Rename {_,}pmap_unwire_pte_hold() to {_,}pmap_unwire_ptp() and update the

comment describing them.  Both the function names and the comment had grown
stale.  Quite some time has passed since these pmap implementations last
used the page's hold count to track the number of valid mapping within a
page table page.  Also, returning TRUE from pmap_unwire_ptp() rather than
_pmap_unwire_ptp() eliminates a few instructions from callers like
pmap_enter_quick_locked() where pmap_unwire_ptp()'s return value is used
directly by a conditional statement.

4 files changed, 76 insertions, 78 deletions

diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index 1114a6b..03d9ae7 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -323,8 +323,8 @@ static vm_page_t pmap_allocpde(pmap_t pmap, vm_offset_t va,
 static vm_page_t pmap_allocpte(pmap_t pmap, vm_offset_t va,
 		struct rwlock **lockp);
 
-static int _pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m,
-                vm_page_t* free);
+static void _pmap_unwire_ptp(pmap_t pmap, vm_offset_t va, vm_page_t m,
+                vm_page_t *free);
 static int pmap_unuse_pt(pmap_t, vm_offset_t, pd_entry_t, vm_page_t *);
 static vm_offset_t pmap_kmem_choose(vm_offset_t addr);
 
@@ -1557,23 +1557,25 @@ pmap_remove_pt_page(pmap_t pmap, vm_page_t mpte)
 }
 
 /*
- * This routine unholds page table pages, and if the hold count
- * drops to zero, then it decrements the wire count.
+ * Decrements a page table page's wire count, which is used to record the
+ * number of valid page table entries within the page.  If the wire count
+ * drops to zero, then the page table page is unmapped.  Returns TRUE if the
+ * page table page was unmapped and FALSE otherwise.
  */
-static __inline int
-pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_page_t *free)
+static inline boolean_t
+pmap_unwire_ptp(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_page_t *free)
 {
 
 	--m->wire_count;
-	if (m->wire_count == 0)
-		return (_pmap_unwire_pte_hold(pmap, va, m, free));
-	else
-		return (0);
+	if (m->wire_count == 0) {
+		_pmap_unwire_ptp(pmap, va, m, free);
+		return (TRUE);
+	} else
+		return (FALSE);
 }
 
-static int 
-_pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m, 
-    vm_page_t *free)
+static void
+_pmap_unwire_ptp(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_page_t *free)
 {
 
 	PMAP_LOCK_ASSERT(pmap, MA_OWNED);
@@ -1602,14 +1604,14 @@ _pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m,
 		vm_page_t pdpg;
 
 		pdpg = PHYS_TO_VM_PAGE(*pmap_pdpe(pmap, va) & PG_FRAME);
-		pmap_unwire_pte_hold(pmap, va, pdpg, free);
+		pmap_unwire_ptp(pmap, va, pdpg, free);
 	}
 	if (m->pindex >= NUPDE && m->pindex < (NUPDE + NUPDPE)) {
 		/* We just released a PD, unhold the matching PDP */
 		vm_page_t pdppg;
 
 		pdppg = PHYS_TO_VM_PAGE(*pmap_pml4e(pmap, va) & PG_FRAME);
-		pmap_unwire_pte_hold(pmap, va, pdppg, free);
+		pmap_unwire_ptp(pmap, va, pdppg, free);
 	}
 
 	/*
@@ -1624,8 +1626,6 @@ _pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m,
 	 * *ALL* TLB shootdown is done
 	 */
 	pmap_add_delayed_free_list(m, free, TRUE);
-	
-	return (1);
 }
 
 /*
@@ -1641,7 +1641,7 @@ pmap_unuse_pt(pmap_t pmap, vm_offset_t va, pd_entry_t ptepde, vm_page_t *free)
 		return (0);
 	KASSERT(ptepde != 0, ("pmap_unuse_pt: ptepde != 0"));
 	mpte = PHYS_TO_VM_PAGE(ptepde & PG_FRAME);
-	return (pmap_unwire_pte_hold(pmap, va, mpte, free));
+	return (pmap_unwire_ptp(pmap, va, mpte, free));
 }
 
