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nvme: add separate poll queue map

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Adds support for defining a variable number of poll queues, currently
configurable with the 'poll_queues' module parameter. Defaults to
a single poll queue.

And now we finally have poll support without triggering interrupts!

Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2018-11-05 12:44:33 -07:00
parent d1e36282b0
commit 4b04cc6a8f
2 changed files with 81 additions and 18 deletions
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83
drivers/nvme/host/pci.c
View File

@ -86,6 +86,10 @@ MODULE_PARM_DESC(write_queues,
"Number of queues to use for writes. If not set, reads and writes "
"will share a queue set.");
static int poll_queues = 1;
module_param_cb(poll_queues, &queue_count_ops, &poll_queues, 0644);
MODULE_PARM_DESC(poll_queues, "Number of queues to use for polled IO.");
struct nvme_dev;
struct nvme_queue;
@ -94,6 +98,7 @@ static void nvme_dev_disable(struct nvme_dev *dev, bool shutdown);
enum {
NVMEQ_TYPE_READ,
NVMEQ_TYPE_WRITE,
NVMEQ_TYPE_POLL,
NVMEQ_TYPE_NR,
};
@ -202,6 +207,7 @@ struct nvme_queue {
u16 last_cq_head;
u16 qid;
u8 cq_phase;
u8 polled;
u32 *dbbuf_sq_db;
u32 *dbbuf_cq_db;
u32 *dbbuf_sq_ei;
@ -250,7 +256,7 @@ static inline void _nvme_check_size(void)
static unsigned int max_io_queues(void)
{
return num_possible_cpus() + write_queues;
return num_possible_cpus() + write_queues + poll_queues;
}
static unsigned int max_queue_count(void)
@ -500,8 +506,15 @@ static int nvme_pci_map_queues(struct blk_mq_tag_set *set)
offset = queue_irq_offset(dev);
}
/*
* The poll queue(s) doesn't have an IRQ (and hence IRQ
* affinity), so use the regular blk-mq cpu mapping
*/
map->queue_offset = qoff;
if (i != NVMEQ_TYPE_POLL)
blk_mq_pci_map_queues(map, to_pci_dev(dev->dev), offset);
else
blk_mq_map_queues(map);
qoff += map->nr_queues;
offset += map->nr_queues;
}
@ -892,7 +905,7 @@ static blk_status_t nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
* We should not need to do this, but we're still using this to
* ensure we can drain requests on a dying queue.
*/
if (unlikely(nvmeq->cq_vector < 0))
if (unlikely(nvmeq->cq_vector < 0 && !nvmeq->polled))
return BLK_STS_IOERR;
ret = nvme_setup_cmd(ns, req, &cmnd);
@ -921,6 +934,8 @@ out_free_cmd:
static int nvme_rq_flags_to_type(struct request_queue *q, unsigned int flags)
{
if ((flags & REQ_HIPRI) && test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
return NVMEQ_TYPE_POLL;
if ((flags & REQ_OP_MASK) == REQ_OP_READ)
return NVMEQ_TYPE_READ;
@ -1094,7 +1109,10 @@ static int adapter_alloc_cq(struct nvme_dev *dev, u16 qid,
struct nvme_queue *nvmeq, s16 vector)
{
struct nvme_command c;
int flags = NVME_QUEUE_PHYS_CONTIG | NVME_CQ_IRQ_ENABLED;
int flags = NVME_QUEUE_PHYS_CONTIG;
if (vector != -1)
flags |= NVME_CQ_IRQ_ENABLED;
/*
* Note: we (ab)use the fact that the prp fields survive if no data
@ -1106,7 +1124,10 @@ static int adapter_alloc_cq(struct nvme_dev *dev, u16 qid,
c.create_cq.cqid = cpu_to_le16(qid);
c.create_cq.qsize = cpu_to_le16(nvmeq->q_depth - 1);
c.create_cq.cq_flags = cpu_to_le16(flags);
if (vector != -1)
c.create_cq.irq_vector = cpu_to_le16(vector);
else
c.create_cq.irq_vector = 0;
return nvme_submit_sync_cmd(dev->ctrl.admin_q, &c, NULL, 0);
}
@ -1348,13 +1369,14 @@ static int nvme_suspend_queue(struct nvme_queue *nvmeq)
int vector;
spin_lock_irq(&nvmeq->cq_lock);
if (nvmeq->cq_vector == -1) {
if (nvmeq->cq_vector == -1 && !nvmeq->polled) {
spin_unlock_irq(&nvmeq->cq_lock);
return 1;
}
vector = nvmeq->cq_vector;
nvmeq->dev->online_queues--;
nvmeq->cq_vector = -1;
nvmeq->polled = false;
spin_unlock_irq(&nvmeq->cq_lock);
/*
@ -1366,6 +1388,7 @@ static int nvme_suspend_queue(struct nvme_queue *nvmeq)
