diff options
| author | Bob Picco <bob.picco@hp.com> | 2006-05-20 15:00:31 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-05-21 12:59:22 -0700 |
| commit | e984bb43f7450312ba66fe0e67a99efa6be3b246 (patch) | |
| tree | 54c86240172136fc81c773f71cd70eda54fed6f2 /include | |
| parent | ae57a856429dd932c547530df1b234eb7e642297 (diff) | |
[PATCH] Align the node_mem_map endpoints to a MAX_ORDER boundary
Andy added code to buddy allocator which does not require the zone's
endpoints to be aligned to MAX_ORDER. An issue is that the buddy allocator
requires the node_mem_map's endpoints to be MAX_ORDER aligned. Otherwise
__page_find_buddy could compute a buddy not in node_mem_map for partial
MAX_ORDER regions at zone's endpoints. page_is_buddy will detect that
these pages at endpoints are not PG_buddy (they were zeroed out by bootmem
allocator and not part of zone). Of course the negative here is we could
waste a little memory but the positive is eliminating all the old checks
for zone boundary conditions.
SPARSEMEM won't encounter this issue because of MAX_ORDER size constraint
when SPARSEMEM is configured. ia64 VIRTUAL_MEM_MAP doesn't need the logic
either because the holes and endpoints are handled differently. This
leaves checking alloc_remap and other arches which privately allocate for
node_mem_map.
Signed-off-by: Bob Picco <bob.picco@hp.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mmzone.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index b5c21122c299..36740354d4db 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -22,6 +22,7 @@ #else #define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER #endif +#define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1)) struct free_area { struct list_head free_list; |