linux-kernel - [PATCH 4/4] xen/balloon: Move dec_totalhigh_pages() from __balloon_append() to balloon

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Date:	Mon, 28 Mar 2011 11:35:59 +0200
From:	Daniel Kiper <dkiper@...-space.pl>
To:	ian.campbell@...rix.com, akpm@...ux-foundation.org,
	andi.kleen@...el.com, haicheng.li@...ux.intel.com,
	fengguang.wu@...el.com, jeremy@...p.org, konrad.wilk@...cle.com,
	dan.magenheimer@...cle.com, v.tolstov@...fip.ru, pasik@....fi,
	dave@...ux.vnet.ibm.com, wdauchy@...il.com, rientjes@...gle.com,
	xen-devel@...ts.xensource.com, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Subject: [PATCH 4/4] xen/balloon: Move dec_totalhigh_pages() from __balloon_append() to balloon_append()

git commit 9be4d4575906af9698de660e477f949a076c87e1 (xen: add
extra pages to balloon) splited balloon_append() into two functions
(balloon_append() and __balloon_append()) and left decrementation
of totalram_pages counter in __balloon_append(). In this situation
if __balloon_append() is called on i386 with highmem page referenced
then totalhigh_pages is decremented, however, it should not. This
patch corrects that issue and moves dec_totalhigh_pages() from
__balloon_append() to balloon_append(). Now totalram_pages and
totalhigh_pages are decremented simultaneously only when
balloon_append() is called.

Signed-off-by: Daniel Kiper <dkiper@...-space.pl>
---
 drivers/xen/balloon.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index a6d8e59..f54290b 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -114,7 +114,6 @@ static void __balloon_append(struct page *page)
 	if (PageHighMem(page)) {
 		list_add_tail(&page->lru, &ballooned_pages);
 		balloon_stats.balloon_high++;
-		dec_totalhigh_pages();
 	} else {
 		list_add(&page->lru, &ballooned_pages);
 		balloon_stats.balloon_low++;
@@ -124,6 +123,8 @@ static void __balloon_append(struct page *page)
 static void balloon_append(struct page *page)
 {
 	__balloon_append(page);
+	if (PageHighMem(page))
+		dec_totalhigh_pages();
 	totalram_pages--;
 }
 
@@ -462,7 +463,7 @@ static int __init balloon_init(void)
 	     pfn < extra_pfn_end;
 	     pfn++) {
 		page = pfn_to_page(pfn);
-		/* totalram_pages doesn't include the boot-time
+		/* totalram_pages and totalhigh_pages do not include the boot-time
 		   balloon extension, so don't subtract from it. */
 		__balloon_append(page);
 	}
-- 
1.5.6.5
--
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