From: Yu Kuai yukuai3@huawei.com
[ Upstream commit 671fae5e51297fc76b3758ca2edd514858734a6a ]
Commit b5dc5d4d1f4f ("block,bfq: Disable writeback throttling") tries to disable wbt for bfq, it's done by calling wbt_disable_default() in bfq_init_queue(). However, wbt is still enabled if default elevator is bfq:
device_add_disk elevator_init_mq bfq_init_queue wbt_disable_default -> done nothing
blk_register_queue wbt_enable_default -> wbt is enabled
Fix the problem by adding a new flag ELEVATOR_FLAG_DISBALE_WBT, bfq will set the flag in bfq_init_queue, and following wbt_enable_default() won't enable wbt while the flag is set.
Signed-off-by: Yu Kuai yukuai3@huawei.com Reviewed-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20221019121518.3865235-7-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe axboe@kernel.dk Stable-dep-of: f814bdda774c ("blk-wbt: Fix detection of dirty-throttled tasks") Signed-off-by: Sasha Levin sashal@kernel.org --- block/bfq-iosched.c | 2 ++ block/blk-wbt.c | 11 ++++++++--- block/elevator.h | 3 ++- 3 files changed, 12 insertions(+), 4 deletions(-)
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 52eb79d60a3f3..e4699291aee23 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -7059,6 +7059,7 @@ static void bfq_exit_queue(struct elevator_queue *e) #endif
blk_stat_disable_accounting(bfqd->queue); + clear_bit(ELEVATOR_FLAG_DISABLE_WBT, &e->flags); wbt_enable_default(bfqd->queue);
kfree(bfqd); @@ -7204,6 +7205,7 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e) /* We dispatch from request queue wide instead of hw queue */ blk_queue_flag_set(QUEUE_FLAG_SQ_SCHED, q);
+ set_bit(ELEVATOR_FLAG_DISABLE_WBT, &eq->flags); wbt_disable_default(q); blk_stat_enable_accounting(q);
diff --git a/block/blk-wbt.c b/block/blk-wbt.c index c5a8c10028a08..afb1782b4255e 100644 --- a/block/blk-wbt.c +++ b/block/blk-wbt.c @@ -27,6 +27,7 @@
#include "blk-wbt.h" #include "blk-rq-qos.h" +#include "elevator.h"
#define CREATE_TRACE_POINTS #include <trace/events/wbt.h> @@ -638,11 +639,15 @@ void wbt_set_write_cache(struct request_queue *q, bool write_cache_on) */ void wbt_enable_default(struct request_queue *q) { - struct rq_qos *rqos = wbt_rq_qos(q); + struct rq_qos *rqos; + bool disable_flag = q->elevator && + test_bit(ELEVATOR_FLAG_DISABLE_WBT, &q->elevator->flags);
/* Throttling already enabled? */ + rqos = wbt_rq_qos(q); if (rqos) { - if (RQWB(rqos)->enable_state == WBT_STATE_OFF_DEFAULT) + if (!disable_flag && + RQWB(rqos)->enable_state == WBT_STATE_OFF_DEFAULT) RQWB(rqos)->enable_state = WBT_STATE_ON_DEFAULT; return; } @@ -651,7 +656,7 @@ void wbt_enable_default(struct request_queue *q) if (!blk_queue_registered(q)) return;
- if (queue_is_mq(q)) + if (queue_is_mq(q) && !disable_flag) wbt_init(q); } EXPORT_SYMBOL_GPL(wbt_enable_default); diff --git a/block/elevator.h b/block/elevator.h index ed574bf3e629e..75382471222d1 100644 --- a/block/elevator.h +++ b/block/elevator.h @@ -104,7 +104,8 @@ struct elevator_queue DECLARE_HASHTABLE(hash, ELV_HASH_BITS); };
-#define ELEVATOR_FLAG_REGISTERED 0 +#define ELEVATOR_FLAG_REGISTERED 0 +#define ELEVATOR_FLAG_DISABLE_WBT 1
/* * block elevator interface