@@ -483,8 +483,8 @@ static int hctx_tags_bitmap_show(void *data, struct seq_file *m)
res = mutex_lock_interruptible(&q->sysfs_lock);
if (res)
goto out;
- if (hctx->tags)
- sbitmap_bitmap_show(&hctx->tags->bitmap_tags.sb, m);
+ if (hctx->tags) /* We should just iterate the relevant bits for this hctx FIXME */
Bart's solution to this problem seemed ok, if he doesn't mind us
borrowing his idea:
https://lore.kernel.org/linux-block/5183ab13-0c81-95f0-95ba-40318569c6c6@xxxxxxxxxx/T/#m24394fe70b1ea79a154dfd9620f5e553c3e7e7da
See hctx_tags_bitmap_show().
It might be also reasonable to put that in another follow on patch, as
there would be no enablers of the "shared" bitmap until later patches.
+ sbitmap_bitmap_show(&hctx->tags->bitmap_tags->sb, m);
mutex_unlock(&q->sysfs_lock);
out:
@@ -518,7 +518,7 @@ static int hctx_sched_tags_bitmap_show(void *data, struct seq_file *m)
if (res)
goto out;
if (hctx->sched_tags)
- sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags.sb, m);
+ sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags->sb, m);
mutex_unlock(&q->sysfs_lock);
out:
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index ca22afd47b3d..1855f8f5edd4 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -492,6 +492,7 @@ static void blk_mq_sched_tags_teardown(struct request_queue *q)
int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e)
{
+ struct blk_mq_tag_set *tag_set = q->tag_set;
struct blk_mq_hw_ctx *hctx;
struct elevator_queue *eq;
unsigned int i;
@@ -537,6 +538,19 @@ int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e)
blk_mq_debugfs_register_sched_hctx(q, hctx);
}
+ if (blk_mq_is_sbitmap_shared(tag_set)) {
+ if (!blk_mq_init_sched_shared_sbitmap(tag_set, q->nr_requests)) {
+ ret = -ENOMEM;
+ goto err;
+ }
+ queue_for_each_hw_ctx(q, hctx, i) {
+ struct blk_mq_tags *tags = hctx->sched_tags;
+
+ tags->bitmap_tags = &tag_set->__sched_bitmap_tags;
+ tags->breserved_tags = &tag_set->__sched_breserved_tags;
+ }
+ }
+
return 0;
err:
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index f5009587e1b5..2e714123e846 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -20,7 +20,7 @@ bool blk_mq_has_free_tags(struct blk_mq_tags *tags)
if (!tags)
return true;
- return sbitmap_any_bit_clear(&tags->bitmap_tags.sb);
+ return sbitmap_any_bit_clear(&tags->bitmap_tags->sb);
}
/*
@@ -43,9 +43,9 @@ bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
*/
void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve)
{
- sbitmap_queue_wake_all(&tags->bitmap_tags);
+ sbitmap_queue_wake_all(tags->bitmap_tags);
if (include_reserve)
- sbitmap_queue_wake_all(&tags->breserved_tags);
+ sbitmap_queue_wake_all(tags->breserved_tags);
}
/*
@@ -121,10 +121,10 @@ unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
WARN_ON_ONCE(1);
return BLK_MQ_TAG_FAIL;
}
- bt = &tags->breserved_tags;
+ bt = tags->breserved_tags;
We could put all of this in an earlier patch (as you had in v4, modulo
dynamic memory part), which would be easier to review and get accepted.
tag_offset = 0;
} else {
- bt = &tags->bitmap_tags;
+ bt = tags->bitmap_tags;
tag_offset = tags->nr_reserved_tags;
}
[...]
if (!set)
@@ -3160,6 +3179,7 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr,
false);
} else {
+ sched_tags = true;
ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags,
nr, true);
}
@@ -3169,8 +3189,43 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
q->elevator->type->ops.depth_updated(hctx);
}
- if (!ret)
+ /*
+ * if ret is 0, all queues should have been updated to the same depth
+ * if not, then maybe some have been updated - yuk, need to handle this for shared sbitmap...
+ * if some are updated, we should probably roll back the change altogether. FIXME
+ */
If you don't have a shared sched bitmap - which I didn't think we needed
- then all we need is a simple sbitmap_queue_resize(&tagset->__bitmap_tags)
Otherwise it's horrible to resize shared sched bitmaps...
