From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- lib/sbitmap.c | 769 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 769 insertions(+) create mode 100644 lib/sbitmap.c (limited to 'lib/sbitmap.c') diff --git a/lib/sbitmap.c b/lib/sbitmap.c new file mode 100644 index 000000000..d0a5081df --- /dev/null +++ b/lib/sbitmap.c @@ -0,0 +1,769 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2016 Facebook + * Copyright (C) 2013-2014 Jens Axboe + */ + +#include +#include +#include +#include + +static int init_alloc_hint(struct sbitmap *sb, gfp_t flags) +{ + unsigned depth = sb->depth; + + sb->alloc_hint = alloc_percpu_gfp(unsigned int, flags); + if (!sb->alloc_hint) + return -ENOMEM; + + if (depth && !sb->round_robin) { + int i; + + for_each_possible_cpu(i) + *per_cpu_ptr(sb->alloc_hint, i) = get_random_u32_below(depth); + } + return 0; +} + +static inline unsigned update_alloc_hint_before_get(struct sbitmap *sb, + unsigned int depth) +{ + unsigned hint; + + hint = this_cpu_read(*sb->alloc_hint); + if (unlikely(hint >= depth)) { + hint = depth ? get_random_u32_below(depth) : 0; + this_cpu_write(*sb->alloc_hint, hint); + } + + return hint; +} + +static inline void update_alloc_hint_after_get(struct sbitmap *sb, + unsigned int depth, + unsigned int hint, + unsigned int nr) +{ + if (nr == -1) { + /* If the map is full, a hint won't do us much good. */ + this_cpu_write(*sb->alloc_hint, 0); + } else if (nr == hint || unlikely(sb->round_robin)) { + /* Only update the hint if we used it. */ + hint = nr + 1; + if (hint >= depth - 1) + hint = 0; + this_cpu_write(*sb->alloc_hint, hint); + } +} + +/* + * See if we have deferred clears that we can batch move + */ +static inline bool sbitmap_deferred_clear(struct sbitmap_word *map) +{ + unsigned long mask; + + if (!READ_ONCE(map->cleared)) + return false; + + /* + * First get a stable cleared mask, setting the old mask to 0. + */ + mask = xchg(&map->cleared, 0); + + /* + * Now clear the masked bits in our free word + */ + atomic_long_andnot(mask, (atomic_long_t *)&map->word); + BUILD_BUG_ON(sizeof(atomic_long_t) != sizeof(map->word)); + return true; +} + +int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift, + gfp_t flags, int node, bool round_robin, + bool alloc_hint) +{ + unsigned int bits_per_word; + + if (shift < 0) + shift = sbitmap_calculate_shift(depth); + + bits_per_word = 1U << shift; + if (bits_per_word > BITS_PER_LONG) + return -EINVAL; + + sb->shift = shift; + sb->depth = depth; + sb->map_nr = DIV_ROUND_UP(sb->depth, bits_per_word); + sb->round_robin = round_robin; + + if (depth == 0) { + sb->map = NULL; + return 0; + } + + if (alloc_hint) { + if (init_alloc_hint(sb, flags)) + return -ENOMEM; + } else { + sb->alloc_hint = NULL; + } + + sb->map = kvzalloc_node(sb->map_nr * sizeof(*sb->map), flags, node); + if (!sb->map) { + free_percpu(sb->alloc_hint); + return -ENOMEM; + } + + return 0; +} +EXPORT_SYMBOL_GPL(sbitmap_init_node); + +void sbitmap_resize(struct sbitmap *sb, unsigned int depth) +{ + unsigned int bits_per_word = 1U << sb->shift; + unsigned int i; + + for (i = 0; i < sb->map_nr; i++) + sbitmap_deferred_clear(&sb->map[i]); + + sb->depth = depth; + sb->map_nr = DIV_ROUND_UP(sb->depth, bits_per_word); +} +EXPORT_SYMBOL_GPL(sbitmap_resize); + +static int __sbitmap_get_word(unsigned long *word, unsigned long depth, + unsigned int hint, bool wrap) +{ + int