Provide basic page cache statistics

* Makefrag.am (EXTRA_DIST): Add kern/gnumach.srv.
(include_mach_HEADERS): Add include/mach/gnumach.defs and
include/mach/vm_cache_statistics.h
(nodist_libkernel_a_SOURCES): Add kern/gnumach.server.defs.c,
kern/gnumach.server.h, kern/gnumach.server.c, kern/gnumach.server.msgids,
kern/gnumach.server.defs.
* include/mach/mach_types.h: Add #include <mach/vm_cache_statistics.h>.
* kern/ipc_kobject.c (ipc_kobject_server): Declare and call
gnumach_server_routine.
* vm/vm_object.c (vm_object_cached_pages): New variable.
(vm_object_cached_pages_lock_data): Likewise.
(vm_object_deallocate): Update number of cached pages.
(vm_object_lookup): Likewise.
(vm_object_lookup_name): Likewise.
(vm_object_destroy): Likewise.
(vm_object_enter): Likewise.
* vm/vm_object.h (ref_count): Declare as int.
(resident_page_count): Likewise.
(vm_object_cached_count): Add extern declaration.
(vm_object_cached_pages): Likewise.
(vm_object_cached_pages_lock_data): Likewise.
(vm_object_cached_pages_update): New macro.
* vm/vm_resident.c (vm_page_insert): Assert resident page count doesn't
overflow, update number of cached pages as appropriate.
(vm_page_replace): Likewise.
(vm_page_remove): Update number of cached pages as appropriate.
* vm/vm_user.c: Add #include <mach/vm_cache_statistics.h>.
(vm_cache_statistics): New function.
* vm/vm_user.h: Add #include <mach/mach_types.h>.
(vm_cache_statistics): New declaration.
* include/mach/gnumach.defs: New file.

5 files changed, 76 insertions, 2 deletions

diff --git a/vm/vm_object.c b/vm/vm_object.c
index f101708..7eae3d7 100644
--- a/vm/vm_object.c
+++ b/vm/vm_object.c
@@ -192,6 +192,15 @@ decl_simple_lock_data(,vm_object_cached_lock_data)
 		simple_unlock(&vm_object_cached_lock_data)
 
 /*
+ *	Number of physical pages referenced by cached objects.
+ *	This counter is protected by its own lock to work around
+ *	lock ordering issues.
+ */
+int		vm_object_cached_pages;
+
+decl_simple_lock_data(,vm_object_cached_pages_lock_data)
+
+/*
  *	Virtual memory objects are initialized from
  *	a template (see vm_object_allocate).
  *
@@ -410,6 +419,7 @@ void vm_object_deallocate(
 			queue_enter(&vm_object_cached_list, object,
 				vm_object_t, cached_list);
 			overflow = (++vm_object_cached_count > vm_object_cached_max);
+			vm_object_cached_pages_update(object->resident_page_count);
 			vm_object_cache_unlock();
 
 			vm_object_deactivate_pages(object);
@@ -1860,6 +1870,7 @@ vm_object_t vm_object_lookup(
 				queue_remove(&vm_object_cached_list, object,
 					     vm_object_t, cached_list);
 				vm_object_cached_count--;
+				vm_object_cached_pages_update(-object->resident_page_count);
 			}
 
 			object->ref_count++;
@@ -1891,6 +1902,7 @@ vm_object_t vm_object_lookup_name(
 				queue_remove(&vm_object_cached_list, object,
 					     vm_object_t, cached_list);
 				vm_object_cached_count--;
+				vm_object_cached_pages_update(-object->resident_page_count);
 			}
 
 			object->ref_count++;
@@ -1927,6 +1939,7 @@ void vm_object_destroy(
 		queue_remove(&vm_object_cached_list, object,
 				vm_object_t, cached_list);
 		vm_object_cached_count--;
+		vm_object_cached_pages_update(-object->resident_page_count);
 	}
 	object->ref_count++;
 
@@ -2080,6 +2093,7 @@ restart:
 			queue_remove(&vm_object_cached_list, object,
 					vm_object_t, cached_list);
 			vm_object_cached_count--;
+			vm_object_cached_pages_update(-object->resident_page_count);
 		}
 		object->ref_count++;
 		vm_object_unlock(object);
diff --git a/vm/vm_object.h b/vm/vm_object.h
index c992570..4e4c949 100644
--- a/vm/vm_object.h
+++ b/vm/vm_object.h
@@ -71,8 +71,8 @@ struct vm_object {
 						 * if internal)
 						 */
 
-	short			ref_count;	/* Number of references */
-	short			resident_page_count;
+	int			ref_count;	/* Number of references */
+	int			resident_page_count;
 						/* number of resident pages */
 
 	struct vm_object	*copy;		/* Object that should receive
@@ -370,4 +370,23 @@ MACRO_END
 #define	vm_object_lock_taken(object)	simple_lock_taken(&(object)->Lock)
 #endif	/* VM_OBJECT_DEBUG */
 
