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dm bufio: remove code that merges slab caches

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All slab allocators can merge duplicate caches.  So dm-bufio doesn't
need extra slab merging logic.  Instead it can just allocate one slab
cache per client and let the allocator merge them.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Mikulas Patocka 2018-03-26 20:29:42 +02:00 committed by Mike Snitzer
parent eeb67a0ba0
commit 21bb132767
1 changed files with 14 additions and 39 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

53
drivers/md/dm-bufio.c
View file

@ -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_bufio_client *c,
{
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_create(struct block_device *bdev, unsign
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_create(struct block_device *bdev, unsign
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 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign
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_bufio_client *c)
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);