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-rw-r--r--block/blk-throttle.c74
1 files changed, 20 insertions, 54 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 3960787358b6..7dbd0e695df0 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -85,9 +85,6 @@ struct throtl_grp {
unsigned long slice_start[2];
unsigned long slice_end[2];
- /* Some throttle limits got updated for the group */
- int limits_changed;
-
/* Per cpu stats pointer */
struct tg_stats_cpu __percpu *stats_cpu;
@@ -112,8 +109,6 @@ struct throtl_data
/* Work for dispatching throttled bios */
struct delayed_work throtl_work;
-
- int limits_changed;
};
/* list and work item to allocate percpu group stats */
@@ -223,7 +218,6 @@ static void throtl_pd_init(struct blkcg_gq *blkg)
RB_CLEAR_NODE(&tg->rb_node);
bio_list_init(&tg->bio_lists[0]);
bio_list_init(&tg->bio_lists[1]);
- tg->limits_changed = false;
tg->bps[READ] = -1;
tg->bps[WRITE] = -1;
@@ -826,45 +820,6 @@ static int throtl_select_dispatch(struct throtl_data *td, struct bio_list *bl)
return nr_disp;
}
-static void throtl_process_limit_change(struct throtl_data *td)
-{
- struct request_queue *q = td->queue;
- struct blkcg_gq *blkg, *n;
-
- if (!td->limits_changed)
- return;
-
- xchg(&td->limits_changed, false);
-
- throtl_log(td, "limits changed");
-
- list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) {
- struct throtl_grp *tg = blkg_to_tg(blkg);
-
- if (!tg->limits_changed)
- continue;
-
- if (!xchg(&tg->limits_changed, false))
- continue;
-
- throtl_log_tg(td, tg, "limit change rbps=%llu wbps=%llu"
- " 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);
- }
-}
-
/* Dispatch throttled bios. Should be called without queue lock held. */
static int throtl_dispatch(struct request_queue *q)
{
@@ -876,8 +831,6 @@ static int throtl_dispatch(struct request_queue *q)
spin_lock_irq(q->queue_lock);
- throtl_process_limit_change(td);
-
if (!total_nr_queued(td))
goto out;
@@ -925,8 +878,7 @@ throtl_schedule_delayed_work(struct throtl_data *td, unsigned long delay)
struct delayed_work *dwork = &td->throtl_work;
- /* schedule work if limits changed even if no bio is queued */
- if (total_nr_queued(td) || td->limits_changed) {
+ if (total_nr_queued(td)) {
mod_delayed_work(kthrotld_workqueue, dwork, delay);
throtl_log(td, "schedule work. delay=%lu jiffies=%lu",
delay, jiffies);
@@ -1023,10 +975,25 @@ static int tg_set_conf(struct cgroup *cgrp, struct cftype *cft, const char *buf,
else
*(unsigned int *)((void *)tg + cft->private) = ctx.v;
- /* XXX: we don't need the following deferred processing */
- xchg(&tg->limits_changed, true);
- xchg(&td->limits_changed, true);
- throtl_schedule_delayed_work(td, 0);
+ throtl_log_tg(td, tg, "limit change rbps=%llu wbps=%llu riops=%u wiops=%u",
+ tg->bps[READ], tg->bps[WRITE],
+ tg->iops[READ], tg->iops[WRITE]);
+
+ /*
+ * We're already holding queue_lock and know @tg is valid. Let's
+ * apply the new config directly.
+ *
+ * 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);
+ throtl_schedule_next_dispatch(td);
+ }
blkg_conf_finish(&ctx);
return 0;
@@ -1239,7 +1206,6 @@ int blk_throtl_init(struct request_queue *q)
return -ENOMEM;
td->tg_service_tree = THROTL_RB_ROOT;
- td->limits_changed = false;
INIT_DELAYED_WORK(&td->throtl_work, blk_throtl_work);
q->td = td;