Skip site navigation (1)Skip section navigation (2) 
Date:      Sat, 8 Sep 2012 17:43:20 +0000 (UTC)
From:      Alan Cox <alc@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r240241 - head/sys/mips/mips
Message-ID:  <201209081743.q88HhKBw029744@svn.freebsd.org>
next in thread | raw e-mail | index | archive | help 
Author: alc
Date: Sat Sep  8 17:43:20 2012
New Revision: 240241
URL: http://svn.freebsd.org/changeset/base/240241

Log:
  pmap_remove:
  
    Avoid re-walking the page table from the root for every PTE examined.
  
    Tidy up some of pmap_remove()'s helper functions.
  
  pmap_enter:
  
    Set PV_TABLE_REF whenever the physical page being mapped is managed, not
    just when it is writeable.
  
    Only call pmap_update_page() when the old mapping was valid.  If there was
    no prior valid mapping, then pmap_update_page() serves no useful purpose.
    However, it will interrupt every processor that has the pmap active.
  
  pmap_enter_quick_locked:
  
    Always set PTE_RO.
  
  pmap_emulate_modified:
  
    Don't set PV_TABLE_REF.
  
    Eliminate a nonsensical comment.

Modified:
  head/sys/mips/mips/pmap.c

Modified: head/sys/mips/mips/pmap.c
==============================================================================
--- head/sys/mips/mips/pmap.c	Sat Sep  8 16:47:52 2012	(r240240)
+++ head/sys/mips/mips/pmap.c	Sat Sep  8 17:43:20 2012	(r240241)
@@ -1677,6 +1677,11 @@ pmap_remove_pte(struct pmap *pmap, pt_en
 	rw_assert(&pvh_global_lock, RA_WLOCKED);
 	PMAP_LOCK_ASSERT(pmap, MA_OWNED);
 
+	/*
+	 * Write back all cache lines from the page being unmapped.
+	 */
+	mips_dcache_wbinv_range_index(va, PAGE_SIZE);
+
 	oldpte = *ptq;
 	if (is_kernel_pmap(pmap))
 		*ptq = PTE_G;
@@ -1723,24 +1728,13 @@ pmap_remove_page(struct pmap *pmap, vm_o
 	ptq = pmap_pde_to_pte(pde, va);
 
 	/*
-	 * if there is no pte for this address, just skip it!!!
+	 * If there is no pte for this address, just skip it!
 	 */
-	if (!pte_test(ptq, PTE_V)) {
+	if (!pte_test(ptq, PTE_V))
 		return;
-	}
 
-	/*
-	 * Write back all caches from the page being destroyed
-	 */
-	mips_dcache_wbinv_range_index(va, PAGE_SIZE);
-
-	/*
-	 * get a local va for mappings for this pmap.
-	 */
 	(void)pmap_remove_pte(pmap, ptq, va, *pde);
 	pmap_invalidate_page(pmap, va);
-
-	return;
 }
 
 /*
@@ -1789,9 +1783,12 @@ pmap_remove(struct pmap *pmap, vm_offset
 			continue;
 		if (va_next > eva)
 			va_next = eva;
-		for (pte = pmap_pde_to_pte(pde, sva); sva != va_next; 
-		    pte++, sva += PAGE_SIZE) {
-			pmap_remove_page(pmap, sva);
+		for (pte = pmap_pde_to_pte(pde, sva); sva != va_next; pte++,
+		    sva += PAGE_SIZE) {
+			if (!pte_test(pte, PTE_V))
+				continue;
+			pmap_remove_pte(pmap, pte, sva, *pde);
+			pmap_invalidate_page(pmap, sva);
 		}
 	}
 out:
@@ -2035,6 +2032,7 @@ pmap_enter(pmap_t pmap, vm_offset_t va, 
 			mpte->wire_count--;
 
