Merge r132141 and r111272 from amd64/i386:

  Reduce the size of a PV entry by eliminating pv_ptem.  There is no need
  to store a pointer to the page table page in the PV entry because it is
  easily computed during the walk down the page table.

  Eliminate the ptphint from the pmap.  Long, long ago, page table pages
  belonged to a vm object, and we would look up page table pages based
  upon their offset within this vm object.  In those days, this hint may
  have had tangible benefits.

Tested by:	jchandra

2 files changed, 38 insertions, 63 deletions

diff --git a/sys/mips/include/pmap.h b/sys/mips/include/pmap.h
index fbe8dd3..e10212b 100644
--- a/sys/mips/include/pmap.h
+++ b/sys/mips/include/pmap.h
@@ -90,7 +90,6 @@ struct pmap {
 		u_int32_t gen:ASIDGEN_BITS;	/* its generation number */
 	}      pm_asid[MAXSMPCPU];
 	struct pmap_statistics pm_stats;	/* pmap statistics */
-	struct vm_page *pm_ptphint;	/* pmap ptp hint */
 	struct mtx pm_mtx;
 };
 
@@ -126,7 +125,6 @@ typedef struct pv_entry {
 	vm_offset_t pv_va;	/* virtual address for mapping */
 	TAILQ_ENTRY(pv_entry) pv_list;
 	TAILQ_ENTRY(pv_entry) pv_plist;
-	vm_page_t pv_ptem;	/* VM page for pte */
 }       *pv_entry_t;
 
 /*
diff --git a/sys/mips/mips/pmap.c b/sys/mips/mips/pmap.c
index d4b364b..d1e6cde 100644
--- a/sys/mips/mips/pmap.c
+++ b/sys/mips/mips/pmap.c
@@ -164,7 +164,8 @@ static pv_entry_t pmap_pvh_remove(struct md_page *pvh, pmap_t pmap,
 static __inline void pmap_changebit(vm_page_t m, int bit, boolean_t setem);
 static vm_page_t pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va,
     vm_page_t m, vm_prot_t prot, vm_page_t mpte);
-static int pmap_remove_pte(struct pmap *pmap, pt_entry_t *ptq, vm_offset_t va);
+static int pmap_remove_pte(struct pmap *pmap, pt_entry_t *ptq, vm_offset_t va,
+    pd_entry_t pde);
 static void pmap_remove_page(struct pmap *pmap, vm_offset_t va);
 static void pmap_remove_entry(struct pmap *pmap, vm_page_t m, vm_offset_t va);
 static boolean_t pmap_try_insert_pv_entry(pmap_t pmap, vm_page_t mpte,
@@ -176,7 +177,7 @@ static int _pmap_unwire_pte_hold(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);
-static int pmap_unuse_pt(pmap_t, vm_offset_t, vm_page_t);
+static int pmap_unuse_pt(pmap_t, vm_offset_t, pd_entry_t);
 static pt_entry_t init_pte_prot(vm_offset_t va, vm_page_t m, vm_prot_t prot);
 
 #ifdef SMP
@@ -973,8 +974,6 @@ _pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m)
 		pmap_unwire_pte_hold(pmap, va, pdpg);
 	}
 #endif
-	if (pmap->pm_ptphint == m)
-		pmap->pm_ptphint = NULL;
 
 	/*
 	 * If the page is finally unwired, simply free it.
@@ -989,25 +988,14 @@ _pmap_unwire_pte_hold(pmap_t pmap, vm_offset_t va, vm_page_t m)
  * conditionally free the page, and manage the hold/wire counts.
  */
 static int
-pmap_unuse_pt(pmap_t pmap, vm_offset_t va, vm_page_t mpte)
+pmap_unuse_pt(pmap_t pmap, vm_offset_t va, pd_entry_t pde)
 {
-	unsigned ptepindex;
-	pd_entry_t pteva;
+	vm_page_t mpte;
 
 	if (va >= VM_MAXUSER_ADDRESS)
 		return (0);
-
-	if (mpte == NULL) {
-		ptepindex = pmap_pde_pindex(va);
-		if (pmap->pm_ptphint &&
-		    (pmap->pm_ptphint->pindex == ptepindex)) {
-			mpte = pmap->pm_ptphint;
-		} else {
-			pteva = *pmap_pde(pmap, va);
-			mpte = PHYS_TO_VM_PAGE(MIPS_DIRECT_TO_PHYS(pteva));
-			pmap->pm_ptphint = mpte;
-		}
-	}
+	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));
 }
 
