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authorDavid Vrabel <david.vrabel@citrix.com>2011-09-28 17:46:33 +0100
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-09-29 11:12:09 -0400
commitb1cbf9b1d6af22ba262d99abcfd71d5d90dbd57a (patch)
treeff8a5c8d68451f5ef23bc427351e061ef42ae7a4 /drivers
parentaa24411b6717fd1e6ecef281bec497f6f30bbd66 (diff)
downloadlinux-b1cbf9b1d6af22ba262d99abcfd71d5d90dbd57a.tar.gz
xen/balloon: simplify test for the end of usable RAM
When initializing the balloon only max_pfn needs to be checked
(max_pfn will always be <= e820_end_of_ram_pfn()) and improve the
confusing comment.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/xen/balloon.c18
1 files changed, 9 insertions, 9 deletions
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 4f59fb373381..9efb993090aa 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -586,16 +586,16 @@ static int __init balloon_init(void)
 #endif
 
 	/*
-	 * Initialise the balloon with excess memory space.  We need
-	 * to make sure we don't add memory which doesn't exist or
-	 * logically exist.  The E820 map can be trimmed to be smaller
-	 * than the amount of physical memory due to the mem= command
-	 * line parameter.  And if this is a 32-bit non-HIGHMEM kernel
-	 * on a system with memory which requires highmem to access,
-	 * don't try to use it.
+	 * Initialize the balloon with pages from the extra memory
+	 * region (see arch/x86/xen/setup.c).
+	 *
+	 * If the amount of usable memory has been limited (e.g., with
+	 * the 'mem' command line parameter), don't add pages beyond
+	 * this limit.
 	 */
-	extra_pfn_end = min(min(max_pfn, e820_end_of_ram_pfn()),
-			    (unsigned long)PFN_DOWN(xen_extra_mem_start + xen_extra_mem_size));
+	extra_pfn_end = min(max_pfn,
+			    (unsigned long)PFN_DOWN(xen_extra_mem_start
+						    + xen_extra_mem_size));
 	for (pfn = PFN_UP(xen_extra_mem_start);
 	     pfn < extra_pfn_end;
 	     pfn++) {