Reimplement the page's NOSYNC flag as an object-synchronized instead of a

page queues-synchronized flag.  Reduce the scope of the page queues lock in
vm_fault() accordingly.

Move vm_fault()'s call to vm_object_set_writeable_dirty() outside of the
scope of the page queues lock.  Reviewed by: tegge
Additionally, eliminate an unnecessary dereference in computing the
argument that is passed to vm_object_set_writeable_dirty().

4 files changed, 12 insertions, 12 deletions

diff --git a/sys/vm/vm_fault.c b/sys/vm/vm_fault.c
index b122c36..5922ff6 100644
--- a/sys/vm/vm_fault.c
+++ b/sys/vm/vm_fault.c
@@ -842,14 +842,15 @@ readrest:
 	if (prot & VM_PROT_WRITE) {
 		vm_page_lock_queues();
 		vm_page_flag_set(fs.m, PG_WRITEABLE);
-		vm_object_set_writeable_dirty(fs.m->object);
+		vm_page_unlock_queues();
+		vm_object_set_writeable_dirty(fs.object);
 
 		/*
 		 * If the fault is a write, we know that this page is being
 		 * written NOW so dirty it explicitly to save on 
 		 * pmap_is_modified() calls later.
 		 *
-		 * If this is a NOSYNC mmap we do not want to set PG_NOSYNC
+		 * If this is a NOSYNC mmap we do not want to set VPO_NOSYNC
 		 * if the page is already dirty to prevent data written with
 		 * the expectation of being synced from not being synced.
 		 * Likewise if this entry does not request NOSYNC then make
@@ -861,11 +862,10 @@ readrest:
 		 */
 		if (fs.entry->eflags & MAP_ENTRY_NOSYNC) {
 			if (fs.m->dirty == 0)
-				vm_page_flag_set(fs.m, PG_NOSYNC);
+				fs.m->oflags |= VPO_NOSYNC;
 		} else {
-			vm_page_flag_clear(fs.m, PG_NOSYNC);
+			fs.m->oflags &= ~VPO_NOSYNC;
 		}
-		vm_page_unlock_queues();
 		if (fault_flags & VM_FAULT_DIRTY) {
 			vm_page_dirty(fs.m);
 			vm_pager_page_unswapped(fs.m);
diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c
index fd34f40..cef7b6a 100644
--- a/sys/vm/vm_object.c
+++ b/sys/vm/vm_object.c
@@ -687,7 +687,7 @@ vm_object_terminate(vm_object_t object)
  *
  *	Clean all dirty pages in the specified range of object.  Leaves page 
  * 	on whatever queue it is currently on.   If NOSYNC is set then do not
- *	write out pages with PG_NOSYNC set (originally comes from MAP_NOSYNC),
+ *	write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC),
  *	leaving the object dirty.
  *
  *	When stuffing pages asynchronously, allow clustering.  XXX we need a
@@ -765,7 +765,7 @@ vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, int
 			 * If we have been asked to skip nosync pages and 
 			 * this is a nosync page, we can't continue.
 			 */
-			if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) {
+			if ((flags & OBJPC_NOSYNC) && (p->oflags & VPO_NOSYNC)) {
 				if (--scanlimit == 0)
 					break;
 				++tscan;
@@ -805,7 +805,7 @@ vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, int
 	clearobjflags = 1;
 	TAILQ_FOREACH(p, &object->memq, listq) {
 		vm_page_flag_set(p, PG_CLEANCHK);
-		if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC))
+		if ((flags & OBJPC_NOSYNC) && (p->oflags & VPO_NOSYNC))
 			clearobjflags = 0;
 		else
 			pmap_remove_write(p);
@@ -853,7 +853,7 @@ again:
 		 * nosync page, skip it.  Note that the object flags were
 		 * not cleared in this case so we do not have to set them.
 		 */
-		if ((flags & OBJPC_NOSYNC) && (p->flags & PG_NOSYNC)) {
+		if ((flags & OBJPC_NOSYNC) && (p->oflags & VPO_NOSYNC)) {
 			vm_page_flag_clear(p, PG_CLEANCHK);
 			continue;
 		}
diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index 8e4bf6f..bc62a8b 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -1580,7 +1580,7 @@ vm_page_set_validclean(vm_page_t m, int base, int size)
 	/*
 	 * Set valid, clear dirty bits.  If validating the entire
 	 * page we can safely clear the pmap modify bit.  We also
-	 * use this opportunity to clear the PG_NOSYNC flag.  If a process
+	 * use this opportunity to clear the VPO_NOSYNC flag.  If a process
 	 * takes a write fault on a MAP_NOSYNC memory area the flag will
 	 * be set again.
 	 *
@@ -1603,7 +1603,7 @@ vm_page_set_validclean(vm_page_t m, int base, int size)
 	m->dirty &= ~pagebits;
 	if (base == 0 && size == PAGE_SIZE) {
 		pmap_clear_modify(m);
-		vm_page_flag_clear(m, PG_NOSYNC);
+		m->oflags &= ~VPO_NOSYNC;
 	}
 }
 
diff --git a/sys/vm/vm_page.h b/sys/vm/vm_page.h
index 428aee5..f09d91f 100644
--- a/sys/vm/vm_page.h
+++ b/sys/vm/vm_page.h
@@ -144,6 +144,7 @@ struct vm_page {
  */
 #define	VPO_WANTED	0x0002	/* someone is waiting for page */
 #define	VPO_SWAPINPROG	0x0200	/* swap I/O in progress on page */
+#define	VPO_NOSYNC	0x0400	/* do not collect for syncer */
 
 /* Make sure that u_long is at least 64 bits when PAGE_SIZE is 32K. */
 #if PAGE_SIZE == 32768
@@ -226,7 +227,6 @@ extern struct pq_coloring page_queue_coloring;
 #define	PG_ZERO		0x0040		/* page is zeroed */
 #define PG_REFERENCED	0x0080		/* page has been referenced */
 #define PG_CLEANCHK	0x0100		/* page will be checked for cleaning */
-#define PG_NOSYNC	0x0400		/* do not collect for syncer */
 #define PG_UNMANAGED	0x0800		/* No PV management for page */
 #define PG_MARKER	0x1000		/* special queue marker page */
 #define	PG_SLAB		0x2000		/* object pointer is actually a slab */