Add auto zone ordering configuration.
This function will select ZONE_ORDER_NODE when
- There are only ZONE_DMA or ZONE_DMA32.
(or) size of (ZONE_DMA/DMA32) > (System Total Memory)/2
(or) Assume Node(A)
* Node (A)'s total memory > System Total Memory/num_of_node+1
(and) Node (A)'s ZONE_DMA/DMA32 occupies 60% of Node(A)'s memory.
otherwise, ZONE_ORDER_ZONE is selected.
Note: a user can specifiy this ordering from boot option.
Signed-Off-By: KAMEZAWA Hiroyuki <[EMAIL PROTECTED]>
---
mm/page_alloc.c | 44 +++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 43 insertions(+), 1 deletion(-)
Index: linux-2.6.21-rc7-mm2/mm/page_alloc.c
===================================================================
--- linux-2.6.21-rc7-mm2.orig/mm/page_alloc.c 2007-04-27 15:39:49.000000000
+0900
+++ linux-2.6.21-rc7-mm2/mm/page_alloc.c 2007-04-27 15:55:51.000000000
+0900
@@ -2211,8 +2211,50 @@
static int estimate_zonelist_order(void)
{
- /* dummy, just select node order. */
- return ZONELIST_ORDER_NODE;
+ int nid, zone_type;
+ unsigned long low_kmem_size,total_size;
+ struct zone *z;
+ int average_size;
+ /* ZONE_DMA and ZONE_DMA32 can be very small area in the sytem.
+ If they are really small and used heavily,
+ the system can fall into OOM very easily.
+ This function detect ZONE_DMA/DMA32 size and confgigure
+ zone ordering */
+ /* Is there ZONE_NORMAL ? (ex. ppc has only DMA zone..) */
+ low_kmem_size = 0;
+ total_size = 0;
+ for_each_online_node(nid) {
+ for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
+ z = &NODE_DATA(nid)->node_zones[zone_type];
+ if (populated_zone(z)) {
+ if (zone_type < ZONE_NORMAL)
+ low_kmem_size += z->present_pages;
+ total_size += z->present_pages;
+ }
+ }
+ }
+ if (!low_kmem_size || /* there is no DMA area. */
+ !low_kmem_size > total_size/2) /* DMA/DMA32 is big. */
+ return ZONELIST_ORDER_NODE;
+ /* look into each node's config. where all processes starts... */
+ /* average size..a bit smaller than real average size */
+ average_size = total_size / (num_online_nodes() + 1);
+ for_each_online_node(nid) {
+ low_kmem_size = 0;
+ total_size = 0;
+ for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
+ z = &NODE_DATA(nid)->node_zones[zone_type];
+ if (populated_zone(z)) {
+ if (zone_type < ZONE_NORMAL)
+ low_kmem_size += z->present_pages;
+ total_size += z->present_pages;
+ }
+ }
+ if (total_size > average_size && /* ignore unbalanced node */
+ low_kmem_size > total_size * 60/100)
+ return ZONELIST_ORDER_NODE;
+ }
+ return ZONELIST_ORDER_ZONE;
}
-
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