 void
@@ -3666,7 +3666,7 @@ pmap_enter_pde(pmap_t pmap, vm_offset_t va, vm_page_t m, vm_prot_t prot,
 		if (!pmap_pv_insert_pde(pmap, va, VM_PAGE_TO_PHYS(m),
 		    lockp)) {
 			free = NULL;
-			if (pmap_unwire_pte_hold(pmap, va, mpde, &free)) {
+			if (pmap_unwire_ptp(pmap, va, mpde, &free)) {
 				pmap_invalidate_page(pmap, va);
 				pmap_free_zero_pages(free);
 			}
@@ -3842,7 +3842,7 @@ pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va, vm_page_t m,
 	    !pmap_try_insert_pv_entry(pmap, va, m, lockp)) {
 		if (mpte != NULL) {
 			free = NULL;
-			if (pmap_unwire_pte_hold(pmap, va, mpte, &free)) {
+			if (pmap_unwire_ptp(pmap, va, mpte, &free)) {
 				pmap_invalidate_page(pmap, va);
 				pmap_free_zero_pages(free);
 			}
@@ -4149,8 +4149,8 @@ pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vm_offset_t dst_addr, vm_size_t len,
 					pmap_resident_count_inc(dst_pmap, 1);
 	 			} else {
 					free = NULL;
-					if (pmap_unwire_pte_hold(dst_pmap,
-					    addr, dstmpte, &free)) {
+					if (pmap_unwire_ptp(dst_pmap, addr,
+					    dstmpte, &free)) {
 					    	pmap_invalidate_page(dst_pmap,
 					 	    addr);
 				    	    	pmap_free_zero_pages(free);
diff --git a/sys/i386/i386/pmap.c b/sys/i386/i386/pmap.c
index 55f6c4a..9e81117 100644
--- a/sys/i386/i386/pmap.c
+++ b/sys/i386/i386/pmap.c
@@ -344,7 +344,7 @@ static void pmap_update_pde_invalidate(vm_offset_t va, pd_entry_t newpde);
 static vm_page_t pmap_allocpte(pmap_t pmap, vm_offset_t va, int flags);
 
 static vm_page_t _pmap_allocpte(pmap_t pmap, u_int ptepindex, int flags);
-static int _pmap_unwire_pte_hold(pmap_t pmap, vm_page_t m, vm_page_t *free);
+static void _pmap_unwire_ptp(pmap_t pmap, vm_page_t m, vm_page_t *free);
 static pt_entry_t *pmap_pte_quick(pmap_t pmap, vm_offset_t va);
 static void pmap_pte_release(pt_entry_t *pte);
 static int pmap_unuse_pt(pmap_t, vm_offset_t, vm_page_t *);
@@ -1672,22 +1672,25 @@ pmap_remove_pt_page(pmap_t pmap, vm_page_t mpte)
 }
 
 /*
- * This routine unholds page table pages, and if the hold count
- * drops to zero, then it decrements the wire count.
+ * Decrements a page table page's wire count, which is used to record the
+ * number of valid page table entries within the page.  If the wire count
+ * drops to zero, then the page table page is unmapped.  Returns TRUE if the
+ * page table page was unmapped and FALSE otherwise.
  */
-static __inline int
-pmap_unwire_pte_hold(pmap_t pmap, vm_page_t m, vm_page_t *free)
+static inline boolean_t
+pmap_unwire_ptp(pmap_t pmap, vm_page_t m, vm_page_t *free)
 {
 
 	--m->wire_count;
-	if (m->wire_count == 0)
-		return (_pmap_unwire_pte_hold(pmap, m, free));
-	else
-		return (0);
+	if (m->wire_count == 0) {
+		_pmap_unwire_ptp(pmap, m, free);
+		return (TRUE);
+	} else
+		return (FALSE);
 }
 
-static int 
-_pmap_unwire_pte_hold(pmap_t pmap, vm_page_t m, vm_page_t *free)
+static void
+_pmap_unwire_ptp(pmap_t pmap, vm_page_t m, vm_page_t *free)
 {
 	vm_offset_t pteva;
 
@@ -1716,8 +1719,6 @@ _pmap_unwire_pte_hold(pmap_t pmap, vm_page_t m, vm_page_t *free)
 	 * *ALL* TLB shootdown is done
 	 */
 	pmap_add_delayed_free_list(m, free, TRUE);
-
-	return (1);
 }
 
 /*
@@ -1734,7 +1735,7 @@ pmap_unuse_pt(pmap_t pmap, vm_offset_t va, vm_page_t *free)
 		return (0);
 	ptepde = *pmap_pde(pmap, va);
 	mpte = PHYS_TO_VM_PAGE(ptepde & PG_FRAME);
-	return (pmap_unwire_pte_hold(pmap, mpte, free));
+	return (pmap_unwire_ptp(pmap, mpte, free));
 }
 
