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dm thin: use slab mempools

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Use dedicated caches prefixed with a "dm_" name rather than relying on
kmalloc mempools backed by generic slab caches so the memory usage of
thin provisioning (and any leaks) can be accounted for independently.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Mike Snitzer 2012-06-03 00:30:00 +01:00 committed by Alasdair G Kergon
parent 35991652ba
commit a24c25696b
1 changed files with 99 additions and 62 deletions
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161
drivers/md/dm-thin.c
View file

@ -111,7 +111,7 @@ struct cell_key {
dm_block_t block;
};
struct cell {
struct dm_bio_prison_cell {
struct hlist_node list;
struct bio_prison *prison;
struct cell_key key;
@ -141,6 +141,8 @@ static uint32_t calc_nr_buckets(unsigned nr_cells)
return n;
}
static struct kmem_cache *_cell_cache;
/*
* @nr_cells should be the number of cells you want in use _concurrently_.
* Don't confuse it with the number of distinct keys.
@ -157,8 +159,7 @@ static struct bio_prison *prison_create(unsigned nr_cells)
return NULL;
spin_lock_init(&prison->lock);
prison->cell_pool = mempool_create_kmalloc_pool(nr_cells,
sizeof(struct cell));
prison->cell_pool = mempool_create_slab_pool(nr_cells, _cell_cache);
if (!prison->cell_pool) {
kfree(prison);
return NULL;
@ -194,10 +195,10 @@ static int keys_equal(struct cell_key *lhs, struct cell_key *rhs)
(lhs->block == rhs->block);
}
static struct cell *__search_bucket(struct hlist_head *bucket,
struct cell_key *key)
static struct dm_bio_prison_cell *__search_bucket(struct hlist_head *bucket,
struct cell_key *key)
{
struct cell *cell;
struct dm_bio_prison_cell *cell;
struct hlist_node *tmp;
hlist_for_each_entry(cell, tmp, bucket, list)
@ -214,12 +215,12 @@ static struct cell *__search_bucket(struct hlist_head *bucket,
* Returns 1 if the cell was already held, 0 if @inmate is the new holder.
*/
static int bio_detain(struct bio_prison *prison, struct cell_key *key,
struct bio *inmate, struct cell **ref)
struct bio *inmate, struct dm_bio_prison_cell **ref)
{
int r = 1;
unsigned long flags;
uint32_t hash = hash_key(prison, key);
struct cell *cell, *cell2;
struct dm_bio_prison_cell *cell, *cell2;
BUG_ON(hash > prison->nr_buckets);
@ -273,7 +274,7 @@ static int bio_detain(struct bio_prison *prison, struct cell_key *key,
/*
* @inmates must have been initialised prior to this call
*/
static void __cell_release(struct cell *cell, struct bio_list *inmates)
static void __cell_release(struct dm_bio_prison_cell *cell, struct bio_list *inmates)
{
struct bio_prison *prison = cell->prison;
@ -287,7 +288,7 @@ static void __cell_release(struct cell *cell, struct bio_list *inmates)
mempool_free(cell, prison->cell_pool);
}
static void cell_release(struct cell *cell, struct bio_list *bios)
static void cell_release(struct dm_bio_prison_cell *cell, struct bio_list *bios)
{
unsigned long flags;
struct bio_prison *prison = cell->prison;
@ -303,7 +304,7 @@ static void cell_release(struct cell *cell, struct bio_list *bios)
* bio may be in the cell. This function releases the cell, and also does
* a sanity check.
*/
static void __cell_release_singleton(struct cell *cell, struct bio *bio)
static void __cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *bio)
{
BUG_ON(cell->holder != bio);
BUG_ON(!bio_list_empty(&cell->bios));
@ -311,7 +312,7 @@ static void __cell_release_singleton(struct cell *cell, struct bio *bio)
__cell_release(cell, NULL);
}
static void cell_release_singleton(struct cell *cell, struct bio *bio)
static void cell_release_singleton(struct dm_bio_prison_cell *cell, struct bio *bio)
{
unsigned long flags;
struct bio_prison *prison = cell->prison;
@ -324,7 +325,8 @@ static void cell_release_singleton(struct cell *cell, struct bio *bio)
/*
* Sometimes we don't want the holder, just the additional bios.