nr; + + /* don't wrap if starting from 0 */ + wrap = wrap && hint; + + while (1) { + nr = find_next_zero_bit(word, depth, hint); + if (unlikely(nr >= depth)) { + /* + * We started with an offset, and we didn't reset the + * offset to 0 in a failure case, so start from 0 to + * exhaust the map. + */ + if (hint && wrap) { + hint = 0; + continue; + } + return -1; + } + + if (!test_and_set_bit_lock(nr, word)) + break; + + hint = nr + 1; + if (hint >= depth - 1) + hint = 0; + } + + return nr; +} + +static int sbitmap_find_bit_in_word(struct sbitmap_word *map, + unsigned int depth, + unsigned int alloc_hint, + bool wrap) +{ + int nr; + + do { + nr = __sbitmap_get_word(&map->word, depth, + alloc_hint, wrap); + if (nr != -1) + break; + if (!sbitmap_deferred_clear(map)) + break; + } while (1); + + return nr; +} + +static int sbitmap_find_bit(struct sbitmap *sb, + unsigned int depth, + unsigned int index, + unsigned int alloc_hint, + bool wrap) +{ + unsigned int i; + int nr = -1; + + for (i = 0; i < sb->map_nr; i++) { + nr = sbitmap_find_bit_in_word(&sb->map[index], + min_t(unsigned int, + __map_depth(sb, index), + depth), + alloc_hint, wrap); + + if (nr != -1) { + nr += index << sb->shift; + break; + } + + /* Jump to next index. */ + alloc_hint = 0; + if (++index >= sb->map_nr) + index = 0; + } + + return nr; +} + +static int __sbitmap_get(struct sbitmap *sb, unsigned int alloc_hint) +{ + unsigned int index; + + index = SB_NR_TO_INDEX(sb, alloc_hint); + + /* + * Unless we're doing round robin tag allocation, just use the + * alloc_hint to find the right word index. No point in looping + * twice in find_next_zero_bit() for that case. + */ + if (sb->round_robin) + alloc_hint = SB_NR_TO_BIT(sb, alloc_hint); + else + alloc_hint = 0; + + return sbitmap_find_bit(sb, UINT_MAX, index, alloc_hint, + !sb->round_robin); +} + +int sbitmap_get(struct sbitmap *sb) +{ + int nr; + unsigned int hint, depth; + + if (WARN_ON_ONCE(unlikely(!sb->alloc_hint))) + return -1; + + depth = READ_ONCE(sb->depth); + hint = update_alloc_hint_before_get(sb, depth); + nr = __sbitmap_get(sb, hint); + update_alloc_hint_after_get(sb, depth, hint, nr); + + return nr; +} +EXPORT_SYMBOL_GPL(sbitmap_get); + +static int __sbitmap_get_shallow(struct sbitmap *sb, + unsigned int alloc_hint, + unsigned long shallow_depth) +{ + unsigned int index; + + index = SB_NR_TO_INDEX(sb, alloc_hint); + alloc_hint = SB_NR_TO_BIT(sb, alloc_hint); + + return sbitmap_find_bit(sb, shallow_depth, index, alloc_hint, true); +} + +int sbitmap_get_shallow(struct sbitmap *sb, unsigned long shallow_depth) +{ + int nr; + unsigned int hint, depth; + + if (WARN_ON_ONCE(unlikely(!sb->alloc_hint))) + return -1; + + depth = READ_ONCE(sb->depth); + hint = update_alloc_hint_before_get(sb, depth); + nr = __sbitmap_get_shallow(sb, hint, shallow_depth); + update_alloc_hint_after_get(sb, depth, hint, nr); + + return nr; +} +EXPORT_SYMBOL_GPL(sbitmap_get_shallow); + +bool sbitmap_any_bit_set(const struct sbitmap *sb) +{ + unsigned int i; + + for (i = 0; i < sb->map_nr; i++) { + if (sb->map[i].word & ~sb->map[i].cleared) + return true; + } + return false; +} +EXPORT_SYMBOL_GPL(sbitmap_any_bit_set); + +static unsigned int __sbitmap_weight(const struct sbitmap *sb, bool set) +{ + unsigned int i, weight = 0; + + for (i = 0; i < sb->map_nr; i++) { + const struct sbitmap_word *word = &sb->map[i]; + unsigned int word_depth = __map_depth(sb, i); + + if (set) + weight += bitmap_weight(&word->word, word_depth); + else + weight += bitmap_weight(&word->cleared, word_depth); + } + return weight; +} + +static unsigned int sbitmap_cleared(const struct sbitmap *sb) +{ + return __sbitmap_weight(sb, false); +} + +unsigned int sbitmap_weight(const struct sbitmap *sb) +{ + return __sbitmap_weight(sb, true) - sbitmap_cleared(sb); +} +EXPORT_SYMBOL_GPL(sbitmap_weight); + +void sbitmap_show(struct sbitmap *sb, struct seq_file *m) +{ + seq_printf(m, "depth=%u\n", sb->depth); + seq_printf(m, "busy=%u\n", sbitmap_weight(sb)); + seq_printf(m, "cleared=%u\n", sbitmap_cleared(sb)); + seq_printf(m, "bits_per_word=%u\n", 1U << sb->shift); + seq_printf(m, "map_nr=%u\n", sb->map_nr); +} +EXPORT_SYMBOL_GPL(sbitmap_show); + +static inline void emit_byte(struct seq_file *m, unsigned int offset, u8 byte) +{ + if ((offset & 0xf) == 0) { + if (offset != 0) + seq_putc(m, '\n'); + seq_printf(m, "%08x:", offset); + } + if ((offset & 0x1) == 0) + seq_putc(m, ' '); + seq_printf(m, "%02x", byte); +} + +void sbitmap_bitmap_show(struct sbitmap *sb, struct seq_file *m) +{ + u8 byte = 0; + unsigned int byte_bits = 0; + unsigned int offset = 0; + int i; + + for (i = 0; i < sb->map_nr; i++) { + unsigned long word = READ_ONCE(sb->map[i].word); + unsigned long cleared = READ_ONCE(sb->map[i].cleared); + unsigned int word_bits = __map_depth(sb, i); + + word &= ~cleared; + + while (word_bits > 0) { + unsigned int bits = min(8 - byte_bits, word_bits); + + byte |= (word & (BIT(bits) - 1)) << byte_bits; + byte_bits += bits; + if (byte_bits == 8) { + emit_byte(m, offset, byte); + byte = 0; + byte_bits = 0; + offset++; + } + word >>= bits; + word_bits -= bits; + } + } + if (byte_bits) { + emit_byte(m, offset, byte); + offset++; + } + if (offset) + seq_putc(m, '\n'); +} +EXPORT_SYMBOL_GPL(sbitmap_bitmap_show); + +static unsigned int sbq_calc_wake_batch(struct sbitmap_queue *sbq, + unsigned int depth) +{ + unsigned int wake_batch; + unsigned int shallow_depth; + + /* + * For each batch, we wake up one queue. We need to make sure that our + * batch size is small enough that the full depth of the bitmap, + * potentially limited by a shallow depth, is enough to wake up all of + * the queues. + * + * Each full word of the bitmap has bits_per_word bits, and there might + * be a partial word. There are depth / bits_per_word full words and + * depth % bits_per_word bits left over. In bitwise arithmetic: + * + * bits_per_word = 1 << shift + * depth / bits_per_word = depth >> shift + * depth % bits_per_word = depth & ((1 << shift) - 1) + * + * Each word can be limited to sbq->min_shallow_depth bits. + */ + shallow_depth = min(1U << sbq->sb.shift, sbq->min_shallow_depth); + depth = ((depth >> sbq->sb.shift) * shallow_depth + + min(depth & ((1U << sbq->sb.shift) - 1), shallow_depth)); + wake_batch = clamp_t(unsigned int, depth / SBQ_WAIT_QUEUES, 1, + SBQ_WAKE_BATCH); + + return wake_batch; +} + +int sbitmap_queue_init_node(struct sbitmap_queue *sbq, unsigned int depth, + int shift, bool round_robin, gfp_t flags, int node) +{ + int ret; + int i; + + ret = sbitmap_init_node(&sbq->sb, depth, shift, flags, node, + round_robin, true); + if (ret) + return ret; + + sbq->min_shallow_depth = UINT_MAX; + sbq->wake_batch = sbq_calc_wake_batch(sbq, depth); + atomic_set(&sbq->wake_index, 0); + atomic_set(&sbq->ws_active, 