@ 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)
+ if (!cic->ioc->task || !cfqd->cfq_slice_idle || cfqd->hw_tag)
enable_idle = 0;
else if (sample_valid(cic->ttime_samples)) {
if (cic->ttime_mean > cfqd->cfq_slice_idle)
@@ -1733,14 +1750,24 @@ cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
+ cic = crq->io_context;
+
/*
* 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 (!cfq_crq_is_sync(crq)) {
+ /*
+ * 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);
+ }
return;
-
- cic = crq->io_context;
+ }
cfq_update_io_thinktime(cfqd, cic);
cfq_update_io_seektime(cfqd, cic, crq);
@@ -2158,10 +2185,9 @@ static void cfq_idle_class_timer(unsigned long data)
* race with a non-idle queue, reset timer
*/
end = cfqd->last_end_request + CFQ_IDLE_GRACE;
- if (!time_after_eq(jiffies, end)) {
- cfqd->idle_class_timer.expires = end;
- add_timer(&cfqd->idle_class_timer);
- } else
+ if (!time_after_eq(jiffies, end))
+ mod_timer(&cfqd->idle_class_timer, end);
+ else
cfq_schedule_dispatch(cfqd);
spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
@@ -2181,7 +2207,7 @@ static void cfq_exit_queue(elevator_t *e)
cfq_shutdown_timer_wq(cfqd);
- write_lock(&cfq_exit_lock);
+ spin_lock(&cfq_exit_lock);
spin_lock_irq(q->queue_lock);
if (cfqd->active_queue)
@@ -2204,7 +2230,7 @@ static void cfq_exit_queue(elevator_t *e)
}
spin_unlock_irq(q->queue_lock);
- write_unlock(&cfq_exit_lock);
+ spin_unlock(&cfq_exit_lock);
cfq_shutdown_timer_wq(cfqd);
@@ -2214,14 +2240,14 @@ static void cfq_exit_queue(elevator_t *e)
kfree(cfqd);
}
-static int cfq_init_queue(request_queue_t *q, elevator_t *e)
+static void *cfq_init_queue(request_queue_t *q, elevator_t *e)
{
struct cfq_data *cfqd;
int i;
cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL);
if (!cfqd)
- return -ENOMEM;
+ return NULL;
memset(cfqd, 0, sizeof(*cfqd));
@@ -2251,8 +2277,6 @@ static int cfq_init_queue(request_queue_t *q, elevator_t *e)
for (i = 0; i < CFQ_QHASH_ENTRIES; i++)
INIT_HLIST_HEAD(&cfqd->cfq_hash[i]);
- e->elevator_data = cfqd;
-
cfqd->queue = q;
cfqd->max_queued = q->nr_requests / 4;
@@ -2279,14 +2303,14 @@ static int cfq_init_queue(request_queue_t *q, elevator_t *e)
cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
cfqd->cfq_slice_idle = cfq_slice_idle;
- return 0;
+ return cfqd;
out_crqpool:
kfree(cfqd->cfq_hash);
out_cfqhash:
kfree(cfqd->crq_hash);
out_crqhash:
kfree(cfqd);
- return -ENOMEM;
+ return NULL;
}
static void cfq_slab_kill(void)
diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c
index 06962d8402a3..c94de8e12fbf 100644
--- a/block/deadline-iosched.c
+++ b/block/deadline-iosched.c
@@ -612,24 +612,24 @@ static void deadline_exit_queue(elevator_t *e)
* initialize elevator private data (deadline_data), and alloc a drq for
* each request on the free lists
*/
-static int deadline_init_queue(request_queue_t *q, elevator_t *e)
+static void *deadline_init_queue(request_queue_t *q, elevator_t *e)
{
struct deadline_data *dd;
int i;
if (!drq_pool)
- return -ENOMEM;
+ return NULL;
dd = kmalloc_node(sizeof(*dd), GFP_KERNEL, q->node);
if (!dd)
- return -ENOMEM;
+ return NULL;
memset(dd, 0, sizeof(*dd));
dd->hash = kmalloc_node(sizeof(struct list_head)*DL_HASH_ENTRIES,
GFP_KERNEL, q->node);
if (!dd->hash) {
kfree(dd);
- return -ENOMEM;
+ return NULL;
}
dd->drq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
@@ -637,7 +637,7 @@ static int deadline_init_queue(request_queue_t *q, elevator_t *e)
if (!dd->drq_pool) {
kfree(dd->hash);
