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, 27 insertions, 18 deletions

diff --git a/sys/uvm/uvm_vnode.c b/sys/uvm/uvm_vnode.c
index 6a8c17d7bfc..b4270fbf9f1 100644
--- a/sys/uvm/uvm_vnode.c
+++ b/sys/uvm/uvm_vnode.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_vnode.c,v 1.45 2007/04/04 17:44:45 art Exp $	*/
+/*	$OpenBSD: uvm_vnode.c,v 1.46 2007/04/13 18:57:49 art Exp $	*/
 /*	$NetBSD: uvm_vnode.c,v 1.36 2000/11/24 20:34:01 chs Exp $	*/
 
 /*
@@ -873,7 +873,8 @@ uvn_flush(uobj, start, stop, flags)
 				if (!all &&
 				    (pp->offset < start || pp->offset >= stop))
 					continue;
-				pp->pg_flags &= ~PG_CLEANCHK;
+				atomic_clearbits_int(&pp->pg_flags,
+				    PG_CLEANCHK);
 			}
 
 		} else {   /* by hash */
@@ -881,7 +882,8 @@ uvn_flush(uobj, start, stop, flags)
 			    curoff += PAGE_SIZE) {
 				pp = uvm_pagelookup(uobj, curoff);
 				if (pp)
-					pp->pg_flags &= ~PG_CLEANCHK;
+					atomic_clearbits_int(&pp->pg_flags,
+					    PG_CLEANCHK);
 			}
 		}
 	}
@@ -958,12 +960,12 @@ uvn_flush(uobj, start, stop, flags)
 			 */
 			if ((pp->pg_flags & PG_CLEAN) != 0 &&
 			    (flags & PGO_FREE) != 0 &&
-			    (pp->pqflags & PQ_ACTIVE) != 0)
+			    (pp->pg_flags & PQ_ACTIVE) != 0)
 				pmap_page_protect(pp, VM_PROT_NONE);
 			if ((pp->pg_flags & PG_CLEAN) != 0 &&
 			    pmap_is_modified(pp))
-				pp->pg_flags &= ~(PG_CLEAN);
-			pp->pg_flags |= PG_CLEANCHK;	/* update "hint" */
+				atomic_clearbits_int(&pp->pg_flags, PG_CLEAN);
+			atomic_setbits_int(&pp->pg_flags, PG_CLEANCHK);
 
 			needs_clean = ((pp->pg_flags & PG_CLEAN) == 0);
 		}
@@ -982,7 +984,7 @@ uvn_flush(uobj, start, stop, flags)
 
 			/* now dispose of pp */
 			if (flags & PGO_DEACTIVATE) {
-				if ((pp->pqflags & PQ_INACTIVE) == 0 &&
+				if ((pp->pg_flags & PQ_INACTIVE) == 0 &&
 				    pp->wire_count == 0) {
 					pmap_page_protect(pp, VM_PROT_NONE);
 					uvm_pagedeactivate(pp);
@@ -991,7 +993,8 @@ uvn_flush(uobj, start, stop, flags)
 			} else if (flags & PGO_FREE) {
 				if (pp->pg_flags & PG_BUSY) {
 					/* release busy pages */
-					pp->pg_flags |= PG_RELEASED;
+					atomic_setbits_int(&pp->pg_flags,
+					    PG_RELEASED);
 				} else {
 					pmap_page_protect(pp, VM_PROT_NONE);
 					/* removed page from object */
@@ -1011,7 +1014,7 @@ uvn_flush(uobj, start, stop, flags)
 		 * note: locked: uobj and page queues.
 		 */
 
-		pp->pg_flags |= PG_BUSY;	/* we 'own' page now */
+		atomic_setbits_int(&pp->pg_flags, PG_BUSY);
 		UVM_PAGE_OWN(pp, "uvn_flush");
 		pmap_page_protect(pp, VM_PROT_READ);
 		pp_version = pp->pg_version;
@@ -1147,7 +1150,8 @@ ReTry:
 					/* still holding object lock */
 					wakeup(ptmp);
 
-				ptmp->pg_flags &= ~(PG_WANTED|PG_BUSY);
+				atomic_clearbits_int(&ptmp->pg_flags,
+				    PG_WANTED|PG_BUSY);
 				UVM_PAGE_OWN(ptmp, NULL);
 				if (ptmp->pg_flags & PG_RELEASED) {
 
