Merge branch 'for-3.16/blk-mq-tagging' into for-3.16/core
Signed-off-by: Jens Axboe <axboe@fb.com>
Conflicts:
block/blk-mq-tag.c
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 8145b5b..99a60a8 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -208,6 +208,11 @@
return blk_mq_tag_sysfs_show(hctx->tags, page);
}
+static ssize_t blk_mq_hw_sysfs_active_show(struct blk_mq_hw_ctx *hctx, char *page)
+{
+ return sprintf(page, "%u\n", atomic_read(&hctx->nr_active));
+}
+
static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
{
unsigned int i, first = 1;
@@ -267,6 +272,10 @@
.attr = {.name = "dispatched", .mode = S_IRUGO },
.show = blk_mq_hw_sysfs_dispatched_show,
};
+static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_active = {
+ .attr = {.name = "active", .mode = S_IRUGO },
+ .show = blk_mq_hw_sysfs_active_show,
+};
static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_pending = {
.attr = {.name = "pending", .mode = S_IRUGO },
.show = blk_mq_hw_sysfs_rq_list_show,
@@ -287,6 +296,7 @@
&blk_mq_hw_sysfs_pending.attr,
&blk_mq_hw_sysfs_tags.attr,
&blk_mq_hw_sysfs_cpus.attr,
+ &blk_mq_hw_sysfs_active.attr,
NULL,
};
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 03ce6a11..e6b3fba 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -7,13 +7,12 @@
#include "blk-mq.h"
#include "blk-mq-tag.h"
-void blk_mq_wait_for_tags(struct blk_mq_tags *tags, struct blk_mq_hw_ctx *hctx,
- bool reserved)
+void blk_mq_wait_for_tags(struct blk_mq_hw_ctx *hctx, bool reserved)
{
int tag, zero = 0;
- tag = blk_mq_get_tag(tags, hctx, &zero, __GFP_WAIT, reserved);
- blk_mq_put_tag(tags, tag, &zero);
+ tag = blk_mq_get_tag(hctx, &zero, __GFP_WAIT, reserved);
+ blk_mq_put_tag(hctx, tag, &zero);
}
static bool bt_has_free_tags(struct blk_mq_bitmap_tags *bt)
@@ -40,6 +39,84 @@
return bt_has_free_tags(&tags->bitmap_tags);
}
+static inline void bt_index_inc(unsigned int *index)
+{
+ *index = (*index + 1) & (BT_WAIT_QUEUES - 1);
+}
+
+/*
+ * If a previously inactive queue goes active, bump the active user count.
+ */
+bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
+{
+ if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state) &&
+ !test_and_set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
+ atomic_inc(&hctx->tags->active_queues);
+
+ return true;
+}
+
+/*
+ * If a previously busy queue goes inactive, potential waiters could now
+ * be allowed to queue. Wake them up and check.
+ */
+void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
+{
+ struct blk_mq_tags *tags = hctx->tags;
+ struct blk_mq_bitmap_tags *bt;
+ int i, wake_index;
+
+ if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
+ return;
+
+ atomic_dec(&tags->active_queues);
+
+ /*
+ * Will only throttle depth on non-reserved tags
+ */
+ bt = &tags->bitmap_tags;
+ wake_index = bt->wake_index;
+ for (i = 0; i < BT_WAIT_QUEUES; i++) {
+ struct bt_wait_state *bs = &bt->bs[wake_index];
+
+ if (waitqueue_active(&bs->wait))
+ wake_up(&bs->wait);
+
+ bt_index_inc(&wake_index);
+ }
+}
+
+/*
+ * For shared tag users, we track the number of currently active users
+ * and attempt to provide a fair share of the tag depth for each of them.
+ */
+static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
+ struct blk_mq_bitmap_tags *bt)
+{
+ unsigned int depth, users;
+
+ if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_SHARED))
+ return true;
+ if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
+ return true;
+
+ /*
+ * Don't try dividing an ant
+ */
+ if (bt->depth == 1)
+ return true;
+
+ users = atomic_read(&hctx->tags->active_queues);
+ if (!users)
+ return true;
+
+ /*
+ * Allow at least some tags
+ */
+ depth = max((bt->depth + users - 1) / users, 4U);
+ return atomic_read(&hctx->nr_active) < depth;
+}
+
static int __bt_get_word(struct blk_align_bitmap *bm, unsigned int last_tag)
{
int tag, org_last_tag, end;
@@ -78,11 +155,15 @@
* multiple users will tend to stick to different cachelines, at least
* until the map is exhausted.