 		if (pte_test(&origpte, PTE_MANAGED)) {
+			m->md.pv_flags |= PV_TABLE_REF;
 			om = m;
 			newpte |= PTE_MANAGED;
 			if (!pte_test(&newpte, PTE_RO))
@@ -2070,6 +2068,7 @@ pmap_enter(pmap_t pmap, vm_offset_t va, 
 	 * Enter on the PV list if part of our managed memory.
 	 */
 	if ((m->oflags & VPO_UNMANAGED) == 0) {
+		m->md.pv_flags |= PV_TABLE_REF;
 		if (pv == NULL)
 			pv = get_pv_entry(pmap, FALSE);
 		pv->pv_va = va;
@@ -2087,8 +2086,6 @@ pmap_enter(pmap_t pmap, vm_offset_t va, 
 		pmap->pm_stats.wired_count++;
 
 validate:
-	if ((access & VM_PROT_WRITE) != 0)
-		m->md.pv_flags |= PV_TABLE_REF;
 
 #ifdef PMAP_DEBUG
 	printf("pmap_enter:  va: %p -> pa: %p\n", (void *)va, (void *)pa);
@@ -2099,8 +2096,8 @@ validate:
 	 * update the pte.
 	 */
 	if (origpte != newpte) {
+		*pte = newpte;
 		if (pte_test(&origpte, PTE_V)) {
-			*pte = newpte;
 			if (pte_test(&origpte, PTE_MANAGED) && opa != pa) {
 				if (om->md.pv_flags & PV_TABLE_REF)
 					vm_page_aflag_set(om, PGA_REFERENCED);
@@ -2116,11 +2113,9 @@ validate:
 			if (pte_test(&origpte, PTE_MANAGED) &&
 			    TAILQ_EMPTY(&om->md.pv_list))
 				vm_page_aflag_clear(om, PGA_WRITEABLE);
-		} else {
-			*pte = newpte;
+			pmap_update_page(pmap, va, newpte);
 		}
 	}
-	pmap_update_page(pmap, va, newpte);
 
 	/*
 	 * Sync I & D caches for executable pages.  Do this only if the
@@ -2239,7 +2234,7 @@ pmap_enter_quick_locked(pmap_t pmap, vm_
 	/*
 	 * Now validate mapping with RO protection
 	 */
-	*pte = TLBLO_PA_TO_PFN(pa) | PTE_V;
+	*pte = PTE_RO | TLBLO_PA_TO_PFN(pa) | PTE_V;
 	if ((m->oflags & VPO_UNMANAGED) == 0)
 		*pte |= PTE_MANAGED;
 
@@ -2251,7 +2246,6 @@ pmap_enter_quick_locked(pmap_t pmap, vm_
 	if (is_kernel_pmap(pmap))
 		*pte |= PTE_G;
 	else {
-		*pte |= PTE_RO;
 		/*
 		 * Sync I & D caches.  Do this only if the target pmap
 		 * belongs to the current process.  Otherwise, an
@@ -3255,9 +3249,7 @@ init_pte_prot(vm_page_t m, vm_prot_t acc
 int
 pmap_emulate_modified(pmap_t pmap, vm_offset_t va)
 {
-	vm_page_t m;
 	pt_entry_t *pte;
- 	vm_paddr_t pa;
 
 	PMAP_LOCK(pmap);
 	pte = pmap_pte(pmap, va);
@@ -3275,7 +3267,6 @@ pmap_emulate_modified(pmap_t pmap, vm_of
 		panic("pmap_emulate_modified: invalid pte");
 #endif
 	if (pte_test(pte, PTE_RO)) {
-		/* write to read only page in the kernel */
 		PMAP_UNLOCK(pmap);
 		return (1);
 	}
@@ -3283,9 +3274,6 @@ pmap_emulate_modified(pmap_t pmap, vm_of
 	tlb_update(pmap, va, *pte);
 	if (!pte_test(pte, PTE_MANAGED))
 		panic("pmap_emulate_modified: unmanaged page");
-	pa = TLBLO_PTE_TO_PA(*pte);
-	m = PHYS_TO_VM_PAGE(pa);
-	m->md.pv_flags |= PV_TABLE_REF;
 	PMAP_UNLOCK(pmap);
 	return (0);
 }

Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201209081743.q88HhKBw029744>