if (!nvmeq->qid && nvmeq->dev->ctrl.admin_q)
blk_mq_quiesce_queue(nvmeq->dev->ctrl.admin_q);
if (vector != -1)
pci_free_irq(to_pci_dev(nvmeq->dev->dev), vector, nvmeq);
return 0;
@ -1500,7 +1523,7 @@ static void nvme_init_queue(struct nvme_queue *nvmeq, u16 qid)
spin_unlock_irq(&nvmeq->cq_lock);
}
static int nvme_create_queue(struct nvme_queue *nvmeq, int qid)
static int nvme_create_queue(struct nvme_queue *nvmeq, int qid, bool polled)
{
struct nvme_dev *dev = nvmeq->dev;
int result;
@ -1510,7 +1533,11 @@ static int nvme_create_queue(struct nvme_queue *nvmeq, int qid)
* A queue's vector matches the queue identifier unless the controller
* has only one vector available.
*/
if (!polled)
vector = dev->num_vecs == 1 ? 0 : qid;
else
vector = -1;
result = adapter_alloc_cq(dev, qid, nvmeq, vector);
if (result)
return result;
@ -1527,15 +1554,20 @@ static int nvme_create_queue(struct nvme_queue *nvmeq, int qid)
* xxx' warning if the create CQ/SQ command times out.
*/
nvmeq->cq_vector = vector;
nvmeq->polled = polled;
nvme_init_queue(nvmeq, qid);
if (vector != -1) {
result = queue_request_irq(nvmeq);
if (result < 0)
goto release_sq;
}
return result;
release_sq:
nvmeq->cq_vector = -1;
nvmeq->polled = false;
dev->online_queues--;
adapter_delete_sq(dev, qid);
release_cq:
@ -1686,7 +1718,7 @@ static int nvme_pci_configure_admin_queue(struct nvme_dev *dev)
static int nvme_create_io_queues(struct nvme_dev *dev)
{
unsigned i, max;
unsigned i, max, rw_queues;
int ret = 0;
for (i = dev->ctrl.queue_count; i <= dev->max_qid; i++) {
@ -1697,8 +1729,17 @@ static int nvme_create_io_queues(struct nvme_dev *dev)
}
max = min(dev->max_qid, dev->ctrl.queue_count - 1);
if (max != 1 && dev->io_queues[NVMEQ_TYPE_POLL]) {
rw_queues = dev->io_queues[NVMEQ_TYPE_READ] +
dev->io_queues[NVMEQ_TYPE_WRITE];
} else {
rw_queues = max;
}
for (i = dev->online_queues; i <= max; i++) {
ret = nvme_create_queue(&dev->queues[i], i);
bool polled = i > rw_queues;
ret = nvme_create_queue(&dev->queues[i], i, polled);
if (ret)
break;
}
@ -1973,6 +2014,7 @@ static int nvme_setup_host_mem(struct nvme_dev *dev)
static void nvme_calc_io_queues(struct nvme_dev *dev, unsigned int nr_io_queues)
{
unsigned int this_w_queues = write_queues;
unsigned int this_p_queues = poll_queues;
/*
* Setup read/write queue split
@ -1980,9 +2022,28 @@ static void nvme_calc_io_queues(struct nvme_dev *dev, unsigned int nr_io_queues)
if (nr_io_queues == 1) {
dev->io_queues[NVMEQ_TYPE_READ] = 1;
dev->io_queues[NVMEQ_TYPE_WRITE] = 0;
dev->io_queues[NVMEQ_TYPE_POLL] = 0;
return;
}
/*
* Configure number of poll queues, if set
*/
if (this_p_queues) {
/*
* We need at least one queue left. With just one queue, we'll
* have a single shared read/write set.
*/
if (this_p_queues >= nr_io_queues) {
this_w_queues = 0;
this_p_queues = nr_io_queues - 1;
}
dev->io_queues[NVMEQ_TYPE_POLL] = this_p_queues;
nr_io_queues -= this_p_queues;
} else
dev->io_queues[NVMEQ_TYPE_POLL] = 0;
/*
* If 'write_queues' is set, ensure it leaves room for at least
* one read queue
@ -2099,11 +2160,13 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
return -EIO;
dev->num_vecs = result;
dev->max_qid = max(result - 1, 1);
result = max(result - 1, 1);
dev->max_qid = result + dev->io_queues[NVMEQ_TYPE_POLL];
dev_info(dev->ctrl.device, "%d/%d read/write queues\n",
dev_info(dev->ctrl.device, "%d/%d/%d read/write/poll queues\n",
dev->io_queues[NVMEQ_TYPE_READ],
dev->io_queues[NVMEQ_TYPE_WRITE]);
dev->io_queues[NVMEQ_TYPE_WRITE],
dev->io_queues[NVMEQ_TYPE_POLL]);
/*
* Should investigate if there's a performance win from allocating

2
include/linux/blk-mq.h
View File

@ -82,7 +82,7 @@ struct blk_mq_queue_map {
};
enum {
HCTX_MAX_TYPES = 2,
HCTX_MAX_TYPES = 3,
};
struct blk_mq_tag_set {