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authorLinus Torvalds <torvalds@linux-foundation.org>2015-11-10 17:23:49 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-10 17:23:49 -0800
commit3419b45039c6b799c974a8019361c045e7ca232c (patch)
tree36a63602036cc50f34fadcbd5d5d8fca94e44297 /block
parent01504f5e9e071f1dde1062e3be15f54d4555308f (diff)
parentc1c534609fe8a859f9c8108a5591e6e8a97e34d1 (diff)
downloadlinux-sh-3419b45039c6b799c974a8019361c045e7ca232c.tar.gz
Merge branch 'for-4.4/io-poll' of git://git.kernel.dk/linux-block
Pull block IO poll support from Jens Axboe: "Various groups have been doing experimentation around IO polling for (really) fast devices. The code has been reviewed and has been sitting on the side for a few releases, but this is now good enough for coordinated benchmarking and further experimentation. Currently O_DIRECT sync read/write are supported. A framework is in the works that allows scalable stats tracking so we can auto-tune this. And we'll add libaio support as well soon. Fow now, it's an opt-in feature for test purposes" * 'for-4.4/io-poll' of git://git.kernel.dk/linux-block: direct-io: be sure to assign dio->bio_bdev for both paths directio: add block polling support NVMe: add blk polling support block: add block polling support blk-mq: return tag/queue combo in the make_request_fn handlers block: change ->make_request_fn() and users to return a queue cookie
Diffstat (limited to 'block')
-rw-r--r--block/blk-core.c67
-rw-r--r--block/blk-mq-sysfs.c10
-rw-r--r--block/blk-mq.c59
-rw-r--r--block/blk-sysfs.c35
4 files changed, 138 insertions, 33 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 590cca21c24a..2bbf08cd2900 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -809,7 +809,7 @@ blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
}
EXPORT_SYMBOL(blk_init_queue_node);
-static void blk_queue_bio(struct request_queue *q, struct bio *bio);
+static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio);
struct request_queue *
blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
@@ -1678,7 +1678,7 @@ void init_request_from_bio(struct request *req, struct bio *bio)
blk_rq_bio_prep(req->q, req, bio);
}
-static void blk_queue_bio(struct request_queue *q, struct bio *bio)
+static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
{
const bool sync = !!(bio->bi_rw & REQ_SYNC);
struct blk_plug *plug;
@@ -1698,7 +1698,7 @@ static void blk_queue_bio(struct request_queue *q, struct bio *bio)
if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
bio->bi_error = -EIO;
bio_endio(bio);
- return;
+ return BLK_QC_T_NONE;
}
if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) {
@@ -1713,7 +1713,7 @@ static void blk_queue_bio(struct request_queue *q, struct bio *bio)
*/
if (!blk_queue_nomerges(q)) {
if (blk_attempt_plug_merge(q, bio, &request_count, NULL))
- return;
+ return BLK_QC_T_NONE;
} else
request_count = blk_plug_queued_count(q);
@@ -1791,6 +1791,8 @@ get_rq:
out_unlock:
spin_unlock_irq(q->queue_lock);
}
+
+ return BLK_QC_T_NONE;
}
/*
@@ -1996,12 +1998,13 @@ end_io:
* a lower device by calling into generic_make_request recursively, which
* means the bio should NOT be touched after the call to ->make_request_fn.
*/
-void generic_make_request(struct bio *bio)
+blk_qc_t generic_make_request(struct bio *bio)
{
struct bio_list bio_list_on_stack;
+ blk_qc_t ret = BLK_QC_T_NONE;
if (!generic_make_request_checks(bio))
- return;
+ goto out;
/*
* We only want one ->make_request_fn to be active at a time, else
@@ -2015,7 +2018,7 @@ void generic_make_request(struct bio *bio)
*/
if (current->bio_list) {
bio_list_add(current->bio_list, bio);
- return;
+ goto out;
}
/* following loop may be a bit non-obvious, and so deserves some
@@ -2040,7 +2043,7 @@ void generic_make_request(struct bio *bio)
if (likely(blk_queue_enter(q, __GFP_DIRECT_RECLAIM) == 0)) {
- q->make_request_fn(q, bio);
+ ret = q->make_request_fn(q, bio);
blk_queue_exit(q);
@@ -2053,6 +2056,9 @@ void generic_make_request(struct bio *bio)
}
} while (bio);
current->bio_list = NULL; /* deactivate */
+
+out:
+ return ret;
}
EXPORT_SYMBOL(generic_make_request);
@@ -2066,7 +2072,7 @@ EXPORT_SYMBOL(generic_make_request);
* interfaces; @bio must be presetup and ready for I/O.