*/
static void __cell_release_no_holder(struct cell *cell, struct bio_list *inmates)
static void __cell_release_no_holder(struct dm_bio_prison_cell *cell,
struct bio_list *inmates)
{
struct bio_prison *prison = cell->prison;
@ -334,7 +336,8 @@ static void __cell_release_no_holder(struct cell *cell, struct bio_list *inmates
mempool_free(cell, prison->cell_pool);
}
static void cell_release_no_holder(struct cell *cell, struct bio_list *inmates)
static void cell_release_no_holder(struct dm_bio_prison_cell *cell,
struct bio_list *inmates)
{
unsigned long flags;
struct bio_prison *prison = cell->prison;
@ -344,7 +347,7 @@ static void cell_release_no_holder(struct cell *cell, struct bio_list *inmates)
spin_unlock_irqrestore(&prison->lock, flags);
}
static void cell_error(struct cell *cell)
static void cell_error(struct dm_bio_prison_cell *cell)
{
struct bio_prison *prison = cell->prison;
struct bio_list bios;
@ -491,7 +494,7 @@ static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,
* also provides the interface for creating and destroying internal
* devices.
*/
struct new_mapping;
struct dm_thin_new_mapping;
struct pool_features {
unsigned zero_new_blocks:1;
@ -537,7 +540,7 @@ struct pool {
struct deferred_set shared_read_ds;
struct deferred_set all_io_ds;
struct new_mapping *next_mapping;
struct dm_thin_new_mapping *next_mapping;
mempool_t *mapping_pool;
mempool_t *endio_hook_pool;
};
@ -630,11 +633,11 @@ static struct pool *__pool_table_lookup_metadata_dev(struct block_device *md_dev
/*----------------------------------------------------------------*/
struct endio_hook {
struct dm_thin_endio_hook {
struct thin_c *tc;
struct deferred_entry *shared_read_entry;
struct deferred_entry *all_io_entry;
struct new_mapping *overwrite_mapping;
struct dm_thin_new_mapping *overwrite_mapping;
};
static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
@ -647,7 +650,8 @@ static void __requeue_bio_list(struct thin_c *tc, struct bio_list *master)
bio_list_init(master);
while ((bio = bio_list_pop(&bios))) {
struct endio_hook *h = dm_get_mapinfo(bio)->ptr;
struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
if (h->tc == tc)
bio_endio(bio, DM_ENDIO_REQUEUE);
else
@ -736,7 +740,7 @@ static void wake_worker(struct pool *pool)
/*
* Bio endio functions.
*/
struct new_mapping {
struct dm_thin_new_mapping {
struct list_head list;
unsigned quiesced:1;
@ -746,7 +750,7 @@ struct new_mapping {
struct thin_c *tc;
dm_block_t virt_block;
dm_block_t data_block;
struct cell *cell, *cell2;
struct dm_bio_prison_cell *cell, *cell2;
int err;
/*
@ -759,7 +763,7 @@ struct new_mapping {
bio_end_io_t *saved_bi_end_io;
};
static void __maybe_add_mapping(struct new_mapping *m)
static void __maybe_add_mapping(struct dm_thin_new_mapping *m)
{
struct pool *pool = m->tc->pool;
@ -772,7 +776,7 @@ static void __maybe_add_mapping(struct new_mapping *m)
static void copy_complete(int read_err, unsigned long write_err, void *context)
{
unsigned long flags;
struct new_mapping *m = context;
struct dm_thin_new_mapping *m = context;
struct pool *pool = m->tc->pool;
m->err = read_err || write_err ? -EIO : 0;
@ -786,8 +790,8 @@ static void copy_complete(int read_err, unsigned long write_err, void *context)
static void overwrite_endio(struct bio *bio, int err)
{
unsigned long flags;
struct endio_hook *h = dm_get_mapinfo(bio)->ptr;
struct new_mapping *m = h->overwrite_mapping;
struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
struct dm_thin_new_mapping *m = h->overwrite_mapping;
struct pool *pool = m->tc->pool;
m->err = err;
@ -811,7 +815,7 @@ static void overwrite_endio(struct bio *bio, int err)
/*
* This sends the bios in the cell back to the deferred_bios list.