*/
-static int __bt_get(struct blk_mq_bitmap_tags *bt, unsigned int *tag_cache)
+static int __bt_get(struct blk_mq_hw_ctx *hctx, struct blk_mq_bitmap_tags *bt,
+ unsigned int *tag_cache)
{
unsigned int last_tag, org_last_tag;
int index, i, tag;
+ if (!hctx_may_queue(hctx, bt))
+ return -1;
+
last_tag = org_last_tag = *tag_cache;
index = TAG_TO_INDEX(bt, last_tag);
@@ -117,11 +198,6 @@
return tag;
}
-static inline void bt_index_inc(unsigned int *index)
-{
- *index = (*index + 1) & (BT_WAIT_QUEUES - 1);
-}
-
static struct bt_wait_state *bt_wait_ptr(struct blk_mq_bitmap_tags *bt,
struct blk_mq_hw_ctx *hctx)
{
@@ -142,7 +218,7 @@
DEFINE_WAIT(wait);
int tag;
- tag = __bt_get(bt, last_tag);
+ tag = __bt_get(hctx, bt, last_tag);
if (tag != -1)
return tag;
@@ -156,7 +232,7 @@
was_empty = list_empty(&wait.task_list);
prepare_to_wait(&bs->wait, &wait, TASK_UNINTERRUPTIBLE);
- tag = __bt_get(bt, last_tag);
+ tag = __bt_get(hctx, bt, last_tag);
if (tag != -1)
break;
@@ -200,14 +276,13 @@
return tag;
}
-unsigned int blk_mq_get_tag(struct blk_mq_tags *tags,
- struct blk_mq_hw_ctx *hctx, unsigned int *last_tag,
+unsigned int blk_mq_get_tag(struct blk_mq_hw_ctx *hctx, unsigned int *last_tag,
gfp_t gfp, bool reserved)
{
if (!reserved)
- return __blk_mq_get_tag(tags, hctx, last_tag, gfp);
+ return __blk_mq_get_tag(hctx->tags, hctx, last_tag, gfp);
- return __blk_mq_get_reserved_tag(tags, gfp);
+ return __blk_mq_get_reserved_tag(hctx->tags, gfp);
}
static struct bt_wait_state *bt_wake_ptr(struct blk_mq_bitmap_tags *bt)
@@ -265,9 +340,11 @@
bt_clear_tag(&tags->breserved_tags, tag);
}
-void blk_mq_put_tag(struct blk_mq_tags *tags, unsigned int tag,
+void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, unsigned int tag,
unsigned int *last_tag)
{
+ struct blk_mq_tags *tags = hctx->tags;
+
if (tag >= tags->nr_reserved_tags) {
const int real_tag = tag - tags->nr_reserved_tags;
@@ -465,6 +542,7 @@
res = bt_unused_tags(&tags->breserved_tags);
page += sprintf(page, "nr_free=%u, nr_reserved=%u\n", free, res);
+ page += sprintf(page, "active_queues=%u\n", atomic_read(&tags->active_queues));
return page - orig_page;
}
diff --git a/block/blk-mq-tag.h b/block/blk-mq-tag.h
index 9014269..e144f68 100644
--- a/block/blk-mq-tag.h
+++ b/block/blk-mq-tag.h
@@ -35,6 +35,8 @@
unsigned int nr_tags;
unsigned int nr_reserved_tags;
+ atomic_t active_queues;
+
struct blk_mq_bitmap_tags bitmap_tags;
struct blk_mq_bitmap_tags breserved_tags;
@@ -46,9 +48,9 @@
extern struct blk_mq_tags *blk_mq_init_tags(unsigned int nr_tags, unsigned int reserved_tags, int node);
extern void blk_mq_free_tags(struct blk_mq_tags *tags);
-extern unsigned int blk_mq_get_tag(struct blk_mq_tags *tags, struct blk_mq_hw_ctx *hctx, unsigned int *last_tag, gfp_t gfp, bool reserved);
-extern void blk_mq_wait_for_tags(struct blk_mq_tags *tags, struct blk_mq_hw_ctx *hctx, bool reserved);
-extern void blk_mq_put_tag(struct blk_mq_tags *tags, unsigned int tag, unsigned int *last_tag);
+extern unsigned int blk_mq_get_tag(struct blk_mq_hw_ctx *hctx, unsigned int *last_tag, gfp_t gfp, bool reserved);
+extern void blk_mq_wait_for_tags(struct blk_mq_hw_ctx *hctx, bool reserved);
+extern void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, unsigned int tag, unsigned int *last_tag);
extern void blk_mq_tag_busy_iter(struct blk_mq_tags *tags, void (*fn)(void *data, unsigned long *), void *data);
extern bool blk_mq_has_free_tags(struct blk_mq_tags *tags);
extern ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page);
@@ -65,4 +67,23 @@
BLK_MQ_TAG_MAX = BLK_MQ_TAG_FAIL - 1,
};
