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-rw-r--r--block/cfq-iosched.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 61010511c5a0..e280d08ef6d7 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -16,6 +16,7 @@
#include <linux/blktrace_api.h>
#include <linux/blk-cgroup.h>
#include "blk.h"
+#include "blk-wbt.h"
/*
* tunables
@@ -3762,9 +3763,11 @@ static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
struct cfq_data *cfqd = cic_to_cfqd(cic);
struct cfq_queue *cfqq;
uint64_t serial_nr;
+ bool nonroot_cg;
rcu_read_lock();
serial_nr = bio_blkcg(bio)->css.serial_nr;
+ nonroot_cg = bio_blkcg(bio) != &blkcg_root;
rcu_read_unlock();
/*
@@ -3775,6 +3778,17 @@ static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
return;
/*
+ * If we have a non-root cgroup, we can depend on that to
+ * do proper throttling of writes. Turn off wbt for that
+ * case.
+ */
+ if (nonroot_cg) {
+ struct request_queue *q = cfqd->queue;
+
+ wbt_disable(q->rq_wb);
+ }
+
+ /*
* Drop reference to queues. New queues will be assigned in new
* group upon arrival of fresh requests.
*/