svn commit: r247343 - user/attilio/vmc-playground/sys/vm

[Attilio Rao]

Author: attilio
Date: Tue Feb 26 20:18:25 2013
New Revision: 247343
URL: http://svnweb.freebsd.org/changeset/base/247343

Log:
  Revert the moving of vm_object objects initialization:
  the objects zone ensures type-stability and thus we want to execute
  actual lock initialization only when the objects are brought into the
  zone otherwise there could be races between lock threads doing
  re-initilization and other threads that want to acquire the lock
  without a reference.
  
  Sponsored by:	EMC / Isilon storage division
  Reported by:	alc

Modified:
  user/attilio/vmc-playground/sys/vm/vm_object.c

Modified: user/attilio/vmc-playground/sys/vm/vm_object.c
==============================================================================
--- user/attilio/vmc-playground/sys/vm/vm_object.c	Tue Feb 26 20:02:17 2013	(r247342)
+++ user/attilio/vmc-playground/sys/vm/vm_object.c	Tue Feb 26 20:18:25 2013	(r247343)
@@ -194,23 +194,20 @@ vm_object_zinit(void *mem, int size, int
 	vm_object_t object;
 
 	object = (vm_object_t)mem;
+	bzero(&object->mtx, sizeof(object->mtx));
+	mtx_init(&object->mtx, "vm object", NULL, MTX_DEF | MTX_DUPOK);
 
 	/* These are true for any object that has been freed */
 	object->paging_in_progress = 0;
 	object->resident_page_count = 0;
 	object->shadow_count = 0;
-
-	/* It relies on vm object mutex to be initialized afterwards. */
 	return (0);
 }
 
 static void
-_vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object,
-    const char *mtxname)
+_vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object)
 {
 
-	bzero(&object->mtx, sizeof(object->mtx));
-	mtx_init(&object->mtx, "vm object", mtxname, MTX_DEF | MTX_DUPOK);
 	TAILQ_INIT(&object->memq);
 	LIST_INIT(&object->shadow_head);
 
@@ -270,15 +267,17 @@ vm_object_init(void)
 	TAILQ_INIT(&vm_object_list);
 	mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF);
 	
+	mtx_init(&kernel_object->mtx, "vm object", "kernel object", MTX_DEF);
 	_vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
-	    kernel_object, "kernel object");
+	    kernel_object);
 #if VM_NRESERVLEVEL > 0
 	kernel_object->flags |= OBJ_COLORED;
 	kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
 #endif
 
+	mtx_init(&kmem_object->mtx, "vm object", "kmem object", MTX_DEF);
 	_vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS),
-	    kmem_object, "kmem object");
+	    kmem_object);
 #if VM_NRESERVLEVEL > 0
 	kmem_object->flags |= OBJ_COLORED;
 	kmem_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS);
@@ -404,7 +403,7 @@ vm_object_allocate(objtype_t type, vm_pi
 	vm_object_t object;
 
 	object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK);
-	_vm_object_allocate(type, size, object, NULL);
+	_vm_object_allocate(type, size, object);
 	return (object);
 }