blob: 5e98eeb2af3b970220c7743016f9f85b0213ae8b [file] [log] [blame]
* Basic general purpose allocator for managing special purpose
* memory, for example, memory that is not managed by the regular
* kmalloc/kfree interface. Uses for this includes on-device special
* memory, uncached memory etc.
* It is safe to use the allocator in NMI handlers and other special
* unblockable contexts that could otherwise deadlock on locks. This
* is implemented by using atomic operations and retries on any
* conflicts. The disadvantage is that there may be livelocks in
* extreme cases. For better scalability, one allocator can be used
* for each CPU.
* The lockless operation only works if there is enough memory
* available. If new memory is added to the pool a lock has to be
* still taken. So any user relying on locklessness has to ensure
* that sufficient memory is preallocated.
* The basic atomic operation of this allocator is cmpxchg on long.
* On architectures that don't have NMI-safe cmpxchg implementation,
* the allocator can NOT be used in NMI handler. So code uses the
* allocator in NMI handler should depend on
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
#ifndef __GENALLOC_H__
#define __GENALLOC_H__
* General purpose special memory pool descriptor.
struct gen_pool {
spinlock_t lock;
struct list_head chunks; /* list of chunks in this pool */
int min_alloc_order; /* minimum allocation order */
* General purpose special memory pool chunk descriptor.
struct gen_pool_chunk {
struct list_head next_chunk; /* next chunk in pool */
atomic_t avail;
phys_addr_t phys_addr; /* physical starting address of memory chunk */
unsigned long start_addr; /* starting address of memory chunk */
unsigned long end_addr; /* ending address of memory chunk */
unsigned long bits[0]; /* bitmap for allocating memory chunk */
extern struct gen_pool *gen_pool_create(int, int);
extern phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long);
extern int gen_pool_add_virt(struct gen_pool *, unsigned long, phys_addr_t,
size_t, int);
* gen_pool_add - add a new chunk of special memory to the pool
* @pool: pool to add new memory chunk to
* @addr: starting address of memory chunk to add to pool
* @size: size in bytes of the memory chunk to add to pool
* @nid: node id of the node the chunk structure and bitmap should be
* allocated on, or -1
* Add a new chunk of special memory to the specified pool.
* Returns 0 on success or a -ve errno on failure.
static inline int gen_pool_add(struct gen_pool *pool, unsigned long addr,
size_t size, int nid)
return gen_pool_add_virt(pool, addr, -1, size, nid);
extern void gen_pool_destroy(struct gen_pool *);
extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);
extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);
extern void gen_pool_for_each_chunk(struct gen_pool *,
void (*)(struct gen_pool *, struct gen_pool_chunk *, void *), void *);
extern size_t gen_pool_avail(struct gen_pool *);
extern size_t gen_pool_size(struct gen_pool *);
#endif /* __GENALLOC_H__ */