```
It is possible that VA right before the current anonymous clustering
location was unmapped, e.g. this could happen when the malloc
allocations interleave with explicit mmaps of the anonymous memory, and
frees/unmaps.
Mark anon mappings with a new map entry flag MAP_ENTRY_ANON_LOC_UPD, and
update the map->anon_loc with the previous entry' end if freed entry is
flagged.
```
```
ASLR: add a new mode for anonymous clustering control
The value 3 for vm.cluster_anon still initializes the clustering point
at the image creation, and never update it. So, all virtual address
allocations are performed using an address-ordered, first-fit policy,
just like we do when ASLR is turned off.
```
```
vm_map_find(): the address hint is almost always non-zero
Adopt to the observation and fix cluster mode 1 by enabling clustering
if hint is zero or less then current clustering location.
```