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diff --git a/sys/vm/vm_map.c b/sys/vm/vm_map.c
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@@ -1978,23 +1978,30 @@
static int cluster_anon = 1;
SYSCTL_INT(_vm, OID_AUTO, cluster_anon, CTLFLAG_RW,
&cluster_anon, 0,
- "Cluster anonymous mappings: 0 = no, 1 = yes if no hint, 2 = always");
+ "Cluster anonymous mappings: "
+ "0 = no, 1 = yes if no hint, 2 = always, 3 = keep anon_loc const");
static bool
-clustering_anon_allowed(vm_offset_t addr)
+clustering_anon_allowed(vm_offset_t addr, vm_offset_t anon_loc)
{
switch (cluster_anon) {
case 0:
return (false);
case 1:
- return (addr == 0);
+ return (addr == 0 || addr <= anon_loc);
case 2:
default:
return (true);
}
}
+static bool
+clustering_anon_loc_const(void)
+{
+ return (cluster_anon == 3);
+}
+
static long aslr_restarts;
SYSCTL_LONG(_vm, OID_AUTO, aslr_restarts, CTLFLAG_RD,
&aslr_restarts, 0,
@@ -2093,6 +2100,7 @@
vm_size_t length, vm_offset_t max_addr, int find_space,
vm_prot_t prot, vm_prot_t max, int cow)
{
+ vm_map_entry_t entry;
vm_offset_t alignment, curr_min_addr, min_addr;
int gap, pidx, rv, try;
bool cluster, en_aslr, update_anon;
@@ -2111,7 +2119,7 @@
} else
alignment = 0;
en_aslr = (map->flags & MAP_ASLR) != 0;
- update_anon = cluster = clustering_anon_allowed(*addr) &&
+ update_anon = cluster = clustering_anon_allowed(*addr, map->anon_loc) &&
(map->flags & MAP_IS_SUB_MAP) == 0 && max_addr == 0 &&
find_space != VMFS_NO_SPACE && object == NULL &&
(cow & (MAP_INHERIT_SHARE | MAP_STACK_GROWS_UP |
@@ -2127,6 +2135,9 @@
curr_min_addr = map->anon_loc;
if (curr_min_addr == 0)
cluster = false;
+ else if (!clustering_anon_loc_const() &&
+ !vm_map_lookup_entry(map, curr_min_addr, &entry))
+ curr_min_addr = entry->end;
}
if (find_space != VMFS_NO_SPACE) {
KASSERT(find_space == VMFS_ANY_SPACE ||
@@ -2226,7 +2237,7 @@
rv = vm_map_insert(map, object, offset, *addr, *addr + length,
prot, max, cow);
}
- if (rv == KERN_SUCCESS && update_anon)
+ if (rv == KERN_SUCCESS && update_anon && !clustering_anon_loc_const())
map->anon_loc = *addr + length;
done:
vm_map_unlock(map);
@@ -3966,7 +3977,7 @@
entry->object.vm_object != NULL)
pmap_map_delete(map->pmap, entry->start, entry->end);
- if (entry->end == map->anon_loc)
+ if (entry->end == map->anon_loc && !clustering_anon_loc_const())
map->anon_loc = entry->start;
/*

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