[PATCH] blk-mq: account higher order dispatch
flat view
STALE3673d
From: Jens Axboe <hidden>
Date: 2016-09-15 21:16:56
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
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 <redacted>
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 885a4a59acd9..39840c37b7ce 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c@@ -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; }
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4b8034e54478..fb4b6795ec57 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c@@ -802,6 +802,14 @@ 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
@@ -890,10 +898,7 @@ 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,
--
Jens Axboe