188459642SOmar Sandoval /* 288459642SOmar Sandoval * Fast and scalable bitmaps. 388459642SOmar Sandoval * 488459642SOmar Sandoval * Copyright (C) 2016 Facebook 588459642SOmar Sandoval * Copyright (C) 2013-2014 Jens Axboe 688459642SOmar Sandoval * 788459642SOmar Sandoval * This program is free software; you can redistribute it and/or 888459642SOmar Sandoval * modify it under the terms of the GNU General Public 988459642SOmar Sandoval * License v2 as published by the Free Software Foundation. 1088459642SOmar Sandoval * 1188459642SOmar Sandoval * This program is distributed in the hope that it will be useful, 1288459642SOmar Sandoval * but WITHOUT ANY WARRANTY; without even the implied warranty of 1388459642SOmar Sandoval * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 1488459642SOmar Sandoval * General Public License for more details. 1588459642SOmar Sandoval * 1688459642SOmar Sandoval * You should have received a copy of the GNU General Public License 1788459642SOmar Sandoval * along with this program. If not, see <https://www.gnu.org/licenses/>. 1888459642SOmar Sandoval */ 1988459642SOmar Sandoval 2088459642SOmar Sandoval #ifndef __LINUX_SCALE_BITMAP_H 2188459642SOmar Sandoval #define __LINUX_SCALE_BITMAP_H 2288459642SOmar Sandoval 2388459642SOmar Sandoval #include <linux/kernel.h> 2488459642SOmar Sandoval #include <linux/slab.h> 2588459642SOmar Sandoval 2614b470b5SArnd Bergmann struct seq_file; 2714b470b5SArnd Bergmann 2888459642SOmar Sandoval /** 2988459642SOmar Sandoval * struct sbitmap_word - Word in a &struct sbitmap. 3088459642SOmar Sandoval */ 3188459642SOmar Sandoval struct sbitmap_word { 3288459642SOmar Sandoval /** 33ea86ea2cSJens Axboe * @depth: Number of bits being used in @word/@cleared 3488459642SOmar Sandoval */ 3588459642SOmar Sandoval unsigned long depth; 36ea86ea2cSJens Axboe 37ea86ea2cSJens Axboe /** 38ea86ea2cSJens Axboe * @word: word holding free bits 39ea86ea2cSJens Axboe */ 40ea86ea2cSJens Axboe unsigned long word ____cacheline_aligned_in_smp; 41ea86ea2cSJens Axboe 42ea86ea2cSJens Axboe /** 43ea86ea2cSJens Axboe * @cleared: word holding cleared bits 44ea86ea2cSJens Axboe */ 45ea86ea2cSJens Axboe unsigned long cleared ____cacheline_aligned_in_smp; 46ea86ea2cSJens Axboe 47ea86ea2cSJens Axboe /** 48ea86ea2cSJens Axboe * @swap_lock: Held while swapping word <-> cleared 49ea86ea2cSJens Axboe */ 50ea86ea2cSJens Axboe spinlock_t swap_lock; 5188459642SOmar Sandoval } ____cacheline_aligned_in_smp; 5288459642SOmar Sandoval 5388459642SOmar Sandoval /** 5488459642SOmar Sandoval * struct sbitmap - Scalable bitmap. 5588459642SOmar Sandoval * 5688459642SOmar Sandoval * A &struct sbitmap is spread over multiple cachelines to avoid ping-pong. This 5788459642SOmar Sandoval * trades off higher memory usage for better scalability. 5888459642SOmar Sandoval */ 5988459642SOmar Sandoval struct sbitmap { 6088459642SOmar Sandoval /** 6188459642SOmar Sandoval * @depth: Number of bits used in the whole bitmap. 6288459642SOmar Sandoval */ 6388459642SOmar Sandoval unsigned int depth; 6488459642SOmar Sandoval 6588459642SOmar Sandoval /** 6688459642SOmar Sandoval * @shift: log2(number of bits used per word) 6788459642SOmar Sandoval */ 6888459642SOmar Sandoval unsigned int shift; 6988459642SOmar Sandoval 7088459642SOmar Sandoval /** 7188459642SOmar Sandoval * @map_nr: Number of words (cachelines) being used for the bitmap. 7288459642SOmar Sandoval */ 7388459642SOmar Sandoval unsigned int map_nr; 7488459642SOmar Sandoval 7588459642SOmar Sandoval /** 7688459642SOmar Sandoval * @map: Allocated bitmap. 7788459642SOmar Sandoval */ 7888459642SOmar Sandoval struct sbitmap_word *map; 7988459642SOmar Sandoval }; 8088459642SOmar Sandoval 8188459642SOmar Sandoval #define SBQ_WAIT_QUEUES 8 8288459642SOmar Sandoval #define SBQ_WAKE_BATCH 8 8388459642SOmar Sandoval 8488459642SOmar Sandoval /** 8588459642SOmar Sandoval * struct sbq_wait_state - Wait queue in a &struct sbitmap_queue. 