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authorJens Axboe <jaxboe@fusionio.com>2011-03-10 08:52:07 +0100
committerJens Axboe <jaxboe@fusionio.com>2011-03-10 08:52:07 +0100
commit7eaceaccab5f40bbfda044629a6298616aeaed50 (patch)
tree33954d12f63e25a47eb6d86ef3d3d0a5e62bf752 /block
parent73c101011926c5832e6e141682180c4debe2cf45 (diff)
downloadlinux-0-day-7eaceaccab5f40bbfda044629a6298616aeaed50.tar.gz
block: remove per-queue plugging
Code has been converted over to the new explicit on-stack plugging, and delay users have been converted to use the new API for that. So lets kill off the old plugging along with aops->sync_page(). Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'block')
-rw-r--r--block/blk-core.c173
-rw-r--r--block/blk-exec.c4
-rw-r--r--block/blk-flush.c3
-rw-r--r--block/blk-settings.c8
-rw-r--r--block/blk-throttle.c1
-rw-r--r--block/blk.h2
-rw-r--r--block/cfq-iosched.c8
-rw-r--r--block/deadline-iosched.c9
-rw-r--r--block/elevator.c43
-rw-r--r--block/noop-iosched.c8
10 files changed, 26 insertions, 233 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 6efb55c..82a4589 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -198,6 +198,19 @@ void blk_dump_rq_flags(struct request *rq, char *msg)
}
EXPORT_SYMBOL(blk_dump_rq_flags);
+/*
+ * Make sure that plugs that were pending when this function was entered,
+ * are now complete and requests pushed to the queue.
+*/
+static inline void queue_sync_plugs(struct request_queue *q)
+{
+ /*
+ * If the current process is plugged and has barriers submitted,
+ * we will livelock if we don't unplug first.
+ */
+ blk_flush_plug(current);
+}
+
static void blk_delay_work(struct work_struct *work)
{
struct request_queue *q;
@@ -224,137 +237,6 @@ void blk_delay_queue(struct request_queue *q, unsigned long msecs)
}
EXPORT_SYMBOL(blk_delay_queue);
-/*
- * "plug" the device if there are no outstanding requests: this will
- * force the transfer to start only after we have put all the requests
- * on the list.
- *
- * This is called with interrupts off and no requests on the queue and
- * with the queue lock held.
- */
-void blk_plug_device(struct request_queue *q)
-{
- WARN_ON(!irqs_disabled());
-
- /*
- * don't plug a stopped queue, it must be paired with blk_start_queue()
- * which will restart the queueing
- */
- if (blk_queue_stopped(q))
- return;
-
- if (!queue_flag_test_and_set(QUEUE_FLAG_PLUGGED, q)) {
- mod_timer(&q->unplug_timer, jiffies + q->unplug_delay);
- trace_block_plug(q);
- }
-}
-EXPORT_SYMBOL(blk_plug_device);
-
-/**
- * blk_plug_device_unlocked - plug a device without queue lock held
- * @q: The &struct request_queue to plug
- *
- * Description:
- * Like @blk_plug_device(), but grabs the queue lock and disables
- * interrupts.
- **/
-void blk_plug_device_unlocked(struct request_queue *q)
-{
- unsigned long flags;
-
- spin_lock_irqsave(q->queue_lock, flags);
- blk_plug_device(q);
- spin_unlock_irqrestore(q->queue_lock, flags);
-}
-EXPORT_SYMBOL(blk_plug_device_unlocked);
-
-/*
- * remove the queue from the plugged list, if present. called with
- * queue lock held and interrupts disabled.
- */
-int blk_remove_plug(struct request_queue *q)
-{
- WARN_ON(!irqs_disabled());
-
- if (!queue_flag_test_and_clear(QUEUE_FLAG_PLUGGED, q))
- return 0;
-
- del_timer(&q->unplug_timer);
- return 1;
-}
-EXPORT_SYMBOL(blk_remove_plug);
-
-/*
- * remove the plug and let it rip..
- */
-void __generic_unplug_device(struct request_queue *q)
-{
- if (unlikely(blk_queue_stopped(q)))
- return;
- if (!blk_remove_plug(q) && !blk_queue_nonrot(q))
- return;
-
- q->request_fn(q);
-}
-
-/**
- * generic_unplug_device - fire a request queue
- * @q: The &struct request_queue in question
- *
- * Description:
- * Linux uses plugging to build bigger requests queues before letting
- * the device have at them. If a queue is plugged, the I/O scheduler
- * is still adding and merging requests on the queue. Once the queue
- * gets unplugged, the request_fn defined for the queue is invoked and
- * transfers started.
