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blk-mq: Record nr_active_requests per queue for when using shared sbitmap

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The per-hctx nr_active value can no longer be used to fairly assign a share
of tag depth per request queue for when using a shared sbitmap, as it does
not consider that the tags are shared tags over all hctx's.

For this case, record the nr_active_requests per request_queue, and make
the judgement based on that value.

Co-developed-with: 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 23:20:26 +08:00 committed by Jens Axboe
parent a0235d230f
commit bccf5e26d9
4 changed files with 30 additions and 4 deletions
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2
block/blk-core.c
View file

@ -543,6 +543,8 @@ struct request_queue *blk_alloc_queue(int node_id)
q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK;
q->node = node_id;
atomic_set(&q->nr_active_requests_shared_sbitmap, 0);
timer_setup(&q->backing_dev_info->laptop_mode_wb_timer,
laptop_mode_timer_fn, 0);
timer_setup(&q->timeout, blk_rq_timed_out_timer, 0);

4
block/blk-mq.c
View file

@ -519,7 +519,7 @@ void blk_mq_free_request(struct request *rq)
ctx->rq_completed[rq_is_sync(rq)]++;
if (rq->rq_flags & RQF_MQ_INFLIGHT)
atomic_dec(&hctx->nr_active);
__blk_mq_dec_active_requests(hctx);
if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq)))
laptop_io_completion(q->backing_dev_info);
@ -1127,7 +1127,7 @@ static bool blk_mq_get_driver_tag(struct request *rq)
if ((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) &&
!(rq->rq_flags & RQF_MQ_INFLIGHT)) {
rq->rq_flags |= RQF_MQ_INFLIGHT;
atomic_inc(&hctx->nr_active);
__blk_mq_inc_active_requests(hctx);
}
hctx->tags->rqs[rq->tag] = rq;
return true;

26
block/blk-mq.h
View file

@ -199,6 +199,28 @@ static inline bool blk_mq_get_dispatch_budget(struct request_queue *q)
return true;
}
static inline void __blk_mq_inc_active_requests(struct blk_mq_hw_ctx *hctx)
{
if (blk_mq_is_sbitmap_shared(hctx->flags))
atomic_inc(&hctx->queue->nr_active_requests_shared_sbitmap);
else
atomic_inc(&hctx->nr_active);
}
static inline void __blk_mq_dec_active_requests(struct blk_mq_hw_ctx *hctx)
{
if (blk_mq_is_sbitmap_shared(hctx->flags))
atomic_dec(&hctx->queue->nr_active_requests_shared_sbitmap);
else
atomic_dec(&hctx->nr_active);
}
static inline int __blk_mq_active_requests(struct blk_mq_hw_ctx *hctx)
{
if (blk_mq_is_sbitmap_shared(hctx->flags))
return atomic_read(&hctx->queue->nr_active_requests_shared_sbitmap);
return atomic_read(&hctx->nr_active);
}
static inline void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx,
struct request *rq)
{
@ -207,7 +229,7 @@ static inline void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx,
if (rq->rq_flags & RQF_MQ_INFLIGHT) {
rq->rq_flags &= ~RQF_MQ_INFLIGHT;
atomic_dec(&hctx->nr_active);
__blk_mq_dec_active_requests(hctx);
}
}
@ -287,7 +309,7 @@ static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
* Allow at least some tags
*/
depth = max((bt->sb.depth + users - 1) / users, 4U);
return atomic_read(&hctx->nr_active) < depth;
return __blk_mq_active_requests(hctx) < depth;
}

2
include/linux/blkdev.h
View file

@ -485,6 +485,8 @@ struct request_queue {
struct timer_list timeout;
struct work_struct timeout_work;
atomic_t nr_active_requests_shared_sbitmap;
struct list_head icq_list;
#ifdef CONFIG_BLK_CGROUP
DECLARE_BITMAP (blkcg_pols, BLKCG_MAX_POLS);