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-rw-r--r--lib/rhashtable.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 798f01d..9623be3 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -261,8 +261,8 @@ EXPORT_SYMBOL_GPL(rhashtable_expand);
* rhashtable_shrink - Shrink hash table while allowing concurrent lookups
* @ht: the hash table to shrink
*
- * This function may only be called in a context where it is safe to call
- * synchronize_rcu(), e.g. not within a rcu_read_lock() section.
+ * This function shrinks the hash table to fit, i.e., the smallest
+ * size would not cause it to expand right away automatically.
*
* The caller must ensure that no concurrent resizing occurs by holding
* ht->mutex.
@@ -276,10 +276,17 @@ EXPORT_SYMBOL_GPL(rhashtable_expand);
int rhashtable_shrink(struct rhashtable *ht)
{
struct bucket_table *new_tbl, *old_tbl = rht_dereference(ht->tbl, ht);
+ unsigned size = roundup_pow_of_two(atomic_read(&ht->nelems) * 3 / 2);
ASSERT_RHT_MUTEX(ht);
- new_tbl = bucket_table_alloc(ht, old_tbl->size / 2);
+ if (size < ht->p.min_size)
+ size = ht->p.min_size;
+
+ if (old_tbl->size <= size)
+ return 0;
+
+ new_tbl = bucket_table_alloc(ht, size);
if (new_tbl == NULL)
return -ENOMEM;
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