*/
static void cell_defer(struct thin_c *tc, struct cell *cell,
static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell,
dm_block_t data_block)
{
struct pool *pool = tc->pool;
@ -828,7 +832,7 @@ static void cell_defer(struct thin_c *tc, struct cell *cell,
* Same as cell_defer above, except it omits one particular detainee,
* a write bio that covers the block and has already been processed.
*/
static void cell_defer_except(struct thin_c *tc, struct cell *cell)
static void cell_defer_except(struct thin_c *tc, struct dm_bio_prison_cell *cell)
{
struct bio_list bios;
struct pool *pool = tc->pool;
@ -843,7 +847,7 @@ static void cell_defer_except(struct thin_c *tc, struct cell *cell)
wake_worker(pool);
}
static void process_prepared_mapping(struct new_mapping *m)
static void process_prepared_mapping(struct dm_thin_new_mapping *m)
{
struct thin_c *tc = m->tc;
struct bio *bio;
@ -886,7 +890,7 @@ static void process_prepared_mapping(struct new_mapping *m)
mempool_free(m, tc->pool->mapping_pool);
}
static void process_prepared_discard(struct new_mapping *m)
static void process_prepared_discard(struct dm_thin_new_mapping *m)
{
int r;
struct thin_c *tc = m->tc;
@ -909,11 +913,11 @@ static void process_prepared_discard(struct new_mapping *m)
}
static void process_prepared(struct pool *pool, struct list_head *head,
void (*fn)(struct new_mapping *))
void (*fn)(struct dm_thin_new_mapping *))
{
unsigned long flags;
struct list_head maps;
struct new_mapping *m, *tmp;
struct dm_thin_new_mapping *m, *tmp;
INIT_LIST_HEAD(&maps);
spin_lock_irqsave(&pool->lock, flags);
@ -957,9 +961,9 @@ static int ensure_next_mapping(struct pool *pool)
return pool->next_mapping ? 0 : -ENOMEM;
}
static struct new_mapping *get_next_mapping(struct pool *pool)
static struct dm_thin_new_mapping *get_next_mapping(struct pool *pool)
{
struct new_mapping *r = pool->next_mapping;
struct dm_thin_new_mapping *r = pool->next_mapping;
BUG_ON(!pool->next_mapping);
@ -971,11 +975,11 @@ static struct new_mapping *get_next_mapping(struct pool *pool)
static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
struct dm_dev *origin, dm_block_t data_origin,
dm_block_t data_dest,
struct cell *cell, struct bio *bio)
struct dm_bio_prison_cell *cell, struct bio *bio)
{
int r;
struct pool *pool = tc->pool;
struct new_mapping *m = get_next_mapping(pool);
struct dm_thin_new_mapping *m = get_next_mapping(pool);
INIT_LIST_HEAD(&m->list);
m->quiesced = 0;
@ -997,7 +1001,8 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
* bio immediately. Otherwise we use kcopyd to clone the data first.
