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10825410b9
Commit180dccb0db
("blk-mq: fix tag_get wait task can't be awakened") will recalculate wake_batch when incrementing or decrementing active_queues to avoid wake_batch > hctx_max_depth. At the same time, in order to not affect performance as much as possible, the minimum wakeup batch is set to 4. But when the QD is small (such as QD=1), if inc or dec active_queues increases wakeup batch, that can lead to a hang: Fix this problem with the following strategies: QD : >= 32 | < 32 --------------------------------- wakeup batch: 8~4 | 3~1 Fixes:180dccb0db
("blk-mq: fix tag_get wait task can't be awakened") Link: https://lore.kernel.org/linux-block/78cafe94-a787-e006-8851-69906f0c2128@huawei.com/T/#t Reported-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca> Signed-off-by: Laibin Qiu <qiulaibin@huawei.com> Tested-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca> Link: https://lore.kernel.org/r/20220127100047.1763746-1-qiulaibin@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
823 lines
19 KiB
C
823 lines
19 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2016 Facebook
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* Copyright (C) 2013-2014 Jens Axboe
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*/
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#include <linux/sched.h>
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#include <linux/random.h>
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#include <linux/sbitmap.h>
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#include <linux/seq_file.h>
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static int init_alloc_hint(struct sbitmap *sb, gfp_t flags)
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{
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unsigned depth = sb->depth;
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sb->alloc_hint = alloc_percpu_gfp(unsigned int, flags);
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if (!sb->alloc_hint)
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return -ENOMEM;
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if (depth && !sb->round_robin) {
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int i;
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for_each_possible_cpu(i)
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*per_cpu_ptr(sb->alloc_hint, i) = prandom_u32() % depth;
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}
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return 0;
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}
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static inline unsigned update_alloc_hint_before_get(struct sbitmap *sb,
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unsigned int depth)
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{
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unsigned hint;
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hint = this_cpu_read(*sb->alloc_hint);
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if (unlikely(hint >= depth)) {
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hint = depth ? prandom_u32() % depth : 0;
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this_cpu_write(*sb->alloc_hint, hint);
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}
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return hint;
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}
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static inline void update_alloc_hint_after_get(struct sbitmap *sb,
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unsigned int depth,
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unsigned int hint,
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unsigned int nr)
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{
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if (nr == -1) {
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/* If the map is full, a hint won't do us much good. */
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this_cpu_write(*sb->alloc_hint, 0);
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} else if (nr == hint || unlikely(sb->round_robin)) {
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/* Only update the hint if we used it. */
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hint = nr + 1;
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if (hint >= depth - 1)
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hint = 0;
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this_cpu_write(*sb->alloc_hint, hint);
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}
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}
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/*
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* See if we have deferred clears that we can batch move
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*/
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static inline bool sbitmap_deferred_clear(struct sbitmap_word *map)
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{
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unsigned long mask;
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if (!READ_ONCE(map->cleared))
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return false;
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/*
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* First get a stable cleared mask, setting the old mask to 0.
