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blk-mq: Record active_queues_shared_sbitmap per tag_set for when using shared sbitmap

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For when using a shared sbitmap, no longer should the number of active
request queues per hctx be relied on for when judging how to share the tag
bitmap.

Instead maintain the number of active request queues per tag_set, and make
the judgement based on that.

Originally-from: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Tested-by: Don Brace<don.brace@microsemi.com> #SCSI resv cmds patches used
Tested-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
John Garry 2020-08-19 23:20:27 +08:00 committed by Jens Axboe
parent bccf5e26d9
commit f1b49fdc1c
5 changed files with 41 additions and 10 deletions
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31
block/blk-mq-tag.c
View File

@ -23,9 +23,18 @@
*/
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);
if (blk_mq_is_sbitmap_shared(hctx->flags)) {
struct request_queue *q = hctx->queue;
struct blk_mq_tag_set *set = q->tag_set;
if (!test_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags) &&
!test_and_set_bit(QUEUE_FLAG_HCTX_ACTIVE, &q->queue_flags))
atomic_inc(&set->active_queues_shared_sbitmap);
} else {
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;
}
@ -47,11 +56,19 @@ void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve)
void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
{
struct blk_mq_tags *tags = hctx->tags;
struct request_queue *q = hctx->queue;
struct blk_mq_tag_set *set = q->tag_set;
if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
return;
atomic_dec(&tags->active_queues);
if (blk_mq_is_sbitmap_shared(hctx->flags)) {
if (!test_and_clear_bit(QUEUE_FLAG_HCTX_ACTIVE,
&q->queue_flags))
return;
atomic_dec(&set->active_queues_shared_sbitmap);
} else {
if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
return;
atomic_dec(&tags->active_queues);
}
blk_mq_tag_wakeup_all(tags, false);
}

2
block/blk-mq.c
View File

@ -3442,6 +3442,8 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
goto out_free_mq_map;
if (blk_mq_is_sbitmap_shared(set->flags)) {
atomic_set(&set->active_queues_shared_sbitmap, 0);
if (blk_mq_init_shared_sbitmap(set, set->flags)) {
ret = -ENOMEM;
goto out_free_mq_rq_maps;

16
block/blk-mq.h
View File

@ -292,8 +292,6 @@ static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED))
return true;
if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
return true;
/*
* Don't try dividing an ant
@ -301,7 +299,19 @@ static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
if (bt->sb.depth == 1)
return true;
users = atomic_read(&hctx->tags->active_queues);
if (blk_mq_is_sbitmap_shared(hctx->flags)) {
struct request_queue *q = hctx->queue;
struct blk_mq_tag_set *set = q->tag_set;
if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &q->queue_flags))
return true;
users = atomic_read(&set->active_queues_shared_sbitmap);
} else {
if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
return true;
users = atomic_read(&hctx->tags->active_queues);
}
if (!users)
return true;

1
include/linux/blk-mq.h
View File

@ -252,6 +252,7 @@ struct blk_mq_tag_set {
unsigned int timeout;
unsigned int flags;
void *driver_data;
atomic_t active_queues_shared_sbitmap;
struct sbitmap_queue __bitmap_tags;
struct sbitmap_queue __breserved_tags;

1
include/linux/blkdev.h
View File

@ -618,6 +618,7 @@ struct request_queue {
#define QUEUE_FLAG_PCI_P2PDMA 25 /* device supports PCI p2p requests */
#define QUEUE_FLAG_ZONE_RESETALL 26 /* supports Zone Reset All */
#define QUEUE_FLAG_RQ_ALLOC_TIME 27 /* record rq->alloc_time_ns */
#define QUEUE_FLAG_HCTX_ACTIVE 28 /* at least one blk-mq hctx is active */
#define QUEUE_FLAG_MQ_DEFAULT ((1 << QUEUE_FLAG_IO_STAT) | \
(1 << QUEUE_FLAG_SAME_COMP))