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blk-mq: account higher order dispatch

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We currently account a '0' dispatch, and anything above that still falls
below the range set by BLK_MQ_MAX_DISPATCH_ORDER. If we dispatch more,
we don't account it.

Change the last bucket to be inclusive of anything above the range we
track, and have the sysfs file reflect that by including a '+' in the
output:

$ cat /sys/block/nvme0n1/mq/0/dispatched
        0	1006
        1	20229
        2	1
        4	0
        8	0
       16	0
       32+	0

Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
This commit is contained in:
Jens Axboe 2016-09-16 13:59:14 -06:00
parent 2849450ad3
commit 703fd1c0f1
2 changed files with 14 additions and 7 deletions
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8
block/blk-mq-sysfs.c
View file

@ -208,12 +208,14 @@ static ssize_t blk_mq_hw_sysfs_dispatched_show(struct blk_mq_hw_ctx *hctx,
page += sprintf(page, "%8u\t%lu\n", 0U, hctx->dispatched[0]); page += sprintf(page, "%8u\t%lu\n", 0U, hctx->dispatched[0]);
for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER; i++) { for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER - 1; i++) {
unsigned long d = 1U << (i - 1); unsigned int d = 1U << (i - 1);
page += sprintf(page, "%8lu\t%lu\n", d, hctx->dispatched[i]); page += sprintf(page, "%8u\t%lu\n", d, hctx->dispatched[i]);
} }
page += sprintf(page, "%8u+\t%lu\n", 1U << (i - 1),
hctx->dispatched[i]);
return page - start_page; return page - start_page;
} }

13
block/blk-mq.c
View file

@ -789,6 +789,14 @@ static void flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list)
} }
} }
static inline unsigned int queued_to_index(unsigned int queued)
{
if (!queued)
return 0;
return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1);
}
/* /*
* Run this hardware queue, pulling any software queues mapped to it in. * Run this hardware queue, pulling any software queues mapped to it in.
* Note that this function currently has various problems around ordering * Note that this function currently has various problems around ordering
@ -877,10 +885,7 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
dptr = &driver_list; dptr = &driver_list;
} }
if (!queued) hctx->dispatched[queued_to_index(queued)]++;
hctx->dispatched[0]++;
else if (queued < (1 << (BLK_MQ_MAX_DISPATCH_ORDER - 1)))
hctx->dispatched[ilog2(queued) + 1]++;
/* /*
* Any items that need requeuing? Stuff them into hctx->dispatch, * Any items that need requeuing? Stuff them into hctx->dispatch,