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*/
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mask = xchg(&map->cleared, 0);
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/*
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* Now clear the masked bits in our free word
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*/
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atomic_long_andnot(mask, (atomic_long_t *)&map->word);
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BUILD_BUG_ON(sizeof(atomic_long_t) != sizeof(map->word));
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return true;
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}
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int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift,
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gfp_t flags, int node, bool round_robin,
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bool alloc_hint)
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{
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unsigned int bits_per_word;
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unsigned int i;
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if (shift < 0)
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shift = sbitmap_calculate_shift(depth);
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bits_per_word = 1U << shift;
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if (bits_per_word > BITS_PER_LONG)
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return -EINVAL;
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sb->shift = shift;
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sb->depth = depth;
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sb->map_nr = DIV_ROUND_UP(sb->depth, bits_per_word);
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sb->round_robin = round_robin;
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if (depth == 0) {
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sb->map = NULL;
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return 0;
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}
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if (alloc_hint) {
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if (init_alloc_hint(sb, flags))
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return -ENOMEM;
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} else {
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sb->alloc_hint = NULL;
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}
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sb->map = kcalloc_node(sb->map_nr, sizeof(*sb->map), flags, node);
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if (!sb->map) {
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free_percpu(sb->alloc_hint);
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return -ENOMEM;
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}
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for (i = 0; i < sb->map_nr; i++) {
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sb->map[i].depth = min(depth, bits_per_word);
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depth -= sb->map[i].depth;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(sbitmap_init_node);
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void sbitmap_resize(struct sbitmap *sb, unsigned int depth)
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{
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unsigned int bits_per_word = 1U << sb->shift;
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unsigned int i;
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for (i = 0; i < sb->map_nr; i++)
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sbitmap_deferred_clear(&sb->map[i]);
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sb->depth = depth;
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sb->map_nr = DIV_ROUND_UP(sb->depth, bits_per_word);
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for (i = 0; i < sb->map_nr; i++) {
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sb->map[i].depth = min(depth, bits_per_word);
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depth -= sb->map[i].depth;
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}
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}
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EXPORT_SYMBOL_GPL(sbitmap_resize);
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static int __sbitmap_get_word(unsigned long *word, unsigned long depth,
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unsigned int hint, bool wrap)
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{
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int nr;
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/* don't wrap if starting from 0 */
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wrap = wrap && hint;
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while (1) {
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nr = find_next_zero_bit(word, depth, hint);
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if (unlikely(nr >= depth)) {
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/*
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* We started with an offset, and we didn't reset the
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* offset to 0 in a failure case, so start from 0 to
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* exhaust the map.
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*/
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if (hint && wrap) {
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hint = 0;
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continue;
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}
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return -1;
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}
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if (!test_and_set_bit_lock(nr, word))
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break;
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hint = nr + 1;
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if (hint >= depth - 1)
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hint = 0;
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}
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return nr;
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}
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static int sbitmap_find_bit_in_index(struct sbitmap *sb, int index,
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unsigned int alloc_hint)
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{
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struct sbitmap_word *map = &sb->map[index];
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int nr;
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do {
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nr = __sbitmap_get_word(&map->word, map->depth, alloc_hint,
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!sb->round_robin);
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if (nr != -1)
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break;
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if (!sbitmap_deferred_clear(map))
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break;
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} while (1);
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return nr;
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}
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static int __sbitmap_get(struct sbitmap *sb, unsigned int alloc_hint)
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{
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unsigned int i, index;
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int nr = -1;
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index = SB_NR_TO_INDEX(sb, alloc_hint);
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/*
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* Unless we're doing round robin tag allocation, just use the
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* alloc_hint to find the right word index. No point in looping
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* twice in find_next_zero_bit() for that case.
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*/
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if (sb->round_robin)
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alloc_hint = SB_NR_TO_BIT(sb, alloc_hint);
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else
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alloc_hint = 0;
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for (i = 0; i < sb->map_nr; i++) {
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nr = sbitmap_find_bit_in_index(sb, index, alloc_hint);
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if (nr != -1) {
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nr += index << sb->shift;
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break;
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}
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/* Jump to next index. */
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alloc_hint = 0;
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if (++index >= sb->map_nr)
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index = 0;
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}
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return nr;
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}
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int sbitmap_get(struct sbitmap *sb)
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{
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int nr;
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unsigned int hint, depth;
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if (WARN_ON_ONCE(unlikely(!sb->alloc_hint)))
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return -1;
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depth = READ_ONCE(sb->depth);
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hint = update_alloc_hint_before_get(sb, depth);
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nr = __sbitmap_get(sb, hint);
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update_alloc_hint_after_get(sb, depth, hint, nr);
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return nr;
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}
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EXPORT_SYMBOL_GPL(sbitmap_get);
