Author: kib
Date: Mon Jul 14 09:30:37 2014
New Revision: 268615
URL: http://svnweb.freebsd.org/changeset/base/268615
Log:
The OBJ_TMPFS flag of vm_object means that there is unreclaimed tmpfs
vnode for the tmpfs node owning this object. The flag is currently
used for two purposes. First, it allows to correctly handle VV_TEXT
for tmpfs vnode when the ref count on the object is decremented to 1,
similar to vnode_pager_dealloc() for regular filesystems. Second, it
prevents some operations, which are done on OBJT_SWAP vm objects
backing user anonymous memory, but are incorrect for the object owned
by tmpfs node.
The second kind of use of the OBJ_TMPFS flag is incorrect, since the
vnode might be reclaimed, which clears the flag, but vm object
operations must still be disallowed.
Introduce one more flag, OBJ_TMPFS_NODE, which is permanently set on
the object for VREG tmpfs node, and used instead of OBJ_TMPFS to test
whether vm object collapse and similar actions should be disabled.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Modified:
head/sys/vm/vm_object.c
head/sys/vm/vm_object.h
Modified: head/sys/vm/vm_object.c
==============================================================================
--- head/sys/vm/vm_object.c Mon Jul 14 09:16:55 2014 (r268614)
+++ head/sys/vm/vm_object.c Mon Jul 14 09:30:37 2014 (r268615)
@@ -553,13 +553,13 @@ vm_object_deallocate(vm_object_t object)
object->handle == NULL &&
(object->type == OBJT_DEFAULT ||
(object->type == OBJT_SWAP &&
- (object->flags & OBJ_TMPFS) == 0))) {
+ (object->flags & OBJ_TMPFS_NODE) == 0))) {
vm_object_set_flag(object, OBJ_ONEMAPPING);
} else if ((object->shadow_count == 1) &&
(object->handle == NULL) &&
(object->type == OBJT_DEFAULT ||
object->type == OBJT_SWAP)) {
- KASSERT((object->flags & OBJ_TMPFS) == 0,
+ KASSERT((object->flags & OBJ_TMPFS_NODE) == 0,
("shadowed tmpfs v_object %p", object));
vm_object_t robject;
@@ -2103,7 +2103,7 @@ vm_object_coalesce(vm_object_t prev_obje
VM_OBJECT_WLOCK(prev_object);
if ((prev_object->type != OBJT_DEFAULT &&
prev_object->type != OBJT_SWAP) ||
- (prev_object->flags & OBJ_TMPFS) != 0) {
+ (prev_object->flags & OBJ_TMPFS_NODE) != 0) {
VM_OBJECT_WUNLOCK(prev_object);
return (FALSE);
}
Modified: head/sys/vm/vm_object.h
==============================================================================
--- head/sys/vm/vm_object.h Mon Jul 14 09:16:55 2014 (r268614)
+++ head/sys/vm/vm_object.h Mon Jul 14 09:30:37 2014 (r268615)
@@ -186,10 +186,11 @@ struct vm_object {
#define OBJ_NOSPLIT 0x0010 /* dont split this object */
#define OBJ_PIPWNT 0x0040 /* paging in progress wanted */
#define OBJ_MIGHTBEDIRTY 0x0100 /* object might be dirty, only
for vnode */
+#define OBJ_TMPFS_NODE 0x0200 /* object belongs to tmpfs VREG
node */
#define OBJ_COLORED 0x1000 /* pg_color is defined */
#define OBJ_ONEMAPPING 0x2000 /* One USE (a single,
non-forked) mapping flag */
#define OBJ_DISCONNECTWNT 0x4000 /* disconnect from vnode wanted
*/
-#define OBJ_TMPFS 0x8000
+#define OBJ_TMPFS 0x8000 /* has tmpfs vnode allocated */
#define IDX_TO_OFF(idx) (((vm_ooffset_t)(idx)) << PAGE_SHIFT)
#define OFF_TO_IDX(off) ((vm_pindex_t)(((vm_ooffset_t)(off)) >> PAGE_SHIFT))
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