Primarily a fix so that pages are properly tracked for being

modified.  Pages that are removed by the pageout daemon were
the worst affected.  Additionally, numerous minor cleanups,
including better handling of busy page table pages.  This
commit fixes the worst of the pmap problems recently introduced.

1 files changed, 62 insertions, 35 deletions

diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index 97620bd..9be3542 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -39,7 +39,7 @@
  * SUCH DAMAGE.
  *
  *	from:	@(#)pmap.c	7.7 (Berkeley)	5/12/91
- *	$Id: pmap.c,v 1.116 1996/09/08 20:44:10 dyson Exp $
+ *	$Id: pmap.c,v 1.117 1996/09/11 03:46:41 dyson Exp $
  */
 
 /*
@@ -179,7 +179,7 @@ static void	pmap_alloc_pv_entry __P((void));
 static void	pmap_changebit __P((vm_offset_t pa, int bit, boolean_t setem));
 
 static int	pmap_is_managed __P((vm_offset_t pa));
-static int	pmap_remove_all __P((vm_offset_t pa));
+static void	pmap_remove_all __P((vm_offset_t pa));
 static vm_page_t pmap_enter_quick __P((pmap_t pmap, vm_offset_t va,
 				      vm_offset_t pa, vm_page_t mpte));
 static int pmap_remove_pte __P((struct pmap *pmap, unsigned *ptq,
@@ -694,6 +694,27 @@ pmap_page_alloc(object, pindex)
 	return m;
 }
 
+vm_page_t
+pmap_page_lookup(object, pindex)
+	vm_object_t object;
+	vm_pindex_t pindex;
+{
+	vm_page_t m;
+retry:
+	m = vm_page_lookup(object, pindex);
+	if (m) {
+		if (m->flags & PG_BUSY) {
+			m->flags |= PG_WANTED;
+			tsleep(m, PVM, "pplookp", 0);
+			goto retry;
+		}
+	}
+
+	return m;
+}
+		
+
+
 
 /***************************************************
  * Page table page management routines.....
@@ -705,10 +726,19 @@ pmap_page_alloc(object, pindex)
  */
 static int
 pmap_unwire_pte_hold(pmap_t pmap, vm_page_t m) {
+	int s;
+
 	vm_page_unhold(m);
+
+	s = splvm();
+	while (m->flags & PG_BUSY) {
+		m->flags |= PG_WANTED;
+		tsleep(m, PVM, "pmuwpt", 0);
+	}
+	splx(s);
+
 	if (m->hold_count == 0) {
 		vm_offset_t pteva;
-		int s;
 		/*
 		 * unmap the page table page
 		 */
@@ -723,26 +753,23 @@ pmap_unwire_pte_hold(pmap_t pmap, vm_page_t m) {
 			pteva = UPT_MIN_ADDRESS + i386_ptob(m->pindex);
 			pmap_update_1pg(pteva);
 		}
+
 #if defined(PTPHINT)
 		if (pmap->pm_ptphint == m)
 			pmap->pm_ptphint = NULL;
 #endif
-		s = splvm();
-		while (m->flags & PG_BUSY) {
-			m->flags |= PG_WANTED;
-			tsleep(m, PVM, "pmuwpt", 0);
-		}
-		splx(s);
-		if (m->flags & PG_WANTED) {
-			m->flags &= ~PG_WANTED;
-			wakeup(m);
-		}
 
 		/*
 		 * If the page is finally unwired, simply free it.
 		 */
 		--m->wire_count;
 		if (m->wire_count == 0) {
+
+			if (m->flags & PG_WANTED) {
+				m->flags &= ~PG_WANTED;
+				wakeup(m);
+			}
+
 			vm_page_free_zero(m);
 			--cnt.v_wire_count;
 		}
@@ -772,11 +799,11 @@ pmap_unuse_pt(pmap, va, mpte)
 			(pmap->pm_ptphint->pindex == ptepindex)) {
 			mpte = pmap->pm_ptphint;
 		} else {
-			mpte = vm_page_lookup( pmap->pm_pteobj, ptepindex);
+			mpte = pmap_page_lookup( pmap->pm_pteobj, ptepindex);
 			pmap->pm_ptphint = mpte;
 		}
 #else
-		mpte = vm_page_lookup( pmap->pm_pteobj, ptepindex);
+		mpte = pmap_page_lookup( pmap->pm_pteobj, ptepindex);
 #endif
 	}
 
@@ -977,6 +1004,7 @@ retry:
 		}
 	}
 
+	m->valid = VM_PAGE_BITS_ALL;
 	m->flags |= PG_MAPPED;
 
 	return m;
@@ -1015,11 +1043,11 @@ pmap_allocpte(pmap, va)
 			(pmap->pm_ptphint->pindex == ptepindex)) {
 			m = pmap->pm_ptphint;
 		} else {
-			m = vm_page_lookup( pmap->pm_pteobj, ptepindex);
+			m = pmap_page_lookup( pmap->pm_pteobj, ptepindex);
 			pmap->pm_ptphint = m;
 		}
 #else
-		m = vm_page_lookup( pmap->pm_pteobj, ptepindex);
+		m = pmap_page_lookup( pmap->pm_pteobj, ptepindex);
 #endif
 		++m->hold_count;
 		return m;
@@ -1074,6 +1102,7 @@ retry:
 		kmem_free(kernel_map, (vm_offset_t) pmap->pm_pdir, PAGE_SIZE);
 	}
 	pmap->pm_pdir = 0;
+	pmap_update();
 }
 