0); + atomic_set(&sbq->completion_cnt, 0); + atomic_set(&sbq->wakeup_cnt, 0); + + sbq->ws = kzalloc_node(SBQ_WAIT_QUEUES * sizeof(*sbq->ws), flags, node); + if (!sbq->ws) { + sbitmap_free(&sbq->sb); + return -ENOMEM; + } + + for (i = 0; i < SBQ_WAIT_QUEUES; i++) + init_waitqueue_head(&sbq->ws[i].wait); + + return 0; +} +EXPORT_SYMBOL_GPL(sbitmap_queue_init_node); + +static void sbitmap_queue_update_wake_batch(struct sbitmap_queue *sbq, + unsigned int depth) +{ + unsigned int wake_batch; + + wake_batch = sbq_calc_wake_batch(sbq, depth); + if (sbq->wake_batch != wake_batch) + WRITE_ONCE(sbq->wake_batch, wake_batch); +} + +void sbitmap_queue_recalculate_wake_batch(struct sbitmap_queue *sbq, + unsigned int users) +{ + unsigned int wake_batch; + unsigned int depth = (sbq->sb.depth + users - 1) / users; + + wake_batch = clamp_val(depth / SBQ_WAIT_QUEUES, + 1, SBQ_WAKE_BATCH); + + WRITE_ONCE(sbq->wake_batch, wake_batch); +} +EXPORT_SYMBOL_GPL(sbitmap_queue_recalculate_wake_batch); + +void sbitmap_queue_resize(struct sbitmap_queue *sbq, unsigned int depth) +{ + sbitmap_queue_update_wake_batch(sbq, depth); + sbitmap_resize(&sbq->sb, depth); +} +EXPORT_SYMBOL_GPL(sbitmap_queue_resize); + +int __sbitmap_queue_get(struct sbitmap_queue *sbq) +{ + return sbitmap_get(&sbq->sb); +} +EXPORT_SYMBOL_GPL(__sbitmap_queue_get); + +unsigned long __sbitmap_queue_get_batch(struct sbitmap_queue *sbq, int nr_tags, + unsigned int *offset) +{ + struct sbitmap *sb = &sbq->sb; + unsigned int hint, depth; + unsigned long index, nr; + int i; + + if (unlikely(sb->round_robin)) + return 0; + + depth = READ_ONCE(sb->depth); + hint = update_alloc_hint_before_get(sb, depth); + + index = SB_NR_TO_INDEX(sb, hint); + + for (i = 0; i < sb->map_nr; i++) { + struct sbitmap_word *map = &sb->map[index]; + unsigned long get_mask; + unsigned int map_depth = __map_depth(sb, index); + + sbitmap_deferred_clear(map); + if (map->word == (1UL << (map_depth - 1)) - 1) + goto next; + + nr = find_first_zero_bit(&map->word, map_depth); + if (nr + nr_tags <= map_depth) { + atomic_long_t *ptr = (atomic_long_t *) &map->word; + unsigned long val; + + get_mask = ((1UL << nr_tags) - 1) << nr; + val = READ_ONCE(map->word); + while (!atomic_long_try_cmpxchg(ptr, &val, + get_mask | val)) + ; + get_mask = (get_mask & ~val) >> nr; + if (get_mask) { + *offset = nr + (index << sb->shift); + update_alloc_hint_after_get(sb, depth, hint, + *offset + nr_tags - 1); + return get_mask; + } + } +next: + /* Jump to next index. */ + if (++index >= sb->map_nr) + index = 0; + } + + return 0; +} + +int sbitmap_queue_get_shallow(struct sbitmap_queue *sbq, + unsigned int shallow_depth) +{ + WARN_ON_ONCE(shallow_depth < sbq->min_shallow_depth); + + return sbitmap_get_shallow(&sbq->sb, shallow_depth); +} +EXPORT_SYMBOL_GPL(sbitmap_queue_get_shallow); + +void sbitmap_queue_min_shallow_depth(struct sbitmap_queue *sbq, + unsigned int min_shallow_depth) +{ + sbq->min_shallow_depth = min_shallow_depth; + sbitmap_queue_update_wake_batch(sbq, sbq->sb.depth); +} +EXPORT_SYMBOL_GPL(sbitmap_queue_min_shallow_depth); + +static void __sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr) +{ + int i, wake_index, woken; + + if (!atomic_read(&sbq->ws_active)) + return; + + wake_index = atomic_read(&sbq->wake_index); + for (i = 0; i < SBQ_WAIT_QUEUES; i++) { + struct sbq_wait_state *ws = &sbq->ws[wake_index]; + + /* + * Advance