@@ -1160,7 +1164,8 @@ ReTry:
 					continue;		/* next page */
 
 				} else {
-					ptmp->pg_flags |= (PG_CLEAN|PG_CLEANCHK);
+					atomic_setbits_int(&ptmp->pg_flags,
+					    PG_CLEAN|PG_CLEANCHK);
 					if ((flags & PGO_FREE) == 0)
 						pmap_clear_modify(ptmp);
 				}
@@ -1171,7 +1176,7 @@ ReTry:
 			 */
 
 			if (flags & PGO_DEACTIVATE) {
-				if ((pp->pqflags & PQ_INACTIVE) == 0 &&
+				if ((pp->pg_flags & PQ_INACTIVE) == 0 &&
 				    pp->wire_count == 0) {
 					pmap_page_protect(ptmp, VM_PROT_NONE);
 					uvm_pagedeactivate(ptmp);
@@ -1181,7 +1186,9 @@ ReTry:
 				if (result == VM_PAGER_PEND) {
 					if ((ptmp->pg_flags & PG_BUSY) != 0)
 						/* signal for i/o done */
-						ptmp->pg_flags |= PG_RELEASED;
+						atomic_setbits_int(
+						    &ptmp->pg_flags,
+						    PG_RELEASED);
 				} else {
 					if (result != VM_PAGER_OK) {
 						printf("uvn_flush: obj=%p, "
@@ -1360,7 +1367,7 @@ uvn_get(uobj, offset, pps, npagesp, centeridx, access_type, advice, flags)
 			 * useful page: busy/lock it and plug it in our
 			 * result array
 			 */
-			ptmp->pg_flags |= PG_BUSY;	/* loan up to caller */
+			atomic_setbits_int(&ptmp->pg_flags, PG_BUSY);
 			UVM_PAGE_OWN(ptmp, "uvn_get1");
 			pps[lcv] = ptmp;
 			gotpages++;
@@ -1456,7 +1463,7 @@ uvn_get(uobj, offset, pps, npagesp, centeridx, access_type, advice, flags)
 
 			/* page is there, see if we need to wait on it */
 			if ((ptmp->pg_flags & (PG_BUSY|PG_RELEASED)) != 0) {
-				ptmp->pg_flags |= PG_WANTED;
+				atomic_setbits_int(&ptmp->pg_flags, PG_WANTED);
 				UVM_UNLOCK_AND_WAIT(ptmp,
 				    &uobj->vmobjlock, FALSE, "uvn_get",0);
 				simple_lock(&uobj->vmobjlock);
@@ -1469,7 +1476,7 @@ uvn_get(uobj, offset, pps, npagesp, centeridx, access_type, advice, flags)
 			 * now (so we own it) and set pps[lcv] (so that we
 			 * exit the while loop).
 			 */
-			ptmp->pg_flags |= PG_BUSY;
+			atomic_setbits_int(&ptmp->pg_flags, PG_BUSY);
 			UVM_PAGE_OWN(ptmp, "uvn_get2");
 			pps[lcv] = ptmp;
 		}
@@ -1505,7 +1512,8 @@ uvn_get(uobj, offset, pps, npagesp, centeridx, access_type, advice, flags)
 				/* object lock still held */
 				wakeup(ptmp);
 
-			ptmp->pg_flags &= ~(PG_WANTED|PG_BUSY);
+			atomic_clearbits_int(&ptmp->pg_flags,
+			    PG_WANTED|PG_BUSY);
 			UVM_PAGE_OWN(ptmp, NULL);
 			uvm_lock_pageq();
 			uvm_pagefree(ptmp);
@@ -1525,7 +1533,8 @@ uvn_get(uobj, offset, pps, npagesp, centeridx, access_type, advice, flags)
 		 * => activate the page
 		 */
 
-		ptmp->pg_flags &= ~PG_FAKE;		/* data is valid ... */
+		/* data is valid ... */
+		atomic_clearbits_int(&ptmp->pg_flags, PG_FAKE);
 		pmap_clear_modify(ptmp);		/* ... and clean */
 		pps[lcv] = ptmp;