kfree(dd);
- return -ENOMEM;
+ return NULL;
}
for (i = 0; i < DL_HASH_ENTRIES; i++)
@@ -652,8 +652,7 @@ static int deadline_init_queue(request_queue_t *q, elevator_t *e)
dd->writes_starved = writes_starved;
dd->front_merges = 1;
dd->fifo_batch = fifo_batch;
- e->elevator_data = dd;
- return 0;
+ return dd;
}
static void deadline_put_request(request_queue_t *q, struct request *rq)
diff --git a/block/elevator.c b/block/elevator.c
index 29825792cbd5..a0afdd317cef 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -121,16 +121,16 @@ static struct elevator_type *elevator_get(const char *name)
return e;
}
-static int elevator_attach(request_queue_t *q, struct elevator_queue *eq)
+static void *elevator_init_queue(request_queue_t *q, struct elevator_queue *eq)
{
- int ret = 0;
+ return eq->ops->elevator_init_fn(q, eq);
+}
+static void elevator_attach(request_queue_t *q, struct elevator_queue *eq,
+ void *data)
+{
q->elevator = eq;
-
- if (eq->ops->elevator_init_fn)
- ret = eq->ops->elevator_init_fn(q, eq);
-
- return ret;
+ eq->elevator_data = data;
}
static char chosen_elevator[16];
@@ -181,6 +181,7 @@ int elevator_init(request_queue_t *q, char *name)
struct elevator_type *e = NULL;
struct elevator_queue *eq;
int ret = 0;
+ void *data;
INIT_LIST_HEAD(&q->queue_head);
q->last_merge = NULL;
@@ -202,10 +203,13 @@ int elevator_init(request_queue_t *q, char *name)
if (!eq)
return -ENOMEM;
- ret = elevator_attach(q, eq);
- if (ret)
+ data = elevator_init_queue(q, eq);
+ if (!data) {
kobject_put(&eq->kobj);
+ return -ENOMEM;
+ }
+ elevator_attach(q, eq, data);
return ret;
}
@@ -333,6 +337,7 @@ void elv_insert(request_queue_t *q, struct request *rq, int where)
{
struct list_head *pos;
unsigned ordseq;
+ int unplug_it = 1;
blk_add_trace_rq(q, rq, BLK_TA_INSERT);
@@ -399,6 +404,11 @@ void elv_insert(request_queue_t *q, struct request *rq, int where)
}
list_add_tail(&rq->queuelist, pos);
+ /*
+ * most requeues happen because of a busy condition, don't
+ * force unplug of the queue for that case.
+ */
+ unplug_it = 0;
break;
default:
@@ -407,7 +417,7 @@ void elv_insert(request_queue_t *q, struct request *rq, int where)
BUG();
}
- if (blk_queue_plugged(q)) {
+ if (unplug_it && blk_queue_plugged(q)) {
int nrq = q->rq.count[READ] + q->rq.count[WRITE]
- q->in_flight;
@@ -716,13 +726,16 @@ int elv_register_queue(struct request_queue *q)
return error;
}
+static void __elv_unregister_queue(elevator_t *e)
+{
+ kobject_uevent(&e->kobj, KOBJ_REMOVE);
+ kobject_del(&e->kobj);
+}
+
void elv_unregister_queue(struct request_queue *q)
{
- if (q) {
- elevator_t *e = q->elevator;
- kobject_uevent(&e->kobj, KOBJ_REMOVE);
- kobject_del(&e->kobj);
- }
+ if (q)
+ __elv_unregister_queue(q->elevator);
}
int elv_register(struct elevator_type *e)
@@ -774,6 +787,7 @@ EXPORT_SYMBOL_GPL(elv_unregister);
static int elevator_switch(request_queue_t *q, struct elevator_type *new_e)
{
elevator_t *old_elevator, *e;
+ void *data;
/*
* Allocate new elevator
@@ -782,6 +796,12 @@ static int elevator_switch(request_queue_t *q, struct elevator_type *new_e)
if (!e)
return 0;
+ data = elevator_init_queue(q, e);
+ if (!data) {
+ kobject_put(&e->kobj);
+ return 0;
+ }
+
/*
* Turn on BYPASS and drain all requests w/ elevator private data
*/
@@ -800,19 +820,19 @@ static int elevator_switch(request_queue_t *q, struct elevator_type *new_e)
elv_drain_elevator(q);
}
- spin_unlock_irq(q->queue_lock);
-
/*
- * unregister old elevator data
+ * Remember old elevator.
