* Optional debug feature for tracking which page queue a page should be

in.
* New debugger command "find_page", which searches all page queues to
  find out, which one a page is actually in.
* Solved nasty race condition between the page scrubber and
  vm_page_allocate_page_run(): The page scrubber didn't mark the pages
  it was processing busy, so that vm_page_allocate_page_run() could claim
  them in the meantime. They would end up in the clear pages queue,
  although being assigned to a cache at the same time. This should
  finally solve bug #1056.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@20474 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/vm_types.h

@@ -17,6 +17,11 @@
 #include <sys/uio.h>
 
 
+// Enables the vm_page::queue, i.e. it is tracked which queue the page should
+// be in.
+//#define DEBUG_PAGE_QUEUE	1
+
+
 #ifdef __cplusplus
 struct vm_page_mapping;
 typedef DoublyLinkedListLink<vm_page_mapping> vm_page_mapping_link;
@@ -83,6 +88,10 @@ typedef struct vm_page {
 
 	vm_page_mappings	mappings;
 
+	#ifdef DEBUG_PAGE_QUEUE
+	void*				queue;
+	#endif
+
 	uint8				type : 2;
 	uint8				state : 3;
 	uint8				busy_reading : 1;