 /*
@@ -3819,7 +3820,7 @@ pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va, vm_page_t m,
 	    !pmap_try_insert_pv_entry(pmap, va, m)) {
 		if (mpte != NULL) {
 			free = NULL;
-			if (pmap_unwire_pte_hold(pmap, mpte, &free)) {
+			if (pmap_unwire_ptp(pmap, mpte, &free)) {
 				pmap_invalidate_page(pmap, va);
 				pmap_free_zero_pages(free);
 			}
@@ -4088,8 +4089,8 @@ pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vm_offset_t dst_addr, vm_size_t len,
 					dst_pmap->pm_stats.resident_count++;
 	 			} else {
 					free = NULL;
-					if (pmap_unwire_pte_hold(dst_pmap,
-					    dstmpte, &free)) {
+					if (pmap_unwire_ptp(dst_pmap, dstmpte,
+					    &free)) {
 						pmap_invalidate_page(dst_pmap,
 						    addr);
 						pmap_free_zero_pages(free);
diff --git a/sys/i386/xen/pmap.c b/sys/i386/xen/pmap.c
index 61bc35f..b0e1624 100644
--- a/sys/i386/xen/pmap.c
+++ b/sys/i386/xen/pmap.c
@@ -300,7 +300,7 @@ static boolean_t pmap_try_insert_pv_entry(pmap_t pmap, vm_offset_t va,
 static vm_page_t pmap_allocpte(pmap_t pmap, vm_offset_t va, int flags);
 
 static vm_page_t _pmap_allocpte(pmap_t pmap, u_int ptepindex, int flags);
-static int _pmap_unwire_pte_hold(pmap_t pmap, vm_page_t m, vm_page_t *free);
+static void _pmap_unwire_ptp(pmap_t pmap, vm_page_t m, vm_page_t *free);
 static pt_entry_t *pmap_pte_quick(pmap_t pmap, vm_offset_t va);
 static void pmap_pte_release(pt_entry_t *pte);
 static int pmap_unuse_pt(pmap_t, vm_offset_t, vm_page_t *);
@@ -1333,22 +1333,25 @@ pmap_free_zero_pages(vm_page_t free)
 }
 
 /*
- * This routine unholds page table pages, and if the hold count
- * drops to zero, then it decrements the wire count.
+ * Decrements a page table page's wire count, which is used to record the
+ * number of valid page table entries within the page.  If the wire count
+ * drops to zero, then the page table page is unmapped.  Returns TRUE if the
+ * page table page was unmapped and FALSE otherwise.
  */
-static __inline int
-pmap_unwire_pte_hold(pmap_t pmap, vm_page_t m, vm_page_t *free)
+static inline boolean_t
+pmap_unwire_ptp(pmap_t pmap, vm_page_t m, vm_page_t *free)
 {
 
 	--m->wire_count;
-	if (m->wire_count == 0)
-		return (_pmap_unwire_pte_hold(pmap, m, free));
-	else
-		return (0);
+	if (m->wire_count == 0) {
+		_pmap_unwire_ptp(pmap, m, free);
+		return (TRUE);
+	} else
+		return (FALSE);
 }
 
-static int 
-_pmap_unwire_pte_hold(pmap_t pmap, vm_page_t m, vm_page_t *free)
+static void
+_pmap_unwire_ptp(pmap_t pmap, vm_page_t m, vm_page_t *free)
 {
 	vm_offset_t pteva;
 
@@ -1384,8 +1387,6 @@ _pmap_unwire_pte_hold(pmap_t pmap, vm_page_t m, vm_page_t *free)
 	 */
 	m->right = *free;
 	*free = m;
-
-	return (1);
 }
 
 /*
@@ -1402,7 +1403,7 @@ pmap_unuse_pt(pmap_t pmap, vm_offset_t va, vm_page_t *free)
 		return (0);
 	ptepde = PT_GET(pmap_pde(pmap, va));
 	mpte = PHYS_TO_VM_PAGE(ptepde & PG_FRAME);
-	return (pmap_unwire_pte_hold(pmap, mpte, free));
+	return (pmap_unwire_ptp(pmap, mpte, free));
 }
 
