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dm delay: use per-bio data instead of a mempool and slab cache

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Starting with commit c0820cf5ad ("dm: introduce per_bio_data"),
device mapper has the capability to pre-allocate a target-specific
structure with the bio.

This patch changes dm-delay to use this facility instead of a slab cache
and mempool.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mikulas Patocka 2013-11-15 16:12:51 -05:00 committed by Mike Snitzer
parent 57a2f23856
commit 42065460ae
1 changed files with 7 additions and 28 deletions
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35
drivers/md/dm-delay.c
View File

@ -24,7 +24,6 @@ struct delay_c {
struct work_struct flush_expired_bios;
struct list_head delayed_bios;
atomic_t may_delay;
mempool_t *delayed_pool;
struct dm_dev *dev_read;
sector_t start_read;
@ -40,14 +39,11 @@ struct delay_c {
struct dm_delay_info {
struct delay_c *context;
struct list_head list;
struct bio *bio;
unsigned long expires;
};
static DEFINE_MUTEX(delayed_bios_lock);
static struct kmem_cache *delayed_cache;
static void handle_delayed_timer(unsigned long data)
{
struct delay_c *dc = (struct delay_c *)data;
@ -87,13 +83,14 @@ static struct bio *flush_delayed_bios(struct delay_c *dc, int flush_all)
mutex_lock(&delayed_bios_lock);
list_for_each_entry_safe(delayed, next, &dc->delayed_bios, list) {
if (flush_all || time_after_eq(jiffies, delayed->expires)) {
struct bio *bio = dm_bio_from_per_bio_data(delayed,
sizeof(struct dm_delay_info));
list_del(&delayed->list);
bio_list_add(&flush_bios, delayed->bio);
if ((bio_data_dir(delayed->bio) == WRITE))
bio_list_add(&flush_bios, bio);
if ((bio_data_dir(bio) == WRITE))
delayed->context->writes--;
else
delayed->context->reads--;
mempool_free(delayed, dc->delayed_pool);
continue;
}
@ -185,12 +182,6 @@ static int delay_ctr(struct dm_target *ti, unsigned int argc, char **argv)
}
out:
dc->delayed_pool = mempool_create_slab_pool(128, delayed_cache);
if (!dc->delayed_pool) {
DMERR("Couldn't create delayed bio pool.");
goto bad_dev_write;
}
dc->kdelayd_wq = alloc_workqueue("kdelayd", WQ_MEM_RECLAIM, 0);
if (!dc->kdelayd_wq) {
DMERR("Couldn't start kdelayd");
@ -206,12 +197,11 @@ out:
ti->num_flush_bios = 1;
ti->num_discard_bios = 1;
ti->per_bio_data_size = sizeof(struct dm_delay_info);
ti->private = dc;
return 0;
bad_queue:
mempool_destroy(dc->delayed_pool);
bad_dev_write:
if (dc->dev_write)
dm_put_device(ti, dc->dev_write);
bad_dev_read:
@ -232,7 +222,6 @@ static void delay_dtr(struct dm_target *ti)
if (dc->dev_write)
dm_put_device(ti, dc->dev_write);
mempool_destroy(dc->delayed_pool);
kfree(dc);
}
@ -244,10 +233,9 @@ static int delay_bio(struct delay_c *dc, int delay, struct bio *bio)
if (!delay || !atomic_read(&dc->may_delay))
return 1;
delayed = mempool_alloc(dc->delayed_pool, GFP_NOIO);
delayed = dm_per_bio_data(bio, sizeof(struct dm_delay_info));
delayed->context = dc;
delayed->bio = bio;
delayed->expires = expires = jiffies + (delay * HZ / 1000);
mutex_lock(&delayed_bios_lock);
@ -356,13 +344,7 @@ static struct target_type delay_target = {
static int __init dm_delay_init(void)
{
int r = -ENOMEM;
delayed_cache = KMEM_CACHE(dm_delay_info, 0);
if (!delayed_cache) {
DMERR("Couldn't create delayed bio cache.");
goto bad_memcache;
}
int r;
r = dm_register_target(&delay_target);
if (r < 0) {
@ -373,15 +355,12 @@ static int __init dm_delay_init(void)
return 0;
bad_register:
kmem_cache_destroy(delayed_cache);
bad_memcache:
return r;
}
static void __exit dm_delay_exit(void)
{
dm_unregister_target(&delay_target);
kmem_cache_destroy(delayed_cache);
}
/* Module hooks */