While splitting flags and pqflags might have been a good idea in theory

to separate locking, on most modern machines this is not enough
since operations on short types touch other short types that share the
same word in memory.

Merge pg_flags and pqflags again and now use atomic operations to change
the flags. Also bump wire_count to an int and pg_version might go
int as well, just for alignment.

tested by many, many. ok miod@

1 files changed, 30 insertions, 25 deletions

diff --git a/sys/uvm/uvm_pdaemon.c b/sys/uvm/uvm_pdaemon.c
index 0ca61319c31..4e6d7757214 100644
--- a/sys/uvm/uvm_pdaemon.c
+++ b/sys/uvm/uvm_pdaemon.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_pdaemon.c,v 1.31 2007/04/04 17:44:45 art Exp $	*/
+/*	$OpenBSD: uvm_pdaemon.c,v 1.32 2007/04/13 18:57:49 art Exp $	*/
 /*	$NetBSD: uvm_pdaemon.c,v 1.23 2000/08/20 10:24:14 bjh21 Exp $	*/
 
 /* 
@@ -473,7 +473,7 @@ uvmpd_scan_inactive(pglst)
 			 */
 
 			/* is page part of an anon or ownerless ? */
-			if ((p->pqflags & PQ_ANON) || p->uobject == NULL) {
+			if ((p->pg_flags & PQ_ANON) || p->uobject == NULL) {
 				anon = p->uanon;
 				KASSERT(anon != NULL);
 				if (!simple_lock_try(&anon->an_lock)) {
@@ -486,10 +486,11 @@ uvmpd_scan_inactive(pglst)
 				 * name of "anon"!
 				 */
 
-				if ((p->pqflags & PQ_ANON) == 0) {
+				if ((p->pg_flags & PQ_ANON) == 0) {
 					KASSERT(p->loan_count > 0);
 					p->loan_count--;
-					p->pqflags |= PQ_ANON;
+					atomic_setbits_int(&p->pg_flags,
+					    PQ_ANON);
 					/* anon now owns it */
 				}
 				if (p->pg_flags & PG_BUSY) {
@@ -522,7 +523,7 @@ uvmpd_scan_inactive(pglst)
 			 */
 
 			if (p->pg_flags & PG_CLEAN) {
-				if (p->pqflags & PQ_SWAPBACKED) {
+				if (p->pg_flags & PQ_SWAPBACKED) {
 					/* this page now lives only in swap */
 					simple_lock(&uvm.swap_data_lock);
 					uvmexp.swpgonly++;
@@ -576,7 +577,7 @@ uvmpd_scan_inactive(pglst)
 			 */
 
 			KASSERT(uvmexp.swpgonly <= uvmexp.swpages);
-			if ((p->pqflags & PQ_SWAPBACKED) &&
+			if ((p->pg_flags & PQ_SWAPBACKED) &&
 			    uvmexp.swpgonly == uvmexp.swpages) {
 				dirtyreacts++;
 				uvm_pageactivate(p);
@@ -595,15 +596,15 @@ uvmpd_scan_inactive(pglst)
 			 */
 
 			KASSERT(uvmexp.swpginuse <= uvmexp.swpages);
-			if ((p->pqflags & PQ_SWAPBACKED) &&
+			if ((p->pg_flags & PQ_SWAPBACKED) &&
 			    uvmexp.swpginuse == uvmexp.swpages) {
 
-				if ((p->pqflags & PQ_ANON) &&
+				if ((p->pg_flags & PQ_ANON) &&
 				    p->uanon->an_swslot) {
 					uvm_swap_free(p->uanon->an_swslot, 1);
 					p->uanon->an_swslot = 0;
 				}
-				if (p->pqflags & PQ_AOBJ) {
+				if (p->pg_flags & PQ_AOBJ) {
 					uao_dropswap(p->uobject,
 						     p->offset >> PAGE_SHIFT);
 				}
@@ -618,8 +619,8 @@ uvmpd_scan_inactive(pglst)
 			 * in I/O.
 			 */
 
