From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Wed, 21 Sep 2011 14:21:21 +0000 (-0400)
Subject: rculfhash: handle small and negative table size approximation
X-Git-Tag: v0.7.0~43^2~131
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=e3ecefd6319001d15f8abc05f28fce0feb5c82bb;p=userspace-rcu.git

rculfhash: handle small and negative table size approximation

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/rculfhash.c b/rculfhash.c
index 7e959fb..9a95be2 100644
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -556,7 +556,7 @@ void ht_count_add(struct cds_lfht *ht, unsigned long size)
 		return;
 	percpu_count = uatomic_add_return(&ht->percpu_count[cpu].add, 1);
 	if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) {
-		unsigned long count;
+		long count;
 
 		dbg_printf("add percpu %lu\n", percpu_count);
 		count = uatomic_add_return(&ht->count,
@@ -565,7 +565,13 @@ void ht_count_add(struct cds_lfht *ht, unsigned long size)
 		if (!(count & (count - 1))) {
 			if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) < size)
 				return;
-			dbg_printf("add set global %lu\n", count);
+			dbg_printf("add set global %ld\n", count);
+			/*
+			 * Don't resize table if the number of nodes is below a
+			 * certain threshold.
+			 */
+			if (count < (1UL << COUNT_COMMIT_ORDER))
+				return;
 			cds_lfht_resize_lazy_count(ht, size,
 				count >> (CHAIN_LEN_TARGET - 1));
 		}
@@ -585,7 +591,7 @@ void ht_count_del(struct cds_lfht *ht, unsigned long size)
 		return;
 	percpu_count = uatomic_add_return(&ht->percpu_count[cpu].del, 1);
 	if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) {
-		unsigned long count;
+		long count;
 
 		dbg_printf("del percpu %lu\n", percpu_count);
 		count = uatomic_add_return(&ht->count,
@@ -594,7 +600,13 @@ void ht_count_del(struct cds_lfht *ht, unsigned long size)
 		if (!(count & (count - 1))) {
 			if ((count >> CHAIN_LEN_RESIZE_THRESHOLD) >= size)
 				return;
-			dbg_printf("del set global %lu\n", count);
+			dbg_printf("del set global %ld\n", count);
+			/*
+			 * Don't resize table if the number of nodes is below a
+			 * certain threshold.
+			 */
+			if (count < (1UL << COUNT_COMMIT_ORDER))
+				return;
 			cds_lfht_resize_lazy_count(ht, size,
 				count >> (CHAIN_LEN_TARGET - 1));
 		}