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-rw-r--r--block/blk-throttle.c39
1 files changed, 27 insertions, 12 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 381b09bb562b..e36cc10a346c 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -20,6 +20,11 @@ static int throtl_quantum = 32;
/* Throttling is performed over 100ms slice and after that slice is renewed */
static unsigned long throtl_slice = HZ/10; /* 100 ms */
+/* A workqueue to queue throttle related work */
+static struct workqueue_struct *kthrotld_workqueue;
+static void throtl_schedule_delayed_work(struct throtl_data *td,
+ unsigned long delay);
+
struct throtl_rb_root {
struct rb_root rb;
struct rb_node *left;
@@ -168,7 +173,15 @@ static struct throtl_grp * throtl_find_alloc_tg(struct throtl_data *td,
* tree of blkg (instead of traversing through hash list all
* the time.
*/
- tg = tg_of_blkg(blkiocg_lookup_group(blkcg, key));
+
+ /*
+ * This is the common case when there are no blkio cgroups.
+ * Avoid lookup in this case
+ */
+ if (blkcg == &blkio_root_cgroup)
+ tg = &td->root_tg;
+ else
+ tg = tg_of_blkg(blkiocg_lookup_group(blkcg, key));
/* Fill in device details for root group */
if (tg && !tg->blkg.dev && bdi->dev && dev_name(bdi->dev)) {
@@ -337,10 +350,9 @@ static void throtl_schedule_next_dispatch(struct throtl_data *td)
update_min_dispatch_time(st);
if (time_before_eq(st->min_disptime, jiffies))
- throtl_schedule_delayed_work(td->queue, 0);
+ throtl_schedule_delayed_work(td, 0);
else
- throtl_schedule_delayed_work(td->queue,
- (st->min_disptime - jiffies));
+ throtl_schedule_delayed_work(td, (st->min_disptime - jiffies));
}
static inline void
@@ -807,10 +819,10 @@ void blk_throtl_work(struct work_struct *work)
}
/* Call with queue lock held */
-void throtl_schedule_delayed_work(struct request_queue *q, unsigned long delay)
+static void
+throtl_schedule_delayed_work(struct throtl_data *td, unsigned long delay)
{
- struct throtl_data *td = q->td;
struct delayed_work *dwork = &td->throtl_work;
if (total_nr_queued(td) > 0) {
@@ -819,12 +831,11 @@ void throtl_schedule_delayed_work(struct request_queue *q, unsigned long delay)
* Cancel that and schedule a new one.
*/
__cancel_delayed_work(dwork);
- kblockd_schedule_delayed_work(q, dwork, delay);
+ queue_delayed_work(kthrotld_workqueue, dwork, delay);
throtl_log(td, "schedule work. delay=%lu jiffies=%lu",
delay, jiffies);
}
}
-EXPORT_SYMBOL(throtl_schedule_delayed_work);
static void
throtl_destroy_tg(struct throtl_data *td, struct throtl_grp *tg)
@@ -912,7 +923,7 @@ static void throtl_update_blkio_group_read_bps(void *key,
smp_mb__after_atomic_inc();
/* Schedule a work now to process the limit change */
- throtl_schedule_delayed_work(td->queue, 0);
+ throtl_schedule_delayed_work(td, 0);
}
static void throtl_update_blkio_group_write_bps(void *key,
@@ -926,7 +937,7 @@ static void throtl_update_blkio_group_write_bps(void *key,
smp_mb__before_atomic_inc();
atomic_inc(&td->limits_changed);
smp_mb__after_atomic_inc();
- throtl_schedule_delayed_work(td->queue, 0);
+ throtl_schedule_delayed_work(td, 0);
}
static void throtl_update_blkio_group_read_iops(void *key,
@@ -940,7 +951,7 @@ static void throtl_update_blkio_group_read_iops(void *key,
smp_mb__before_atomic_inc();
atomic_inc(&td->limits_changed);
smp_mb__after_atomic_inc();
- throtl_schedule_delayed_work(td->queue, 0);
+ throtl_schedule_delayed_work(td, 0);
}
static void throtl_update_blkio_group_write_iops(void *key,
@@ -954,7 +965,7 @@ static void throtl_update_blkio_group_write_iops(void *key,
smp_mb__before_atomic_inc();
atomic_inc(&td->limits_changed);
smp_mb__after_atomic_inc();
- throtl_schedule_delayed_work(td->queue, 0);
+ throtl_schedule_delayed_work(td, 0);
}
void throtl_shutdown_timer_wq(struct request_queue *q)
@@ -1127,6 +1138,10 @@ void blk_throtl_exit(struct request_queue *q)
static int __init throtl_init(void)
{
+ kthrotld_workqueue = alloc_workqueue("kthrotld", WQ_MEM_RECLAIM, 0);
+ if (!kthrotld_workqueue)
+ panic("Failed to create kthrotld\n");
+
blkio_policy_register(&blkio_policy_throtl);
return 0;
}