+ if (!ret) {
+ if (blk_mq_is_sbitmap_shared(set)) {
+ if (sched_tags) {
+ blk_mq_exit_shared_sched_sbitmap(set);
+ if (!blk_mq_init_sched_shared_sbitmap(set, nr))
+ return -ENOMEM; /* fixup error handling */
+
+ queue_for_each_hw_ctx(q, hctx, i) {
+ hctx->sched_tags->bitmap_tags =
+ &set->__sched_bitmap_tags;
+ hctx->sched_tags->breserved_tags =
+ &set->__sched_breserved_tags;
+ }
+ } else {
+ blk_mq_exit_shared_sbitmap(set);
+ if (!blk_mq_init_shared_sbitmap(set))
+ return -ENOMEM; /* fixup error handling */
+
+ queue_for_each_hw_ctx(q, hctx, i) {
+ hctx->tags->bitmap_tags =
+ &set->__bitmap_tags;
+ hctx->tags->breserved_tags =
+ &set->__breserved_tags;
+ }
+ }
+ }
q->nr_requests = nr;
+ }
+ /*
+ * if ret != 0, q->nr_requests would not be updated, yet the depth
+ * for some hctx may have changed - is that right?
+ */
blk_mq_unquiesce_queue(q);
blk_mq_unfreeze_queue(q);
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 78d38b5f2793..4c1ea206d3f4 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -166,6 +166,11 @@ struct blk_mq_alloc_data {
struct blk_mq_hw_ctx *hctx;
};
+static inline bool blk_mq_is_sbitmap_shared(struct blk_mq_tag_set *tag_set)
+{
+ return !!(tag_set->flags & BLK_MQ_F_TAG_HCTX_SHARED);
Bart already gave some comments on this
+}
+
static inline struct blk_mq_tags *blk_mq_tags_from_data(struct blk_mq_alloc_data *data)
{
if (data->flags & BLK_MQ_REQ_INTERNAL)
diff --git a/block/kyber-iosched.c b/block/kyber-iosched.c
index 34dcea0ef637..a7a537501d70 100644
--- a/block/kyber-iosched.c
+++ b/block/kyber-iosched.c
@@ -359,7 +359,7 @@ static unsigned int kyber_sched_tags_shift(struct request_queue *q)
* All of the hardware queues have the same depth, so we can just grab
* the shift of the first one.
*/
- return q->queue_hw_ctx[0]->sched_tags->bitmap_tags.sb.shift;
+ return q->queue_hw_ctx[0]->sched_tags->bitmap_tags->sb.shift;
}
static struct kyber_queue_data *kyber_queue_data_alloc(struct request_queue *q)
@@ -502,7 +502,7 @@ static int kyber_init_hctx(struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
khd->batching = 0;
hctx->sched_data = khd;
- sbitmap_queue_min_shallow_depth(&hctx->sched_tags->bitmap_tags,
+ sbitmap_queue_min_shallow_depth(hctx->sched_tags->bitmap_tags,
kqd->async_depth);
return 0;
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 147185394a25..10c9ed3dbe80 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -109,6 +109,12 @@ struct blk_mq_tag_set {
unsigned int flags; /* BLK_MQ_F_* */
void *driver_data;
+ struct sbitmap_queue __bitmap_tags;
+ struct sbitmap_queue __breserved_tags;
+
+ struct sbitmap_queue __sched_bitmap_tags;
+ struct sbitmap_queue __sched_breserved_tags;
+
struct blk_mq_tags **tags;
struct mutex tag_list_lock;
@@ -226,6 +232,9 @@ struct blk_mq_ops {
enum {
BLK_MQ_F_SHOULD_MERGE = 1 << 0,
BLK_MQ_F_TAG_QUEUE_SHARED = 1 << 1,
+ BLK_MQ_F_TAG_HCTX_SHARED = 1 << 2,
+ BLK_MQ_F_TAG_BITMAP_ALLOCATED = 1 << 3,
+ BLK_MQ_F_TAG_SCHED_BITMAP_ALLOCATED = 1 << 4,
BLK_MQ_F_BLOCKING = 1 << 5,
BLK_MQ_F_NO_SCHED = 1 << 6,
BLK_MQ_F_ALLOC_POLICY_START_BIT = 8,
