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rbd: allocate image object names with a slab allocator 

The names of objects used for image object requests are always fixed
size.  So create a slab cache to manage them.  Define a new function
rbd_segment_name_free() to match rbd_segment_name() (which is what
supplies the dynamically-allocated name buffer).

This is part of:
    http://tracker.ceph.com/issues/3926

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
This commit is contained in:
Alex Elder 2013-05-01 12:43:04 -05:00
parent 868311b1eb
commit 78c2a44aae
1 changed files with 29 additions and 3 deletions
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32
drivers/block/rbd.c
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@ -345,8 +345,11 @@ static DEFINE_SPINLOCK(rbd_dev_list_lock);
static LIST_HEAD(rbd_client_list); /* clients */
static DEFINE_SPINLOCK(rbd_client_list_lock);
/* Slab caches for frequently-allocated structures */
static struct kmem_cache *rbd_img_request_cache;
static struct kmem_cache *rbd_obj_request_cache;
static struct kmem_cache *rbd_segment_name_cache;
static int rbd_img_request_submit(struct rbd_img_request *img_request);
@ -985,7 +988,7 @@ static const char *rbd_segment_name(struct rbd_device *rbd_dev, u64 offset)
u64 segment;
int ret;
name = kmalloc(MAX_OBJ_NAME_SIZE + 1, GFP_NOIO);
name = kmem_cache_alloc(rbd_segment_name_cache, GFP_NOIO);
if (!name)
return NULL;
segment = offset >> rbd_dev->header.obj_order;
@ -1001,6 +1004,13 @@ static const char *rbd_segment_name(struct rbd_device *rbd_dev, u64 offset)
return name;
}
static void rbd_segment_name_free(const char *name)
{
/* The explicit cast here is needed to drop the const qualifier */
kmem_cache_free(rbd_segment_name_cache, (void *)name);
}
static u64 rbd_segment_offset(struct rbd_device *rbd_dev, u64 offset)
{
u64 segment_size = (u64) 1 << rbd_dev->header.obj_order;
@ -2033,7 +2043,8 @@ static int rbd_img_request_fill(struct rbd_img_request *img_request,
length = rbd_segment_length(rbd_dev, img_offset, resid);
obj_request = rbd_obj_request_create(object_name,
offset, length, type);
kfree(object_name); /* object request has its own copy */
/* object request has its own copy of the object name */
rbd_segment_name_free(object_name);
if (!obj_request)
goto out_unwind;
@ -5018,8 +5029,19 @@ static int rbd_slab_init(void)
sizeof (struct rbd_obj_request),
__alignof__(struct rbd_obj_request),
0, NULL);
if (rbd_obj_request_cache)
if (!rbd_obj_request_cache)
goto out_err;
rbd_assert(!rbd_segment_name_cache);
rbd_segment_name_cache = kmem_cache_create("rbd_segment_name",
MAX_OBJ_NAME_SIZE + 1, 1, 0, NULL);
if (rbd_segment_name_cache)
return 0;
out_err:
if (rbd_obj_request_cache) {
kmem_cache_destroy(rbd_obj_request_cache);
rbd_obj_request_cache = NULL;
}
kmem_cache_destroy(rbd_img_request_cache);
rbd_img_request_cache = NULL;
@ -5029,6 +5051,10 @@ static int rbd_slab_init(void)
static void rbd_slab_exit(void)
{
rbd_assert(rbd_segment_name_cache);
kmem_cache_destroy(rbd_segment_name_cache);
rbd_segment_name_cache = NULL;
rbd_assert(rbd_obj_request_cache);
kmem_cache_destroy(rbd_obj_request_cache);
rbd_obj_request_cache = NULL;