Commit 78c2a44a authored by Alex Elder's avatar Alex Elder
Browse files

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: default avatarAlex Elder <elder@inktank.com>
Reviewed-by: default avatarJosh Durgin <josh.durgin@inktank.com>
parent 868311b1

drivers/block/rbd.c

+29 −3
Original line number Diff line number Diff line
@@ -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;

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