On kernels from v2.6.18 to v2.6.37, buddy page is marked by the
PG_buddy flag.
kernel version | PG_buddy
------------------ +---------------------------------
v2.6.17 to v2.6.26 | 19
v2.6.27 to v2.6.37 | 19 if CONFIG_PAGEFLAGS_EXTEND=y
| 18 otherwise
Note for hard coding: it's possible to determine whether
CONFIG_PAGEFLAGS_EXTEND=yes or not by looking at error_status array
defined in mm/memory-failure.c, for example.
Signed-off-by: HATAYAMA Daisuke <d.hatayama at jp.fujitsu.com>
---
makedumpfile.c | 27 ++++++++++++++++++++-------
1 files changed, 20 insertions(+), 7 deletions(-)
diff --git a/makedumpfile.c b/makedumpfile.c
index aea956f..675b47e 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -3518,6 +3518,16 @@ exclude_free_page(void)
}
static int
+page_is_buddy_v2(unsigned long flags, unsigned int _mapcount,
+ unsigned long private, unsigned int _count)
+{
+ if (flags & (1UL << NUMBER(PG_buddy)))
+ return TRUE;
+
+ return FALSE;
+}
+
+static int
page_is_buddy_v3(unsigned long flags, unsigned int _mapcount,
unsigned long private, unsigned int _count)
{
@@ -3533,13 +3543,16 @@ page_is_buddy_v3(unsigned long flags, unsigned int _mapcount,
static void
setup_page_is_buddy(void)
{
- if (NUMBER(PG_buddy) == NOT_FOUND_NUMBER
- && SIZE(pageflags) != NOT_FOUND_STRUCTURE
- && NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE) != NOT_FOUND_NUMBER)
- info->page_is_buddy = page_is_buddy_v3;
-
- MSG("Can't select page_is_buddy handler; "
- "filtering free pages is disabled.\n");
+ if (NUMBER(PG_buddy) == NOT_FOUND_NUMBER) {
+ if (SIZE(pageflags) != NOT_FOUND_STRUCTURE
+ && NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE) != NOT_FOUND_NUMBER)
+ info->page_is_buddy = page_is_buddy_v3;
+ else {
+ MSG("Can't select page_is_buddy handler; "
+ "filtering free pages is disabled.\n");
+ }
+ } else
+ info->page_is_buddy = page_is_buddy_v2;
}
/*