8688459642SOmar Sandoval */ 8788459642SOmar Sandoval struct sbq_wait_state { 8888459642SOmar Sandoval /** 8988459642SOmar Sandoval * @wait_cnt: Number of frees remaining before we wake up. 9088459642SOmar Sandoval */ 9188459642SOmar Sandoval atomic_t wait_cnt; 9288459642SOmar Sandoval 9388459642SOmar Sandoval /** 9488459642SOmar Sandoval * @wait: Wait queue. 9588459642SOmar Sandoval */ 9688459642SOmar Sandoval wait_queue_head_t wait; 9788459642SOmar Sandoval } ____cacheline_aligned_in_smp; 9888459642SOmar Sandoval 9988459642SOmar Sandoval /** 10088459642SOmar Sandoval * struct sbitmap_queue - Scalable bitmap with the added ability to wait on free 10188459642SOmar Sandoval * bits. 10288459642SOmar Sandoval * 10388459642SOmar Sandoval * A &struct sbitmap_queue uses multiple wait queues and rolling wakeups to 10488459642SOmar Sandoval * avoid contention on the wait queue spinlock. This ensures that we don't hit a 10588459642SOmar Sandoval * scalability wall when we run out of free bits and have to start putting tasks 10688459642SOmar Sandoval * to sleep. 10788459642SOmar Sandoval */ 10888459642SOmar Sandoval struct sbitmap_queue { 10988459642SOmar Sandoval /** 11088459642SOmar Sandoval * @sb: Scalable bitmap. 11188459642SOmar Sandoval */ 11288459642SOmar Sandoval struct sbitmap sb; 11388459642SOmar Sandoval 11440aabb67SOmar Sandoval /* 11540aabb67SOmar Sandoval * @alloc_hint: Cache of last successfully allocated or freed bit. 11640aabb67SOmar Sandoval * 11740aabb67SOmar Sandoval * This is per-cpu, which allows multiple users to stick to different 11840aabb67SOmar Sandoval * cachelines until the map is exhausted. 11940aabb67SOmar Sandoval */ 12040aabb67SOmar Sandoval unsigned int __percpu *alloc_hint; 12140aabb67SOmar Sandoval 12288459642SOmar Sandoval /** 12388459642SOmar Sandoval * @wake_batch: Number of bits which must be freed before we wake up any 12488459642SOmar Sandoval * waiters. 12588459642SOmar Sandoval */ 12688459642SOmar Sandoval unsigned int wake_batch; 12788459642SOmar Sandoval 12888459642SOmar Sandoval /** 12988459642SOmar Sandoval * @wake_index: Next wait queue in @ws to wake up. 13088459642SOmar Sandoval */ 13188459642SOmar Sandoval atomic_t wake_index; 13288459642SOmar Sandoval 13388459642SOmar Sandoval /** 13488459642SOmar Sandoval * @ws: Wait queues. 13588459642SOmar Sandoval */ 13688459642SOmar Sandoval struct sbq_wait_state *ws; 137f4a644dbSOmar Sandoval 1385d2ee712SJens Axboe /* 1395d2ee712SJens Axboe * @ws_active: count of currently active ws waitqueues 1405d2ee712SJens Axboe */ 1415d2ee712SJens Axboe atomic_t ws_active; 1425d2ee712SJens Axboe 143f4a644dbSOmar Sandoval /** 144f4a644dbSOmar Sandoval * @round_robin: Allocate bits in strict round-robin order. 145f4a644dbSOmar Sandoval */ 146f4a644dbSOmar Sandoval bool round_robin; 147a3275539SOmar Sandoval 148a3275539SOmar Sandoval /** 149a3275539SOmar Sandoval * @min_shallow_depth: The minimum shallow depth which may be passed to 150a3275539SOmar Sandoval * sbitmap_queue_get_shallow() or __sbitmap_queue_get_shallow(). 151a3275539SOmar Sandoval */ 152a3275539SOmar Sandoval unsigned int min_shallow_depth; 15388459642SOmar Sandoval }; 15488459642SOmar Sandoval 15588459642SOmar Sandoval /** 15688459642SOmar Sandoval * sbitmap_init_node() - Initialize a &struct sbitmap on a specific memory node. 15788459642SOmar Sandoval * @sb: Bitmap to initialize. 15888459642SOmar Sandoval * @depth: Number of bits to allocate. 15988459642SOmar Sandoval * @shift: Use 2^@shift bits per word in the bitmap; if a negative number if 16088459642SOmar Sandoval * given, a good default is chosen. 16188459642SOmar Sandoval * @flags: Allocation flags. 16288459642SOmar Sandoval * @node: Memory node to allocate on. 16388459642SOmar Sandoval * 16488459642SOmar Sandoval * Return: Zero on success or negative errno on failure. 