@@ -1019,7 +1007,6 @@ pmap_pinit0(pmap_t pmap)
 	PMAP_LOCK_INIT(pmap);
 	pmap->pm_segtab = kernel_segmap;
 	CPU_ZERO(&pmap->pm_active);
-	pmap->pm_ptphint = NULL;
 	for (i = 0; i < MAXCPU; i++) {
 		pmap->pm_asid[i].asid = PMAP_ASID_RESERVED;
 		pmap->pm_asid[i].gen = 0;
@@ -1079,7 +1066,6 @@ pmap_pinit(pmap_t pmap)
 	ptdva = MIPS_PHYS_TO_DIRECT(VM_PAGE_TO_PHYS(ptdpg));
 	pmap->pm_segtab = (pd_entry_t *)ptdva;
 	CPU_ZERO(&pmap->pm_active);
-	pmap->pm_ptphint = NULL;
 	for (i = 0; i < MAXCPU; i++) {
 		pmap->pm_asid[i].asid = PMAP_ASID_RESERVED;
 		pmap->pm_asid[i].gen = 0;
@@ -1156,17 +1142,11 @@ _pmap_allocpte(pmap_t pmap, unsigned ptepindex, int flags)
 		/* Next level entry */
 		pde = (pd_entry_t *)*pdep;
 		pde[pdeindex] = (pd_entry_t)pageva;
-		pmap->pm_ptphint = m;
 	}
 #else
 	pmap->pm_segtab[ptepindex] = (pd_entry_t)pageva;
 #endif
 	pmap->pm_stats.resident_count++;
-
-	/*
-	 * Set the page table hint
-	 */
-	pmap->pm_ptphint = m;
 	return (m);
 }
 
@@ -1196,16 +1176,7 @@ retry:
 	 * count, and activate it.
 	 */
 	if (pde != NULL && *pde != NULL) {
-		/*
-		 * In order to get the page table page, try the hint first.
-		 */
-		if (pmap->pm_ptphint &&
-		    (pmap->pm_ptphint->pindex == ptepindex)) {
-			m = pmap->pm_ptphint;
-		} else {
-			m = PHYS_TO_VM_PAGE(MIPS_DIRECT_TO_PHYS(*pde));
-			pmap->pm_ptphint = m;
-		}
+		m = PHYS_TO_VM_PAGE(MIPS_DIRECT_TO_PHYS(*pde));
 		m->wire_count++;
 	} else {
 		/*
@@ -1351,6 +1322,7 @@ get_pv_entry(pmap_t locked_pmap)
 	static const struct timeval printinterval = { 60, 0 };
 	static struct timeval lastprint;
 	struct vpgqueues *vpq;
+	pd_entry_t *pde;
 	pt_entry_t *pte, oldpte;
 	pmap_t pmap;
 	pv_entry_t allocated_pv, next_pv, pv;
@@ -1389,8 +1361,10 @@ retry:
 			else if (pmap != locked_pmap && !PMAP_TRYLOCK(pmap))
 				continue;
 			pmap->pm_stats.resident_count--;
-			pte = pmap_pte(pmap, va);
-			KASSERT(pte != NULL, ("pte"));
+			pde = pmap_pde(pmap, va);
+			KASSERT(pde != NULL && *pde != 0,
+			    ("get_pv_entry: pde"));
+			pte = pmap_pde_to_pte(pde, va);
 			oldpte = *pte;
 			if (is_kernel_pmap(pmap))
 				*pte = PTE_G;
@@ -1406,7 +1380,7 @@ retry:
 			TAILQ_REMOVE(&pmap->pm_pvlist, pv, pv_plist);
 			m->md.pv_list_count--;
 			TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
-			pmap_unuse_pt(pmap, va, pv->pv_ptem);
+			pmap_unuse_pt(pmap, va, *pde);
 			if (pmap != locked_pmap)
 				PMAP_UNLOCK(pmap);
 			if (allocated_pv == NULL)
@@ -1513,7 +1487,6 @@ pmap_try_insert_pv_entry(pmap_t pmap, vm_page_t mpte, vm_offset_t va,
 		pv_entry_count++;
 		pv->pv_va = va;
 		pv->pv_pmap = pmap;
-		pv->pv_ptem = mpte;
 		TAILQ_INSERT_TAIL(&pmap->pm_pvlist, pv, pv_plist);
 		TAILQ_INSERT_TAIL(&m->md.pv_list, pv, pv_list);
 		m->md.pv_list_count++;
@@ -1526,7 +1499,8 @@ pmap_try_insert_pv_entry(pmap_t pmap, vm_page_t mpte, vm_offset_t va,
  * pmap_remove_pte: do the things to unmap a page in a process
  */
 static int
-pmap_remove_pte(struct pmap *pmap, pt_entry_t *ptq, vm_offset_t va)
+pmap_remove_pte(struct pmap *pmap, pt_entry_t *ptq, vm_offset_t va, 
+    pd_entry_t pde)
 {
 	pt_entry_t oldpte;
 	vm_page_t m;
@@ -1561,7 +1535,7 @@ pmap_remove_pte(struct pmap *pmap, pt_entry_t *ptq, vm_offset_t va)
 
