diff options
| -rw-r--r-- | include/linux/genalloc.h | 27 | ||||
| -rw-r--r-- | lib/genalloc.c | 88 |
2 files changed, 111 insertions, 4 deletions
diff --git a/include/linux/genalloc.h b/include/linux/genalloc.h index 5e98eeb2af3b..dd7c569aacad 100644 --- a/include/linux/genalloc.h +++ b/include/linux/genalloc.h @@ -29,6 +29,20 @@ #ifndef __GENALLOC_H__ #define __GENALLOC_H__ +/** + * Allocation callback function type definition + * @map: Pointer to bitmap + * @size: The bitmap size in bits + * @start: The bitnumber to start searching at + * @nr: The number of zeroed bits we're looking for + * @data: optional additional data used by @genpool_algo_t + */ +typedef unsigned long (*genpool_algo_t)(unsigned long *map, + unsigned long size, + unsigned long start, + unsigned int nr, + void *data); + /* * General purpose special memory pool descriptor. */ @@ -36,6 +50,9 @@ struct gen_pool { spinlock_t lock; struct list_head chunks; /* list of chunks in this pool */ int min_alloc_order; /* minimum allocation order */ + + genpool_algo_t algo; /* allocation function */ + void *data; }; /* @@ -78,4 +95,14 @@ 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 *); + +extern void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, + void *data); + +extern unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size, + unsigned long start, unsigned int nr, void *data); + +extern unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size, + unsigned long start, unsigned int nr, void *data); + #endif /* __GENALLOC_H__ */ diff --git a/lib/genalloc.c b/lib/genalloc.c index 6bc04aab6ec7..ca208a92628c 100644 --- a/lib/genalloc.c +++ b/lib/genalloc.c @@ -152,6 +152,8 @@ struct gen_pool *gen_pool_create(int min_alloc_order, int nid) spin_lock_init(&pool->lock); INIT_LIST_HEAD(&pool->chunks); pool->min_alloc_order = min_alloc_order; + pool->algo = gen_pool_first_fit; + pool->data = NULL; } return pool; } @@ -255,8 +257,9 @@ EXPORT_SYMBOL(gen_pool_destroy); * @size: number of bytes to allocate from the pool * * Allocate the requested number of bytes from the specified pool. - * Uses a first-fit algorithm. Can not be used in NMI handler on - * architectures without NMI-safe cmpxchg implementation. + * Uses the pool allocation function (with first-fit algorithm by default). + * Can not be used in NMI handler on architectures without + * NMI-safe cmpxchg implementation. */ unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size) { @@ -280,8 +283,8 @@ unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size) end_bit = (chunk->end_addr - chunk->start_addr) >> order; retry: - start_bit = bitmap_find_next_zero_area(chunk->bits, end_bit, - start_bit, nbits, 0); + start_bit = pool->algo(chunk->bits, end_bit, start_bit, nbits, + pool->data); if (start_bit >= end_bit) continue; remain = bitmap_set_ll(chunk->bits, start_bit, nbits); @@ -400,3 +403,80 @@ size_t gen_pool_size(struct gen_pool *pool) return size; } EXPORT_SYMBOL_GPL(gen_pool_size); + +/** + * gen_pool_set_algo - set the allocation algorithm + * @pool: pool to change allocation algorithm + * @algo: custom algorithm function + * @data: additional data used by @algo + * + * Call @algo for each memory allocation in the pool. + * If @algo is NULL use gen_pool_first_fit as default + * memory allocation function. + */ +void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, void *data) +{ + rcu_read_lock(); + + pool->algo = algo; + if (!pool->algo) + pool->algo = gen_pool_first_fit; + + pool->data = data; + + rcu_read_unlock(); +} +EXPORT_SYMBOL(gen_pool_set_algo); + +/** + * gen_pool_first_fit - find the first available region + * of memory matching the size requirement (no alignment constraint) + * @map: The address to base the search on + * @size: The bitmap size in bits + * @start: The bitnumber to start searching at + * @nr: The number of zeroed bits we're looking for + * @data: additional data - unused + */ +unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size, + unsigned long start, unsigned int nr, void *data) +{ + return bitmap_find_next_zero_area(map, size, start, nr, 0); +} +EXPORT_SYMBOL(gen_pool_first_fit); + +/** + * gen_pool_best_fit - find the best fitting region of memory + * macthing the size requirement (no alignment constraint) + * @map: The address to base the search on + * @size: The bitmap size in bits + * @start: The bitnumber to start searching at + * @nr: The number of zeroed bits we're looking for + * @data: additional data - unused + * + * Iterate over the bitmap to find the smallest free region + * which we can allocate the memory. + */ +unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size, + unsigned long start, unsigned int nr, void *data) +{ + unsigned long start_bit = size; + unsigned long len = size + 1; + unsigned long index; + + index = bitmap_find_next_zero_area(map, size, start, nr, 0); + + while (index < size) { + int next_bit = find_next_bit(map, size, index + nr); + if ((next_bit - index) < len) { + len = next_bit - index; + start_bit = index; + if (len == nr) + return start_bit; + } + index = bitmap_find_next_zero_area(map, size, + next_bit + 1, nr, 0); + } + + return start_bit; +} +EXPORT_SYMBOL(gen_pool_best_fit); |