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static int __sbitmap_get_shallow(struct sbitmap *sb,
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unsigned int alloc_hint,
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unsigned long shallow_depth)
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{
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unsigned int i, index;
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int nr = -1;
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index = SB_NR_TO_INDEX(sb, alloc_hint);
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for (i = 0; i < sb->map_nr; i++) {
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again:
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nr = __sbitmap_get_word(&sb->map[index].word,
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min(sb->map[index].depth, shallow_depth),
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SB_NR_TO_BIT(sb, alloc_hint), true);
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if (nr != -1) {
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nr += index << sb->shift;
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break;
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}
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if (sbitmap_deferred_clear(&sb->map[index]))
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goto again;
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/* Jump to next index. */
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index++;
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alloc_hint = index << sb->shift;
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if (index >= sb->map_nr) {
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index = 0;
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alloc_hint = 0;
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}
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}
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return nr;
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}
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int sbitmap_get_shallow(struct sbitmap *sb, unsigned long shallow_depth)
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{
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int nr;
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unsigned int hint, depth;
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if (WARN_ON_ONCE(unlikely(!sb->alloc_hint)))
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return -1;
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depth = READ_ONCE(sb->depth);
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hint = update_alloc_hint_before_get(sb, depth);
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nr = __sbitmap_get_shallow(sb, hint, shallow_depth);
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update_alloc_hint_after_get(sb, depth, hint, nr);
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return nr;
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}
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EXPORT_SYMBOL_GPL(sbitmap_get_shallow);
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bool sbitmap_any_bit_set(const struct sbitmap *sb)
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{
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unsigned int i;
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for (i = 0; i < sb->map_nr; i++) {
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if (sb->map[i].word & ~sb->map[i].cleared)
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return true;
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}
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return false;
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}
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EXPORT_SYMBOL_GPL(sbitmap_any_bit_set);
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static unsigned int __sbitmap_weight(const struct sbitmap *sb, bool set)
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{
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unsigned int i, weight = 0;
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for (i = 0; i < sb->map_nr; i++) {
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const struct sbitmap_word *word = &sb->map[i];
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if (set)
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weight += bitmap_weight(&word->word, word->depth);
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else
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weight += bitmap_weight(&word->cleared, word->depth);
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}
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return weight;
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}
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static unsigned int sbitmap_cleared(const struct sbitmap *sb)
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{
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return __sbitmap_weight(sb, false);
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}
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unsigned int sbitmap_weight(const struct sbitmap *sb)
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{
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return __sbitmap_weight(sb, true) - sbitmap_cleared(sb);
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}
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EXPORT_SYMBOL_GPL(sbitmap_weight);
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void sbitmap_show(struct sbitmap *sb, struct seq_file *m)
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{
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seq_printf(m, "depth=%u\n", sb->depth);
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seq_printf(m, "busy=%u\n", sbitmap_weight(sb));
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seq_printf(m, "cleared=%u\n", sbitmap_cleared(sb));
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seq_printf(m, "bits_per_word=%u\n", 1U << sb->shift);
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seq_printf(m, "map_nr=%u\n", sb->map_nr);
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}
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EXPORT_SYMBOL_GPL(sbitmap_show);
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static inline void emit_byte(struct seq_file *m, unsigned int offset, u8 byte)
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{
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if ((offset & 0xf) == 0) {
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if (offset != 0)
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seq_putc(m, '\n');
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seq_printf(m, "%08x:", offset);
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}
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if ((offset & 0x1) == 0)
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seq_putc(m, ' ');
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seq_printf(m, "%02x", byte);
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}
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void sbitmap_bitmap_show(struct sbitmap *sb, struct seq_file *m)
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{
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u8 byte = 0;
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unsigned int byte_bits = 0;
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unsigned int offset = 0;
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int i;
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for (i = 0; i < sb->map_nr; i++) {
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unsigned long word = READ_ONCE(sb->map[i].word);
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unsigned long cleared = READ_ONCE(sb->map[i].cleared);
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unsigned int word_bits = READ_ONCE(sb->map[i].depth);
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word &= ~cleared;
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while (word_bits > 0) {
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unsigned int bits = min(8 - byte_bits, word_bits);
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byte |= (word & (BIT(bits) - 1)) << byte_bits;
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byte_bits += bits;
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if (byte_bits == 8) {
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emit_byte(m, offset, byte);
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byte = 0;
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byte_bits = 0;
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offset++;
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}
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word >>= bits;
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word_bits -= bits;
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}
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}
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if (byte_bits) {
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emit_byte(m, offset, byte);
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offset++;
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}
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if (offset)
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seq_putc(m, '\n');
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}
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EXPORT_SYMBOL_GPL(sbitmap_bitmap_show);
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static unsigned int sbq_calc_wake_batch(struct sbitmap_queue *sbq,
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unsigned int depth)
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{
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unsigned int wake_batch;
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unsigned int shallow_depth;
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/*
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* For each batch, we wake up one queue. We need to make sure that our
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* batch size is small enough that the full depth of the bitmap,
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* potentially limited by a shallow depth, is enough to wake up all of
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* the queues.
