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 <[email protected]>
Signed-off-by: Paolo Valente <[email protected]>
Tested-by: Oleksandr Natalenko <[email protected]>
Tested-by: Lee Tibbert <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 70f9177c4f5b2c3b4d2bd8380aa1c77499940390..261f98695910fa0e6f98bce82f96cfb8fbe41a45 100644 (file)
--- 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:

diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index 6a9a0f03a67bd9ac9839ba667fb407a03694a304..e59d59c11ebbb308fe2cc41562fedfd90eecfe6c 100644 (file)
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -654,7 +654,7 @@ void wbt_set_write_cache(struct rq_wb *rwb, bool write_cache_on)
 }
 
 /*
- * Disable wbt, if enabled by default. Only called from CFQ.
+ * Disable wbt, if enabled by default.
  */
 void wbt_disable_default(struct request_queue *q)
 {