 /*
@@ -1147,7 +1176,7 @@ pmap_destroy(pmap)
 
 	count = --pmap->pm_count;
 	if (count == 0) {
-		pmap_lock(pmap);
+		pmap_release(pmap);
 		free((caddr_t) pmap, M_VMPMAP);
 	}
 }
@@ -1527,14 +1556,13 @@ pmap_remove(pmap, sva, eva)
  *		pmap_remove (slow...)
  */
 
-static int
+static void
 pmap_remove_all(pa)
 	vm_offset_t pa;
 {
-	register pv_entry_t pv, npv;
+	register pv_entry_t pv;
 	pv_table_t *ppv;
 	register unsigned *pte, tpte;
-	vm_page_t m;
 	int nmodify;
 	int update_needed;
 	int s;
@@ -1552,11 +1580,8 @@ pmap_remove_all(pa)
 #endif
 
 	s = splvm();
-	m = NULL;
 	ppv = pa_to_pvh(pa);
-	for (pv = TAILQ_FIRST(&ppv->pv_list);
-		pv;
-		pv = npv) {
+	while ((pv = TAILQ_FIRST(&ppv->pv_list)) != NULL) {
 		pmap_lock(pv->pv_pmap);
 		pte = pmap_pte_quick(pv->pv_pmap, pv->pv_va);
 		if (tpte = *pte) {
@@ -1567,15 +1592,14 @@ pmap_remove_all(pa)
 			/*
 			 * Update the vm_page_t clean and reference bits.
 			 */
-			if ((tpte & (PG_M|PG_MANAGED)) == (PG_M|PG_MANAGED)) {
+			if (tpte & PG_M) {
 #if defined(PMAP_DIAGNOSTIC)
 				if (pmap_nw_modified((pt_entry_t) tpte)) {
 					printf("pmap_remove_all: modified page not writable: va: 0x%lx, pte: 0x%lx\n", pv->pv_va, tpte);
 				}
 #endif
-				if ((nmodify == 0) &&
-					pmap_track_modified(pv->pv_va))
-					nmodify = 1;
+				if (pmap_track_modified(pv->pv_va))
+					ppv->pv_vm_page->dirty = VM_PAGE_BITS_ALL;
 			}
 			if (!update_needed &&
 				((!curproc || (&curproc->p_vmspace->vm_pmap == pv->pv_pmap)) ||
@@ -1584,8 +1608,6 @@ pmap_remove_all(pa)
 			}
 		}
 		TAILQ_REMOVE(&pv->pv_pmap->pm_pvlist, pv, pv_plist);
-
-		npv = TAILQ_NEXT(pv, pv_list);
 		TAILQ_REMOVE(&ppv->pv_list, pv, pv_list);
 		--ppv->pv_list_count;
 		pmap_unuse_pt(pv->pv_pmap, pv->pv_va, pv->pv_ptem);
@@ -1596,7 +1618,7 @@ pmap_remove_all(pa)
 	if (update_needed)
 		pmap_update();
 	splx(s);
-	return nmodify;
+	return;
 }
 
 /*
@@ -1858,6 +1880,7 @@ pmap_enter_quick(pmap, va, pa, mpte)
 		if (mpte && (mpte->pindex == ptepindex)) {
 			++mpte->hold_count;
 		} else {
+retry:
 			/*
 			 * Get the page directory entry
 			 */
@@ -1873,12 +1896,14 @@ pmap_enter_quick(pmap, va, pa, mpte)
 					(pmap->pm_ptphint->pindex == ptepindex)) {
 					mpte = pmap->pm_ptphint;
 				} else {
-					mpte = vm_page_lookup( pmap->pm_pteobj, ptepindex);
+					mpte = pmap_page_lookup( pmap->pm_pteobj, ptepindex);
 					pmap->pm_ptphint = mpte;
 				}
 #else
-				mpte = vm_page_lookup( pmap->pm_pteobj, ptepindex);
+				mpte = pmap_page_lookup( pmap->pm_pteobj, ptepindex);
 #endif
+				if (mpte == NULL)
+					goto retry;
 				++mpte->hold_count;
 			} else {
 				mpte = _pmap_allocpte(pmap, ptepindex);
@@ -2193,7 +2218,7 @@ pmap_copy(dst_pmap, src_pmap, dst_addr, len, src_addr)
 			continue;
 
 		srcmpte = vm_page_lookup(src_pmap->pm_pteobj, ptepindex);
-		if (srcmpte->hold_count == 0)
+		if ((srcmpte->hold_count == 0) || (srcmpte->flags & PG_BUSY))
 			continue;
 
 		if (pdnxt > end_addr)
@@ -2351,6 +2376,7 @@ pmap_page_exists(pmap, pa)
 	return (FALSE);
 }
 
+#ifdef NOT_USED_YET
 #define PMAP_REMOVE_PAGES_CURPROC_ONLY
 /*
  * Remove all pages from specified address space
@@ -2421,6 +2447,7 @@ pmap_remove_pages(pmap, sva, eva)
 	pmap_update();
 	pmap_unlock(pmap);
 }
+#endif
 
 /*
  * pmap_testbit tests bits in pte's