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*
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* Each full word of the bitmap has bits_per_word bits, and there might
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* be a partial word. There are depth / bits_per_word full words and
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* depth % bits_per_word bits left over. In bitwise arithmetic:
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*
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* bits_per_word = 1 << shift
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* depth / bits_per_word = depth >> shift
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* depth % bits_per_word = depth & ((1 << shift) - 1)
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*
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* Each word can be limited to sbq->min_shallow_depth bits.
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*/
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shallow_depth = min(1U << sbq->sb.shift, sbq->min_shallow_depth);
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depth = ((depth >> sbq->sb.shift) * shallow_depth +
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min(depth & ((1U << sbq->sb.shift) - 1), shallow_depth));
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wake_batch = clamp_t(unsigned int, depth / SBQ_WAIT_QUEUES, 1,
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SBQ_WAKE_BATCH);
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return wake_batch;
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}
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int sbitmap_queue_init_node(struct sbitmap_queue *sbq, unsigned int depth,
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int shift, bool round_robin, gfp_t flags, int node)
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{
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int ret;
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int i;
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ret = sbitmap_init_node(&sbq->sb, depth, shift, flags, node,
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round_robin, true);
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if (ret)
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return ret;
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sbq->min_shallow_depth = UINT_MAX;
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sbq->wake_batch = sbq_calc_wake_batch(sbq, depth);
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atomic_set(&sbq->wake_index, 0);
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atomic_set(&sbq->ws_active, 0);
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sbq->ws = kzalloc_node(SBQ_WAIT_QUEUES * sizeof(*sbq->ws), flags, node);
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if (!sbq->ws) {
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sbitmap_free(&sbq->sb);
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return -ENOMEM;
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}
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for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
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init_waitqueue_head(&sbq->ws[i].wait);
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atomic_set(&sbq->ws[i].wait_cnt, sbq->wake_batch);
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(sbitmap_queue_init_node);
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static inline void __sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq,
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unsigned int wake_batch)
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{
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int i;
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if (sbq->wake_batch != wake_batch) {
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WRITE_ONCE(sbq->wake_batch, wake_batch);
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/*
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* Pairs with the memory barrier in sbitmap_queue_wake_up()
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* to ensure that the batch size is updated before the wait
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* counts.
