int migratetype)
{
unsigned long page_idx;
+ unsigned long combined_idx;
+ struct page *buddy;
if (unlikely(PageCompound(page)))
if (unlikely(destroy_compound_page(page, order)))
VM_BUG_ON(bad_range(zone, page));
while (order < MAX_ORDER-1) {
- unsigned long combined_idx;
- struct page *buddy;
-
buddy = __page_find_buddy(page, page_idx, order);
if (!page_is_buddy(page, buddy, order))
break;
order++;
}
set_page_order(page, order);
- list_add(&page->lru,
- &zone->free_area[order].free_list[migratetype]);
+
+ /*
+ * If this is not the largest possible page, check if the buddy
+ * of the next-highest order is free. If it is, it's possible
+ * that pages are being freed that will coalesce soon. In case,
+ * that is happening, add the free page to the tail of the list
+ * so it's less likely to be used soon and more likely to be merged
+ * as a higher order page
+ */
+ if ((order < MAX_ORDER-1) && pfn_valid_within(page_to_pfn(buddy))) {
+ struct page *higher_page, *higher_buddy;
+ combined_idx = __find_combined_index(page_idx, order);
+ higher_page = page + combined_idx - page_idx;
+ higher_buddy = __page_find_buddy(higher_page, combined_idx, order + 1);
+ if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
+ list_add_tail(&page->lru,
+ &zone->free_area[order].free_list[migratetype]);
+ goto out;
+ }
+ }
+
+ list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
+out:
zone->free_area[order].nr_free++;
}
if (unlikely(!zonelist->_zonerefs->zone))
return NULL;
+ get_mems_allowed();
/* The preferred zone is used for statistics later */
first_zones_zonelist(zonelist, high_zoneidx, nodemask, &preferred_zone);
- if (!preferred_zone)
+ if (!preferred_zone) {
+ put_mems_allowed();
return NULL;
+ }
/* First allocation attempt */
page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask, order,
page = __alloc_pages_slowpath(gfp_mask, order,
zonelist, high_zoneidx, nodemask,
preferred_zone, migratetype);
+ put_mems_allowed();
trace_mm_page_alloc(page, order, gfp_mask, migratetype);
return page;
* ZONE_DMA and ZONE_DMA32 can be very small area in the system.
* If they are really small and used heavily, the system can fall
* into OOM very easily.
- * This function detect ZONE_DMA/DMA32 size and confgigures zone order.
+ * This function detect ZONE_DMA/DMA32 size and configures zone order.
*/
/* Is there ZONE_NORMAL ? (ex. ppc has only DMA zone..) */
low_kmem_size = 0;
if (zone_type < ZONE_NORMAL)
low_kmem_size += z->present_pages;
total_size += z->present_pages;
+ } else if (zone_type == ZONE_NORMAL) {
+ /*
+ * If any node has only lowmem, then node order
+ * is preferred to allow kernel allocations
+ * locally; otherwise, they can easily infringe
+ * on other nodes when there is an abundance of
+ * lowmem available to allocate from.
+ */
+ return ZONELIST_ORDER_NODE;
}
}
}