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block: use atomic bitops for ->queue_flags

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->queue_flags is generally not set or cleared in the fast path, and also
generally set or cleared one flag at a time.  Make use of the normal
atomic bitops for it so that we don't need to take the queue_lock,
which is otherwise mostly unused in the core block layer now.

Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2018-11-14 17:02:07 +01:00 committed by Jens Axboe
parent 39795d6534
commit 57d74df907
6 changed files with 24 additions and 127 deletions
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54
block/blk-core.c
View File

@ -74,11 +74,7 @@ static struct workqueue_struct *kblockd_workqueue;
*/
void blk_queue_flag_set(unsigned int flag, struct request_queue *q)
{
unsigned long flags;
spin_lock_irqsave(q->queue_lock, flags);
queue_flag_set(flag, q);
spin_unlock_irqrestore(q->queue_lock, flags);
set_bit(flag, &q->queue_flags);
}
EXPORT_SYMBOL(blk_queue_flag_set);
@ -89,11 +85,7 @@ EXPORT_SYMBOL(blk_queue_flag_set);
*/
void blk_queue_flag_clear(unsigned int flag, struct request_queue *q)
{
unsigned long flags;
spin_lock_irqsave(q->queue_lock, flags);
queue_flag_clear(flag, q);
spin_unlock_irqrestore(q->queue_lock, flags);
clear_bit(flag, &q->queue_flags);
}
EXPORT_SYMBOL(blk_queue_flag_clear);
@ -107,38 +99,10 @@ EXPORT_SYMBOL(blk_queue_flag_clear);
*/
bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q)
{
unsigned long flags;
bool res;
spin_lock_irqsave(q->queue_lock, flags);
res = queue_flag_test_and_set(flag, q);
spin_unlock_irqrestore(q->queue_lock, flags);
return res;
return test_and_set_bit(flag, &q->queue_flags);
}
EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set);
/**
* blk_queue_flag_test_and_clear - atomically test and clear a queue flag
* @flag: flag to be cleared
* @q: request queue
*
* Returns the previous value of @flag - 0 if the flag was not set and 1 if
* the flag was set.
*/
bool blk_queue_flag_test_and_clear(unsigned int flag, struct request_queue *q)
{
unsigned long flags;
bool res;
spin_lock_irqsave(q->queue_lock, flags);
res = queue_flag_test_and_clear(flag, q);
spin_unlock_irqrestore(q->queue_lock, flags);
return res;
}
EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_clear);
void blk_rq_init(struct request_queue *q, struct request *rq)
{
memset(rq, 0, sizeof(*rq));
@ -368,12 +332,10 @@ void blk_cleanup_queue(struct request_queue *q)
/* mark @q DYING, no new request or merges will be allowed afterwards */
mutex_lock(&q->sysfs_lock);
blk_set_queue_dying(q);
spin_lock_irq(lock);
queue_flag_set(QUEUE_FLAG_NOMERGES, q);
queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
queue_flag_set(QUEUE_FLAG_DYING, q);
spin_unlock_irq(lock);
blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
blk_queue_flag_set(QUEUE_FLAG_DYING, q);
mutex_unlock(&q->sysfs_lock);
/*
@ -384,9 +346,7 @@ void blk_cleanup_queue(struct request_queue *q)
rq_qos_exit(q);
spin_lock_irq(lock);
queue_flag_set(QUEUE_FLAG_DEAD, q);
spin_unlock_irq(lock);
blk_queue_flag_set(QUEUE_FLAG_DEAD, q);
/*
* make sure all in-progress dispatch are completed because

2
block/blk-mq.c
View File

@ -2756,7 +2756,7 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
if (!(set->flags & BLK_MQ_F_SG_MERGE))
queue_flag_set_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
blk_queue_flag_set(QUEUE_FLAG_NO_SG_MERGE, q);
q->sg_reserved_size = INT_MAX;

