zone allow unaligned zone boundries
Currently the buddy allocator requires that zone boundries be
at MAX_ORDER boundries. This may not always be desirable or
possible. Add a config option to allow these boundies
to be arbitrary.
Signed-off-by: Andy Whitcroft <[email protected]>
---
include/linux/mm.h | 7 +++++--
include/linux/mmzone.h | 4 ++++
mm/page_alloc.c | 21 ++++++++++++++-------
3 files changed, 23 insertions(+), 9 deletions(-)
diff -upN reference/include/linux/mm.h current/include/linux/mm.h
--- reference/include/linux/mm.h
+++ current/include/linux/mm.h
@@ -466,10 +466,13 @@ static inline unsigned long page_zonenum
struct zone;
extern struct zone *zone_table[];
+static inline int page_zone_id(struct page *page)
+{
+ return (page->flags >> ZONETABLE_PGSHIFT) & ZONETABLE_MASK;
+}
static inline struct zone *page_zone(struct page *page)
{
- return zone_table[(page->flags >> ZONETABLE_PGSHIFT) &
- ZONETABLE_MASK];
+ return zone_table[page_zone_id(page)];
}
static inline unsigned long page_to_nid(struct page *page)
diff -upN reference/include/linux/mmzone.h current/include/linux/mmzone.h
--- reference/include/linux/mmzone.h
+++ current/include/linux/mmzone.h
@@ -390,7 +390,11 @@ static inline int is_dma(struct zone *zo
static inline unsigned long zone_boundry_align_pfn(unsigned long pfn)
{
+#ifdef CONFIG_UNALIGNED_ZONE_BOUNDRIES
+ return pfn;
+#else
return pfn & ~((1 << MAX_ORDER) - 1);
+#endif
}
/* These two functions are used to setup the per zone pages min values */
diff -upN reference/mm/page_alloc.c current/mm/page_alloc.c
--- reference/mm/page_alloc.c
+++ current/mm/page_alloc.c
@@ -285,22 +285,28 @@ __find_combined_index(unsigned long page
* we can do coalesce a page and its buddy if
* (a) the buddy is not in a hole &&
* (b) the buddy is in the buddy system &&
- * (c) a page and its buddy have the same order.
+ * (c) a page and its buddy have the same order &&
+ * (d) a page and its buddy are in the same zone.
*
* For recording whether a page is in the buddy system, we use PG_buddy.
* Setting, clearing, and testing PG_buddy is serialized by zone->lock.
*
* For recording page's order, we use page_private(page).
*/
-static inline int page_is_buddy(struct page *page, int order)
+static inline int page_is_buddy(struct page *page, struct page *buddy,
+ int order)
{
#ifdef CONFIG_HOLES_IN_ZONE
- if (!pfn_valid(page_to_pfn(page)))
+ if (!pfn_valid(page_to_pfn(buddy)))
+ return 0;
+#endif
+#ifdef CONFIG_UNALIGNED_ZONE_BOUNDRIES
+ if (page_zone_id(page) != page_zone_id(buddy))
return 0;
#endif
- if (PageBuddy(page) && page_order(page) == order) {
- BUG_ON(page_count(page) != 0);
+ if (PageBuddy(buddy) && page_order(buddy) == order) {
+ BUG_ON(page_count(buddy) != 0);
return 1;
}
return 0;
@@ -351,7 +357,7 @@ static inline void __free_one_page(struc
struct page *buddy;
buddy = __page_find_buddy(page, page_idx, order);
- if (!page_is_buddy(buddy, order))
+ if (!page_is_buddy(page, buddy, order))
break; /* Move the buddy up one level. */
list_del(&buddy->lru);
@@ -2080,7 +2086,8 @@ static void __init free_area_init_core(s
if (zone_boundry_align_pfn(zone_start_pfn) != zone_start_pfn)
printk(KERN_CRIT "node %d zone %s missaligned "
- "start pfn\n", nid, zone_names[j]);
+ "start pfn, enable UNALIGNED_ZONE_BOUNDRIES\n",
+ nid, zone_names[j]);
realsize = size = zones_size[j];
if (zholes_size)
-
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