-			swap_backed = ((p->pqflags & PQ_SWAPBACKED) != 0);
-			p->pg_flags |= PG_BUSY;		/* now we own it */
+			swap_backed = ((p->pg_flags & PQ_SWAPBACKED) != 0);
+			atomic_setbits_int(&p->pg_flags, PG_BUSY);
 			UVM_PAGE_OWN(p, "scan_inactive");
 			pmap_page_protect(p, VM_PROT_READ);
 			uvmexp.pgswapout++;
@@ -656,7 +657,9 @@ uvmpd_scan_inactive(pglst)
 					    TRUE);
 					if (swslot == 0) {
 						/* no swap?  give up! */
-						p->pg_flags &= ~PG_BUSY;
+						atomic_clearbits_int(
+						    &p->pg_flags,
+						    PG_BUSY);
 						UVM_PAGE_OWN(p, NULL);
 						if (anon)
 							simple_unlock(
@@ -784,7 +787,7 @@ uvmpd_scan_inactive(pglst)
 			uvm_lock_pageq();
 			uvmexp.pdpending++;
 			if (p) {
-				if (p->pqflags & PQ_INACTIVE)
+				if (p->pg_flags & PQ_INACTIVE)
 					nextpg = TAILQ_NEXT(p, pageq);
 				else
 					nextpg = TAILQ_FIRST(pglst);
@@ -850,7 +853,7 @@ uvmpd_scan_inactive(pglst)
 				/* still holding object lock */
 				wakeup(p);
 
-			p->pg_flags &= ~(PG_BUSY|PG_WANTED);
+			atomic_clearbits_int(&p->pg_flags, PG_BUSY|PG_WANTED);
 			UVM_PAGE_OWN(p, NULL);
 
 			/* released during I/O? */
@@ -903,7 +906,8 @@ uvmpd_scan_inactive(pglst)
 					/* pageout was a success... */
 					pmap_clear_reference(p);
 					pmap_clear_modify(p);
-					p->pg_flags |= PG_CLEAN;
+					atomic_setbits_int(&p->pg_flags,
+					    PG_CLEAN);
 				}
 			}
 
@@ -937,7 +941,7 @@ uvmpd_scan_inactive(pglst)
 			uvm_lock_pageq();
 		}
 
-		if (nextpg && (nextpg->pqflags & PQ_INACTIVE) == 0) {
+		if (nextpg && (nextpg->pg_flags & PQ_INACTIVE) == 0) {
 			nextpg = TAILQ_FIRST(pglst);	/* reload! */
 		}
 	}
@@ -1042,16 +1046,16 @@ uvmpd_scan()
 		 * lock the page's owner.
 		 */
 		/* is page anon owned or ownerless? */
-		if ((p->pqflags & PQ_ANON) || p->uobject == NULL) {
+		if ((p->pg_flags & PQ_ANON) || p->uobject == NULL) {
 			KASSERT(p->uanon != NULL);
 			if (!simple_lock_try(&p->uanon->an_lock))
 				continue;
 
 			/* take over the page? */
-			if ((p->pqflags & PQ_ANON) == 0) {
+			if ((p->pg_flags & PQ_ANON) == 0) {
 				KASSERT(p->loan_count > 0);
 				p->loan_count--;
-				p->pqflags |= PQ_ANON;
+				atomic_setbits_int(&p->pg_flags, PQ_ANON);
 			}
 		} else {
 			if (!simple_lock_try(&p->uobject->vmobjlock))
@@ -1063,7 +1067,7 @@ uvmpd_scan()
 		 */
 
 		if ((p->pg_flags & PG_BUSY) != 0) {
-			if (p->pqflags & PQ_ANON)
+			if (p->pg_flags & PQ_ANON)
 				simple_unlock(&p->uanon->an_lock);
 			else
 				simple_unlock(&p->uobject->vmobjlock);
@@ -1076,18 +1080,19 @@ uvmpd_scan()
 		 */
 
 		if (swap_shortage > 0) {
-			if ((p->pqflags & PQ_ANON) && p->uanon->an_swslot) {
+			if ((p->pg_flags & PQ_ANON) && p->uanon->an_swslot) {
 				uvm_swap_free(p->uanon->an_swslot, 1);
 				p->uanon->an_swslot = 0;
-				p->pg_flags &= ~PG_CLEAN;
+				atomic_clearbits_int(&p->pg_flags, PG_CLEAN);
 				swap_shortage--;
 			}
-			if (p->pqflags & PQ_AOBJ) {
+			if (p->pg_flags & PQ_AOBJ) {
 				int slot = uao_set_swslot(p->uobject,
 					p->offset >> PAGE_SHIFT, 0);
 				if (slot) {
 					uvm_swap_free(slot, 1);
-					p->pg_flags &= ~PG_CLEAN;
+					atomic_clearbits_int(&p->pg_flags,
+					    PG_CLEAN);
 					swap_shortage--;
 				}
 			}
@@ -1105,7 +1110,7 @@ uvmpd_scan()
 			uvmexp.pddeact++;
 			inactive_shortage--;
 		}
-		if (p->pqflags & PQ_ANON)
+		if (p->pg_flags & PQ_ANON)
 			simple_unlock(&p->uanon->an_lock);
 		else
 			simple_unlock(&p->uobject->vmobjlock);