1 /* SPDX-License-Identifier: GPL-2.0-only */
6  * Copyright (C) 2013-2014 Jens Axboe
22 #include <linux/wait.h>
27  * struct sbitmap_word - Word in a &struct sbitmap.
42  * struct sbitmap - Scalable bitmap.
44  * A &struct sbitmap is spread over multiple cachelines to avoid ping-pong. This
64 	 * @round_robin: Allocate bits in strict round-robin order.
76 	 * This is per-cpu, which allows multiple users to stick to different
86  * struct sbq_wait_state - Wait queue in a &struct sbitmap_queue.
90 	 * @wait: Wait queue.
92 	wait_queue_head_t wait;  member
96  * struct sbitmap_queue - Scalable bitmap with the added ability to wait on free
99  * A &struct sbitmap_queue uses multiple wait queues and rolling wakeups to
100  * avoid contention on the wait queue spinlock. This ensures that we don't hit a
117 	 * @wake_index: Next wait queue in @ws to wake up.
122 	 * @ws: Wait queues.
150  * sbitmap_init_node() - Initialize a &struct sbitmap on a specific memory node.
171 	if (index == sb->map_nr - 1)  in __map_depth()
172 		return sb->depth - (index << sb->shift);  in __map_depth()
173 	return 1U << sb->shift;  in __map_depth()
177  * sbitmap_free() - Free memory used by a &struct sbitmap.
182 	free_percpu(sb->alloc_hint);  in sbitmap_free()
183 	kvfree(sb->map);  in sbitmap_free()
184 	sb->map = NULL;  in sbitmap_free()
188  * sbitmap_resize() - Resize a &struct sbitmap.
198  * sbitmap_get() - Try to allocate a free bit from a &struct sbitmap.
203  * Return: Non-negative allocated bit number if successful, -1 otherwise.
208  * sbitmap_get_shallow() - Try to allocate a free bit from a &struct sbitmap,
214  * different allocation limits. E.g., there can be a high-priority class that
215  * uses sbitmap_get() and a low-priority class that uses sbitmap_get_shallow()
216  * with a @shallow_depth of (1 << (@sb->shift - 1)). Then, the low-priority
218  * from starving out the high-priority class.
220  * Return: Non-negative allocated bit number if successful, -1 otherwise.
225  * sbitmap_any_bit_set() - Check for a set bit in a &struct sbitmap.
232 #define SB_NR_TO_INDEX(sb, bitnr) ((bitnr) >> (sb)->shift)
233 #define SB_NR_TO_BIT(sb, bitnr) ((bitnr) & ((1U << (sb)->shift) - 1U))
238  * __sbitmap_for_each_set() - Iterate over each set bit in a &struct sbitmap.
244  * This is inline even though it's non-trivial so that the function calls to the
255 	if (start >= sb->depth)  in __sbitmap_for_each_set()
260 	while (scanned < sb->depth) {  in __sbitmap_for_each_set()
263 					   __map_depth(sb, index) - nr,  in __sbitmap_for_each_set()
264 					   sb->depth - scanned);  in __sbitmap_for_each_set()
267 		word = sb->map[index].word & ~sb->map[index].cleared;  in __sbitmap_for_each_set()
281 			if (!fn(sb, (index << sb->shift) + nr, data))  in __sbitmap_for_each_set()
288 		if (++index >= sb->map_nr)  in __sbitmap_for_each_set()
294  * sbitmap_for_each_set() - Iterate over each set bit in a &struct sbitmap.
308 	return &sb->map[SB_NR_TO_INDEX(sb, bitnr)].word;  in __sbitmap_word()
325  * sets the corresponding bit in the ->cleared mask instead. Paired with
327  * will clear the previously freed entries in the corresponding ->word.
331 	unsigned long *addr = &sb->map[SB_NR_TO_INDEX(sb, bitnr)].cleared;  in sbitmap_deferred_clear_bit()
344 	if (likely(sb->alloc_hint && !sb->round_robin && bitnr < sb->depth))  in sbitmap_put()
345 		*raw_cpu_ptr(sb->alloc_hint) = bitnr;  in sbitmap_put()
365 			shift--;  in sbitmap_calculate_shift()
372  * sbitmap_show() - Dump &struct sbitmap information to a &struct seq_file.
382  * sbitmap_weight() - Return how many set and not cleared bits in a &struct
391  * sbitmap_bitmap_show() - Write a hex dump of a &struct sbitmap to a &struct
402  * sbitmap_queue_init_node() - Initialize a &struct sbitmap_queue on a specific
404  * @sbq: Bitmap queue to initialize.
417  * sbitmap_queue_free() - Free memory used by a &struct sbitmap_queue.
419  * @sbq: Bitmap queue to free.
423 	kfree(sbq->ws);  in sbitmap_queue_free()
424 	sbitmap_free(&sbq->sb);  in sbitmap_queue_free()
428  * sbitmap_queue_recalculate_wake_batch() - Recalculate wake batch
429  * @sbq: Bitmap queue to recalculate wake batch.
433  * by depth. This interface is for HCTX shared tags or queue shared tags.
439  * sbitmap_queue_resize() - Resize a &struct sbitmap_queue.
440  * @sbq: Bitmap queue to resize.
450  * __sbitmap_queue_get() - Try to allocate a free bit from a &struct
452  * @sbq: Bitmap queue to allocate from.
454  * Return: Non-negative allocated bit number if successful, -1 otherwise.
459  * __sbitmap_queue_get_batch() - Try to allocate a batch of free bits
460  * @sbq: Bitmap queue to allocate from.
472  * sbitmap_queue_get_shallow() - Try to allocate a free bit from a &struct
475  * @sbq: Bitmap queue to allocate from.
482  * Return: Non-negative allocated bit number if successful, -1 otherwise.
488  * sbitmap_queue_get() - Try to allocate a free bit from a &struct
490  * @sbq: Bitmap queue to allocate from.
494  * Return: Non-negative allocated bit number if successful, -1 otherwise.
508  * sbitmap_queue_min_shallow_depth() - Inform a &struct sbitmap_queue of the
510  * @sbq: Bitmap queue in question.
525  * sbitmap_queue_clear() - Free an allocated bit and wake up waiters on a
535  * sbitmap_queue_clear_batch() - Free a batch of allocated bits
547 	return (index + 1) & (SBQ_WAIT_QUEUES - 1);  in sbq_index_inc()
558  * sbq_wait_ptr() - Get the next wait queue to use for a &struct
560  * @sbq: Bitmap queue to wait on.
568 	ws = &sbq->ws[atomic_read(wait_index)];  in sbq_wait_ptr()
574  * sbitmap_queue_wake_all() - Wake up everything waiting on a &struct
576  * @sbq: Bitmap queue to wake up.
581  * sbitmap_queue_wake_up() - Wake up some of waiters in one waitqueue
583  * @sbq: Bitmap queue to wake up.
589  * sbitmap_queue_show() - Dump &struct sbitmap_queue information to a &struct
591  * @sbq: Bitmap queue to show.
600 	struct wait_queue_entry wait;  member
606 		.wait = {							\
609 			.entry		= LIST_HEAD_INIT((name).wait.entry),	\