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: alghouth I don't do in this patch set, 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 | 30 +++++++++++++++++++++++-------
1 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/makedumpfile.c b/makedumpfile.c
index 27ad3e6..838ef53 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -3643,6 +3643,19 @@ exclude_free_page(void)
}
/*
+ * For the kernel versions from v2.6.17 to v2.6.37.
+ */
+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;
+}
+
+/*
* For v2.6.38 and later kernel versions.
*/
static int
@@ -3661,13 +3674,16 @@ 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;
- else
- 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;
}
/*
