Commit 703fd1c0 authored by Jens Axboe's avatar Jens Axboe
Browse files

blk-mq: account higher order dispatch 



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: default avatarJens Axboe <axboe@fb.com>
Reviewed-by: default avatarOmar Sandoval <osandov@fb.com>
parent 2849450a

block/blk-mq-sysfs.c

+5 −3
Original line number Diff line number Diff line
@@ -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]);



	for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER; i++) {

		unsigned long d = 1U << (i - 1);

	for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER - 1; i++) {

		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;

}

block/blk-mq.c

+9 −4
Original line number Diff line number Diff line
@@ -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.

 * 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;

	}



	if (!queued)

		hctx->dispatched[0]++;

	else if (queued < (1 << (BLK_MQ_MAX_DISPATCH_ORDER - 1)))

		hctx->dispatched[ilog2(queued) + 1]++;

	hctx->dispatched[queued_to_index(queued)]++;



	/*

	 * Any items that need requeuing? Stuff them into hctx->dispatch,

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