 		pmap_remove_entry(pmap, m, va);
 	}
-	return (pmap_unuse_pt(pmap, va, NULL));
+	return (pmap_unuse_pt(pmap, va, pde));
 }
 
 /*
@@ -1570,16 +1544,20 @@ pmap_remove_pte(struct pmap *pmap, pt_entry_t *ptq, vm_offset_t va)
 static void
 pmap_remove_page(struct pmap *pmap, vm_offset_t va)
 {
+	pd_entry_t *pde;
 	pt_entry_t *ptq;
 
 	mtx_assert(&vm_page_queue_mtx, MA_OWNED);
 	PMAP_LOCK_ASSERT(pmap, MA_OWNED);
-	ptq = pmap_pte(pmap, va);
+	pde = pmap_pde(pmap, va);
+	if (pde == NULL || *pde == 0)
+		return;
+	ptq = pmap_pde_to_pte(pde, va);
 
 	/*
 	 * if there is no pte for this address, just skip it!!!
 	 */
-	if (!ptq || !pte_test(ptq, PTE_V)) {
+	if (!pte_test(ptq, PTE_V)) {
 		return;
 	}
 
@@ -1591,7 +1569,7 @@ pmap_remove_page(struct pmap *pmap, vm_offset_t va)
 	/*
 	 * get a local va for mappings for this pmap.
 	 */
-	(void)pmap_remove_pte(pmap, ptq, va);
+	(void)pmap_remove_pte(pmap, ptq, va, *pde);
 	pmap_invalidate_page(pmap, va);
 
 	return;
@@ -1673,6 +1651,7 @@ void
 pmap_remove_all(vm_page_t m)
 {
 	pv_entry_t pv;
+	pd_entry_t *pde;
 	pt_entry_t *pte, tpte;
 
 	KASSERT((m->oflags & VPO_UNMANAGED) == 0,
@@ -1694,7 +1673,9 @@ pmap_remove_all(vm_page_t m)
 
 		pv->pv_pmap->pm_stats.resident_count--;
 
-		pte = pmap_pte(pv->pv_pmap, pv->pv_va);
+		pde = pmap_pde(pv->pv_pmap, pv->pv_va);
+		KASSERT(pde != NULL && *pde != 0, ("pmap_remove_all: pde"));
+		pte = pmap_pde_to_pte(pde, pv->pv_va);
 