- **/
-void generic_unplug_device(struct request_queue *q)
-{
- if (blk_queue_plugged(q)) {
- spin_lock_irq(q->queue_lock);
- __generic_unplug_device(q);
- spin_unlock_irq(q->queue_lock);
- }
-}
-EXPORT_SYMBOL(generic_unplug_device);
-
-static void blk_backing_dev_unplug(struct backing_dev_info *bdi,
- struct page *page)
-{
- struct request_queue *q = bdi->unplug_io_data;
-
- blk_unplug(q);
-}
-
-void blk_unplug_work(struct work_struct *work)
-{
- struct request_queue *q =
- container_of(work, struct request_queue, unplug_work);
-
- trace_block_unplug_io(q);
- q->unplug_fn(q);
-}
-
-void blk_unplug_timeout(unsigned long data)
-{
- struct request_queue *q = (struct request_queue *)data;
-
- trace_block_unplug_timer(q);
- kblockd_schedule_work(q, &q->unplug_work);
-}
-
-void blk_unplug(struct request_queue *q)
-{
- /*
- * devices don't necessarily have an ->unplug_fn defined
- */
- if (q->unplug_fn) {
- trace_block_unplug_io(q);
- q->unplug_fn(q);
- }
-}
-EXPORT_SYMBOL(blk_unplug);
-
/**
* blk_start_queue - restart a previously stopped queue
* @q: The &struct request_queue in question
@@ -389,7 +271,6 @@ EXPORT_SYMBOL(blk_start_queue);
**/
void blk_stop_queue(struct request_queue *q)
{
- blk_remove_plug(q);
cancel_delayed_work(&q->delay_work);
queue_flag_set(QUEUE_FLAG_STOPPED, q);
}
@@ -411,11 +292,10 @@ EXPORT_SYMBOL(blk_stop_queue);
*/
void blk_sync_queue(struct request_queue *q)
{
- del_timer_sync(&q->unplug_timer);
del_timer_sync(&q->timeout);
- cancel_work_sync(&q->unplug_work);
throtl_shutdown_timer_wq(q);
cancel_delayed_work_sync(&q->delay_work);
+ queue_sync_plugs(q);
}
EXPORT_SYMBOL(blk_sync_queue);
@@ -430,14 +310,9 @@ EXPORT_SYMBOL(blk_sync_queue);
*/
void __blk_run_queue(struct request_queue *q)
{
- blk_remove_plug(q);
-
if (unlikely(blk_queue_stopped(q)))
return;
- if (elv_queue_empty(q))
- return;
-
/*
* Only recurse once to avoid overrunning the stack, let the unplug
* handling reinvoke the handler shortly if we already got there.
@@ -445,10 +320,8 @@ void __blk_run_queue(struct request_queue *q)
if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
q->request_fn(q);
queue_flag_clear(QUEUE_FLAG_REENTER, q);
- } else {
- queue_flag_set(QUEUE_FLAG_PLUGGED, q);
- kblockd_schedule_work(q, &q->unplug_work);
- }
+ } else
+ queue_delayed_work(kblockd_workqueue, &q->delay_work, 0);
}
EXPORT_SYMBOL(__blk_run_queue);
@@ -535,8 +408,6 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
if (!q)
return NULL;
- q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug;
- q->backing_dev_info.unplug_io_data = q;
q->backing_dev_info.ra_pages =
(VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
q->backing_dev_info.state = 0;
@@ -556,13 +427,11 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
laptop_mode_timer_fn, (unsigned long) q);
- init_timer(&q->unplug_timer);
setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
INIT_LIST_HEAD(&q->timeout_list);
INIT_LIST_HEAD(&q->flush_queue[0]);
INIT_LIST_HEAD(&q->flush_queue[1]);
INIT_LIST_HEAD(&q->flush_data_in_flight);
- INIT_WORK(&q->unplug_work, blk_unplug_work);
INIT_DELAYED_WORK(&q->delay_work, blk_delay_work);
kobject_init(&q->kobj, &blk_queue_ktype);
@@ -652,7 +521,6 @@ blk_init_allocated_queue_node(struct request_queue *q, request_fn_proc *rfn,
q->request_fn = rfn;
q->prep_rq_fn = NULL;
q->unprep_rq_fn = NULL;
- q->unplug_fn = generic_unplug_device;
q->queue_flags = QUEUE_FLAG_DEFAULT;
q->queue_lock = lock;
@@ -910,8 +778,8 @@ out:
}
/*
- * No available requests for this queue, unplug the device and wait for some
- * requests to become available.
+ * No available requests for this queue, wait for some requests to become
+ * available.
*
* Called with q->queue_lock held, and returns with it unlocked.
