blk-mq: add blk_mq_delay_queue
Add a blk-mq equivalent to blk_delay_queue so that the scsi layer can ask
to be kicked again after a delay.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Modified by me to kill the unnecessary preempt disable/enable
in the delayed workqueue handler.
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-core.c b/block/blk-core.c
index ae6227f..90b6e63 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -251,8 +251,10 @@
struct blk_mq_hw_ctx *hctx;
int i;
- queue_for_each_hw_ctx(q, hctx, i)
- cancel_delayed_work_sync(&hctx->delayed_work);
+ queue_for_each_hw_ctx(q, hctx, i) {
+ cancel_delayed_work_sync(&hctx->run_work);
+ cancel_delayed_work_sync(&hctx->delay_work);
+ }
} else {
cancel_delayed_work_sync(&q->delay_work);
}
diff --git a/block/blk-mq.c b/block/blk-mq.c
index da38088..0cf52dd 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -640,7 +640,7 @@
if (!async && cpumask_test_cpu(smp_processor_id(), hctx->cpumask))
__blk_mq_run_hw_queue(hctx);
else if (hctx->queue->nr_hw_queues == 1)
- kblockd_schedule_delayed_work(&hctx->delayed_work, 0);
+ kblockd_schedule_delayed_work(&hctx->run_work, 0);
else {
unsigned int cpu;
@@ -651,7 +651,7 @@
* just queue on the first CPU.
*/
cpu = cpumask_first(hctx->cpumask);
- kblockd_schedule_delayed_work_on(cpu, &hctx->delayed_work, 0);
+ kblockd_schedule_delayed_work_on(cpu, &hctx->run_work, 0);
}
}
@@ -675,7 +675,8 @@
void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
{
- cancel_delayed_work(&hctx->delayed_work);
+ cancel_delayed_work(&hctx->run_work);
+ cancel_delayed_work(&hctx->delay_work);
set_bit(BLK_MQ_S_STOPPED, &hctx->state);
}
EXPORT_SYMBOL(blk_mq_stop_hw_queue);
@@ -717,15 +718,46 @@
}
EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);
-static void blk_mq_work_fn(struct work_struct *work)
+static void blk_mq_run_work_fn(struct work_struct *work)
{
struct blk_mq_hw_ctx *hctx;
- hctx = container_of(work, struct blk_mq_hw_ctx, delayed_work.work);
+ hctx = container_of(work, struct blk_mq_hw_ctx, run_work.work);
__blk_mq_run_hw_queue(hctx);
}
+static void blk_mq_delay_work_fn(struct work_struct *work)
+{
+ struct blk_mq_hw_ctx *hctx;
+
+ hctx = container_of(work, struct blk_mq_hw_ctx, delay_work.work);
+
+ if (test_and_clear_bit(BLK_MQ_S_STOPPED, &hctx->state))
+ __blk_mq_run_hw_queue(hctx);
+}
+
+void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
+{
+ unsigned long tmo = msecs_to_jiffies(msecs);
+
+ if (hctx->queue->nr_hw_queues == 1)
+ kblockd_schedule_delayed_work(&hctx->delay_work, tmo);
+ else {
+ unsigned int cpu;
+
+ /*
+ * It'd be great if the workqueue API had a way to pass
+ * in a mask and had some smarts for more clever placement
+ * than the first CPU. Or we could round-robin here. For now,
+ * just queue on the first CPU.
+ */
+ cpu = cpumask_first(hctx->cpumask);
+ kblockd_schedule_delayed_work_on(cpu, &hctx->delay_work, tmo);
+ }
+}
+EXPORT_SYMBOL(blk_mq_delay_queue);
+
static void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx,
struct request *rq, bool at_head)
{
@@ -1179,7 +1211,8 @@
if (node == NUMA_NO_NODE)
node = hctx->numa_node = set->numa_node;
- INIT_DELAYED_WORK(&hctx->delayed_work, blk_mq_work_fn);
+ INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn);
+ INIT_DELAYED_WORK(&hctx->delay_work, blk_mq_delay_work_fn);
spin_lock_init(&hctx->lock);
INIT_LIST_HEAD(&hctx->dispatch);
hctx->queue = q;
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 9ecfab9..ae868e7 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -18,7 +18,8 @@
} ____cacheline_aligned_in_smp;
unsigned long state; /* BLK_MQ_S_* flags */
- struct delayed_work delayed_work;
+ struct delayed_work run_work;
+ struct delayed_work delay_work;
cpumask_var_t cpumask;
unsigned long flags; /* BLK_MQ_F_* flags */
@@ -158,6 +159,7 @@
void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx);
void blk_mq_stop_hw_queues(struct request_queue *q);
void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async);
+void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs);
/*
* Driver command data is immediately after the request. So subtract request