+extern bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *);
+extern void __blk_mq_tag_idle(struct blk_mq_hw_ctx *);
+
+static inline bool blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
+{
+ if (!(hctx->flags & BLK_MQ_F_TAG_SHARED))
+ return false;
+
+ return __blk_mq_tag_busy(hctx);
+}
+
+static inline void blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
+{
+ if (!(hctx->flags & BLK_MQ_F_TAG_SHARED))
+ return;
+
+ __blk_mq_tag_idle(hctx);
+}
+
#endif
diff --git a/block/blk-mq.c b/block/blk-mq.c
index e862c44..0fbef7e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -99,9 +99,16 @@
struct request *rq;
unsigned int tag;
- tag = blk_mq_get_tag(hctx->tags, hctx, &ctx->last_tag, gfp, reserved);
+ tag = blk_mq_get_tag(hctx, &ctx->last_tag, gfp, reserved);
if (tag != BLK_MQ_TAG_FAIL) {
rq = hctx->tags->rqs[tag];
+
+ rq->cmd_flags = 0;
+ if (blk_mq_tag_busy(hctx)) {
+ rq->cmd_flags = REQ_MQ_INFLIGHT;
+ atomic_inc(&hctx->nr_active);
+ }
+
rq->tag = tag;
return rq;
}
@@ -209,7 +216,7 @@
/* csd/requeue_work/fifo_time is initialized before use */
rq->q = q;
rq->mq_ctx = ctx;
- rq->cmd_flags = rw_flags;
+ rq->cmd_flags |= rw_flags;
rq->cmd_type = 0;
/* do not touch atomic flags, it needs atomic ops against the timer */
rq->cpu = -1;
@@ -281,7 +288,7 @@
break;
}
- blk_mq_wait_for_tags(hctx->tags, hctx, reserved);
+ blk_mq_wait_for_tags(hctx, reserved);
} while (1);
return rq;
@@ -322,8 +329,11 @@
const int tag = rq->tag;
struct request_queue *q = rq->q;
+ if (rq->cmd_flags & REQ_MQ_INFLIGHT)
+ atomic_dec(&hctx->nr_active);
+
clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
- blk_mq_put_tag(hctx->tags, tag, &ctx->last_tag);
+ blk_mq_put_tag(hctx, tag, &ctx->last_tag);
blk_mq_queue_exit(q);
}
@@ -590,8 +600,13 @@
queue_for_each_hw_ctx(q, hctx, i)
blk_mq_hw_ctx_check_timeout(hctx, &next, &next_set);
- if (next_set)
- mod_timer(&q->timeout, round_jiffies_up(next));
+ if (next_set) {
+ next = blk_rq_timeout(round_jiffies_up(next));
+ mod_timer(&q->timeout, next);
+ } else {
+ queue_for_each_hw_ctx(q, hctx, i)
+ blk_mq_tag_idle(hctx);
+ }
}
/*
@@ -1501,6 +1516,56 @@
}
}
+static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set)
+{
+ struct blk_mq_hw_ctx *hctx;
+ struct request_queue *q;
+ bool shared;
+ int i;
+
+ if (set->tag_list.next == set->tag_list.prev)
+ shared = false;
+ else
+ shared = true;
+
+ list_for_each_entry(q, &set->tag_list, tag_set_list) {
+ blk_mq_freeze_queue(q);
+
+ queue_for_each_hw_ctx(q, hctx, i) {
+ if (shared)
+ hctx->flags |= BLK_MQ_F_TAG_SHARED;
+ else
+ hctx->flags &= ~BLK_MQ_F_TAG_SHARED;
+ }
+ blk_mq_unfreeze_queue(q);
+ }
+}
+
+static void blk_mq_del_queue_tag_set(struct request_queue *q)
+{
+ struct blk_mq_tag_set *set = q->tag_set;
+
+ blk_mq_freeze_queue(q);
+
+ mutex_lock(&set->tag_list_lock);
+ list_del_init(&q->tag_set_list);
+ blk_mq_update_tag_set_depth(set);
+ mutex_unlock(&set->tag_list_lock);
+
+ blk_mq_unfreeze_queue(q);
+}
+
+static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
+ struct request_queue *q)
+{
+ q->tag_set = set;
+
+ mutex_lock(&set->tag_list_lock);
+ list_add_tail(&q->tag_set_list, &set->tag_list);
+ blk_mq_update_tag_set_depth(set);
+ mutex_unlock(&set->tag_list_lock);
+}
+
struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
{
struct blk_mq_hw_ctx **hctxs;
@@ -1526,6 +1591,7 @@
if (!zalloc_cpumask_var(&hctxs[i]->cpumask, GFP_KERNEL))
goto err_hctxs;
+ atomic_set(&hctxs[i]->nr_active, 0);
hctxs[i]->numa_node = NUMA_NO_NODE;
hctxs[i]->queue_num = i;
}
@@ -1578,6 +1644,8 @@
list_add_tail(&q->all_q_node, &all_q_list);
