[Xen-changelog] [xen-4.0-testing] page_alloc: Hold heap_lock while adjusting page states to/from PGC_state_free.

["Xen patchbot-4.0-testing" <patchbot-4.0-testing@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1284394746 -3600
# Node ID 12c96d380c48789d6d4c8955af7e014075abf3d9
# Parent  5ca1d7547a42cc469d856b62f1894408ea8e1723
page_alloc: Hold heap_lock while adjusting page states to/from PGC_state_free.

This avoids races with buddy-merging logic in free_heap_pages().

Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
xen-unstable changeset:   22135:69e8bb164683
xen-unstable date:        Mon Sep 13 17:08:31 2010 +0100
---
 xen/common/page_alloc.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff -r 5ca1d7547a42 -r 12c96d380c48 xen/common/page_alloc.c
--- a/xen/common/page_alloc.c   Mon Sep 13 17:18:07 2010 +0100
+++ b/xen/common/page_alloc.c   Mon Sep 13 17:19:06 2010 +0100
@@ -378,8 +378,6 @@ static struct page_info *alloc_heap_page
     total_avail_pages -= request;
     ASSERT(total_avail_pages >= 0);
 
-    spin_unlock(&heap_lock);
-
     cpus_clear(mask);
 
     for ( i = 0; i < (1 << order); i++ )
@@ -400,6 +398,8 @@ static struct page_info *alloc_heap_page
         pg[i].u.inuse.type_info = 0;
         page_set_owner(&pg[i], NULL);
     }
+
+    spin_unlock(&heap_lock);
 
     if ( unlikely(!cpus_empty(mask)) )
     {
@@ -496,6 +496,8 @@ static void free_heap_pages(
     ASSERT(order <= MAX_ORDER);
     ASSERT(node >= 0);
 
+    spin_lock(&heap_lock);
+
     for ( i = 0; i < (1 << order); i++ )
     {
         /*
@@ -523,8 +525,6 @@ static void free_heap_pages(
             pg[i].tlbflush_timestamp = tlbflush_current_time();
     }
 
-    spin_lock(&heap_lock);
-
     avail[node][zone] += 1 << order;
     total_avail_pages += 1 << order;
 

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