block,bfq: Disable writeback throttling

Similarly to CFQ, BFQ has its write-throttling heuristics, and it
is better not to combine them with further write-throttling
heuristics of a different nature.
So this commit disables write-back throttling for a device if BFQ
is used as I/O scheduler for that device.

Signed-off-by: Luca Miccio <lucmiccio@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Lee Tibbert <lee.tibbert@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 2 insertions, 1 deletions

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 70f9177c4f5b..261f98695910 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -108,6 +108,7 @@
 #include "blk-mq-tag.h"
 #include "blk-mq-sched.h"
 #include "bfq-iosched.h"
+#include "blk-wbt.h"
 
 #define BFQ_BFQQ_FNS(name)                                              \
 void bfq_mark_bfqq_##name(struct bfq_queue *bfqq)                       \
@@ -4810,7 +4811,7 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e)
         bfq_init_root_group(bfqd->root_group, bfqd);
         bfq_init_entity(&bfqd->oom_bfqq.entity, bfqd->root_group);
 
-
+        wbt_disable_default(q);
         return 0;
 
 out_free: