From: Ming Lei ming.lei@redhat.com
mainline inclusion from mainline-v5.13-rc1 commit bf2c4282a10a92810ba83e85677a5273d6ca0df5 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IB4C27
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Add helpers for updating allocation hint so that we can avoid duplicate code.
Prepare for moving allocation hint into sbitmap.
Link: https://lore.kernel.org/r/20210122023317.687987-4-ming.lei@redhat.com Cc: Omar Sandoval osandov@fb.com Cc: Kashyap Desai kashyap.desai@broadcom.com Cc: Sumanesh Samanta sumanesh.samanta@broadcom.com Cc: Ewan D. Milne emilne@redhat.com Cc: Hannes Reinecke hare@suse.de Tested-by: Sumanesh Samanta sumanesh.samanta@broadcom.com Reviewed-by: Hannes Reinecke hare@suse.de Signed-off-by: Ming Lei ming.lei@redhat.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Zheng Qixing zhengqixing@huawei.com --- lib/sbitmap.c | 93 ++++++++++++++++++++++++++++++--------------------- 1 file changed, 54 insertions(+), 39 deletions(-)
diff --git a/lib/sbitmap.c b/lib/sbitmap.c index 2d1e545ed97f..578986a905b3 100644 --- a/lib/sbitmap.c +++ b/lib/sbitmap.c @@ -9,6 +9,55 @@ #include <linux/sbitmap.h> #include <linux/seq_file.h>
+static int init_alloc_hint(struct sbitmap_queue *sbq, gfp_t flags) +{ + unsigned depth = sbq->sb.depth; + + sbq->alloc_hint = alloc_percpu_gfp(unsigned int, flags); + if (!sbq->alloc_hint) + return -ENOMEM; + + if (depth && !sbq->sb.round_robin) { + int i; + + for_each_possible_cpu(i) + *per_cpu_ptr(sbq->alloc_hint, i) = prandom_u32() % depth; + } + + return 0; +} + +static inline unsigned update_alloc_hint_before_get(struct sbitmap_queue *sbq, + unsigned int depth) +{ + unsigned hint; + + hint = this_cpu_read(*sbq->alloc_hint); + if (unlikely(hint >= depth)) { + hint = depth ? prandom_u32() % depth : 0; + this_cpu_write(*sbq->alloc_hint, hint); + } + + return hint; +} + +static inline void update_alloc_hint_after_get(struct sbitmap_queue *sbq, + 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(*sbq->alloc_hint, 0); + } else if (nr == hint || unlikely(sbq->sb.round_robin)) { + /* Only update the hint if we used it. */ + hint = nr + 1; + if (hint >= depth - 1) + hint = 0; + this_cpu_write(*sbq->alloc_hint, hint); + } +} + /* * See if we have deferred clears that we can batch move */ @@ -363,17 +412,11 @@ int sbitmap_queue_init_node(struct sbitmap_queue *sbq, unsigned int depth, if (ret) return ret;
- sbq->alloc_hint = alloc_percpu_gfp(unsigned int, flags); - if (!sbq->alloc_hint) { + if (init_alloc_hint(sbq, flags) != 0) { sbitmap_free(&sbq->sb); return -ENOMEM; }
- if (depth && !round_robin) { - for_each_possible_cpu(i) - *per_cpu_ptr(sbq->alloc_hint, i) = prandom_u32() % depth; - } - sbq->min_shallow_depth = UINT_MAX; sbq->wake_batch = sbq_calc_wake_batch(sbq, depth); atomic_set(&sbq->wake_index, 0); @@ -446,24 +489,10 @@ int __sbitmap_queue_get(struct sbitmap_queue *sbq) unsigned int hint, depth; int nr;
- hint = this_cpu_read(*sbq->alloc_hint); depth = READ_ONCE(sbq->sb.depth); - if (unlikely(hint >= depth)) { - hint = depth ? prandom_u32() % depth : 0; - this_cpu_write(*sbq->alloc_hint, hint); - } + hint = update_alloc_hint_before_get(sbq, depth); nr = sbitmap_get(&sbq->sb, hint); - - if (nr == -1) { - /* If the map is full, a hint won't do us much good. */ - this_cpu_write(*sbq->alloc_hint, 0); - } else if (nr == hint || unlikely(sbq->sb.round_robin)) { - /* Only update the hint if we used it. */ - hint = nr + 1; - if (hint >= depth - 1) - hint = 0; - this_cpu_write(*sbq->alloc_hint, hint); - } + update_alloc_hint_after_get(sbq, depth, hint, nr);
return nr; } @@ -477,24 +506,10 @@ int __sbitmap_queue_get_shallow(struct sbitmap_queue *sbq,
WARN_ON_ONCE(shallow_depth < sbq->min_shallow_depth);
- hint = this_cpu_read(*sbq->alloc_hint); depth = READ_ONCE(sbq->sb.depth); - if (unlikely(hint >= depth)) { - hint = depth ? prandom_u32() % depth : 0; - this_cpu_write(*sbq->alloc_hint, hint); - } + hint = update_alloc_hint_before_get(sbq, depth); nr = sbitmap_get_shallow(&sbq->sb, hint, shallow_depth); - - if (nr == -1) { - /* If the map is full, a hint won't do us much good. */ - this_cpu_write(*sbq->alloc_hint, 0); - } else if (nr == hint || unlikely(sbq->sb.round_robin)) { - /* Only update the hint if we used it. */ - hint = nr + 1; - if (hint >= depth - 1) - hint = 0; - this_cpu_write(*sbq->alloc_hint, hint); - } + update_alloc_hint_after_get(sbq, depth, hint, nr);
return nr; }