16588459642SOmar Sandoval */ 16688459642SOmar Sandoval int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift, 16788459642SOmar Sandoval gfp_t flags, int node); 16888459642SOmar Sandoval 16988459642SOmar Sandoval /** 17088459642SOmar Sandoval * sbitmap_free() - Free memory used by a &struct sbitmap. 17188459642SOmar Sandoval * @sb: Bitmap to free. 17288459642SOmar Sandoval */ 17388459642SOmar Sandoval static inline void sbitmap_free(struct sbitmap *sb) 17488459642SOmar Sandoval { 17588459642SOmar Sandoval kfree(sb->map); 17688459642SOmar Sandoval sb->map = NULL; 17788459642SOmar Sandoval } 17888459642SOmar Sandoval 17988459642SOmar Sandoval /** 18088459642SOmar Sandoval * sbitmap_resize() - Resize a &struct sbitmap. 18188459642SOmar Sandoval * @sb: Bitmap to resize. 18288459642SOmar Sandoval * @depth: New number of bits to resize to. 18388459642SOmar Sandoval * 18488459642SOmar Sandoval * Doesn't reallocate anything. It's up to the caller to ensure that the new 18588459642SOmar Sandoval * depth doesn't exceed the depth that the sb was initialized with. 18688459642SOmar Sandoval */ 18788459642SOmar Sandoval void sbitmap_resize(struct sbitmap *sb, unsigned int depth); 18888459642SOmar Sandoval 18988459642SOmar Sandoval /** 19088459642SOmar Sandoval * sbitmap_get() - Try to allocate a free bit from a &struct sbitmap. 19188459642SOmar Sandoval * @sb: Bitmap to allocate from. 19288459642SOmar Sandoval * @alloc_hint: Hint for where to start searching for a free bit. 19388459642SOmar Sandoval * @round_robin: If true, be stricter about allocation order; always allocate 19488459642SOmar Sandoval * starting from the last allocated bit. This is less efficient 19588459642SOmar Sandoval * than the default behavior (false). 19688459642SOmar Sandoval * 1974ace53f1SOmar Sandoval * This operation provides acquire barrier semantics if it succeeds. 1984ace53f1SOmar Sandoval * 19988459642SOmar Sandoval * Return: Non-negative allocated bit number if successful, -1 otherwise. 20088459642SOmar Sandoval */ 20188459642SOmar Sandoval int sbitmap_get(struct sbitmap *sb, unsigned int alloc_hint, bool round_robin); 20288459642SOmar Sandoval 20388459642SOmar Sandoval /** 204c05e6673SOmar Sandoval * sbitmap_get_shallow() - Try to allocate a free bit from a &struct sbitmap, 205c05e6673SOmar Sandoval * limiting the depth used from each word. 206c05e6673SOmar Sandoval * @sb: Bitmap to allocate from. 207c05e6673SOmar Sandoval * @alloc_hint: Hint for where to start searching for a free bit. 208c05e6673SOmar Sandoval * @shallow_depth: The maximum number of bits to allocate from a single word. 209c05e6673SOmar Sandoval * 210c05e6673SOmar Sandoval * This rather specific operation allows for having multiple users with 211c05e6673SOmar Sandoval * different allocation limits. E.g., there can be a high-priority class that 212c05e6673SOmar Sandoval * uses sbitmap_get() and a low-priority class that uses sbitmap_get_shallow() 213c05e6673SOmar Sandoval * with a @shallow_depth of (1 << (@sb->shift - 1)). Then, the low-priority 214c05e6673SOmar Sandoval * class can only allocate half of the total bits in the bitmap, preventing it 215c05e6673SOmar Sandoval * from starving out the high-priority class. 216c05e6673SOmar Sandoval * 217c05e6673SOmar Sandoval * Return: Non-negative allocated bit number if successful, -1 otherwise. 218c05e6673SOmar Sandoval */ 219c05e6673SOmar Sandoval int sbitmap_get_shallow(struct sbitmap *sb, unsigned int alloc_hint, 220c05e6673SOmar Sandoval unsigned long shallow_depth); 221c05e6673SOmar Sandoval 222c05e6673SOmar Sandoval /** 22388459642SOmar Sandoval * sbitmap_any_bit_set() - Check for a set bit in a &struct sbitmap. 22488459642SOmar Sandoval * @sb: Bitmap to check. 22588459642SOmar Sandoval * 22688459642SOmar Sandoval * Return: true if any bit in the bitmap is set, false otherwise. 