the index before checking the current queue. + * It improves fairness, by ensuring the queue doesn't + * need to be fully emptied before trying to wake up + * from the next one. + */ + wake_index = sbq_index_inc(wake_index); + + if (waitqueue_active(&ws->wait)) { + woken = wake_up_nr(&ws->wait, nr); + if (woken == nr) + break; + nr -= woken; + } + } + + if (wake_index != atomic_read(&sbq->wake_index)) + atomic_set(&sbq->wake_index, wake_index); +} + +void sbitmap_queue_wake_up(struct sbitmap_queue *sbq, int nr) +{ + unsigned int wake_batch = READ_ONCE(sbq->wake_batch); + unsigned int wakeups; + + if (!atomic_read(&sbq->ws_active)) + return; + + atomic_add(nr, &sbq->completion_cnt); + wakeups = atomic_read(&sbq->wakeup_cnt); + + do { + if (atomic_read(&sbq->completion_cnt) - wakeups < wake_batch) + return; + } while (!atomic_try_cmpxchg(&sbq->wakeup_cnt, + &wakeups, wakeups + wake_batch)); + + __sbitmap_queue_wake_up(sbq, wake_batch); +} +EXPORT_SYMBOL_GPL(sbitmap_queue_wake_up); + +static inline void sbitmap_update_cpu_hint(struct sbitmap *sb, int cpu, int tag) +{ + if (likely(!sb->round_robin && tag < sb->depth)) + data_race(*per_cpu_ptr(sb->alloc_hint, cpu) = tag); +} + +void sbitmap_queue_clear_batch(struct sbitmap_queue *sbq, int offset, + int *tags, int nr_tags) +{ + struct sbitmap *sb = &sbq->sb; + unsigned long *addr = NULL; + unsigned long mask = 0; + int i; + + smp_mb__before_atomic(); + for (i = 0; i < nr_tags; i++) { + const int tag = tags[i] - offset; + unsigned long *this_addr; + + /* since we're clearing a batch, skip the deferred map */ + this_addr = &sb->map[SB_NR_TO_INDEX(sb, tag)].word; + if (!addr) { + addr = this_addr; + } else if (addr != this_addr) { + atomic_long_andnot(mask, (atomic_long_t *) addr); + mask = 0; + addr = this_addr; + } + mask |= (1UL << SB_NR_TO_BIT(sb, tag)); + } + + if (mask) + atomic_long_andnot(mask, (atomic_long_t *) addr); + + smp_mb__after_atomic(); + sbitmap_queue_wake_up(sbq, nr_tags); + sbitmap_update_cpu_hint(&sbq->sb, raw_smp_processor_id(), + tags[nr_tags - 1] - offset); +} + +void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr, + unsigned int cpu) +{ + /* + * Once the clear bit is set, the bit may be allocated out. + * + * Orders READ/WRITE on the associated instance(such as request + * of blk_mq) by this bit for avoiding race with re-allocation, + * and its pair is the memory barrier implied in __sbitmap_get_word. + * + * One invariant is that the clear bit has to be zero when the bit + * is in use. + */ + smp_mb__before_atomic(); + sbitmap_deferred_clear_bit(&sbq->sb, nr); + + /* + * 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(). + */ + smp_mb__after_atomic(); + sbitmap_queue_wake_up(sbq, 1); + sbitmap_update_cpu_hint(&sbq->sb, cpu, nr); +} +EXPORT_SYMBOL_GPL(sbitmap_queue_clear); + +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]; + + if (waitqueue_active(&ws->wait)) + wake_up(&ws->wait); + + wake_index = sbq_index_inc(wake_index); + } +} +EXPORT_SYMBOL_GPL(sbitmap_queue_wake_all); + +void sbitmap_queue_show(struct sbitmap_queue *sbq, struct seq_file *m) +{ + bool first; + int i; + + sbitmap_show(&sbq->sb, m); + + seq_puts(m, "alloc_hint={"); + 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)); + + 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=%s},\n", + 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); -- cgit v1.2.3