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-rw-r--r--block/blk-throttle.c25
1 files changed, 24 insertions, 1 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 37abbfc68590..5352bdafbcf0 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -756,6 +756,15 @@ static void throtl_process_limit_change(struct throtl_data *td)
" riops=%u wiops=%u", tg->bps[READ], tg->bps[WRITE],
tg->iops[READ], tg->iops[WRITE]);
+ /*
+ * Restart the slices for both READ and WRITES. It
+ * might happen that a group's limit are dropped
+ * suddenly and we don't want to account recently
+ * dispatched IO with new low rate
+ */
+ throtl_start_new_slice(td, tg, 0);
+ throtl_start_new_slice(td, tg, 1);
+
if (throtl_tg_on_rr(tg))
tg_update_disptime(td, tg);
}
@@ -821,7 +830,8 @@ throtl_schedule_delayed_work(struct throtl_data *td, unsigned long delay)
struct delayed_work *dwork = &td->throtl_work;
- if (total_nr_queued(td) > 0) {
+ /* schedule work if limits changed even if no bio is queued */
+ if (total_nr_queued(td) > 0 || td->limits_changed) {
/*
* We might have a work scheduled to be executed in future.
* Cancel that and schedule a new one.
@@ -1002,6 +1012,19 @@ int blk_throtl_bio(struct request_queue *q, struct bio **biop)
/* Bio is with-in rate limit of group */
if (tg_may_dispatch(td, tg, bio, NULL)) {
throtl_charge_bio(tg, bio);
+
+ /*
+ * We need to trim slice even when bios are not being queued
+ * otherwise it might happen that a bio is not queued for
+ * a long time and slice keeps on extending and trim is not
+ * called for a long time. Now if limits are reduced suddenly
+ * we take into account all the IO dispatched so far at new
+ * low rate and * newly queued IO gets a really long dispatch
+ * time.
+ *
+ * So keep on trimming slice even if bio is not queued.
+ */
+ throtl_trim_slice(td, tg, rw);
goto out;
}