Make the man page reflec t the code a bit better.

Specifically, note the condition of the memory on initial
and subsequent allocations is different.

1 files changed, 11 insertions, 2 deletions

diff --git a/share/man/man9/zone.9 b/share/man/man9/zone.9
index 1cd18ca..68393d2 100644
--- a/share/man/man9/zone.9
+++ b/share/man/man9/zone.9
@@ -63,8 +63,11 @@ The zone allocator keeps track of which items are in use and which
 aren't, and provides functions for allocating items from the zone and
 for releasing them back (which makes them available for later use).
 .Pp
-The zone allocator stores state information inside the items proper,
-so structures that will be managed by the zone allocator must reserve
+The zone allocator stores state information inside the items proper
+while they are not allocated,
+so structures that will be managed by the zone allocator
+and wish to use the type stable property of zones by leaving some fields
+pre-filled between allocations, must reserve
 two pointers at the very beginning for internal use by the zone
 allocator, as follows:
 .Bd -literal
@@ -75,6 +78,12 @@ struct my_item {
 };
 .Ed
 .Pp
+Alternatively they should assume those entries corrupted
+after each allocation. After the first allocation of an item,
+it will have been cleared to zeroes, however subsequent allocations 
+will retain the contents as of the last free, with the exception of the 
+fields mentioned above.
+.Pp
 Zones are created in one of two fashions, depending how far along the
 boot process is.
 .Pp