22788459642SOmar Sandoval */ 22888459642SOmar Sandoval bool sbitmap_any_bit_set(const struct sbitmap *sb); 22988459642SOmar Sandoval 23088459642SOmar Sandoval /** 23188459642SOmar Sandoval * sbitmap_any_bit_clear() - Check for an unset bit in a &struct 23288459642SOmar Sandoval * sbitmap. 23388459642SOmar Sandoval * @sb: Bitmap to check. 23488459642SOmar Sandoval * 23588459642SOmar Sandoval * Return: true if any bit in the bitmap is clear, false otherwise. 23688459642SOmar Sandoval */ 23788459642SOmar Sandoval bool sbitmap_any_bit_clear(const struct sbitmap *sb); 23888459642SOmar Sandoval 2397930d0a0SMing Lei #define SB_NR_TO_INDEX(sb, bitnr) ((bitnr) >> (sb)->shift) 2407930d0a0SMing Lei #define SB_NR_TO_BIT(sb, bitnr) ((bitnr) & ((1U << (sb)->shift) - 1U)) 2417930d0a0SMing Lei 24288459642SOmar Sandoval typedef bool (*sb_for_each_fn)(struct sbitmap *, unsigned int, void *); 24388459642SOmar Sandoval 24488459642SOmar Sandoval /** 2457930d0a0SMing Lei * __sbitmap_for_each_set() - Iterate over each set bit in a &struct sbitmap. 2467930d0a0SMing Lei * @start: Where to start the iteration. 24788459642SOmar Sandoval * @sb: Bitmap to iterate over. 24888459642SOmar Sandoval * @fn: Callback. Should return true to continue or false to break early. 24988459642SOmar Sandoval * @data: Pointer to pass to callback. 25088459642SOmar Sandoval * 25188459642SOmar Sandoval * This is inline even though it's non-trivial so that the function calls to the 25288459642SOmar Sandoval * callback will hopefully get optimized away. 25388459642SOmar Sandoval */ 2547930d0a0SMing Lei static inline void __sbitmap_for_each_set(struct sbitmap *sb, 2557930d0a0SMing Lei unsigned int start, 2567930d0a0SMing Lei sb_for_each_fn fn, void *data) 25788459642SOmar Sandoval { 2587930d0a0SMing Lei unsigned int index; 2597930d0a0SMing Lei unsigned int nr; 2607930d0a0SMing Lei unsigned int scanned = 0; 26188459642SOmar Sandoval 2627930d0a0SMing Lei if (start >= sb->depth) 2637930d0a0SMing Lei start = 0; 2647930d0a0SMing Lei index = SB_NR_TO_INDEX(sb, start); 2657930d0a0SMing Lei nr = SB_NR_TO_BIT(sb, start); 26688459642SOmar Sandoval 2677930d0a0SMing Lei while (scanned < sb->depth) { 2687930d0a0SMing Lei struct sbitmap_word *word = &sb->map[index]; 2697930d0a0SMing Lei unsigned int depth = min_t(unsigned int, word->depth - nr, 2707930d0a0SMing Lei sb->depth - scanned); 2717930d0a0SMing Lei 2727930d0a0SMing Lei scanned += depth; 27388459642SOmar Sandoval if (!word->word) 2747930d0a0SMing Lei goto next; 27588459642SOmar Sandoval 2767930d0a0SMing Lei /* 2777930d0a0SMing Lei * On the first iteration of the outer loop, we need to add the 2787930d0a0SMing Lei * bit offset back to the size of the word for find_next_bit(). 2797930d0a0SMing Lei * On all other iterations, nr is zero, so this is a noop. 2807930d0a0SMing Lei */ 2817930d0a0SMing Lei depth += nr; 28288459642SOmar Sandoval while (1) { 2837930d0a0SMing Lei nr = find_next_bit(&word->word, depth, nr); 2847930d0a0SMing Lei if (nr >= depth) 28588459642SOmar Sandoval break; 2867930d0a0SMing Lei if (!fn(sb, (index << sb->shift) + nr, data)) 28788459642SOmar Sandoval return; 28888459642SOmar Sandoval 28988459642SOmar Sandoval nr++; 29088459642SOmar Sandoval } 2917930d0a0SMing Lei next: 2927930d0a0SMing Lei nr = 0; 2937930d0a0SMing Lei if (++index >= sb->map_nr) 2947930d0a0SMing Lei index = 0; 29588459642SOmar Sandoval } 29688459642SOmar Sandoval } 29788459642SOmar Sandoval 2987930d0a0SMing Lei /** 2997930d0a0SMing Lei * sbitmap_for_each_set() - Iterate over each set bit in a &struct sbitmap. 3007930d0a0SMing Lei * @sb: Bitmap to iterate over. 3017930d0a0SMing Lei * @fn: Callback. Should return true to continue or false to break early. 3027930d0a0SMing Lei * @data: Pointer to pass to callback. 