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>

diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index ac5160e..3c385b1 100644 (file)
--- 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 7ddc796..0cb9362 100644 (file)
--- 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,