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dm bufio: conditionally enable branching for DM_BUFIO_CLIENT_NO_SLEEP 

Use jump_label to limit the need for branching unless the optional
DM_BUFIO_CLIENT_NO_SLEEP is used.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
This commit is contained in:
Mike Snitzer 2022-07-25 18:26:48 -04:00
parent df326e7a06
commit 3c1c875d05
1 changed files with 11 additions and 4 deletions
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15
drivers/md/dm-bufio.c
View File

@ -18,6 +18,7 @@
#include <linux/module.h>
#include <linux/rbtree.h>
#include <linux/stacktrace.h>
#include <linux/jump_label.h>
#define DM_MSG_PREFIX "bufio"
@ -164,13 +165,15 @@ struct dm_buffer {
#endif
};
static DEFINE_STATIC_KEY_FALSE(no_sleep_enabled);
/*----------------------------------------------------------------*/
#define dm_bufio_in_request() (!!current->bio_list)
static void dm_bufio_lock(struct dm_bufio_client *c)
{
if (c->no_sleep)
if (static_branch_unlikely(&no_sleep_enabled) && c->no_sleep)
spin_lock_irqsave_nested(&c->spinlock, c->spinlock_flags, dm_bufio_in_request());
else
mutex_lock_nested(&c->lock, dm_bufio_in_request());
@ -178,7 +181,7 @@ static void dm_bufio_lock(struct dm_bufio_client *c)
static int dm_bufio_trylock(struct dm_bufio_client *c)
{
if (c->no_sleep)
if (static_branch_unlikely(&no_sleep_enabled) && c->no_sleep)
return spin_trylock_irqsave(&c->spinlock, c->spinlock_flags);
else
return mutex_trylock(&c->lock);
@ -186,7 +189,7 @@ static int dm_bufio_trylock(struct dm_bufio_client *c)
static void dm_bufio_unlock(struct dm_bufio_client *c)
{
if (c->no_sleep)
if (static_branch_unlikely(&no_sleep_enabled) && c->no_sleep)
spin_unlock_irqrestore(&c->spinlock, c->spinlock_flags);
else
mutex_unlock(&c->lock);
@ -1760,8 +1763,10 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign
c->alloc_callback = alloc_callback;
c->write_callback = write_callback;
if (flags & DM_BUFIO_CLIENT_NO_SLEEP)
if (flags & DM_BUFIO_CLIENT_NO_SLEEP) {
c->no_sleep = true;
static_branch_inc(&no_sleep_enabled);
}
for (i = 0; i < LIST_SIZE; i++) {
INIT_LIST_HEAD(&c->lru[i]);
@ -1895,6 +1900,8 @@ void dm_bufio_client_destroy(struct dm_bufio_client *c)
kmem_cache_destroy(c->slab_buffer);
dm_io_client_destroy(c->dm_io);
mutex_destroy(&c->lock);
if (c->no_sleep)
static_branch_dec(&no_sleep_enabled);
kfree(c);
}
EXPORT_SYMBOL_GPL(dm_bufio_client_destroy);