X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=urcu%2Frculfhash.h;h=de34fae0b424b20a0b7d7538932376209a603969;hb=13f656f996861f47172f34a1ef28e338616ff5e2;hp=c03baf41a2b8405fda996ddb633a250a8bcdd89a;hpb=0b6aa0018b42d0b101c617ef6c6d34d0f4dd2258;p=userspace-rcu.git

diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h
index c03baf4..de34fae 100644
--- a/urcu/rculfhash.h
+++ b/urcu/rculfhash.h
@@ -39,8 +39,15 @@ extern "C" {
  * cds_lfht_node: Contains the next pointers and reverse-hash
  * value required for lookup and traversal of the hash table.
  *
- * struct cds_lfht_node should be aligned on 4-bytes boundaries because
- * the two lower bits are used as flags.
+ * struct cds_lfht_node should be aligned on 8-bytes boundaries because
+ * the three lower bits are used as flags. It is worth noting that the
+ * information contained within these three bits could be represented on
+ * two bits by re-using the same bit for REMOVAL_OWNER_FLAG and
+ * BUCKET_FLAG. This can be done if we ensure that no iterator nor
+ * updater check the BUCKET_FLAG after it detects that the REMOVED_FLAG
+ * is set. Given the minimum size of struct cds_lfht_node is 8 bytes on
+ * 32-bit architectures, we choose to go for simplicity and reserve
+ * three bits.
  *
  * struct cds_lfht_node can be embedded into a structure (as a field).
  * caa_container_of() can be used to get the structure from the struct
@@ -51,9 +58,9 @@ extern "C" {
  * of the hash value for cds_lfht APIs.
  */
 struct cds_lfht_node {
-	struct cds_lfht_node *next;	/* ptr | BUCKET_FLAG | REMOVED_FLAG */
+	struct cds_lfht_node *next;	/* ptr | REMOVAL_OWNER_FLAG | BUCKET_FLAG | REMOVED_FLAG */
 	unsigned long reverse_hash;
-} __attribute__((aligned(4)));
+} __attribute__((aligned(8)));
 
 /* cds_lfht_iter: Used to track state while traversing a hash chain. */
 struct cds_lfht_iter {
@@ -105,6 +112,8 @@ struct cds_lfht_mm_type {
 };
 
 extern const struct cds_lfht_mm_type cds_lfht_mm_order;
+extern const struct cds_lfht_mm_type cds_lfht_mm_chunk;
+extern const struct cds_lfht_mm_type cds_lfht_mm_mmap;
 
 /*
  * _cds_lfht_new - API used by cds_lfht_new wrapper. Do not use directly.
@@ -152,7 +161,7 @@ struct cds_lfht *cds_lfht_new(unsigned long init_size,
 			pthread_attr_t *attr)
 {
 	return _cds_lfht_new(init_size, min_nr_alloc_buckets, max_nr_buckets,
-			flags, &cds_lfht_mm_order, &rcu_flavor, attr);
+			flags, NULL, &rcu_flavor, attr);
 }
 
 /*