dm bufio: use slab cache for dm_buffer structure allocations

kmalloc padded to the next power of two, using a slab cache avoids this.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index 776075ccf775d9d9896e9bfcb36bf02527e76a8a..4a216926ee198d4e2611ecd786cbdd85b612e066 100644 (file)
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -100,10 +100,10 @@ struct dm_bufio_client {
        unsigned block_size;
        unsigned char sectors_per_block_bits;
        unsigned char pages_per_block_bits;
-       unsigned aux_size;
        void (*alloc_callback)(struct dm_buffer *);
        void (*write_callback)(struct dm_buffer *);
 
+       struct kmem_cache *slab_buffer;
        struct kmem_cache *slab_cache;
        struct dm_io_client *dm_io;
 
@@ -435,8 +435,7 @@ static void free_buffer_data(struct dm_bufio_client *c,
  */
 static struct dm_buffer *alloc_buffer(struct dm_bufio_client *c, gfp_t gfp_mask)
 {
-       struct dm_buffer *b = kmalloc(sizeof(struct dm_buffer) + c->aux_size,
-                                     gfp_mask);
+       struct dm_buffer *b = kmem_cache_alloc(c->slab_buffer, gfp_mask);
 
        if (!b)
                return NULL;
@@ -445,7 +444,7 @@ static struct dm_buffer *alloc_buffer(struct dm_bufio_client *c, gfp_t gfp_mask)
 
        b->data = alloc_buffer_data(c, gfp_mask, &b->data_mode);
        if (!b->data) {
-               kfree(b);
+               kmem_cache_free(c->slab_buffer, b);
                return NULL;
        }
 
@@ -467,7 +466,7 @@ static void free_buffer(struct dm_buffer *b)
        adjust_total_allocated(b->data_mode, -(long)c->block_size);
 
        free_buffer_data(c, b->data, b->data_mode);
-       kfree(b);
+       kmem_cache_free(c->slab_buffer, b);
 }
 
 /*
@@ -1641,6 +1640,7 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign
        int r;
        struct dm_bufio_client *c;
        unsigned i;
+       char slab_name[27];
 
        BUG_ON(block_size < 1 << SECTOR_SHIFT ||
               (block_size & (block_size - 1)));
@@ -1658,7 +1658,6 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign
        c->pages_per_block_bits = (__ffs(block_size) >= PAGE_SHIFT) ?
                                  __ffs(block_size) - PAGE_SHIFT : 0;
 
-       c->aux_size = aux_size;
        c->alloc_callback = alloc_callback;
        c->write_callback = write_callback;
 
@@ -1683,15 +1682,24 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign
        }
 
        if (block_size < PAGE_SIZE) {
-               char name[26];
-               snprintf(name, sizeof name, "dm_bufio_cache-%u", c->block_size);
-               c->slab_cache = kmem_cache_create(name, c->block_size, ARCH_KMALLOC_MINALIGN,
+               snprintf(slab_name, sizeof slab_name, "dm_bufio_cache-%u", c->block_size);
+               c->slab_cache = kmem_cache_create(slab_name, c->block_size, ARCH_KMALLOC_MINALIGN,
                                                  SLAB_RECLAIM_ACCOUNT, NULL);
                if (!c->slab_cache) {
                        r = -ENOMEM;
                        goto bad;
                }
        }
+       if (aux_size)
+               snprintf(slab_name, sizeof slab_name, "dm_bufio_buffer-%u", aux_size);
+       else
+               snprintf(slab_name, sizeof slab_name, "dm_bufio_buffer");
+       c->slab_buffer = kmem_cache_create(slab_name, sizeof(struct dm_buffer) + aux_size,
+                                          0, SLAB_RECLAIM_ACCOUNT, NULL);
+       if (!c->slab_buffer) {
+               r = -ENOMEM;
+               goto bad;
+       }
 
        while (c->need_reserved_buffers) {
                struct dm_buffer *b = alloc_buffer(c, GFP_KERNEL);
@@ -1727,6 +1735,7 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign
                free_buffer(b);
        }
        kmem_cache_destroy(c->slab_cache);
+       kmem_cache_destroy(c->slab_buffer);
        dm_io_client_destroy(c->dm_io);
 bad_dm_io:
        mutex_destroy(&c->lock);
@@ -1774,6 +1783,7 @@ void dm_bufio_client_destroy(struct dm_bufio_client *c)
                BUG_ON(c->n_buffers[i]);
 
        kmem_cache_destroy(c->slab_cache);
+       kmem_cache_destroy(c->slab_buffer);
        dm_io_client_destroy(c->dm_io);
        mutex_destroy(&c->lock);
        kfree(c);