3037930d0a0SMing Lei */ 3047930d0a0SMing Lei static inline void sbitmap_for_each_set(struct sbitmap *sb, sb_for_each_fn fn, 3057930d0a0SMing Lei void *data) 3067930d0a0SMing Lei { 3077930d0a0SMing Lei __sbitmap_for_each_set(sb, 0, fn, data); 3087930d0a0SMing Lei } 30988459642SOmar Sandoval 31088459642SOmar Sandoval static inline unsigned long *__sbitmap_word(struct sbitmap *sb, 31188459642SOmar Sandoval unsigned int bitnr) 31288459642SOmar Sandoval { 31388459642SOmar Sandoval return &sb->map[SB_NR_TO_INDEX(sb, bitnr)].word; 31488459642SOmar Sandoval } 31588459642SOmar Sandoval 31688459642SOmar Sandoval /* Helpers equivalent to the operations in asm/bitops.h and linux/bitmap.h */ 31788459642SOmar Sandoval 31888459642SOmar Sandoval static inline void sbitmap_set_bit(struct sbitmap *sb, unsigned int bitnr) 31988459642SOmar Sandoval { 32088459642SOmar Sandoval set_bit(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr)); 32188459642SOmar Sandoval } 32288459642SOmar Sandoval 32388459642SOmar Sandoval static inline void sbitmap_clear_bit(struct sbitmap *sb, unsigned int bitnr) 32488459642SOmar Sandoval { 32588459642SOmar Sandoval clear_bit(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr)); 32688459642SOmar Sandoval } 32788459642SOmar Sandoval 328ea86ea2cSJens Axboe /* 329ea86ea2cSJens Axboe * This one is special, since it doesn't actually clear the bit, rather it 330ea86ea2cSJens Axboe * sets the corresponding bit in the ->cleared mask instead. Paired with 331ea86ea2cSJens Axboe * the caller doing sbitmap_batch_clear() if a given index is full, which 332ea86ea2cSJens Axboe * will clear the previously freed entries in the corresponding ->word. 333ea86ea2cSJens Axboe */ 334ea86ea2cSJens Axboe static inline void sbitmap_deferred_clear_bit(struct sbitmap *sb, unsigned int bitnr) 335ea86ea2cSJens Axboe { 336ea86ea2cSJens Axboe unsigned long *addr = &sb->map[SB_NR_TO_INDEX(sb, bitnr)].cleared; 337ea86ea2cSJens Axboe 338ea86ea2cSJens Axboe set_bit(SB_NR_TO_BIT(sb, bitnr), addr); 339ea86ea2cSJens Axboe } 340ea86ea2cSJens Axboe 3414ace53f1SOmar Sandoval static inline void sbitmap_clear_bit_unlock(struct sbitmap *sb, 3424ace53f1SOmar Sandoval unsigned int bitnr) 3434ace53f1SOmar Sandoval { 3444ace53f1SOmar Sandoval clear_bit_unlock(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr)); 3454ace53f1SOmar Sandoval } 3464ace53f1SOmar Sandoval 34788459642SOmar Sandoval static inline int sbitmap_test_bit(struct sbitmap *sb, unsigned int bitnr) 34888459642SOmar Sandoval { 34988459642SOmar Sandoval return test_bit(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr)); 35088459642SOmar Sandoval } 35188459642SOmar Sandoval 35288459642SOmar Sandoval /** 35324af1ccfSOmar Sandoval * sbitmap_show() - Dump &struct sbitmap information to a &struct seq_file. 35424af1ccfSOmar Sandoval * @sb: Bitmap to show. 35524af1ccfSOmar Sandoval * @m: struct seq_file to write to. 35624af1ccfSOmar Sandoval * 35724af1ccfSOmar Sandoval * This is intended for debugging. The format may change at any time. 35824af1ccfSOmar Sandoval */ 35924af1ccfSOmar Sandoval void sbitmap_show(struct sbitmap *sb, struct seq_file *m); 36024af1ccfSOmar Sandoval 36124af1ccfSOmar Sandoval /** 36224af1ccfSOmar Sandoval * sbitmap_bitmap_show() - Write a hex dump of a &struct sbitmap to a &struct 36324af1ccfSOmar Sandoval * seq_file. 36424af1ccfSOmar Sandoval * @sb: Bitmap to show. 36524af1ccfSOmar Sandoval * @m: struct seq_file to write to. 36624af1ccfSOmar Sandoval * 36724af1ccfSOmar Sandoval * This is intended for debugging. The output isn't guaranteed to be internally 36824af1ccfSOmar Sandoval * consistent. 36924af1ccfSOmar Sandoval */ 37024af1ccfSOmar Sandoval void sbitmap_bitmap_show(struct sbitmap *sb, struct seq_file *m); 37124af1ccfSOmar Sandoval 37224af1ccfSOmar Sandoval /** 37388459642SOmar Sandoval * sbitmap_queue_init_node() - Initialize a &struct sbitmap_queue on a specific 37488459642SOmar Sandoval * memory node. 37588459642SOmar Sandoval * @sbq: Bitmap queue to initialize. 