dm thin: use slab mempools

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>

1 files changed, 99 insertions, 62 deletions

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index eb3d138ff55a..db1b041ce975 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -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 @@ out:
 /*
  * @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;
+