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blk-mq: add blk_mq_delay_queue

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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>
This commit is contained in:
Christoph Hellwig 2014-04-16 10:48:08 -06:00 committed by Jens Axboe
parent 1b4a325858
commit 70f4db639c
3 changed files with 46 additions and 9 deletions
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6
block/blk-core.c
View file

@ -251,8 +251,10 @@ void blk_sync_queue(struct request_queue *q)
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);
}

45
block/blk-mq.c
View file

@ -640,7 +640,7 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
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 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
* 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 @@ EXPORT_SYMBOL(blk_mq_run_queues);
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 @@ void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async)
}
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 @@ static int blk_mq_init_hw_queues(struct request_queue *q,
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;

4
include/linux/blk-mq.h
View file

@ -18,7 +18,8 @@ struct blk_mq_hw_ctx {
} ____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_stop_hw_queue(struct blk_mq_hw_ctx *hctx);
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