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sbitmap: add helper to clear a batch of tags

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sbitmap currently only supports clearing tags one-by-one, add a helper
that allows the caller to pass in an array of tags to clear.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2021-10-08 05:44:23 -06:00
parent 5a72e899ce
commit 1aec5e4a29
2 changed files with 52 additions and 3 deletions
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11
include/linux/sbitmap.h
View file

@ -528,6 +528,17 @@ void sbitmap_queue_min_shallow_depth(struct sbitmap_queue *sbq,
void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr,
unsigned int cpu);
/**
* sbitmap_queue_clear_batch() - Free a batch of allocated bits
* &struct sbitmap_queue.
* @sbq: Bitmap to free from.
* @offset: offset for each tag in array
* @tags: array of tags
* @nr_tags: number of tags in array
*/
void sbitmap_queue_clear_batch(struct sbitmap_queue *sbq, int offset,
int *tags, int nr_tags);
static inline int sbq_index_inc(int index)
{
return (index + 1) & (SBQ_WAIT_QUEUES - 1);

44
lib/sbitmap.c
View file

@ -628,6 +628,46 @@ void sbitmap_queue_wake_up(struct sbitmap_queue *sbq)
}
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))
*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);
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)
{
@ -652,9 +692,7 @@ void sbitmap_queue_clear(struct sbitmap_queue *sbq, unsigned int nr,
*/
smp_mb__after_atomic();
sbitmap_queue_wake_up(sbq);
if (likely(!sbq->sb.round_robin && nr < sbq->sb.depth))
*per_cpu_ptr(sbq->sb.alloc_hint, cpu) = nr;
sbitmap_update_cpu_hint(&sbq->sb, cpu, nr);
}
EXPORT_SYMBOL_GPL(sbitmap_queue_clear);