*/
if (io_overwrites_block(pool, bio)) {
struct endio_hook *h = dm_get_mapinfo(bio)->ptr;
struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
h->overwrite_mapping = m;
m->bio = bio;
save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
@ -1025,7 +1030,7 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block,
static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
dm_block_t data_origin, dm_block_t data_dest,
struct cell *cell, struct bio *bio)
struct dm_bio_prison_cell *cell, struct bio *bio)
{
schedule_copy(tc, virt_block, tc->pool_dev,
data_origin, data_dest, cell, bio);
@ -1033,18 +1038,18 @@ static void schedule_internal_copy(struct thin_c *tc, dm_block_t virt_block,
static void schedule_external_copy(struct thin_c *tc, dm_block_t virt_block,
dm_block_t data_dest,
struct cell *cell, struct bio *bio)
struct dm_bio_prison_cell *cell, struct bio *bio)
{
schedule_copy(tc, virt_block, tc->origin_dev,
virt_block, data_dest, cell, bio);
}
static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
dm_block_t data_block, struct cell *cell,
dm_block_t data_block, struct dm_bio_prison_cell *cell,
struct bio *bio)
{
struct pool *pool = tc->pool;
struct new_mapping *m = get_next_mapping(pool);
struct dm_thin_new_mapping *m = get_next_mapping(pool);
INIT_LIST_HEAD(&m->list);
m->quiesced = 1;
@ -1065,12 +1070,12 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block,
process_prepared_mapping(m);
else if (io_overwrites_block(pool, bio)) {
struct endio_hook *h = dm_get_mapinfo(bio)->ptr;
struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
h->overwrite_mapping = m;
m->bio = bio;
save_and_set_endio(bio, &m->saved_bi_end_io, overwrite_endio);
remap_and_issue(tc, bio, data_block);
} else {
int r;
struct dm_io_region to;
@ -1155,7 +1160,7 @@ static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
*/
static void retry_on_resume(struct bio *bio)
{
struct endio_hook *h = dm_get_mapinfo(bio)->ptr;
struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
struct thin_c *tc = h->tc;
struct pool *pool = tc->pool;
unsigned long flags;
@ -1165,7 +1170,7 @@ static void retry_on_resume(struct bio *bio)
spin_unlock_irqrestore(&pool->lock, flags);
}
static void no_space(struct cell *cell)
static void no_space(struct dm_bio_prison_cell *cell)
{
struct bio *bio;
struct bio_list bios;
@ -1182,11 +1187,11 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
int r;
unsigned long flags;
struct pool *pool = tc->pool;
struct cell *cell, *cell2;
struct dm_bio_prison_cell *cell, *cell2;
struct cell_key key, key2;
dm_block_t block = get_bio_block(tc, bio);
struct dm_thin_lookup_result lookup_result;
struct new_mapping *m;
struct dm_thin_new_mapping *m;
build_virtual_key(tc->td, block, &key);
if (bio_detain(tc->pool->prison, &key, bio, &cell))
@ -1263,7 +1268,7 @@ static void process_discard(struct thin_c *tc, struct bio *bio)
static void break_sharing(struct thin_c *tc, struct bio *bio, dm_block_t block,
struct cell_key *key,
struct dm_thin_lookup_result *lookup_result,
struct cell *cell)
struct dm_bio_prison_cell *cell)
{
int r;
dm_block_t data_block;
@ -1290,7 +1295,7 @@ static void process_shared_bio(struct thin_c *tc, struct bio *bio,
dm_block_t block,
struct dm_thin_lookup_result *lookup_result)
{
struct cell *cell;
struct dm_bio_prison_cell *cell;
struct pool *pool = tc->pool;
struct cell_key key;
@ -1305,7 +1310,7 @@ static void process_shared_bio(struct thin_c *tc, struct bio *bio,
if (bio_data_dir(bio) == WRITE)
break_sharing(tc, bio, block, &key, lookup_result, cell);
else {
struct endio_hook *h = dm_get_mapinfo(bio)->ptr;
struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
h->shared_read_entry = ds_inc(&pool->shared_read_ds);
