diff options
Diffstat (limited to 'module/zfs/dmu_objset.c')
| -rw-r--r-- | module/zfs/dmu_objset.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/module/zfs/dmu_objset.c b/module/zfs/dmu_objset.c index 22deee7f3..af107fb8a 100644 --- a/module/zfs/dmu_objset.c +++ b/module/zfs/dmu_objset.c @@ -399,7 +399,15 @@ static unsigned int dnode_multilist_index_func(multilist_t *ml, void *obj) { dnode_t *dn = obj; - return (dnode_hash(dn->dn_objset, dn->dn_object) % + + /* + * The low order bits of the hash value are thought to be + * distributed evenly. Otherwise, in the case that the multilist + * has a power of two number of sublists, each sublists' usage + * would not be evenly distributed. In this context full 64bit + * division would be a waste of time, so limit it to 32 bits. + */ + return ((unsigned int)dnode_hash(dn->dn_objset, dn->dn_object) % multilist_get_num_sublists(ml)); } |