10
block/blk-settings.c
View File

@ -834,16 +834,14 @@ EXPORT_SYMBOL(blk_set_queue_depth);
*/
void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
{
spin_lock_irq(q->queue_lock);
if (wc)
queue_flag_set(QUEUE_FLAG_WC, q);
blk_queue_flag_set(QUEUE_FLAG_WC, q);
else
queue_flag_clear(QUEUE_FLAG_WC, q);
blk_queue_flag_clear(QUEUE_FLAG_WC, q);
if (fua)
queue_flag_set(QUEUE_FLAG_FUA, q);
blk_queue_flag_set(QUEUE_FLAG_FUA, q);
else
queue_flag_clear(QUEUE_FLAG_FUA, q);
spin_unlock_irq(q->queue_lock);
blk_queue_flag_clear(QUEUE_FLAG_FUA, q);
wbt_set_write_cache(q, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
}

28
block/blk-sysfs.c
View File

@ -316,14 +316,12 @@ static ssize_t queue_nomerges_store(struct request_queue *q, const char *page,
if (ret < 0)
return ret;
spin_lock_irq(q->queue_lock);
queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q);
blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q);
if (nm == 2)
queue_flag_set(QUEUE_FLAG_NOMERGES, q);
blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q);
else if (nm)
queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
spin_unlock_irq(q->queue_lock);
blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
return ret;
}
@ -347,18 +345,16 @@ queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count)
if (ret < 0)
return ret;
spin_lock_irq(q->queue_lock);
if (val == 2) {
queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q);
} else if (val == 1) {
queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q);
blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
} else if (val == 0) {
queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q);
blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q);
}
spin_unlock_irq(q->queue_lock);
#endif
return ret;
}
@ -889,7 +885,7 @@ int blk_register_queue(struct gendisk *disk)
WARN_ONCE(test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags),
"%s is registering an already registered queue\n",
kobject_name(&dev->kobj));
queue_flag_set_unlocked(QUEUE_FLAG_REGISTERED, q);
blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
/*
* SCSI probing may synchronously create and destroy a lot of
@ -901,7 +897,7 @@ int blk_register_queue(struct gendisk *disk)
* request_queues for non-existent devices never get registered.
*/
if (!blk_queue_init_done(q)) {
queue_flag_set_unlocked(QUEUE_FLAG_INIT_DONE, q);
blk_queue_flag_set(QUEUE_FLAG_INIT_DONE, q);
percpu_ref_switch_to_percpu(&q->q_usage_counter);
}

56
block/blk.h
View File

@ -48,62 +48,6 @@ static inline void queue_lockdep_assert_held(struct request_queue *q)
lockdep_assert_held(q->queue_lock);
}
static inline void queue_flag_set_unlocked(unsigned int flag,
struct request_queue *q)
{
if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) &&
kref_read(&q->kobj.kref))
lockdep_assert_held(q->queue_lock);
__set_bit(flag, &q->queue_flags);
}
static inline void queue_flag_clear_unlocked(unsigned int flag,
struct request_queue *q)
{
if (test_bit(QUEUE_FLAG_INIT_DONE, &q->queue_flags) &&
kref_read(&q->kobj.kref))
lockdep_assert_held(q->queue_lock);
__clear_bit(flag, &q->queue_flags);
}
static inline int queue_flag_test_and_clear(unsigned int flag,
struct request_queue *q)
{
queue_lockdep_assert_held(q);
if (test_bit(flag, &q->queue_flags)) {
__clear_bit(flag, &q->queue_flags);
return 1;
}
return 0;
}
static inline int queue_flag_test_and_set(unsigned int flag,
struct request_queue *q)
{
queue_lockdep_assert_held(q);
if (!test_bit(flag, &q->queue_flags)) {
__set_bit(flag, &q->queue_flags);
return 0;
}
return 1;
}
static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
{
queue_lockdep_assert_held(q);
__set_bit(flag, &q->queue_flags);
}
static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
{
queue_lockdep_assert_held(q);
__clear_bit(flag, &q->queue_flags);
}
static inline struct blk_flush_queue *
blk_get_flush_queue(struct request_queue *q, struct blk_mq_ctx *ctx)
{

1
include/linux/blkdev.h
View File

@ -621,7 +621,6 @@ struct request_queue {
void blk_queue_flag_set(unsigned int flag, struct request_queue *q);
void blk_queue_flag_clear(unsigned int flag, struct request_queue *q);
bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q);
bool blk_queue_flag_test_and_clear(unsigned int flag, struct request_queue *q);
#define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
#define blk_queue_dying(q) test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags)