Require that the page lock is held, instead of the object lock, when

clearing the page's PGA_REFERENCED flag.  Since we are typically
manipulating the page's act_count field when we are clearing its
PGA_REFERENCED flag, the page lock is already held everywhere that we clear
the PGA_REFERENCED flag.  So, in fact, this revision only changes some
comments and an assertion.  Nonetheless, it will enable later changes to
object locking in the pageout code.

Introduce vm_page_assert_locked(), which completely hides the implementation
details of the page lock from the caller, and use it in
vm_page_aflag_clear().  (The existing vm_page_lock_assert() could not be
used in vm_page_aflag_clear().)  Over the coming weeks, I expect that we'll
either eliminate or replace the various uses of vm_page_lock_assert() with
vm_page_assert_locked().

Reviewed by:	attilio
Sponsored by:	EMC / Isilon Storage Division

1 files changed, 7 insertions, 0 deletions

diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index 5a1c055..b6fbb93 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -2725,6 +2725,13 @@ vm_page_trylock_KBI(vm_page_t m, const char *file, int line)
 
 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
 void
+vm_page_assert_locked_KBI(vm_page_t m, const char *file, int line)
+{
+
+	vm_page_lock_assert_KBI(m, MA_OWNED, file, line);
+}
+
+void
 vm_page_lock_assert_KBI(vm_page_t m, int a, const char *file, int line)
 {