37688459642SOmar Sandoval * @depth: See sbitmap_init_node(). 37788459642SOmar Sandoval * @shift: See sbitmap_init_node(). 378f4a644dbSOmar Sandoval * @round_robin: See sbitmap_get(). 37988459642SOmar Sandoval * @flags: Allocation flags. 38088459642SOmar Sandoval * @node: Memory node to allocate on. 38188459642SOmar Sandoval * 38288459642SOmar Sandoval * Return: Zero on success or negative errno on failure. 38388459642SOmar Sandoval */ 38488459642SOmar Sandoval int sbitmap_queue_init_node(struct sbitmap_queue *sbq, unsigned int depth, 385f4a644dbSOmar Sandoval int shift, bool round_robin, gfp_t flags, int node); 38688459642SOmar Sandoval 38788459642SOmar Sandoval /** 38888459642SOmar Sandoval * sbitmap_queue_free() - Free memory used by a &struct sbitmap_queue. 38988459642SOmar Sandoval * 39088459642SOmar Sandoval * @sbq: Bitmap queue to free. 39188459642SOmar Sandoval */ 39288459642SOmar Sandoval static inline void sbitmap_queue_free(struct sbitmap_queue *sbq) 39388459642SOmar Sandoval { 39488459642SOmar Sandoval kfree(sbq->ws); 39540aabb67SOmar Sandoval free_percpu(sbq->alloc_hint); 39688459642SOmar Sandoval sbitmap_free(&sbq->sb); 39788459642SOmar Sandoval } 39888459642SOmar Sandoval 39988459642SOmar Sandoval /** 40088459642SOmar Sandoval * sbitmap_queue_resize() - Resize a &struct sbitmap_queue. 40188459642SOmar Sandoval * @sbq: Bitmap queue to resize. 40288459642SOmar Sandoval * @depth: New number of bits to resize to. 40388459642SOmar Sandoval * 40488459642SOmar Sandoval * Like sbitmap_resize(), this doesn't reallocate anything. It has to do 40588459642SOmar Sandoval * some extra work on the &struct sbitmap_queue, so it's not safe to just 40688459642SOmar Sandoval * resize the underlying &struct sbitmap. 40788459642SOmar Sandoval */ 40888459642SOmar Sandoval void sbitmap_queue_resize(struct sbitmap_queue *sbq, unsigned int depth); 40988459642SOmar Sandoval 41088459642SOmar Sandoval /** 41140aabb67SOmar Sandoval * __sbitmap_queue_get() - Try to allocate a free bit from a &struct 41240aabb67SOmar Sandoval * sbitmap_queue with preemption already disabled. 41340aabb67SOmar Sandoval * @sbq: Bitmap queue to allocate from. 41440aabb67SOmar Sandoval * 41540aabb67SOmar Sandoval * Return: Non-negative allocated bit number if successful, -1 otherwise. 41640aabb67SOmar Sandoval */ 417f4a644dbSOmar Sandoval int __sbitmap_queue_get(struct sbitmap_queue *sbq); 41840aabb67SOmar Sandoval 41940aabb67SOmar Sandoval /** 420c05e6673SOmar Sandoval * __sbitmap_queue_get_shallow() - Try to allocate a free bit from a &struct 421c05e6673SOmar Sandoval * sbitmap_queue, limiting the depth used from each word, with preemption 422c05e6673SOmar Sandoval * already disabled. 423c05e6673SOmar Sandoval * @sbq: Bitmap queue to allocate from. 424c05e6673SOmar Sandoval * @shallow_depth: The maximum number of bits to allocate from a single word. 425c05e6673SOmar Sandoval * See sbitmap_get_shallow(). 426c05e6673SOmar Sandoval * 427a3275539SOmar Sandoval * If you call this, make sure to call sbitmap_queue_min_shallow_depth() after 428a3275539SOmar Sandoval * initializing @sbq. 429a3275539SOmar Sandoval * 430c05e6673SOmar Sandoval * Return: Non-negative allocated bit number if successful, -1 otherwise. 431c05e6673SOmar Sandoval */ 432c05e6673SOmar Sandoval int __sbitmap_queue_get_shallow(struct sbitmap_queue *sbq, 433c05e6673SOmar Sandoval unsigned int shallow_depth); 434c05e6673SOmar Sandoval 435c05e6673SOmar Sandoval /** 43640aabb67SOmar Sandoval * sbitmap_queue_get() - Try to allocate a free bit from a &struct 43740aabb67SOmar Sandoval * sbitmap_queue. 43840aabb67SOmar Sandoval * @sbq: Bitmap queue to allocate from. 43940aabb67SOmar Sandoval * @cpu: Output parameter; will contain the CPU we ran on (e.g., to be passed to 44040aabb67SOmar Sandoval * sbitmap_queue_clear()). 44140aabb67SOmar Sandoval * 44240aabb67SOmar Sandoval * Return: Non-negative allocated bit number if successful, -1 otherwise. 