*
*/
-void submit_bio(int rw, struct bio *bio)
+blk_qc_t submit_bio(int rw, struct bio *bio)
{
bio->bi_rw |= rw;
@@ -2100,7 +2106,7 @@ void submit_bio(int rw, struct bio *bio)
}
}
- generic_make_request(bio);
+ return generic_make_request(bio);
}
EXPORT_SYMBOL(submit_bio);
@@ -3306,6 +3312,47 @@ void blk_finish_plug(struct blk_plug *plug)
}
EXPORT_SYMBOL(blk_finish_plug);
+bool blk_poll(struct request_queue *q, blk_qc_t cookie)
+{
+ struct blk_plug *plug;
+ long state;
+
+ if (!q->mq_ops || !q->mq_ops->poll || !blk_qc_t_valid(cookie) ||
+ !test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
+ return false;
+
+ plug = current->plug;
+ if (plug)
+ blk_flush_plug_list(plug, false);
+
+ state = current->state;
+ while (!need_resched()) {
+ unsigned int queue_num = blk_qc_t_to_queue_num(cookie);
+ struct blk_mq_hw_ctx *hctx = q->queue_hw_ctx[queue_num];
+ int ret;
+
+ hctx->poll_invoked++;
+
+ ret = q->mq_ops->poll(hctx, blk_qc_t_to_tag(cookie));
+ if (ret > 0) {
+ hctx->poll_success++;
+ set_current_state(TASK_RUNNING);
+ return true;
+ }
+
+ if (signal_pending_state(state, current))
+ set_current_state(TASK_RUNNING);
+
+ if (current->state == TASK_RUNNING)
+ return true;
+ if (ret < 0)
+ break;
+ cpu_relax();
+ }
+
+ return false;
+}
+
#ifdef CONFIG_PM
/**
* blk_pm_runtime_init - Block layer runtime PM initialization routine
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 6f57a110289c..1cf18784c5cf 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -174,6 +174,11 @@ static ssize_t blk_mq_sysfs_rq_list_show(struct blk_mq_ctx *ctx, char *page)
return ret;
}
+static ssize_t blk_mq_hw_sysfs_poll_show(struct blk_mq_hw_ctx *hctx, char *page)
+{
+ return sprintf(page, "invoked=%lu, success=%lu\n", hctx->poll_invoked, hctx->poll_success);
+}
+
static ssize_t blk_mq_hw_sysfs_queued_show(struct blk_mq_hw_ctx *hctx,
char *page)
{
@@ -295,6 +300,10 @@ static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_cpus = {
.attr = {.name = "cpu_list", .mode = S_IRUGO },
.show = blk_mq_hw_sysfs_cpus_show,
};
+static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_poll = {
+ .attr = {.name = "io_poll", .mode = S_IRUGO },
+ .show = blk_mq_hw_sysfs_poll_show,
+};
static struct attribute *default_hw_ctx_attrs[] = {
&blk_mq_hw_sysfs_queued.attr,
@@ -304,6 +313,7 @@ static struct attribute *default_hw_ctx_attrs[] = {
&blk_mq_hw_sysfs_tags.attr,
&blk_mq_hw_sysfs_cpus.attr,
&blk_mq_hw_sysfs_active.attr,
+ &blk_mq_hw_sysfs_poll.attr,
NULL,
};
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 694f8703f83c..86bd5b25288e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1198,7 +1198,7 @@ static struct request *blk_mq_map_request(struct request_queue *q,
return rq;
}
-static int blk_mq_direct_issue_request(struct request *rq)
+static int blk_mq_direct_issue_request(struct request *rq, blk_qc_t *cookie)
{
int ret;
struct request_queue *q = rq->q;
@@ -1209,6 +1209,7 @@ static int blk_mq_direct_issue_request(struct request *rq)
.list = NULL,
.last = 1
};
+ blk_qc_t new_cookie = blk_tag_to_qc_t(rq->tag, hctx->queue_num);
/*
* For OK queue, we are done. For error, kill it. Any other
@@ -1216,18 +1217,21 @@ static int blk_mq_direct_issue_request(struct request *rq)
* would have done
*/
ret = q->mq_ops->queue_rq(hctx, &bd);
- if (ret == BLK_MQ_RQ_QUEUE_OK)
+ if (ret == BLK_MQ_RQ_QUEUE_OK) {
+ *cookie = new_cookie;
return 0;
- else {
- __blk_mq_requeue_request(rq);
+ }
- if (ret == BLK_MQ_RQ_QUEUE_ERROR) {
- rq->errors = -EIO;
- blk_mq_end_request(rq, rq->errors);
- return 0;
- }
- return -1;
+ __blk_mq_requeue_request(rq);
+
+ if (ret == BLK_MQ_RQ_QUEUE_ERROR) {
+ *cookie = BLK_QC_T_NONE;
+ rq->errors = -EIO;
+ blk_mq_end_request(rq, rq->errors);
+ return 0;
}
+
+ return -1;
}
/*
@@ -1235,7 +1239,7 @@ static int blk_mq_direct_issue_request(struct request *rq)
* but will attempt to bypass the hctx queueing if we can go straight to
* hardware for SYNC IO.