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*/
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smp_mb();
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for (i = 0; i < SBQ_WAIT_QUEUES; i++)
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atomic_set(&sbq->ws[i].wait_cnt, 1);
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}
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}
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static void sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq,
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unsigned int depth)
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{
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unsigned int wake_batch;
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wake_batch = sbq_calc_wake_batch(sbq, depth);
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__sbitmap_queue_update_wake_batch(sbq, wake_batch);
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}
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void sbitmap_queue_recalculate_wake_batch(struct sbitmap_queue *sbq,
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unsigned int users)
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{
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unsigned int wake_batch;
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unsigned int min_batch;
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unsigned int depth = (sbq->sb.depth + users - 1) / users;
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min_batch = sbq->sb.depth >= (4 * SBQ_WAIT_QUEUES) ? 4 : 1;
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wake_batch = clamp_val(depth / SBQ_WAIT_QUEUES,
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min_batch, SBQ_WAKE_BATCH);
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__sbitmap_queue_update_wake_batch(sbq, wake_batch);
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}
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EXPORT_SYMBOL_GPL(sbitmap_queue_recalculate_wake_batch);
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void sbitmap_queue_resize(struct sbitmap_queue *sbq, unsigned int depth)
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{
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sbitmap_queue_update_wake_batch(sbq, depth);
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sbitmap_resize(&sbq->sb, depth);
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}
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EXPORT_SYMBOL_GPL(sbitmap_queue_resize);
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int __sbitmap_queue_get(struct sbitmap_queue *sbq)
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{
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return sbitmap_get(&sbq->sb);
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}
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EXPORT_SYMBOL_GPL(__sbitmap_queue_get);
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unsigned long __sbitmap_queue_get_batch(struct sbitmap_queue *sbq, int nr_tags,
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unsigned int *offset)
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{
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struct sbitmap *sb = &sbq->sb;
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unsigned int hint, depth;
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unsigned long index, nr;
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int i;
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if (unlikely(sb->round_robin))
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return 0;
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depth = READ_ONCE(sb->depth);
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hint = update_alloc_hint_before_get(sb, depth);
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index = SB_NR_TO_INDEX(sb, hint);
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for (i = 0; i < sb->map_nr; i++) {
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struct sbitmap_word *map = &sb->map[index];
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unsigned long get_mask;
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sbitmap_deferred_clear(map);
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if (map->word == (1UL << (map->depth - 1)) - 1)
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continue;
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nr = find_first_zero_bit(&map->word, map->depth);
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if (nr + nr_tags <= map->depth) {
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atomic_long_t *ptr = (atomic_long_t *) &map->word;
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int map_tags = min_t(int, nr_tags, map->depth);
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unsigned long val, ret;
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get_mask = ((1UL << map_tags) - 1) << nr;
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do {
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val = READ_ONCE(map->word);
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ret = atomic_long_cmpxchg(ptr, val, get_mask | val);
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} while (ret != val);
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get_mask = (get_mask & ~ret) >> nr;
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if (get_mask) {
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*offset = nr + (index << sb->shift);
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update_alloc_hint_after_get(sb, depth, hint,
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*offset + map_tags - 1);
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return get_mask;
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}
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}
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/* Jump to next index. */
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if (++index >= sb->map_nr)
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index = 0;
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}
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return 0;
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}
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int __sbitmap_queue_get_shallow(struct sbitmap_queue *sbq,
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unsigned int shallow_depth)
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{
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WARN_ON_ONCE(shallow_depth < sbq->min_shallow_depth);
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return sbitmap_get_shallow(&sbq->sb, shallow_depth);
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}
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EXPORT_SYMBOL_GPL(__sbitmap_queue_get_shallow);
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void sbitmap_queue_min_shallow_depth(struct sbitmap_queue *sbq,
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unsigned int min_shallow_depth)
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{
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sbq->min_shallow_depth = min_shallow_depth;
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sbitmap_queue_update_wake_batch(sbq, sbq->sb.depth);
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}
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EXPORT_SYMBOL_GPL(sbitmap_queue_min_shallow_depth);
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static struct sbq_wait_state *sbq_wake_ptr(struct sbitmap_queue *sbq)
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{
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int i, wake_index;
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if (!atomic_read(&sbq->ws_active))
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return NULL;
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wake_index = atomic_read(&sbq->wake_index);
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for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
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struct sbq_wait_state *ws = &sbq->ws[wake_index];
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if (waitqueue_active(&ws->wait)) {
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if (wake_index != atomic_read(&sbq->wake_index))
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atomic_set(&sbq->wake_index, wake_index);
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return ws;
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}
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wake_index = sbq_index_inc(wake_index);
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}
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return NULL;
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}
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static bool __sbq_wake_up(struct sbitmap_queue *sbq)
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{
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struct sbq_wait_state *ws;
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unsigned int wake_batch;
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int wait_cnt;
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ws = sbq_wake_ptr(sbq);
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if (!ws)
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return false;
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wait_cnt = atomic_dec_return(&ws->wait_cnt);
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if (wait_cnt <= 0) {
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int ret;
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wake_batch = READ_ONCE(sbq->wake_batch);
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/*
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* Pairs with the memory barrier in sbitmap_queue_resize() to
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* ensure that we see the batch size update before the wait
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* count is reset.
