diff options
Diffstat (limited to 'include/linux/sbitmap.h')
| -rw-r--r-- | include/linux/sbitmap.h | 85 |
1 files changed, 59 insertions, 26 deletions
diff --git a/include/linux/sbitmap.h b/include/linux/sbitmap.h index 74cc6384715e..2713e689ad66 100644 --- a/include/linux/sbitmap.h +++ b/include/linux/sbitmap.h @@ -57,9 +57,22 @@ struct sbitmap { unsigned int map_nr; /** + * @round_robin: Allocate bits in strict round-robin order. + */ + bool round_robin; + + /** * @map: Allocated bitmap. */ struct sbitmap_word *map; + + /* + * @alloc_hint: Cache of last successfully allocated or freed bit. + * + * This is per-cpu, which allows multiple users to stick to different + * cachelines until the map is exhausted. + */ + unsigned int __percpu *alloc_hint; }; #define SBQ_WAIT_QUEUES 8 @@ -95,14 +108,6 @@ struct sbitmap_queue { */ struct sbitmap sb; - /* - * @alloc_hint: Cache of last successfully allocated or freed bit. - * - * This is per-cpu, which allows multiple users to stick to different - * cachelines until the map is exhausted. - */ - unsigned int __percpu *alloc_hint; - /** * @wake_batch: Number of bits which must be freed before we wake up any * waiters. @@ -125,11 +130,6 @@ struct sbitmap_queue { atomic_t ws_active; /** - * @round_robin: Allocate bits in strict round-robin order. - */ - bool round_robin; - - /** * @min_shallow_depth: The minimum shallow depth which may be passed to * sbitmap_queue_get_shallow() or __sbitmap_queue_get_shallow(). */ @@ -144,11 +144,16 @@ struct sbitmap_queue { * given, a good default is chosen. * @flags: Allocation flags. * @node: Memory node to allocate on. + * @round_robin: If true, be stricter about allocation order; always allocate + * starting from the last allocated bit. This is less efficient + * than the default behavior (false). + * @alloc_hint: If true, apply percpu hint for where to start searching for + * a free bit. * * Return: Zero on success or negative errno on failure. */ int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift, - gfp_t flags, int node); + gfp_t flags, int node, bool round_robin, bool alloc_hint); /** * sbitmap_free() - Free memory used by a &struct sbitmap. @@ -156,6 +161,7 @@ int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift, */ static inline void sbitmap_free(struct sbitmap *sb) { + free_percpu(sb->alloc_hint); kfree(sb->map); sb->map = NULL; } @@ -173,22 +179,17 @@ void sbitmap_resize(struct sbitmap *sb, unsigned int depth); /** * sbitmap_get() - Try to allocate a free bit from a &struct sbitmap. * @sb: Bitmap to allocate from. - * @alloc_hint: Hint for where to start searching for a free bit. - * @round_robin: If true, be stricter about allocation order; always allocate - * starting from the last allocated bit. This is less efficient - * than the default behavior (false). * * This operation provides acquire barrier semantics if it succeeds. * * Return: Non-negative allocated bit number if successful, -1 otherwise. */ -int sbitmap_get(struct sbitmap *sb, unsigned int alloc_hint, bool round_robin); +int sbitmap_get(struct sbitmap *sb); /** * sbitmap_get_shallow() - Try to allocate a free bit from a &struct sbitmap, * limiting the depth used from each word. * @sb: Bitmap to allocate from. - * @alloc_hint: Hint for where to start searching for a free bit. * @shallow_depth: The maximum number of bits to allocate from a single word. * * This rather specific operation allows for having multiple users with @@ -200,8 +201,7 @@ int sbitmap_get(struct sbitmap *sb, unsigned int alloc_hint, bool round_robin); * * Return: Non-negative allocated bit number if successful, -1 otherwise. */ -int sbitmap_get_shallow(struct sbitmap *sb, unsigned int alloc_hint, - unsigned long shallow_depth); +int sbitmap_get_shallow(struct sbitmap *sb, unsigned long shallow_depth); /** * sbitmap_any_bit_set() - Check for a set bit in a &struct sbitmap. @@ -315,10 +315,16 @@ static inline void sbitmap_deferred_clear_bit(struct sbitmap *sb, unsigned int b set_bit(SB_NR_TO_BIT(sb, bitnr), addr); } -static inline void sbitmap_clear_bit_unlock(struct sbitmap *sb, - unsigned int bitnr) +/* + * Pair of sbitmap_get, and this one applies both cleared bit and + * allocation hint. + */ +static inline void sbitmap_put(struct sbitmap *sb, unsigned int bitnr) { - clear_bit_unlock(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr)); + sbitmap_deferred_clear_bit(sb, bitnr); + + if (likely(sb->alloc_hint && !sb->round_robin && bitnr < sb->depth)) + *raw_cpu_ptr(sb->alloc_hint) = bitnr; } static inline int sbitmap_test_bit(struct sbitmap *sb, unsigned int bitnr) @@ -326,6 +332,24 @@ static inline int sbitmap_test_bit(struct sbitmap *sb, unsigned int bitnr) return test_bit(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr)); } +static inline int sbitmap_calculate_shift(unsigned int depth) +{ + int shift = ilog2(BITS_PER_LONG); + + /* + * If the bitmap is small, shrink the number of bits per word so + * we spread over a few cachelines, at least. If less than 4 + * bits, just forget about it, it's not going to work optimally + * anyway. + */ + if (depth >= 4) { + while ((4U << shift) > depth) + shift--; + } + + return shift; +} + /** * sbitmap_show() - Dump &struct sbitmap information to a &struct seq_file. * @sb: Bitmap to show. @@ -335,6 +359,16 @@ static inline int sbitmap_test_bit(struct sbitmap *sb, unsigned int bitnr) */ void sbitmap_show(struct sbitmap *sb, struct seq_file *m); + +/** + * sbitmap_weight() - Return how many set and not cleared bits in a &struct + * sbitmap. + * @sb: Bitmap to check. + * + * Return: How many set and not cleared bits set + */ +unsigned int sbitmap_weight(const struct sbitmap *sb); + /** * sbitmap_bitmap_show() - Write a hex dump of a &struct sbitmap to a &struct * seq_file. @@ -369,7 +403,6 @@ int sbitmap_queue_init_node(struct sbitmap_queue *sbq, unsigned int depth, static inline void sbitmap_queue_free(struct sbitmap_queue *sbq) { kfree(sbq->ws); - free_percpu(sbq->alloc_hint); sbitmap_free(&sbq->sb); } |