[PATCH 4.14 120/159] block,bfq: Disable writeback throttling

Greg Kroah-Hartman
2017-12-22T09:23:12Z

From: Luca Miccio <lucmiccio@gmail.com>

[ Upstream commit b5dc5d4d1f4ff9032eb6c21a3c571a1317dc9289 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
block/bfq-iosched.c | 3 ++-
block/blk-wbt.c | 2 +-
2 files changed, 3 insertions(+), 2 deletions(-)

--- 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) \
@@ -4775,7 +4776,7 @@ static int bfq_init_queue(struct request
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:
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -654,7 +654,7 @@ void wbt_set_write_cache(struct rq_wb *r
}

/*
- * Disable wbt, if enabled by default. Only called from CFQ.
+ * Disable wbt, if enabled by default.
*/
void wbt_disable_default(struct request_queue *q)
{