From 703fd1c0f177219e3a84e6c095c31dc566514d81 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@fb.com>
Date: Fri, 16 Sep 2016 13:59:14 -0600
Subject: [PATCH] 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: Jens Axboe <axboe@fb.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
---
block/blk-mq-sysfs.c | 8 +++++---
block/blk-mq.c | 13 +++++++++----
2 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index ac5160eb68625..3c385b196bc71 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 7ddc7969fba43..0cb93625d8121 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -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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