*/
@@ -932,7 +800,6 @@ static struct request *get_request_wait(struct request_queue *q, int rw_flags,
trace_block_sleeprq(q, bio, rw_flags & 1);
- __generic_unplug_device(q);
spin_unlock_irq(q->queue_lock);
io_schedule();
@@ -1058,7 +925,7 @@ static void add_acct_request(struct request_queue *q, struct request *rq,
int where)
{
drive_stat_acct(rq, 1);
- __elv_add_request(q, rq, where, 0);
+ __elv_add_request(q, rq, where);
}
/**
@@ -2798,7 +2665,7 @@ static void flush_plug_list(struct blk_plug *plug)
/*
* rq is already accounted, so use raw insert
*/
- __elv_add_request(q, rq, ELEVATOR_INSERT_SORT, 0);
+ __elv_add_request(q, rq, ELEVATOR_INSERT_SORT);
}
if (q) {
diff --git a/block/blk-exec.c b/block/blk-exec.c
index cf1456a..81e3181 100644
--- a/block/blk-exec.c
+++ b/block/blk-exec.c
@@ -54,8 +54,8 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
rq->end_io = done;
WARN_ON(irqs_disabled());
spin_lock_irq(q->queue_lock);
- __elv_add_request(q, rq, where, 1);
- __generic_unplug_device(q);
+ __elv_add_request(q, rq, where);
+ __blk_run_queue(q);
/* the queue is stopped so it won't be plugged+unplugged */
if (rq->cmd_type == REQ_TYPE_PM_RESUME)
q->request_fn(q);
diff --git a/block/blk-flush.c b/block/blk-flush.c
index 1e2aa8a..671fa9d 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -194,7 +194,6 @@ static void flush_end_io(struct request *flush_rq, int error)
{
struct request_queue *q = flush_rq->q;
struct list_head *running = &q->flush_queue[q->flush_running_idx];
- bool was_empty = elv_queue_empty(q);
bool queued = false;
struct request *rq, *n;
@@ -213,7 +212,7 @@ static void flush_end_io(struct request *flush_rq, int error)
}
/* after populating an empty queue, kick it to avoid stall */
- if (queued && was_empty)
+ if (queued)
__blk_run_queue(q);
}
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 36c8c1f..c8d6892 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -164,14 +164,6 @@ void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn)
blk_queue_congestion_threshold(q);
q->nr_batching = BLK_BATCH_REQ;
- q->unplug_thresh = 4; /* hmm */
- q->unplug_delay = msecs_to_jiffies(3); /* 3 milliseconds */
- if (q->unplug_delay == 0)
- q->unplug_delay = 1;
-
- q->unplug_timer.function = blk_unplug_timeout;
- q->unplug_timer.data = (unsigned long)q;
-
blk_set_default_limits(&q->limits);
blk_queue_max_hw_sectors(q, BLK_SAFE_MAX_SECTORS);
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index a89043a..b8dcdc26 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -800,7 +800,6 @@ out:
if (nr_disp) {
while((bio = bio_list_pop(&bio_list_on_stack)))
generic_make_request(bio);
- blk_unplug(q);
}
return nr_disp;
}
diff --git a/block/blk.h b/block/blk.h
index 284b500..49d21af 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -18,8 +18,6 @@ int blk_rq_append_bio(struct request_queue *q, struct request *rq,
void blk_dequeue_request(struct request *rq);
void __blk_queue_free_tags(struct request_queue *q);
-void blk_unplug_work(struct work_struct *work);
-void blk_unplug_timeout(unsigned long data);
void blk_rq_timed_out_timer(unsigned long data);
void blk_delete_timer(struct request *);
void blk_add_timer(struct request *);
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 3202c7e..ef63153 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -499,13 +499,6 @@ static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
}
}
-static int cfq_queue_empty(struct request_queue *q)
-{
- struct cfq_data *cfqd = q->elevator->elevator_data;
-
- return !cfqd->rq_queued;
-}
-
/*
* 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
@@ -4061,7 +4054,6 @@ static struct elevator_type iosched_cfq = {
.elevator_add_req_fn = cfq_insert_request,
.elevator_activate_req_fn = cfq_activate_request,
.elevator_deactivate_req_fn = cfq_deactivate_request,
- .elevator_queue_empty_fn = cfq_queue_empty,
.elevator_completed_req_fn = cfq_completed_request,
.elevator_former_req_fn = elv_rb_former_request,
.elevator_latter_req_fn = elv_rb_latter_request,
diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c
index b547cbc..5139c0e 100644
--- a/block/deadline-iosched.c
+++ b/block/deadline-iosched.c
@@ -326,14 +326,6 @@ dispatch_request:
return 1;
}
-static int deadline_queue_empty(struct request_queue *q)
-{
- struct deadline_data *dd = q->elevator->elevator_data;
-
- return list_empty(&dd->fifo_list[WRITE])
- && list_empty(&dd->fifo_list[READ]);
-}
-
static void deadline_exit_queue(struct elevator_queue *e)
{
struct deadline_data *dd = e->elevator_data;
@@ -445,7 +437,6 @@ static struct elevator_type iosched_deadline = {
.elevator_merge_req_fn = deadline_merged_requests,
.elevator_dispatch_fn = deadline_dispatch_requests,
.elevator_add_req_fn = deadline_add_request,
- .elevator_queue_empty_fn = deadline_queue_empty,
.elevator_former_req_fn = elv_rb_former_request,
.elevator_latter_req_fn = elv_rb_latter_request,
.elevator_init_fn = deadline_init_queue,
diff --git a/block/elevator.c b/block/elevator.c
index 2571392..3ea2082 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -619,21 +619,12 @@ void elv_quiesce_end(struct request_queue *q)
void elv_insert(struct request_queue *q, struct request *rq, int where)
{
- int unplug_it = 1;
-
trace_block_rq_insert(q, rq);
rq->q = q;
switch (where) {
case ELEVATOR_INSERT_REQUEUE:
- /*
- * Most requeues happen because of a busy condition,
- * don't force unplug of the queue for that case.
