On all the architectures, avoid to preallocate the physical memory

for nodes used in vm_radix.
On architectures supporting direct mapping, also avoid to pre-allocate
the KVA for such nodes.

In order to do so make the operations derived from vm_radix_insert()
to fail and handle all the deriving failure of those.

vm_radix-wise introduce a new function called vm_radix_replace(),
which can replace a leaf node, already present, with a new one,
and take into account the possibility, during vm_radix_insert()
allocation, that the operations on the radix trie can recurse.
This means that if operations in vm_radix_insert() recursed
vm_radix_insert() will start from scratch again.

Sponsored by:	EMC / Isilon storage division
Reviewed by:	alc (older version)
Reviewed by:	jeff
Tested by:	pho, scottl

1 files changed, 4 insertions, 2 deletions

diff --git a/sys/vm/vm_page.h b/sys/vm/vm_page.h
index 53cf449..01c4967 100644
--- a/sys/vm/vm_page.h
+++ b/sys/vm/vm_page.h
@@ -438,7 +438,7 @@ void vm_page_dequeue_locked(vm_page_t m);
 vm_page_t vm_page_find_least(vm_object_t, vm_pindex_t);
 vm_page_t vm_page_getfake(vm_paddr_t paddr, vm_memattr_t memattr);
 void vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr);
-void vm_page_insert (vm_page_t, vm_object_t, vm_pindex_t);
+int vm_page_insert (vm_page_t, vm_object_t, vm_pindex_t);
 boolean_t vm_page_is_cached(vm_object_t object, vm_pindex_t pindex);
 vm_page_t vm_page_lookup (vm_object_t, vm_pindex_t);
 vm_page_t vm_page_next(vm_page_t m);
@@ -449,7 +449,9 @@ void vm_page_putfake(vm_page_t m);
 void vm_page_readahead_finish(vm_page_t m);
 void vm_page_reference(vm_page_t m);
 void vm_page_remove (vm_page_t);
-void vm_page_rename (vm_page_t, vm_object_t, vm_pindex_t);
+int vm_page_rename (vm_page_t, vm_object_t, vm_pindex_t);
+vm_page_t vm_page_replace(vm_page_t mnew, vm_object_t object,
+    vm_pindex_t pindex);
 void vm_page_requeue(vm_page_t m);
 void vm_page_requeue_locked(vm_page_t m);
 int vm_page_sbusied(vm_page_t m);