@ -1315,7 +1320,7 @@ static void process_shared_bio(struct thin_c *tc, struct bio *bio,
}
static void provision_block(struct thin_c *tc, struct bio *bio, dm_block_t block,
struct cell *cell)
struct dm_bio_prison_cell *cell)
{
int r;
dm_block_t data_block;
@ -1363,7 +1368,7 @@ static void process_bio(struct thin_c *tc, struct bio *bio)
{
int r;
dm_block_t block = get_bio_block(tc, bio);
struct cell *cell;
struct dm_bio_prison_cell *cell;
struct cell_key key;
struct dm_thin_lookup_result lookup_result;
@ -1432,7 +1437,7 @@ static void process_deferred_bios(struct pool *pool)
spin_unlock_irqrestore(&pool->lock, flags);
while ((bio = bio_list_pop(&bios))) {
struct endio_hook *h = dm_get_mapinfo(bio)->ptr;
struct dm_thin_endio_hook *h = dm_get_mapinfo(bio)->ptr;
struct thin_c *tc = h->tc;
/*
@ -1522,10 +1527,10 @@ static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
wake_worker(pool);
}
static struct endio_hook *thin_hook_bio(struct thin_c *tc, struct bio *bio)
static struct dm_thin_endio_hook *thin_hook_bio(struct thin_c *tc, struct bio *bio)
{
struct pool *pool = tc->pool;
struct endio_hook *h = mempool_alloc(pool->endio_hook_pool, GFP_NOIO);
struct dm_thin_endio_hook *h = mempool_alloc(pool->endio_hook_pool, GFP_NOIO);
h->tc = tc;
h->shared_read_entry = NULL;
@ -1687,6 +1692,9 @@ static void __pool_destroy(struct pool *pool)
kfree(pool);
}
static struct kmem_cache *_new_mapping_cache;
static struct kmem_cache *_endio_hook_cache;
static struct pool *pool_create(struct mapped_device *pool_md,
struct block_device *metadata_dev,
unsigned long block_size, char **error)
@ -1755,16 +1763,16 @@ static struct pool *pool_create(struct mapped_device *pool_md,
ds_init(&pool->all_io_ds);
pool->next_mapping = NULL;
pool->mapping_pool =
mempool_create_kmalloc_pool(MAPPING_POOL_SIZE, sizeof(struct new_mapping));
pool->mapping_pool = mempool_create_slab_pool(MAPPING_POOL_SIZE,
_new_mapping_cache);
if (!pool->mapping_pool) {
*error = "Error creating pool's mapping mempool";
err_p = ERR_PTR(-ENOMEM);
goto bad_mapping_pool;
}
pool->endio_hook_pool =
mempool_create_kmalloc_pool(ENDIO_HOOK_POOL_SIZE, sizeof(struct endio_hook));
pool->endio_hook_pool = mempool_create_slab_pool(ENDIO_HOOK_POOL_SIZE,
_endio_hook_cache);
if (!pool->endio_hook_pool) {
*error = "Error creating pool's endio_hook mempool";
err_p = ERR_PTR(-ENOMEM);
@ -2613,9 +2621,9 @@ static int thin_endio(struct dm_target *ti,
union map_info *map_context)
{
unsigned long flags;
struct endio_hook *h = map_context->ptr;
struct dm_thin_endio_hook *h = map_context->ptr;
struct list_head work;
struct new_mapping *m, *tmp;
struct dm_thin_new_mapping *m, *tmp;
struct pool *pool = h->tc->pool;
if (h->shared_read_entry) {
@ -2755,7 +2763,32 @@ static int __init dm_thin_init(void)
r = dm_register_target(&pool_target);
if (r)
dm_unregister_target(&thin_target);
goto bad_pool_target;
r = -ENOMEM;
_cell_cache = KMEM_CACHE(dm_bio_prison_cell, 0);
if (!_cell_cache)
goto bad_cell_cache;
_new_mapping_cache = KMEM_CACHE(dm_thin_new_mapping, 0);
if (!_new_mapping_cache)
goto bad_new_mapping_cache;
_endio_hook_cache = KMEM_CACHE(dm_thin_endio_hook, 0);
if (!_endio_hook_cache)
goto bad_endio_hook_cache;
return 0;
bad_endio_hook_cache:
kmem_cache_destroy(_new_mapping_cache);
bad_new_mapping_cache:
kmem_cache_destroy(_cell_cache);
bad_cell_cache:
dm_unregister_target(&pool_target);
bad_pool_target:
dm_unregister_target(&thin_target);
return r;
}
@ -2764,6 +2797,10 @@ static void dm_thin_exit(void)
{
dm_unregister_target(&thin_target);
dm_unregister_target(&pool_target);
kmem_cache_destroy(_cell_cache);
kmem_cache_destroy(_new_mapping_cache);
kmem_cache_destroy(_endio_hook_cache);
}
module_init(dm_thin_init);