- * Clear unplug_it and fall through.
- */
- unplug_it = 0;
-
case ELEVATOR_INSERT_FRONT:
rq->cmd_flags |= REQ_SOFTBARRIER;
list_add(&rq->queuelist, &q->queue_head);
@@ -679,24 +670,14 @@ void elv_insert(struct request_queue *q, struct request *rq, int where)
rq->cmd_flags |= REQ_SOFTBARRIER;
blk_insert_flush(rq);
break;
-
default:
printk(KERN_ERR "%s: bad insertion point %d\n",
__func__, where);
BUG();
}
-
- if (unplug_it && blk_queue_plugged(q)) {
- int nrq = q->rq.count[BLK_RW_SYNC] + q->rq.count[BLK_RW_ASYNC]
- - queue_in_flight(q);
-
- if (nrq >= q->unplug_thresh)
- __generic_unplug_device(q);
- }
}
-void __elv_add_request(struct request_queue *q, struct request *rq, int where,
- int plug)
+void __elv_add_request(struct request_queue *q, struct request *rq, int where)
{
BUG_ON(rq->cmd_flags & REQ_ON_PLUG);
@@ -711,38 +692,20 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where,
where == ELEVATOR_INSERT_SORT)
where = ELEVATOR_INSERT_BACK;
- if (plug)
- blk_plug_device(q);
-
elv_insert(q, rq, where);
}
EXPORT_SYMBOL(__elv_add_request);
-void elv_add_request(struct request_queue *q, struct request *rq, int where,
- int plug)
+void elv_add_request(struct request_queue *q, struct request *rq, int where)
{
unsigned long flags;
spin_lock_irqsave(q->queue_lock, flags);
- __elv_add_request(q, rq, where, plug);
+ __elv_add_request(q, rq, where);
spin_unlock_irqrestore(q->queue_lock, flags);
}
EXPORT_SYMBOL(elv_add_request);
-int elv_queue_empty(struct request_queue *q)
-{
- struct elevator_queue *e = q->elevator;
-
- if (!list_empty(&q->queue_head))
- return 0;
-
- if (e->ops->elevator_queue_empty_fn)
- return e->ops->elevator_queue_empty_fn(q);
-
- return 1;
-}
-EXPORT_SYMBOL(elv_queue_empty);
-
struct request *elv_latter_request(struct request_queue *q, struct request *rq)
{
struct elevator_queue *e = q->elevator;
diff --git a/block/noop-iosched.c b/block/noop-iosched.c
index 232c4b3..06389e9 100644
--- a/block/noop-iosched.c
+++ b/block/noop-iosched.c
@@ -39,13 +39,6 @@ static void noop_add_request(struct request_queue *q, struct request *rq)
list_add_tail(&rq->queuelist, &nd->queue);
}
-static int noop_queue_empty(struct request_queue *q)
-{
- struct noop_data *nd = q->elevator->elevator_data;
-
- return list_empty(&nd->queue);
-}
-
static struct request *
noop_former_request(struct request_queue *q, struct request *rq)
{
@@ -90,7 +83,6 @@ static struct elevator_type elevator_noop = {
.elevator_merge_req_fn = noop_merged_requests,
.elevator_dispatch_fn = noop_dispatch,
.elevator_add_req_fn = noop_add_request,
- .elevator_queue_empty_fn = noop_queue_empty,
.elevator_former_req_fn = noop_former_request,
.elevator_latter_req_fn = noop_latter_request,
.elevator_init_fn = noop_init_queue,