*/
- elv_unregister_queue(q);
old_elevator = q->elevator;
/*
* attach and start new elevator
*/
- if (elevator_attach(q, e))
- goto fail;
+ elevator_attach(q, e, data);
+
+ spin_unlock_irq(q->queue_lock);
+
+ __elv_unregister_queue(old_elevator);
if (elv_register_queue(q))
goto fail_register;
@@ -831,7 +851,6 @@ fail_register:
*/
elevator_exit(e);
e = NULL;
-fail:
q->elevator = old_elevator;
elv_register_queue(q);
clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 1755c053fd68..7eb36c53f4b7 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -1732,8 +1732,21 @@ void blk_run_queue(struct request_queue *q)
spin_lock_irqsave(q->queue_lock, flags);
blk_remove_plug(q);
- if (!elv_queue_empty(q))
- q->request_fn(q);
+
+ /*
+ * Only recurse once to avoid overrunning the stack, let the unplug
+ * handling reinvoke the handler shortly if we already got there.
+ */
+ if (!elv_queue_empty(q)) {
+ if (!test_and_set_bit(QUEUE_FLAG_REENTER, &q->queue_flags)) {
+ q->request_fn(q);
+ clear_bit(QUEUE_FLAG_REENTER, &q->queue_flags);
+ } else {
+ blk_plug_device(q);
+ kblockd_schedule_work(&q->unplug_work);
+ }
+ }
+
spin_unlock_irqrestore(q->queue_lock, flags);
}
EXPORT_SYMBOL(blk_run_queue);
@@ -3385,7 +3398,7 @@ static int blk_cpu_notify(struct notifier_block *self, unsigned long action,
}
-static struct notifier_block __devinitdata blk_cpu_notifier = {
+static struct notifier_block blk_cpu_notifier = {
.notifier_call = blk_cpu_notify,
};
@@ -3439,7 +3452,12 @@ void end_that_request_last(struct request *req, int uptodate)
if (unlikely(laptop_mode) && blk_fs_request(req))
laptop_io_completion();
- if (disk && blk_fs_request(req)) {
+ /*
+ * Account IO completion. bar_rq isn't accounted as a normal
+ * IO on queueing nor completion. Accounting the containing
+ * request is enough.
+ */
+ if (disk && blk_fs_request(req) && req != &req->q->bar_rq) {
unsigned long duration = jiffies - req->start_time;
const int rw = rq_data_dir(req);
diff --git a/block/noop-iosched.c b/block/noop-iosched.c
index f370e4a7fe6d..56a7c620574f 100644
--- a/block/noop-iosched.c
+++ b/block/noop-iosched.c
@@ -65,16 +65,15 @@ noop_latter_request(request_queue_t *q, struct request *rq)
return list_entry(rq->queuelist.next, struct request, queuelist);
}
-static int noop_init_queue(request_queue_t *q, elevator_t *e)
+static void *noop_init_queue(request_queue_t *q, elevator_t *e)
{
struct noop_data *nd;
nd = kmalloc(sizeof(*nd), GFP_KERNEL);
if (!nd)
- return -ENOMEM;
+ return NULL;
INIT_LIST_HEAD(&nd->queue);
- e->elevator_data = nd;
- return 0;
+ return nd;
}
static void noop_exit_queue(elevator_t *e)