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*/
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smp_mb__before_atomic();
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/*
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* For concurrent callers of this, the one that failed the
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* atomic_cmpxhcg() race should call this function again
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* to wakeup a new batch on a different 'ws'.
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*/
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ret = atomic_cmpxchg(&ws->wait_cnt, wait_cnt, wake_batch);
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if (ret == wait_cnt) {
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sbq_index_atomic_inc(&sbq->wake_index);
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wake_up_nr(&ws->wait, wake_batch);
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return false;
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}
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return true;
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}
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return false;
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}
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void sbitmap_queue_wake_up(struct sbitmap_queue *sbq)
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{
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while (__sbq_wake_up(sbq))
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;
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}
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EXPORT_SYMBOL_GPL(sbitmap_queue_wake_up);
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static inline void sbitmap_update_cpu_hint(struct sbitmap *sb, int cpu, int tag)
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{
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if (likely(!sb->round_robin && tag < sb->depth))
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data_race(*per_cpu_ptr(sb->alloc_hint, cpu) = tag);
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}
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void sbitmap_queue_clear_batch(struct sbitmap_queue *sbq, int offset,
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int *tags, int nr_tags)
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{
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struct sbitmap *sb = &sbq->sb;
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unsigned long *addr = NULL;
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unsigned long mask = 0;
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int i;
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smp_mb__before_atomic();
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for (i = 0; i < nr_tags; i++) {
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const int tag = tags[i] - offset;
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unsigned long *this_addr;
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/* since we're clearing a batch, skip the deferred map */
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this_addr = &sb->map[SB_NR_TO_INDEX(sb, tag)].word;
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if (!addr) {
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addr = this_addr;
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} else if (addr != this_addr) {
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atomic_long_andnot(mask, (atomic_long_t *) addr);
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mask = 0;
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addr = this_addr;
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}
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mask |= (1UL << SB_NR_TO_BIT(sb, tag));
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}
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if (mask)
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atomic_long_andnot(mask, (atomic_long_t *) addr);
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smp_mb__after_atomic();
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sbitmap_queue_wake_up(sbq);
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sbitmap_update_cpu_hint(&sbq->sb, raw_smp_processor_id(),
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tags[nr_tags - 1] - offset);
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}
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void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr,
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unsigned int cpu)
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|
{
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/*
|
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* Once the clear bit is set, the bit may be allocated out.
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*
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|
* Orders READ/WRITE on the associated instance(such as request
|
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* of blk_mq) by this bit for avoiding race with re-allocation,
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* and its pair is the memory barrier implied in __sbitmap_get_word.
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*
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|
* One invariant is that the clear bit has to be zero when the bit
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* is in use.
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*/
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smp_mb__before_atomic();
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sbitmap_deferred_clear_bit(&sbq->sb, nr);
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/*
|
|
* Pairs with the memory barrier in set_current_state() to ensure the
|
|
* proper ordering of clear_bit_unlock()/waitqueue_active() in the waker
|
|
* and test_and_set_bit_lock()/prepare_to_wait()/finish_wait() in the
|
|
* waiter. See the comment on waitqueue_active().
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|
*/
|
|
smp_mb__after_atomic();
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|
sbitmap_queue_wake_up(sbq);
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|
sbitmap_update_cpu_hint(&sbq->sb, cpu, nr);
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}
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|
EXPORT_SYMBOL_GPL(sbitmap_queue_clear);
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void sbitmap_queue_wake_all(struct sbitmap_queue *sbq)
|
|
{
|
|
int i, wake_index;
|
|
|
|
/*
|
|
* Pairs with the memory barrier in set_current_state() like in
|
|
* sbitmap_queue_wake_up().