44340aabb67SOmar Sandoval */ 444f4a644dbSOmar Sandoval static inline int sbitmap_queue_get(struct sbitmap_queue *sbq, 44540aabb67SOmar Sandoval unsigned int *cpu) 44640aabb67SOmar Sandoval { 44740aabb67SOmar Sandoval int nr; 44840aabb67SOmar Sandoval 44940aabb67SOmar Sandoval *cpu = get_cpu(); 450f4a644dbSOmar Sandoval nr = __sbitmap_queue_get(sbq); 45140aabb67SOmar Sandoval put_cpu(); 45240aabb67SOmar Sandoval return nr; 45340aabb67SOmar Sandoval } 45440aabb67SOmar Sandoval 45540aabb67SOmar Sandoval /** 456c05e6673SOmar Sandoval * sbitmap_queue_get_shallow() - Try to allocate a free bit from a &struct 457c05e6673SOmar Sandoval * sbitmap_queue, limiting the depth used from each word. 458c05e6673SOmar Sandoval * @sbq: Bitmap queue to allocate from. 459c05e6673SOmar Sandoval * @cpu: Output parameter; will contain the CPU we ran on (e.g., to be passed to 460c05e6673SOmar Sandoval * sbitmap_queue_clear()). 461c05e6673SOmar Sandoval * @shallow_depth: The maximum number of bits to allocate from a single word. 462c05e6673SOmar Sandoval * See sbitmap_get_shallow(). 463c05e6673SOmar Sandoval * 464a3275539SOmar Sandoval * If you call this, make sure to call sbitmap_queue_min_shallow_depth() after 465a3275539SOmar Sandoval * initializing @sbq. 466a3275539SOmar Sandoval * 467c05e6673SOmar Sandoval * Return: Non-negative allocated bit number if successful, -1 otherwise. 468c05e6673SOmar Sandoval */ 469c05e6673SOmar Sandoval static inline int sbitmap_queue_get_shallow(struct sbitmap_queue *sbq, 470c05e6673SOmar Sandoval unsigned int *cpu, 471c05e6673SOmar Sandoval unsigned int shallow_depth) 472c05e6673SOmar Sandoval { 473c05e6673SOmar Sandoval int nr; 474c05e6673SOmar Sandoval 475c05e6673SOmar Sandoval *cpu = get_cpu(); 476c05e6673SOmar Sandoval nr = __sbitmap_queue_get_shallow(sbq, shallow_depth); 477c05e6673SOmar Sandoval put_cpu(); 478c05e6673SOmar Sandoval return nr; 479c05e6673SOmar Sandoval } 480c05e6673SOmar Sandoval 481c05e6673SOmar Sandoval /** 482a3275539SOmar Sandoval * sbitmap_queue_min_shallow_depth() - Inform a &struct sbitmap_queue of the 483a3275539SOmar Sandoval * minimum shallow depth that will be used. 484a3275539SOmar Sandoval * @sbq: Bitmap queue in question. 485a3275539SOmar Sandoval * @min_shallow_depth: The minimum shallow depth that will be passed to 486a3275539SOmar Sandoval * sbitmap_queue_get_shallow() or __sbitmap_queue_get_shallow(). 487a3275539SOmar Sandoval * 488a3275539SOmar Sandoval * sbitmap_queue_clear() batches wakeups as an optimization. The batch size 489a3275539SOmar Sandoval * depends on the depth of the bitmap. Since the shallow allocation functions 490a3275539SOmar Sandoval * effectively operate with a different depth, the shallow depth must be taken 491a3275539SOmar Sandoval * into account when calculating the batch size. This function must be called 492a3275539SOmar Sandoval * with the minimum shallow depth that will be used. Failure to do so can result 493a3275539SOmar Sandoval * in missed wakeups. 494a3275539SOmar Sandoval */ 495a3275539SOmar Sandoval void sbitmap_queue_min_shallow_depth(struct sbitmap_queue *sbq, 496a3275539SOmar Sandoval unsigned int min_shallow_depth); 497a3275539SOmar Sandoval 498a3275539SOmar Sandoval /** 49988459642SOmar Sandoval * sbitmap_queue_clear() - Free an allocated bit and wake up waiters on a 50088459642SOmar Sandoval * &struct sbitmap_queue. 