*/
-static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
+static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
{
const int is_sync = rw_is_sync(bio->bi_rw);
const int is_flush_fua = bio->bi_rw & (REQ_FLUSH | REQ_FUA);
@@ -1244,12 +1248,13 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
unsigned int request_count = 0;
struct blk_plug *plug;
struct request *same_queue_rq = NULL;
+ blk_qc_t cookie;
blk_queue_bounce(q, &bio);
if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
bio_io_error(bio);
- return;
+ return BLK_QC_T_NONE;
}
blk_queue_split(q, &bio, q->bio_split);
@@ -1257,13 +1262,15 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
if (!is_flush_fua && !blk_queue_nomerges(q)) {
if (blk_attempt_plug_merge(q, bio, &request_count,
&same_queue_rq))
- return;
+ return BLK_QC_T_NONE;
} else
request_count = blk_plug_queued_count(q);
rq = blk_mq_map_request(q, bio, &data);
if (unlikely(!rq))
- return;
+ return BLK_QC_T_NONE;
+
+ cookie = blk_tag_to_qc_t(rq->tag, data.hctx->queue_num);
if (unlikely(is_flush_fua)) {
blk_mq_bio_to_request(rq, bio);
@@ -1302,11 +1309,11 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
old_rq = rq;
blk_mq_put_ctx(data.ctx);
if (!old_rq)
- return;
- if (!blk_mq_direct_issue_request(old_rq))
- return;
+ goto done;
+ if (!blk_mq_direct_issue_request(old_rq, &cookie))
+ goto done;
blk_mq_insert_request(old_rq, false, true, true);
- return;
+ goto done;
}
if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) {
@@ -1320,13 +1327,15 @@ run_queue:
blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua);
}
blk_mq_put_ctx(data.ctx);
+done:
+ return cookie;
}
/*
* Single hardware queue variant. This will attempt to use any per-process
* plug for merging and IO deferral.
*/
-static void blk_sq_make_request(struct request_queue *q, struct bio *bio)
+static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
{
const int is_sync = rw_is_sync(bio->bi_rw);
const int is_flush_fua = bio->bi_rw & (REQ_FLUSH | REQ_FUA);
@@ -1334,23 +1343,26 @@ static void blk_sq_make_request(struct request_queue *q, struct bio *bio)
unsigned int request_count = 0;
struct blk_map_ctx data;
struct request *rq;
+ blk_qc_t cookie;
blk_queue_bounce(q, &bio);
if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
bio_io_error(bio);
- return;
+ return BLK_QC_T_NONE;
}
blk_queue_split(q, &bio, q->bio_split);
if (!is_flush_fua && !blk_queue_nomerges(q) &&
blk_attempt_plug_merge(q, bio, &request_count, NULL))
- return;
+ return BLK_QC_T_NONE;
rq = blk_mq_map_request(q, bio, &data);
if (unlikely(!rq))
- return;
+ return BLK_QC_T_NONE;
+
+ cookie = blk_tag_to_qc_t(rq->tag, data.hctx->queue_num);
if (unlikely(is_flush_fua)) {
blk_mq_bio_to_request(rq, bio);
@@ -1374,7 +1386,7 @@ static void blk_sq_make_request(struct request_queue *q, struct bio *bio)
}
list_add_tail(&rq->queuelist, &plug->mq_list);
blk_mq_put_ctx(data.ctx);
- return;
+ return cookie;
}
if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) {
@@ -1389,6 +1401,7 @@ run_queue:
}
blk_mq_put_ctx(data.ctx);
+ return cookie;
}
/*
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 31849e328b45..565b8dac5782 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -317,6 +317,34 @@ queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
return ret;
}
+static ssize_t queue_poll_show(struct request_queue *q, char *page)
+{
+ return queue_var_show(test_bit(QUEUE_FLAG_POLL, &q->queue_flags), page);
+}
+
+static ssize_t queue_poll_store(struct request_queue *q, const char *page,
+ size_t count)
+{
+ unsigned long poll_on;
+ ssize_t ret;
+
+ if (!q->mq_ops || !q->mq_ops->poll)
+ return -EINVAL;
+
+ ret = queue_var_store(&poll_on, page, count);
+ if (ret < 0)
+ return ret;
+
+ spin_lock_irq(q->queue_lock);
+ if (poll_on)
+ queue_flag_set(QUEUE_FLAG_POLL, q);
+ else
+ queue_flag_clear(QUEUE_FLAG_POLL, q);
+ spin_unlock_irq(q->queue_lock);
+
+ return ret;
+}
+
static struct queue_sysfs_entry queue_requests_entry = {
.attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
.show = queue_requests_show,
@@ -442,6 +470,12 @@ static struct queue_sysfs_entry queue_random_entry = {
.store = queue_store_random,
};
+static struct queue_sysfs_entry queue_poll_entry = {
+ .attr = {.name = "io_poll", .mode = S_IRUGO | S_IWUSR },
+ .show = queue_poll_show,
+ .store = queue_poll_store,
+};
+
static struct attribute *default_attrs[] = {
&queue_requests_entry.attr,
&queue_ra_entry.attr,
@@ -466,6 +500,7 @@ static struct attribute *default_attrs[] = {
&queue_rq_affinity_entry.attr,
&queue_iostats_entry.attr,
&queue_random_entry.attr,
+ &queue_poll_entry.attr,
NULL,
};