From: Lai Jiangshan Date: Mon, 28 Nov 2011 13:19:26 +0000 (-0500) Subject: add max_nr_buckets argument X-Git-Tag: v0.7.0~43^2~41 X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=747d725c1dd45d5072e0e411642c4d5c6403b4be;p=userspace-rcu.git add max_nr_buckets argument [ Edit by Mathieu Desnoyers: clarify cds_lfht_new() description. ] Signed-off-by: Lai Jiangshan Signed-off-by: Mathieu Desnoyers --- diff --git a/rculfhash.c b/rculfhash.c index 8282f09..4a611a1 100644 --- a/rculfhash.c +++ b/rculfhash.c @@ -267,6 +267,7 @@ struct cds_lfht { struct rcu_table t; unsigned long min_alloc_buckets_order; unsigned long min_nr_alloc_buckets; + unsigned long max_nr_buckets; int flags; /* * We need to put the work threads offline (QSBR) when taking this @@ -1365,6 +1366,7 @@ void cds_lfht_create_bucket(struct cds_lfht *ht, unsigned long size) struct cds_lfht *_cds_lfht_new(unsigned long init_size, unsigned long min_nr_alloc_buckets, + unsigned long max_nr_buckets, int flags, void (*cds_lfht_call_rcu)(struct rcu_head *head, void (*func)(struct rcu_head *head)), @@ -1383,11 +1385,22 @@ struct cds_lfht *_cds_lfht_new(unsigned long init_size, /* min_nr_alloc_buckets must be power of two */ if (!min_nr_alloc_buckets || (min_nr_alloc_buckets & (min_nr_alloc_buckets - 1))) return NULL; + /* init_size must be power of two */ if (!init_size || (init_size & (init_size - 1))) return NULL; + + if (!max_nr_buckets) + max_nr_buckets = 1UL << (MAX_TABLE_ORDER - 1); + + /* max_nr_buckets must be power of two */ + if (!max_nr_buckets || (max_nr_buckets & (max_nr_buckets - 1))) + return NULL; + min_nr_alloc_buckets = max(min_nr_alloc_buckets, MIN_TABLE_SIZE); init_size = max(init_size, MIN_TABLE_SIZE); + max_nr_buckets = max(max_nr_buckets, min_nr_alloc_buckets); + init_size = min(init_size, max_nr_buckets); ht = calloc(1, sizeof(struct cds_lfht)); assert(ht); ht->flags = flags; @@ -1407,6 +1420,7 @@ struct cds_lfht *_cds_lfht_new(unsigned long init_size, ht->t.resize_target = 1UL << order; ht->min_nr_alloc_buckets = min_nr_alloc_buckets; ht->min_alloc_buckets_order = get_count_order_ulong(min_nr_alloc_buckets); + ht->max_nr_buckets = max_nr_buckets; cds_lfht_create_bucket(ht, 1UL << order); ht->t.size = 1UL << order; return ht; @@ -1766,6 +1780,7 @@ void resize_target_update_count(struct cds_lfht *ht, unsigned long count) { count = max(count, MIN_TABLE_SIZE); + count = min(count, ht->max_nr_buckets); uatomic_set(&ht->t.resize_target, count); } @@ -1823,6 +1838,7 @@ void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int grow { unsigned long target_size = size << growth; + target_size = min(target_size, ht->max_nr_buckets); if (resize_target_grow(ht, target_size) >= target_size) return; @@ -1841,6 +1857,7 @@ void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size, if (!(ht->flags & CDS_LFHT_AUTO_RESIZE)) return; count = max(count, MIN_TABLE_SIZE); + count = min(count, ht->max_nr_buckets); if (count == size) return; /* Already the right size, no resize needed */ if (count > size) { /* lazy grow */ diff --git a/tests/test_urcu_hash.c b/tests/test_urcu_hash.c index 01ae01a..043a33a 100644 --- a/tests/test_urcu_hash.c +++ b/tests/test_urcu_hash.c @@ -967,7 +967,7 @@ int main(int argc, char **argv) * thread from the point of view of resize. */ rcu_register_thread(); - test_ht = cds_lfht_new(init_hash_size, min_hash_alloc_size, + test_ht = cds_lfht_new(init_hash_size, min_hash_alloc_size, (1UL << 18), (opt_auto_resize ? CDS_LFHT_AUTO_RESIZE : 0) | CDS_LFHT_ACCOUNTING, NULL); ret = populate_hash(); diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h index d242ff6..6953ad1 100644 --- a/urcu/rculfhash.h +++ b/urcu/rculfhash.h @@ -99,6 +99,7 @@ enum { */ struct cds_lfht *_cds_lfht_new(unsigned long init_size, unsigned long min_nr_alloc_buckets, + unsigned long max_nr_buckets, int flags, void (*cds_lfht_call_rcu)(struct rcu_head *head, void (*func)(struct rcu_head *head)), @@ -113,8 +114,11 @@ struct cds_lfht *_cds_lfht_new(unsigned long init_size, /* * cds_lfht_new - allocate a hash table. - * @init_size: number of nodes to allocate initially. Must be power of two. - * @min_nr_alloc_buckets: the smallest allocation size to use. Must be power of two. + * @init_size: number of buckets to allocate initially. Must be power of two. + * @min_nr_alloc_buckets: the minimum number of allocated buckets. + * (must be power of two) + * @max_nr_buckets: the maximum number of hash table buckets allowed. + * (must be power of two) * @flags: hash table creation flags (can be combined with bitwise or: '|'). * 0: no flags. * CDS_LFHT_AUTO_RESIZE: automatically resize hash table. @@ -138,10 +142,11 @@ struct cds_lfht *_cds_lfht_new(unsigned long init_size, static inline struct cds_lfht *cds_lfht_new(unsigned long init_size, unsigned long min_nr_alloc_buckets, + unsigned long max_nr_buckets, int flags, pthread_attr_t *attr) { - return _cds_lfht_new(init_size, min_nr_alloc_buckets, flags, + return _cds_lfht_new(init_size, min_nr_alloc_buckets, max_nr_buckets, flags, call_rcu, synchronize_rcu, rcu_read_lock, rcu_read_unlock, rcu_thread_offline, rcu_thread_online, rcu_register_thread,