 		tpte = *pte;
 		if (is_kernel_pmap(pv->pv_pmap))
@@ -1719,7 +1700,7 @@ pmap_remove_all(vm_page_t m)
 		TAILQ_REMOVE(&pv->pv_pmap->pm_pvlist, pv, pv_plist);
 		TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
 		m->md.pv_list_count--;
-		pmap_unuse_pt(pv->pv_pmap, pv->pv_va, pv->pv_ptem);
+		pmap_unuse_pt(pv->pv_pmap, pv->pv_va, *pde);
 		PMAP_UNLOCK(pv->pv_pmap);
 		free_pv_entry(pv);
 	}
@@ -1925,7 +1906,6 @@ pmap_enter(pmap_t pmap, vm_offset_t va, vm_prot_t access, vm_page_t m,
 			pv = get_pv_entry(pmap);
 		pv->pv_va = va;
 		pv->pv_pmap = pmap;
-		pv->pv_ptem = mpte;
 		TAILQ_INSERT_TAIL(&pmap->pm_pvlist, pv, pv_plist);
 		TAILQ_INSERT_TAIL(&m->md.pv_list, pv, pv_list);
 		m->md.pv_list_count++;
@@ -2063,14 +2043,8 @@ pmap_enter_quick_locked(pmap_t pmap, vm_offset_t va, vm_page_t m,
 			 * increment the hold count, and activate it.
 			 */
 			if (pde && *pde != 0) {
-				if (pmap->pm_ptphint &&
-				    (pmap->pm_ptphint->pindex == ptepindex)) {
-					mpte = pmap->pm_ptphint;
-				} else {
-					mpte = PHYS_TO_VM_PAGE(
-						MIPS_DIRECT_TO_PHYS(*pde));
-					pmap->pm_ptphint = mpte;
-				}
+				mpte = PHYS_TO_VM_PAGE(
+				    MIPS_DIRECT_TO_PHYS(*pde));
 				mpte->wire_count++;
 			} else {
 				mpte = _pmap_allocpte(pmap, ptepindex,
@@ -2458,6 +2432,7 @@ pmap_page_exists_quick(pmap_t pmap, vm_page_t m)
 void
 pmap_remove_pages(pmap_t pmap)
 {
+	pd_entry_t *pde;
 	pt_entry_t *pte, tpte;
 	pv_entry_t pv, npv;
 	vm_page_t m;
@@ -2470,7 +2445,9 @@ pmap_remove_pages(pmap_t pmap)
 	PMAP_LOCK(pmap);
 	for (pv = TAILQ_FIRST(&pmap->pm_pvlist); pv != NULL; pv = npv) {
 
-		pte = pmap_pte(pv->pv_pmap, pv->pv_va);
+		pde = pmap_pde(pmap, pv->pv_va);
+		KASSERT(pde != NULL && *pde != 0, ("pmap_remove_pages: pde"));
+		pte = pmap_pde_to_pte(pde, pv->pv_va);
 		if (!pte_test(pte, PTE_V))
 			panic("pmap_remove_pages: page on pm_pvlist has no pte");
 		tpte = *pte;
@@ -2488,7 +2465,7 @@ pmap_remove_pages(pmap_t pmap)
 		KASSERT(m != NULL,
 		    ("pmap_remove_pages: bad tpte %#jx", (uintmax_t)tpte));
 
-		pv->pv_pmap->pm_stats.resident_count--;
+		pmap->pm_stats.resident_count--;
 
 		/*
 		 * Update the vm_page_t clean and reference bits.
@@ -2497,14 +2474,14 @@ pmap_remove_pages(pmap_t pmap)
 			vm_page_dirty(m);
 		}
 		npv = TAILQ_NEXT(pv, pv_plist);
-		TAILQ_REMOVE(&pv->pv_pmap->pm_pvlist, pv, pv_plist);
+		TAILQ_REMOVE(&pmap->pm_pvlist, pv, pv_plist);
 
 		m->md.pv_list_count--;
 		TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
 		if (TAILQ_FIRST(&m->md.pv_list) == NULL) {
 			vm_page_aflag_clear(m, PGA_WRITEABLE);
 		}
-		pmap_unuse_pt(pv->pv_pmap, pv->pv_va, pv->pv_ptem);
+		pmap_unuse_pt(pmap, pv->pv_va, *pde);
 		free_pv_entry(pv);
 	}
 	pmap_invalidate_all(pmap);