On Fri, Nov 02, 2012 at 05:31:37PM +0800, Robin Dong wrote:
> From: Robin Dong <san...@taobao.com>
>
> Currently, if the IO is throttled by io-throttle, the system admin has no idea
> of the situation and can't report it to the real application user about that
> he/she has to do something.
>
> So this patch adds a new interface named blkio.throttle.io_submitted which
> exposes the number of bios that have been sent into blk-throttle therefore the
> user could calculate the difference from throttle.io_serviced to see how many
> IOs are currently throttled.
>
> Cc: Tejun Heo <t...@kernel.org>
> Cc: Vivek Goyal <vgo...@redhat.com>
> Cc: Jens Axboe <ax...@kernel.dk>
> Signed-off-by: Tao Ma <boyu...@taobao.com>
> Signed-off-by: Robin Dong <san...@taobao.com>
> ---
Looks good to me.
Acked-by: Vivek Goyal <vgo...@redhat.com>
Vivek
> v3 <-- v2:
> - Use nr-queued[] of struct throtl_grp for stats instaed of adding new
> blkg_rwstat.
>
> v4 <-- v3:
> - Add two new blkg_rwstat arguments to count total bios be sent into
> blk_throttle.
>
> v5 <-- v4:
> - Change name "io_submit_bytes" to "io_submitted_bytes".
>
> block/blk-throttle.c | 43 +++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 43 insertions(+), 0 deletions(-)
>
> diff --git a/block/blk-throttle.c b/block/blk-throttle.c
> index 46ddeff..c6391b5 100644
> --- a/block/blk-throttle.c
> +++ b/block/blk-throttle.c
> @@ -46,6 +46,10 @@ struct tg_stats_cpu {
> struct blkg_rwstat service_bytes;
> /* total IOs serviced, post merge */
> struct blkg_rwstat serviced;
> + /* total bytes submitted into blk-throttle */
> + struct blkg_rwstat submit_bytes;
> + /* total IOs submitted into blk-throttle */
> + struct blkg_rwstat submitted;
> };
>
> struct throtl_grp {
> @@ -266,6 +270,8 @@ static void throtl_pd_reset_stats(struct blkcg_gq *blkg)
>
> blkg_rwstat_reset(&sc->service_bytes);
> blkg_rwstat_reset(&sc->serviced);
> + blkg_rwstat_reset(&sc->submit_bytes);
> + blkg_rwstat_reset(&sc->submitted);
> }
> }
>
> @@ -699,6 +705,30 @@ static void throtl_update_dispatch_stats(struct
> throtl_grp *tg, u64 bytes,
> local_irq_restore(flags);
> }
>
> +static void throtl_update_submit_stats(struct throtl_grp *tg, u64 bytes, int
> rw)
> +{
> + struct tg_stats_cpu *stats_cpu;
> + unsigned long flags;
> +
> + /* If per cpu stats are not allocated yet, don't do any accounting. */
> + if (tg->stats_cpu == NULL)
> + return;
> +
> + /*
> + * Disabling interrupts to provide mutual exclusion between two
> + * writes on same cpu. It probably is not needed for 64bit. Not
> + * optimizing that case yet.
> + */
> + local_irq_save(flags);
> +
> + stats_cpu = this_cpu_ptr(tg->stats_cpu);
> +
> + blkg_rwstat_add(&stats_cpu->submitted, rw, 1);
> + blkg_rwstat_add(&stats_cpu->submit_bytes, rw, bytes);
> +
> + local_irq_restore(flags);
> +}
> +
> static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio)
> {
> bool rw = bio_data_dir(bio);
> @@ -1084,6 +1114,16 @@ static struct cftype throtl_files[] = {
> .private = offsetof(struct tg_stats_cpu, serviced),
> .read_seq_string = tg_print_cpu_rwstat,
> },
> + {
> + .name = "throttle.io_submitted_bytes",
> + .private = offsetof(struct tg_stats_cpu, submit_bytes),
> + .read_seq_string = tg_print_cpu_rwstat,
> + },
> + {
> + .name = "throttle.io_submitted",
> + .private = offsetof(struct tg_stats_cpu, submitted),
> + .read_seq_string = tg_print_cpu_rwstat,
> + },
> { } /* terminate */
> };
>
> @@ -1128,6 +1168,8 @@ bool blk_throtl_bio(struct request_queue *q, struct bio
> *bio)
> if (tg_no_rule_group(tg, rw)) {
> throtl_update_dispatch_stats(tg,
> bio->bi_size, bio->bi_rw);
> + throtl_update_submit_stats(tg,
> + bio->bi_size, bio->bi_rw);
> goto out_unlock_rcu;
> }
> }
> @@ -1141,6 +1183,7 @@ bool blk_throtl_bio(struct request_queue *q, struct bio
> *bio)
> if (unlikely(!tg))
> goto out_unlock;
>
> + throtl_update_submit_stats(tg, bio->bi_size, bio->bi_rw);
> if (tg->nr_queued[rw]) {
> /*
> * There is already another bio queued in same dir. No
> --
> 1.7.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
