On Jun 13, 2017, at 10:01 PM, Jens Axboe <axboe@xxxxxxxxx> wrote:
>
> Useful to verify that things are working the way they should.
> Reading the file will return number of kb written to each
> stream. Writing the file will reset the statistics. No care
> is taken to ensure that we don't race on updates.
>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx>
> ---
> block/blk-core.c | 5 +++++
> block/blk-mq-debugfs.c | 24 ++++++++++++++++++++++++
> include/linux/blkdev.h | 3 +++
> 3 files changed, 32 insertions(+)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index a7421b772d0e..81051e24b5dd 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -2057,6 +2057,11 @@ blk_qc_t generic_make_request(struct bio *bio)
> do {
> struct request_queue *q = bdev_get_queue(bio->bi_bdev);
>
> + if (bio_stream(bio) < BLK_MAX_STREAM) {
> + q->stream_writes[bio_stream(bio)] +=
> + bio->bi_iter.bi_size >> 9;
> + }
> +
> if (likely(blk_queue_enter(q, false) == 0)) {
> struct bio_list lower, same;
>
> diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
> index 803aed4d7221..0a37c848961d 100644
> --- a/block/blk-mq-debugfs.c
> +++ b/block/blk-mq-debugfs.c
> @@ -133,6 +133,29 @@ static void print_stat(struct seq_file *m, struct blk_rq_stat *stat)
> }
> }
>
> +static int queue_streams_show(void *data, struct seq_file *m)
> +{
> + struct request_queue *q = data;
> + int i;
> +
> + for (i = 0; i < BLK_MAX_STREAM; i++)
> + seq_printf(m, "stream%d: %llu\n", i, q->stream_writes[i]);
> +
> + return 0;
> +}
> +
> +static ssize_t queue_streams_store(void *data, const char __user *buf,
> + size_t count, loff_t *ppos)
> +{
> + struct request_queue *q = data;
> + int i;
> +
> + for (i = 0; i < BLK_MAX_STREAM; i++)
> + q->stream_writes[i] = 0;
> +
> + return count;
> +}
> +
> static int queue_poll_stat_show(void *data, struct seq_file *m)
> {
> struct request_queue *q = data;
> @@ -656,6 +679,7 @@ const struct file_operations blk_mq_debugfs_fops = {
> static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
> {"poll_stat", 0400, queue_poll_stat_show},
> {"state", 0600, queue_state_show, queue_state_write},
> + {"streams", 0600, queue_streams_show, queue_streams_store},
> {},
> };
>
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index ab92c4ea138b..88719c6f3edf 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -586,6 +586,9 @@ struct request_queue {
>
> size_t cmd_size;
> void *rq_alloc_data;
> +
> +#define BLK_MAX_STREAM 5
> + u64 stream_writes[BLK_MAX_STREAM];
> };
>
> #define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
> --
> 2.7.4
>
Cheers, Andreas
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