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

2 files changed, 21 insertions, 4 deletions

diff --git a/sys/dev/drm2/i915/i915_gem.c b/sys/dev/drm2/i915/i915_gem.c
index a4276a2..b2edf1a 100644
--- a/sys/dev/drm2/i915/i915_gem.c
+++ b/sys/dev/drm2/i915/i915_gem.c
@@ -64,6 +64,9 @@ __FBSDID("$FreeBSD$");
 #include <sys/sched.h>
 #include <sys/sf_buf.h>
 
+#include <vm/vm.h>
+#include <vm/vm_pageout.h>
+
 static void i915_gem_object_flush_cpu_write_domain(
     struct drm_i915_gem_object *obj);
 static uint32_t i915_gem_get_gtt_size(struct drm_device *dev, uint32_t size,
@@ -1443,8 +1446,14 @@ retry:
 		vm_page_busy_sleep(m, "915pbs");
 		goto retry;
 	}
+	if (vm_page_insert(m, vm_obj, OFF_TO_IDX(offset))) {
+		DRM_UNLOCK(dev);
+		VM_OBJECT_WUNLOCK(vm_obj);
+		VM_WAIT;
+		VM_OBJECT_WLOCK(vm_obj);
+		goto retry;
+	}
 	m->valid = VM_PAGE_BITS_ALL;
-	vm_page_insert(m, vm_obj, OFF_TO_IDX(offset));
 have_page:
 	*mres = m;
 	vm_page_xbusy(m);
diff --git a/sys/dev/drm2/ttm/ttm_bo_vm.c b/sys/dev/drm2/ttm/ttm_bo_vm.c
index 0faf868..366a776 100644
--- a/sys/dev/drm2/ttm/ttm_bo_vm.c
+++ b/sys/dev/drm2/ttm/ttm_bo_vm.c
@@ -47,6 +47,7 @@ __FBSDID("$FreeBSD$");
 
 #include <vm/vm.h>
 #include <vm/vm_page.h>
+#include <vm/vm_pageout.h>
 
 #define TTM_BO_VM_NUM_PREFAULT 16
 
@@ -221,16 +222,23 @@ reserve:
 		ttm_bo_unreserve(bo);
 		goto retry;
 	}
-	m->valid = VM_PAGE_BITS_ALL;
-	*mres = m;
 	m1 = vm_page_lookup(vm_obj, OFF_TO_IDX(offset));
 	if (m1 == NULL) {
-		vm_page_insert(m, vm_obj, OFF_TO_IDX(offset));
+		if (vm_page_insert(m, vm_obj, OFF_TO_IDX(offset))) {
+			VM_OBJECT_WUNLOCK(vm_obj);
+			VM_WAIT;
+			VM_OBJECT_WLOCK(vm_obj);
+			ttm_mem_io_unlock(man);
+			ttm_bo_unreserve(bo);
+			goto retry;
+		}
 	} else {
 		KASSERT(m == m1,
 		    ("inconsistent insert bo %p m %p m1 %p offset %jx",
 		    bo, m, m1, (uintmax_t)offset));
 	}
+	m->valid = VM_PAGE_BITS_ALL;
+	*mres = m;
 	vm_page_xbusy(m);
 
 	if (oldm != NULL) {