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authorJan Kara <jack@suse.cz>2017-04-19 11:33:27 +0200
committerJens Axboe <axboe@fb.com>2017-04-19 08:49:03 -0600
commit8330cdb0fe55c9a9a8e440e56c19233229e0e259 (patch)
tree644af58ba64f8cb431d01abaff81113b4ed6a835 /block
parentea25da48086d3bbebf3a2eeff387ea00ed96f5c4 (diff)
downloadlinux-0-day-8330cdb0fe55c9a9a8e440e56c19233229e0e259.tar.gz
block: Make writeback throttling defaults consistent for SQ devices
When CFQ is used as an elevator, it disables writeback throttling because they don't play well together. Later when a different elevator is chosen for the device, writeback throttling doesn't get enabled again as it should. Make sure CFQ enables writeback throttling (if it should be enabled by default) when we switch from it to another IO scheduler. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
-rw-r--r--block/blk-sysfs.c19
-rw-r--r--block/blk-wbt.c19
-rw-r--r--block/blk-wbt.h4
-rw-r--r--block/elevator.c3
4 files changed, 27 insertions, 18 deletions
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index fc20489..f857233 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -844,23 +844,6 @@ struct kobj_type blk_queue_ktype = {
.release = blk_release_queue,
};
-static void blk_wb_init(struct request_queue *q)
-{
-#ifndef CONFIG_BLK_WBT_MQ
- if (q->mq_ops)
- return;
-#endif
-#ifndef CONFIG_BLK_WBT_SQ
- if (q->request_fn)
- return;
-#endif
-
- /*
- * If this fails, we don't get throttling
- */
- wbt_init(q);
-}
-
int blk_register_queue(struct gendisk *disk)
{
int ret;
@@ -908,7 +891,7 @@ int blk_register_queue(struct gendisk *disk)
kobject_uevent(&q->kobj, KOBJ_ADD);
- blk_wb_init(q);
+ wbt_enable_default(q);
blk_throtl_register_queue(q);
diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index b3b7914..26e1bb6 100644
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -665,6 +665,25 @@ void wbt_disable_default(struct request_queue *q)
}
EXPORT_SYMBOL_GPL(wbt_disable_default);
+/*
+ * Enable wbt if defaults are configured that way
+ */
+void wbt_enable_default(struct request_queue *q)
+{
+ /* Throttling already enabled? */
+ if (q->rq_wb)
+ return;
+
+ /* Queue not registered? Maybe shutting down... */
+ if (!test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags))
+ return;
+
+ if ((q->mq_ops && IS_ENABLED(CONFIG_BLK_WBT_MQ)) ||
+ (q->request_fn && IS_ENABLED(CONFIG_BLK_WBT_SQ)))
+ wbt_init(q);
+}
+EXPORT_SYMBOL_GPL(wbt_enable_default);
+
u64 wbt_default_latency_nsec(struct request_queue *q)
{
/*
diff --git a/block/blk-wbt.h b/block/blk-wbt.h
index ad6c785..df6de50 100644
--- a/block/blk-wbt.h
+++ b/block/blk-wbt.h
@@ -117,6 +117,7 @@ void wbt_update_limits(struct rq_wb *);
void wbt_requeue(struct rq_wb *, struct blk_issue_stat *);
void wbt_issue(struct rq_wb *, struct blk_issue_stat *);
void wbt_disable_default(struct request_queue *);
+void wbt_enable_default(struct request_queue *);
void wbt_set_queue_depth(struct rq_wb *, unsigned int);
void wbt_set_write_cache(struct rq_wb *, bool);
@@ -155,6 +156,9 @@ static inline void wbt_issue(struct rq_wb *rwb, struct blk_issue_stat *stat)
static inline void wbt_disable_default(struct request_queue *q)
{
}
+static inline void wbt_enable_default(struct request_queue *q)
+{
+}
static inline void wbt_set_queue_depth(struct rq_wb *rwb, unsigned int depth)
{
}
diff --git a/block/elevator.c b/block/elevator.c
index dbeecf7..fb50416 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -41,6 +41,7 @@
#include "blk.h"
#include "blk-mq-sched.h"
+#include "blk-wbt.h"
static DEFINE_SPINLOCK(elv_list_lock);
static LIST_HEAD(elv_list);
@@ -877,6 +878,8 @@ void elv_unregister_queue(struct request_queue *q)
kobject_uevent(&e->kobj, KOBJ_REMOVE);
kobject_del(&e->kobj);
e->registered = 0;
+ /* Re-enable throttling in case elevator disabled it */
+ wbt_enable_default(q);
}
}
EXPORT_SYMBOL(elv_unregister_queue);