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>
---
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
--
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