|
|
*/
|
|
smp_mb();
|
|
wake_index = atomic_read(&sbq->wake_index);
|
|
for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
|
|
struct sbq_wait_state *ws = &sbq->ws[wake_index];
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|
|
if (waitqueue_active(&ws->wait))
|
|
wake_up(&ws->wait);
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|
|
|
wake_index = sbq_index_inc(wake_index);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(sbitmap_queue_wake_all);
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|
|
|
void sbitmap_queue_show(struct sbitmap_queue *sbq, struct seq_file *m)
|
|
{
|
|
bool first;
|
|
int i;
|
|
|
|
sbitmap_show(&sbq->sb, m);
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|
|
seq_puts(m, "alloc_hint={");
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|
first = true;
|
|
for_each_possible_cpu(i) {
|
|
if (!first)
|
|
seq_puts(m, ", ");
|
|
first = false;
|
|
seq_printf(m, "%u", *per_cpu_ptr(sbq->sb.alloc_hint, i));
|
|
}
|
|
seq_puts(m, "}\n");
|
|
|
|
seq_printf(m, "wake_batch=%u\n", sbq->wake_batch);
|
|
seq_printf(m, "wake_index=%d\n", atomic_read(&sbq->wake_index));
|
|
seq_printf(m, "ws_active=%d\n", atomic_read(&sbq->ws_active));
|
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|
|
seq_puts(m, "ws={\n");
|
|
for (i = 0; i < SBQ_WAIT_QUEUES; i++) {
|
|
struct sbq_wait_state *ws = &sbq->ws[i];
|
|
|
|
seq_printf(m, "\t{.wait_cnt=%d, .wait=%s},\n",
|
|
atomic_read(&ws->wait_cnt),
|
|
waitqueue_active(&ws->wait) ? "active" : "inactive");
|
|
}
|
|
seq_puts(m, "}\n");
|
|
|
|
seq_printf(m, "round_robin=%d\n", sbq->sb.round_robin);
|
|
seq_printf(m, "min_shallow_depth=%u\n", sbq->min_shallow_depth);
|
|
}
|
|
EXPORT_SYMBOL_GPL(sbitmap_queue_show);
|
|
|
|
void sbitmap_add_wait_queue(struct sbitmap_queue *sbq,
|
|
struct sbq_wait_state *ws,
|
|
struct sbq_wait *sbq_wait)
|
|
{
|
|
if (!sbq_wait->sbq) {
|
|
sbq_wait->sbq = sbq;
|
|
atomic_inc(&sbq->ws_active);
|
|
add_wait_queue(&ws->wait, &sbq_wait->wait);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(sbitmap_add_wait_queue);
|
|
|
|
void sbitmap_del_wait_queue(struct sbq_wait *sbq_wait)
|
|
{
|
|
list_del_init(&sbq_wait->wait.entry);
|
|
if (sbq_wait->sbq) {
|
|
atomic_dec(&sbq_wait->sbq->ws_active);
|
|
sbq_wait->sbq = NULL;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(sbitmap_del_wait_queue);
|
|
|
|
void sbitmap_prepare_to_wait(struct sbitmap_queue *sbq,
|
|
struct sbq_wait_state *ws,
|
|
struct sbq_wait *sbq_wait, int state)
|
|
{
|
|
if (!sbq_wait->sbq) {
|
|
atomic_inc(&sbq->ws_active);
|
|
sbq_wait->sbq = sbq;
|
|
}
|
|
prepare_to_wait_exclusive(&ws->wait, &sbq_wait->wait, state);
|
|
}
|
|
EXPORT_SYMBOL_GPL(sbitmap_prepare_to_wait);
|
|
|
|
void sbitmap_finish_wait(struct sbitmap_queue *sbq, struct sbq_wait_state *ws,
|
|
struct sbq_wait *sbq_wait)
|
|
{
|
|
finish_wait(&ws->wait, &sbq_wait->wait);
|
|
if (sbq_wait->sbq) {
|
|
atomic_dec(&sbq->ws_active);
|
|
sbq_wait->sbq = NULL;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(sbitmap_finish_wait);
|