Currently, all slab allocators can merge duplicate caches. So we don't
need extra merging logic in dm-bufio. We can just allocate one slab cache
per client and let the allocator merge them.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
---
drivers/md/dm-bufio.c | 53 +++++++++++++-------------------------------------
1 file changed, 14 insertions(+), 39 deletions(-)
Index: linux-2.6/drivers/md/dm-bufio.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-bufio.c 2018-03-23 22:40:52.177960000 +0100
+++ linux-2.6/drivers/md/dm-bufio.c 2018-03-26 14:43:49.857250000 +0200
@@ -57,10 +57,9 @@
#define DM_BUFIO_INLINE_VECS 16
/*
- * Don't try to use kmem_cache_alloc for blocks larger than this.
+ * Don't try to use alloc_pages for blocks larger than this.
* For explanation, see alloc_buffer_data below.
*/
-#define DM_BUFIO_BLOCK_SIZE_SLAB_LIMIT (PAGE_SIZE >> 1)
#define DM_BUFIO_BLOCK_SIZE_GFP_LIMIT (PAGE_SIZE << (MAX_ORDER - 1))
/*
@@ -101,11 +100,11 @@ struct dm_bufio_client {
unsigned block_size;
unsigned char sectors_per_block_bits;
unsigned char pages_per_block_bits;
- unsigned char blocks_per_page_bits;
unsigned aux_size;
void (*alloc_callback)(struct dm_buffer *);
void (*write_callback)(struct dm_buffer *);
+ struct kmem_cache *slab_cache;
struct dm_io_client *dm_io;
struct list_head reserved_buffers;
@@ -172,19 +171,6 @@ struct dm_buffer {
/*----------------------------------------------------------------*/
-static struct kmem_cache *dm_bufio_caches[PAGE_SHIFT - SECTOR_SHIFT];
-
-static inline int dm_bufio_cache_index(struct dm_bufio_client *c)
-{
- unsigned ret = c->blocks_per_page_bits - 1;
-
- BUG_ON(ret >= ARRAY_SIZE(dm_bufio_caches));
-
- return ret;
-}
-
-#define DM_BUFIO_CACHE(c) (dm_bufio_caches[dm_bufio_cache_index(c)])
-
#define dm_bufio_in_request() (!!current->bio_list)
static void dm_bufio_lock(struct dm_bufio_client *c)
@@ -384,9 +370,9 @@ static void __cache_size_refresh(void)
static void *alloc_buffer_data(struct dm_bufio_client *c, gfp_t gfp_mask,
enum data_mode *data_mode)
{
- if (c->block_size <= DM_BUFIO_BLOCK_SIZE_SLAB_LIMIT) {
+ if (unlikely(c->slab_cache != NULL)) {
*data_mode = DATA_MODE_SLAB;
- return kmem_cache_alloc(DM_BUFIO_CACHE(c), gfp_mask);
+ return kmem_cache_alloc(c->slab_cache, gfp_mask);
}
if (c->block_size <= DM_BUFIO_BLOCK_SIZE_GFP_LIMIT &&
@@ -426,7 +412,7 @@ static void free_buffer_data(struct dm_b
{
switch (data_mode) {
case DATA_MODE_SLAB:
- kmem_cache_free(DM_BUFIO_CACHE(c), data);
+ kmem_cache_free(c->slab_cache, data);
break;
case DATA_MODE_GET_FREE_PAGES:
@@ -1672,8 +1658,6 @@ struct dm_bufio_client *dm_bufio_client_
c->sectors_per_block_bits = __ffs(block_size) - SECTOR_SHIFT;
c->pages_per_block_bits = (__ffs(block_size) >= PAGE_SHIFT) ?
__ffs(block_size) - PAGE_SHIFT : 0;
- c->blocks_per_page_bits = (__ffs(block_size) < PAGE_SHIFT ?
- PAGE_SHIFT - __ffs(block_size) : 0);
c->aux_size = aux_size;
c->alloc_callback = alloc_callback;
@@ -1699,20 +1683,15 @@ struct dm_bufio_client *dm_bufio_client_
goto bad_dm_io;
}
- mutex_lock(&dm_bufio_clients_lock);
- if (c->blocks_per_page_bits) {
- if (!DM_BUFIO_CACHE(c)) {
- char name[26];
- snprintf(name, sizeof name, "dm_bufio_cache-%u", c->block_size);
- DM_BUFIO_CACHE(c) = kmem_cache_create(name, c->block_size, c->block_size, 0, NULL);
- if (!DM_BUFIO_CACHE(c)) {
- r = -ENOMEM;
- mutex_unlock(&dm_bufio_clients_lock);
- goto bad;
- }
+ 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, c->block_size, 0, NULL);
+ if (!c->slab_cache) {
+ r = -ENOMEM;
+ goto bad;
}
}
- mutex_unlock(&dm_bufio_clients_lock);
while (c->need_reserved_buffers) {
struct dm_buffer *b = alloc_buffer(c, GFP_KERNEL);
@@ -1747,6 +1726,7 @@ bad:
list_del(&b->lru_list);
free_buffer(b);
}
+ kmem_cache_destroy(c->slab_cache);
dm_io_client_destroy(c->dm_io);
bad_dm_io:
mutex_destroy(&c->lock);
@@ -1793,6 +1773,7 @@ void dm_bufio_client_destroy(struct dm_b
for (i = 0; i < LIST_SIZE; i++)
BUG_ON(c->n_buffers[i]);
+ kmem_cache_destroy(c->slab_cache);
dm_io_client_destroy(c->dm_io);
mutex_destroy(&c->lock);
kfree(c);
@@ -1896,8 +1877,6 @@ static int __init dm_bufio_init(void)
dm_bufio_allocated_vmalloc = 0;
dm_bufio_current_allocated = 0;
- memset(&dm_bufio_caches, 0, sizeof dm_bufio_caches);
-
mem = (__u64)mult_frac(totalram_pages - totalhigh_pages,
DM_BUFIO_MEMORY_PERCENT, 100) << PAGE_SHIFT;
@@ -1932,14 +1911,10 @@ static int __init dm_bufio_init(void)
static void __exit dm_bufio_exit(void)
{
int bug = 0;
- int i;
cancel_delayed_work_sync(&dm_bufio_work);
destroy_workqueue(dm_bufio_wq);
- for (i = 0; i < ARRAY_SIZE(dm_bufio_caches); i++)
- kmem_cache_destroy(dm_bufio_caches[i]);
-
if (dm_bufio_client_count) {
DMCRIT("%s: dm_bufio_client_count leaked: %d",
__func__, dm_bufio_client_count);
--
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