+/*
+ *	Page cache accounting.
+ *
+ *	The number of cached objects and pages can be read
+ *	without holding any lock.
+ */
+
+extern int	vm_object_cached_count;
+
+extern int	vm_object_cached_pages;
+decl_simple_lock_data(extern,vm_object_cached_pages_lock_data)
+
+#define vm_object_cached_pages_update(page_count)			\
+	MACRO_BEGIN							\
+	simple_lock(&vm_object_cached_pages_lock_data);			\
+	vm_object_cached_pages += (page_count);				\
+	simple_unlock(&vm_object_cached_pages_lock_data);		\
+	MACRO_END
+
 #endif	/* _VM_VM_OBJECT_H_ */
diff --git a/vm/vm_resident.c b/vm/vm_resident.c
index ae71a74..581a9c4 100644
--- a/vm/vm_resident.c
+++ b/vm/vm_resident.c
@@ -517,6 +517,10 @@ void vm_page_insert(
 	 */
 
 	object->resident_page_count++;
+	assert(object->resident_page_count >= 0);
+
+	if (object->can_persist && (object->ref_count == 0))
+		vm_object_cached_pages_update(1);
 
 	/*
 	 *	Detect sequential access and inactivate previous page.
@@ -585,6 +589,10 @@ void vm_page_replace(
 				m->tabled = FALSE;
 				object->resident_page_count--;
 
+				if (object->can_persist
+				    && (object->ref_count == 0))
+					vm_object_cached_pages_update(-1);
+
 				/*
 				 * Return page to the free list.
 				 * Note the page is not tabled now, so this
@@ -616,6 +624,10 @@ void vm_page_replace(
 	 */
 
 	object->resident_page_count++;
+	assert(object->resident_page_count >= 0);
+
+	if (object->can_persist && (object->ref_count == 0))
+		vm_object_cached_pages_update(1);
 }
 
 /*
@@ -671,6 +683,9 @@ void vm_page_remove(
 	mem->object->resident_page_count--;
 
 	mem->tabled = FALSE;
+
+	if (mem->object->can_persist && (mem->object->ref_count == 0))
+		vm_object_cached_pages_update(-1);
 }
 
 /*
diff --git a/vm/vm_user.c b/vm/vm_user.c
index 59c2a36..a8ce982 100644
--- a/vm/vm_user.c
+++ b/vm/vm_user.c
@@ -38,6 +38,7 @@
 #include <mach/vm_attributes.h>
 #include <mach/vm_param.h>
 #include <mach/vm_statistics.h>
+#include <mach/vm_cache_statistics.h>
 #include <kern/host.h>
 #include <kern/task.h>
 #include <vm/vm_fault.h>
@@ -189,6 +190,29 @@ kern_return_t vm_statistics(map, stat)
 	return(KERN_SUCCESS);
 }
 
+kern_return_t vm_cache_statistics(
+	vm_map_t			map,
+	vm_cache_statistics_data_t	*stats)
+{
+	if (map == VM_MAP_NULL)
+		return KERN_INVALID_ARGUMENT;
+
+	stats->cache_object_count = vm_object_cached_count;
+	stats->cache_count = vm_object_cached_pages;
+
+	/* XXX Not implemented yet */
+	stats->active_tmp_count = 0;
+	stats->inactive_tmp_count = 0;
+	stats->active_perm_count = 0;
+	stats->inactive_perm_count = 0;
+	stats->dirty_count = 0;
+	stats->laundry_count = 0;
+	stats->writeback_count = 0;
+	stats->slab_count = 0;
+	stats->slab_reclaim_count = 0;
+	return KERN_SUCCESS;
+}
+
 /*
  * Handle machine-specific attributes for a mapping, such
  * as cachability, migrability, etc.
diff --git a/vm/vm_user.h b/vm/vm_user.h
index 3f15e5e..c6f20a8 100644
--- a/vm/vm_user.h
+++ b/vm/vm_user.h
@@ -37,6 +37,7 @@
 
 #include <mach/kern_return.h>
 #include <mach/std_types.h>
+#include <mach/mach_types.h>
 
 extern kern_return_t	vm_allocate(vm_map_t, vm_offset_t *, vm_size_t,
 				    boolean_t);
@@ -46,6 +47,7 @@ extern kern_return_t	vm_inherit(vm_map_t, vm_offset_t, vm_size_t,
 extern kern_return_t	vm_protect(vm_map_t, vm_offset_t, vm_size_t, boolean_t,
 				   vm_prot_t);
 extern kern_return_t	vm_statistics(vm_map_t, vm_statistics_data_t *);
+extern kern_return_t	vm_cache_statistics(vm_map_t, vm_cache_statistics_data_t *);
 extern kern_return_t	vm_read(vm_map_t, vm_address_t, vm_size_t, pointer_t *,
 				vm_size_t *);
 extern kern_return_t	vm_write(vm_map_t, vm_address_t, pointer_t, vm_size_t);