50188459642SOmar Sandoval * @sbq: Bitmap to free from. 50288459642SOmar Sandoval * @nr: Bit number to free. 50340aabb67SOmar Sandoval * @cpu: CPU the bit was allocated on. 50488459642SOmar Sandoval */ 50540aabb67SOmar Sandoval void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr, 506f4a644dbSOmar Sandoval unsigned int cpu); 50788459642SOmar Sandoval 50888459642SOmar Sandoval static inline int sbq_index_inc(int index) 50988459642SOmar Sandoval { 51088459642SOmar Sandoval return (index + 1) & (SBQ_WAIT_QUEUES - 1); 51188459642SOmar Sandoval } 51288459642SOmar Sandoval 51388459642SOmar Sandoval static inline void sbq_index_atomic_inc(atomic_t *index) 51488459642SOmar Sandoval { 51588459642SOmar Sandoval int old = atomic_read(index); 51688459642SOmar Sandoval int new = sbq_index_inc(old); 51788459642SOmar Sandoval atomic_cmpxchg(index, old, new); 51888459642SOmar Sandoval } 51988459642SOmar Sandoval 52088459642SOmar Sandoval /** 52188459642SOmar Sandoval * sbq_wait_ptr() - Get the next wait queue to use for a &struct 52288459642SOmar Sandoval * sbitmap_queue. 52388459642SOmar Sandoval * @sbq: Bitmap queue to wait on. 52488459642SOmar Sandoval * @wait_index: A counter per "user" of @sbq. 52588459642SOmar Sandoval */ 52688459642SOmar Sandoval static inline struct sbq_wait_state *sbq_wait_ptr(struct sbitmap_queue *sbq, 52788459642SOmar Sandoval atomic_t *wait_index) 52888459642SOmar Sandoval { 52988459642SOmar Sandoval struct sbq_wait_state *ws; 53088459642SOmar Sandoval 53188459642SOmar Sandoval ws = &sbq->ws[atomic_read(wait_index)]; 53288459642SOmar Sandoval sbq_index_atomic_inc(wait_index); 53388459642SOmar Sandoval return ws; 53488459642SOmar Sandoval } 53588459642SOmar Sandoval 53688459642SOmar Sandoval /** 53788459642SOmar Sandoval * sbitmap_queue_wake_all() - Wake up everything waiting on a &struct 53888459642SOmar Sandoval * sbitmap_queue. 53988459642SOmar Sandoval * @sbq: Bitmap queue to wake up. 54088459642SOmar Sandoval */ 54188459642SOmar Sandoval void sbitmap_queue_wake_all(struct sbitmap_queue *sbq); 54288459642SOmar Sandoval 54324af1ccfSOmar Sandoval /** 544e6fc4649SMing Lei * sbitmap_queue_wake_up() - Wake up some of waiters in one waitqueue 545e6fc4649SMing Lei * on a &struct sbitmap_queue. 546e6fc4649SMing Lei * @sbq: Bitmap queue to wake up. 547e6fc4649SMing Lei */ 548e6fc4649SMing Lei void sbitmap_queue_wake_up(struct sbitmap_queue *sbq); 549e6fc4649SMing Lei 550e6fc4649SMing Lei /** 55124af1ccfSOmar Sandoval * sbitmap_queue_show() - Dump &struct sbitmap_queue information to a &struct 55224af1ccfSOmar Sandoval * seq_file. 55324af1ccfSOmar Sandoval * @sbq: Bitmap queue to show. 55424af1ccfSOmar Sandoval * @m: struct seq_file to write to. 55524af1ccfSOmar Sandoval * 55624af1ccfSOmar Sandoval * This is intended for debugging. The format may change at any time. 55724af1ccfSOmar Sandoval */ 55824af1ccfSOmar Sandoval void sbitmap_queue_show(struct sbitmap_queue *sbq, struct seq_file *m); 55924af1ccfSOmar Sandoval 5605d2ee712SJens Axboe struct sbq_wait { 5615d2ee712SJens Axboe int accounted; 5625d2ee712SJens Axboe struct wait_queue_entry wait; 5635d2ee712SJens Axboe }; 5645d2ee712SJens Axboe 5655d2ee712SJens Axboe #define DEFINE_SBQ_WAIT(name) \ 5665d2ee712SJens Axboe struct sbq_wait name = { \ 5675d2ee712SJens Axboe .accounted = 0, \ 5685d2ee712SJens Axboe .wait = { \ 5695d2ee712SJens Axboe .private = current, \ 5705d2ee712SJens Axboe .func = autoremove_wake_function, \ 5715d2ee712SJens Axboe .entry = LIST_HEAD_INIT((name).wait.entry), \ 5725d2ee712SJens Axboe } \ 5735d2ee712SJens Axboe } 5745d2ee712SJens Axboe 5755d2ee712SJens Axboe /* 5765d2ee712SJens Axboe * Wrapper around prepare_to_wait_exclusive(), which maintains some extra 5775d2ee712SJens Axboe * internal state. 5785d2ee712SJens Axboe */ 5795d2ee712SJens Axboe void sbitmap_prepare_to_wait(struct sbitmap_queue *sbq, 5805d2ee712SJens Axboe struct sbq_wait_state *ws, 5815d2ee712SJens Axboe struct sbq_wait *sbq_wait, int state); 5825d2ee712SJens Axboe 5835d2ee712SJens Axboe /* 5845d2ee712SJens Axboe * Must be paired with sbitmap_prepare_to_wait(). 5855d2ee712SJens Axboe */ 5865d2ee712SJens Axboe void sbitmap_finish_wait(struct sbitmap_queue *sbq, struct sbq_wait_state *ws, 5875d2ee712SJens Axboe struct sbq_wait *sbq_wait); 5885d2ee712SJens Axboe 58988459642SOmar Sandoval #endif /* __LINUX_SCALE_BITMAP_H */ 590