mutex_unlock(&all_q_mutex);
+ blk_mq_add_queue_tag_set(set, q);
+
return q;
err_flush_rq:
@@ -1605,6 +1673,8 @@
struct blk_mq_hw_ctx *hctx;
int i;
+ blk_mq_del_queue_tag_set(q);
+
queue_for_each_hw_ctx(q, hctx, i) {
kfree(hctx->ctxs);
blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier);
@@ -1696,6 +1766,9 @@
goto out_unwind;
}
+ mutex_init(&set->tag_list_lock);
+ INIT_LIST_HEAD(&set->tag_list);
+
return 0;
out_unwind:
diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index 4487456..43e8b51 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -166,6 +166,17 @@
}
EXPORT_SYMBOL_GPL(blk_abort_request);
+unsigned long blk_rq_timeout(unsigned long timeout)
+{
+ unsigned long maxt;
+
+ maxt = round_jiffies_up(jiffies + BLK_MAX_TIMEOUT);
+ if (time_after(timeout, maxt))
+ timeout = maxt;
+
+ return timeout;
+}
+
/**
* blk_add_timer - Start timeout timer for a single request
* @req: request that is about to start running.
@@ -200,7 +211,7 @@
* than an existing one, modify the timer. Round up to next nearest
* second.
*/
- expiry = round_jiffies_up(req->deadline);
+ expiry = blk_rq_timeout(round_jiffies_up(req->deadline));
if (!timer_pending(&q->timeout) ||
time_before(expiry, q->timeout.expires)) {
diff --git a/block/blk.h b/block/blk.h
index 79be2cb..95cab70 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -9,6 +9,9 @@
/* Number of requests a "batching" process may submit */
#define BLK_BATCH_REQ 32
+/* Max future timer expiry for timeouts */
+#define BLK_MAX_TIMEOUT (5 * HZ)
+
extern struct kmem_cache *blk_requestq_cachep;
extern struct kmem_cache *request_cachep;
extern struct kobj_type blk_queue_ktype;
@@ -37,6 +40,7 @@
void blk_rq_timed_out_timer(unsigned long data);
void blk_rq_check_expired(struct request *rq, unsigned long *next_timeout,
unsigned int *next_set);
+unsigned long blk_rq_timeout(unsigned long timeout);
void blk_add_timer(struct request *req);
void blk_delete_timer(struct request *);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 952e558..a06ca7b 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -54,6 +54,8 @@
unsigned int numa_node;
unsigned int cmd_size; /* per-request extra data */
+ atomic_t nr_active;
+
struct blk_mq_cpu_notifier cpu_notifier;
struct kobject kobj;
};
@@ -70,6 +72,9 @@
void *driver_data;
struct blk_mq_tags **tags;
+
+ struct mutex tag_list_lock;
+ struct list_head tag_list;
};
typedef int (queue_rq_fn)(struct blk_mq_hw_ctx *, struct request *);
@@ -132,8 +137,10 @@
BLK_MQ_F_SHOULD_MERGE = 1 << 0,
BLK_MQ_F_SHOULD_SORT = 1 << 1,
+ BLK_MQ_F_TAG_SHARED = 1 << 2,
BLK_MQ_S_STOPPED = 0,
+ BLK_MQ_S_TAG_ACTIVE = 1,
BLK_MQ_MAX_DEPTH = 2048,
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index aa0eaa2..d8e4cea 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -190,6 +190,7 @@
__REQ_PM, /* runtime pm request */
__REQ_END, /* last of chain of requests */
__REQ_HASHED, /* on IO scheduler merge hash */
+ __REQ_MQ_INFLIGHT, /* track inflight for MQ */
__REQ_NR_BITS, /* stops here */
};
@@ -243,5 +244,6 @@
#define REQ_PM (1ULL << __REQ_PM)
#define REQ_END (1ULL << __REQ_END)
#define REQ_HASHED (1ULL << __REQ_HASHED)
+#define REQ_MQ_INFLIGHT (1ULL << __REQ_MQ_INFLIGHT)
#endif /* __LINUX_BLK_TYPES_H */
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 94b2721..6bc011a 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -481,6 +481,9 @@
wait_queue_head_t mq_freeze_wq;
struct percpu_counter mq_usage_counter;
struct list_head all_q_node;
+
+ struct blk_mq_tag_set *tag_set;
+ struct list_head tag_set_list;
};
#define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */