linux-master/mm/zbud.c

62  * freelists maintained in each pool. NCHUNKS_ORDER of 6 means that the
66  * 63 freelists per pool.
78  * struct zbud_pool - stores metadata for each zbud pool
79  * @lock:	protects all pool fields and first|last_chunk fields of any
80  *		zbud page in the pool
86  * @pages_nr:	number of zbud pages in the pool.
88  * This structure is allocated at pool creation time and maintains metadata
89  * pertaining to a particular zbud pool.
107  * @buddy:	links the zbud page into the unbuddied/buddied lists in the pool
194  * zbud_create_pool() - create a new zbud pool
195  * @gfp:	gfp flags when allocating the zbud pool structure
197  * Return: pointer to the new zbud pool or NULL if the metadata allocation
202 	struct zbud_pool *pool;
205 	pool = kzalloc(sizeof(struct zbud_pool), gfp);
206 	if (!pool)
208 	spin_lock_init(&pool->lock);
210 		INIT_LIST_HEAD(&pool->unbuddied[i]);
211 	INIT_LIST_HEAD(&pool->buddied);
212 	pool->pages_nr = 0;
213 	return pool;
217  * zbud_destroy_pool() - destroys an existing zbud pool
218  * @pool:	the zbud pool to be destroyed
220  * The pool should be emptied before this function is called.
222 static void zbud_destroy_pool(struct zbud_pool *pool)
224 	kfree(pool);
229  * @pool:	zbud pool from which to allocate
231  * @gfp:	gfp flags used if the pool needs to grow
234  * This function will attempt to find a free region in the pool large enough to
237  * allocated and added to the pool to satisfy the request.
240  * as zbud pool pages.
243  * gfp arguments are invalid or -ENOMEM if the pool was unable to allocate
246 static int zbud_alloc(struct zbud_pool *pool, size_t size, gfp_t gfp,
259 	spin_lock(&pool->lock);
263 		if (!list_empty(&pool->unbuddied[i])) {
264 			zhdr = list_first_entry(&pool->unbuddied[i],
276 	spin_unlock(&pool->lock);
280 	spin_lock(&pool->lock);
281 	pool->pages_nr++;
294 		list_add(&zhdr->buddy, &pool->unbuddied[freechunks]);
297 		list_add(&zhdr->buddy, &pool->buddied);
301 	spin_unlock(&pool->lock);
308  * @pool:	pool in which the allocation resided
311 static void zbud_free(struct zbud_pool *pool, unsigned long handle)
316 	spin_lock(&pool->lock);
331 		pool->pages_nr--;
335 		list_add(&zhdr->buddy, &pool->unbuddied[freechunks]);
338 	spin_unlock(&pool->lock);
343  * @pool:	pool in which the allocation resides
353 static void *zbud_map(struct zbud_pool *pool, unsigned long handle)
360  * @pool:	pool in which the allocation resides
363 static void zbud_unmap(struct zbud_pool *pool, unsigned long handle)
368  * zbud_get_pool_size() - gets the zbud pool size in pages
369  * @pool:	pool whose size is being queried
371  * Returns: size in pages of the given pool.  The pool lock need not be
374 static u64 zbud_get_pool_size(struct zbud_pool *pool)
376 	return pool->pages_nr;
388 static void zbud_zpool_destroy(void *pool)
390 	zbud_destroy_pool(pool);
393 static int zbud_zpool_malloc(void *pool, size_t size, gfp_t gfp,
396 	return zbud_alloc(pool, size, gfp, handle);
398 static void zbud_zpool_free(void *pool, unsigned long handle)
400 	zbud_free(pool, handle);
403 static void *zbud_zpool_map(void *pool, unsigned long handle,
406 	return zbud_map(pool, handle);
408 static void zbud_zpool_unmap(void *pool, unsigned long handle)
410 	zbud_unmap(pool, handle);
413 static u64 zbud_zpool_total_size(void *pool)
415 	return zbud_get_pool_size(pool) * PAGE_SIZE;