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Date:      Mon, 31 Aug 2009 18:41:13 +0000 (UTC)
From:      John Baldwin <jhb@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r196707 - in head/sys: amd64/amd64 i386/i386
Message-ID:  <200908311841.n7VIfD58035690@svn.freebsd.org>
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Author: jhb
Date: Mon Aug 31 18:41:13 2009
New Revision: 196707
URL: http://svn.freebsd.org/changeset/base/196707

Log:
  Simplify pmap_change_attr() a bit:
  - Always calculate the cache bits instead of doing it on-demand.
  - Always set changed to TRUE rather than only doing it if it is false.
  
  Discussed with:	alc
  MFC after:	3 days

Modified:
  head/sys/amd64/amd64/pmap.c
  head/sys/i386/i386/pmap.c

Modified: head/sys/amd64/amd64/pmap.c
==============================================================================
--- head/sys/amd64/amd64/pmap.c	Mon Aug 31 17:50:33 2009	(r196706)
+++ head/sys/amd64/amd64/pmap.c	Mon Aug 31 18:41:13 2009	(r196707)
@@ -4476,7 +4476,8 @@ pmap_change_attr_locked(vm_offset_t va, 
 	if (base < DMAP_MIN_ADDRESS)
 		return (EINVAL);
 
-	cache_bits_pde = cache_bits_pte = -1;
+	cache_bits_pde = pmap_cache_bits(mode, 1);
+	cache_bits_pte = pmap_cache_bits(mode, 0);
 	changed = FALSE;
 
 	/*
@@ -4493,8 +4494,6 @@ pmap_change_attr_locked(vm_offset_t va, 
 			 * memory type, then we need not demote this page. Just
 			 * increment tmpva to the next 1GB page frame.
 			 */
-			if (cache_bits_pde < 0)
-				cache_bits_pde = pmap_cache_bits(mode, 1);
 			if ((*pdpe & PG_PDE_CACHE) == cache_bits_pde) {
 				tmpva = trunc_1gpage(tmpva) + NBPDP;
 				continue;
@@ -4522,8 +4521,6 @@ pmap_change_attr_locked(vm_offset_t va, 
 			 * memory type, then we need not demote this page. Just
 			 * increment tmpva to the next 2MB page frame.
 			 */
-			if (cache_bits_pde < 0)
-				cache_bits_pde = pmap_cache_bits(mode, 1);
 			if ((*pde & PG_PDE_CACHE) == cache_bits_pde) {
 				tmpva = trunc_2mpage(tmpva) + NBPDR;
 				continue;
@@ -4557,12 +4554,9 @@ pmap_change_attr_locked(vm_offset_t va, 
 	for (tmpva = base; tmpva < base + size; ) {
 		pdpe = pmap_pdpe(kernel_pmap, tmpva);
 		if (*pdpe & PG_PS) {
-			if (cache_bits_pde < 0)
-				cache_bits_pde = pmap_cache_bits(mode, 1);
 			if ((*pdpe & PG_PDE_CACHE) != cache_bits_pde) {
 				pmap_pde_attr(pdpe, cache_bits_pde);
-				if (!changed)
-					changed = TRUE;
+				changed = TRUE;
 			}
 			if (tmpva >= VM_MIN_KERNEL_ADDRESS) {
 				if (pa_start == pa_end) {
@@ -4588,12 +4582,9 @@ pmap_change_attr_locked(vm_offset_t va, 
 		}
 		pde = pmap_pdpe_to_pde(pdpe, tmpva);
 		if (*pde & PG_PS) {
-			if (cache_bits_pde < 0)
-				cache_bits_pde = pmap_cache_bits(mode, 1);
 			if ((*pde & PG_PDE_CACHE) != cache_bits_pde) {
 				pmap_pde_attr(pde, cache_bits_pde);
-				if (!changed)
-					changed = TRUE;
+				changed = TRUE;
 			}
 			if (tmpva >= VM_MIN_KERNEL_ADDRESS) {
 				if (pa_start == pa_end) {
@@ -4616,13 +4607,10 @@ pmap_change_attr_locked(vm_offset_t va, 
 			}
 			tmpva = trunc_2mpage(tmpva) + NBPDR;
 		} else {
-			if (cache_bits_pte < 0)
-				cache_bits_pte = pmap_cache_bits(mode, 0);
 			pte = pmap_pde_to_pte(pde, tmpva);
 			if ((*pte & PG_PTE_CACHE) != cache_bits_pte) {
 				pmap_pte_attr(pte, cache_bits_pte);
-				if (!changed)
-					changed = TRUE;
+				changed = TRUE;
 			}
 			if (tmpva >= VM_MIN_KERNEL_ADDRESS) {
 				if (pa_start == pa_end) {

Modified: head/sys/i386/i386/pmap.c
==============================================================================
--- head/sys/i386/i386/pmap.c	Mon Aug 31 17:50:33 2009	(r196706)
+++ head/sys/i386/i386/pmap.c	Mon Aug 31 18:41:13 2009	(r196707)
@@ -4635,7 +4635,8 @@ pmap_change_attr(vm_offset_t va, vm_size
 	if (base < VM_MIN_KERNEL_ADDRESS)
 		return (EINVAL);
 
-	cache_bits_pde = cache_bits_pte = -1;
+	cache_bits_pde = pmap_cache_bits(mode, 1);
+	cache_bits_pte = pmap_cache_bits(mode, 0);
 	changed = FALSE;
 
 	/*
@@ -4656,8 +4657,6 @@ pmap_change_attr(vm_offset_t va, vm_size
 			 * demote this page.  Just increment tmpva to
 			 * the next 2/4MB page frame.
 			 */
-			if (cache_bits_pde < 0)
-				cache_bits_pde = pmap_cache_bits(mode, 1);
 			if ((*pde & PG_PDE_CACHE) == cache_bits_pde) {
 				tmpva = trunc_4mpage(tmpva) + NBPDR;
 				continue;
@@ -4688,8 +4687,6 @@ pmap_change_attr(vm_offset_t va, vm_size
 	}
 	PMAP_UNLOCK(kernel_pmap);
 
-	changed = FALSE;
-
 	/*
 	 * Ok, all the pages exist, so run through them updating their
 	 * cache mode if required.
@@ -4697,22 +4694,16 @@ pmap_change_attr(vm_offset_t va, vm_size
 	for (tmpva = base; tmpva < base + size; ) {
 		pde = pmap_pde(kernel_pmap, tmpva);
 		if (*pde & PG_PS) {
-			if (cache_bits_pde < 0)
-				cache_bits_pde = pmap_cache_bits(mode, 1);
 			if ((*pde & PG_PDE_CACHE) != cache_bits_pde) {
 				pmap_pde_attr(pde, cache_bits_pde);
-				if (!changed)
-					changed = TRUE;
+				changed = TRUE;
 			}
 			tmpva = trunc_4mpage(tmpva) + NBPDR;
 		} else {
-			if (cache_bits_pte < 0)
-				cache_bits_pte = pmap_cache_bits(mode, 0);
 			pte = vtopte(tmpva);
 			if ((*pte & PG_PTE_CACHE) != cache_bits_pte) {
 				pmap_pte_attr(pte, cache_bits_pte);
-				if (!changed)
-					changed = TRUE;
+				changed = TRUE;
 			}
 			tmpva += PAGE_SIZE;
 		}

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