 /*
@@ -3015,7 +3016,7 @@ pmap_enter_quick_locked(multicall_entry_t **mclpp, int *count, pmap_t pmap, vm_o
 	    !pmap_try_insert_pv_entry(pmap, va, m)) {
 		if (mpte != NULL) {
 			free = NULL;
-			if (pmap_unwire_pte_hold(pmap, mpte, &free)) {
+			if (pmap_unwire_ptp(pmap, mpte, &free)) {
 				pmap_invalidate_page(pmap, va);
 				pmap_free_zero_pages(free);
 			}
@@ -3294,8 +3295,8 @@ pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vm_offset_t dst_addr, vm_size_t len,
 					dst_pmap->pm_stats.resident_count++;
 	 			} else {
 					free = NULL;
-					if (pmap_unwire_pte_hold(dst_pmap,
-					    dstmpte, &free)) {
+					if (pmap_unwire_ptp(dst_pmap, dstmpte,
+					    &free)) {
 						pmap_invalidate_page(dst_pmap,
 						    addr);
 						pmap_free_zero_pages(free);
diff --git a/sys/mips/mips/pmap.c b/sys/mips/mips/pmap.c
index 75a511b..4c12788 100644
--- a/sys/mips/mips/pmap.c
+++ b/sys/mips/mips/pmap.c
@@ -190,7 +190,7 @@ static boolean_t pmap_try_insert_pv_entry(pmap_t pmap, vm_page_t mpte,
 static void pmap_update_page(pmap_t pmap, vm_offset_t va, pt_entry_t pte);
 static void pmap_invalidate_all(pmap_t pmap);
 static void pmap_invalidate_page(pmap_t pmap, vm_offset_t va);
-static int _pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m);
+static void _pmap_unwire_ptp(pmap_t pmap, vm_offset_t va, vm_page_t m);
 
 static vm_page_t pmap_allocpte(pmap_t pmap, vm_offset_t va, int flags);
 static vm_page_t _pmap_allocpte(pmap_t pmap, unsigned ptepindex, int flags);
@@ -928,29 +928,26 @@ pmap_qremove(vm_offset_t va, int count)
  * Page table page management routines.....
  ***************************************************/
 
-/*  Revision 1.507
- *
- * Simplify the reference counting of page table pages.	 Specifically, use
- * the page table page's wired count rather than its hold count to contain
- * the reference count.
- */
-
 /*
- * This routine unholds page table pages, and if the hold count
- * drops to zero, then it decrements the wire count.
+ * Decrements a page table page's wire count, which is used to record the
+ * number of valid page table entries within the page.  If the wire count
+ * drops to zero, then the page table page is unmapped.  Returns TRUE if the
+ * page table page was unmapped and FALSE otherwise.
  */
-static PMAP_INLINE int
-pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m)
+static PMAP_INLINE boolean_t
+pmap_unwire_ptp(pmap_t pmap, vm_offset_t va, vm_page_t m)
 {
+
 	--m->wire_count;
-	if (m->wire_count == 0)
-		return (_pmap_unwire_pte_hold(pmap, va, m));
-	else
-		return (0);
+	if (m->wire_count == 0) {
+		_pmap_unwire_ptp(pmap, va, m);
+		return (TRUE);
+	} else
+		return (FALSE);
 }
 
-static int
-_pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m)
+static void
+_pmap_unwire_ptp(pmap_t pmap, vm_offset_t va, vm_page_t m)
 {
 	pd_entry_t *pde;
 
@@ -979,7 +976,7 @@ _pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m)
 		 */
 		pdp = (pd_entry_t *)*pmap_segmap(pmap, va);
 		pdpg = PHYS_TO_VM_PAGE(MIPS_DIRECT_TO_PHYS(pdp));
-		pmap_unwire_pte_hold(pmap, va, pdpg);
+		pmap_unwire_ptp(pmap, va, pdpg);
 	}
 #endif
 
@@ -988,7 +985,6 @@ _pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m)
 	 */
 	vm_page_free_zero(m);
 	atomic_subtract_int(&cnt.v_wire_count, 1);
-	return (1);
 }
 
 /*
@@ -1004,7 +1000,7 @@ pmap_unuse_pt(pmap_t pmap, vm_offset_t va, pd_entry_t pde)
 		return (0);
 	KASSERT(pde != 0, ("pmap_unuse_pt: pde != 0"));
 	mpte = PHYS_TO_VM_PAGE(MIPS_DIRECT_TO_PHYS(pde));
-	return (pmap_unwire_pte_hold(pmap, va, mpte));
+	return (pmap_unwire_ptp(pmap, va, mpte));
 }
 
 void
@@ -2227,7 +2223,7 @@ pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va, vm_page_t m,
 	if ((m->oflags & VPO_UNMANAGED) == 0 &&
 	    !pmap_try_insert_pv_entry(pmap, mpte, va, m)) {
 		if (mpte != NULL) {
-			pmap_unwire_pte_hold(pmap, va, mpte);
+			pmap_unwire_ptp(pmap, va, mpte);
 			mpte = NULL;
 		}
 		return (mpte);