[Devel] problem with ZONE_MOVABLE.

[KAMEZAWA Hiroyuki]

Hi, 

While I'm playing with memory controller of 2.6.23-rc4-mm1, I met following.

==
[root at drpq test-2.6.23-rc4-mm1]# echo $$ > /opt/mem_control/group_1/tasks
[root at drpq test-2.6.23-rc4-mm1]# cat /opt/mem_control/group_1/memory.limit
32768
[root at drpq test-2.6.23-rc4-mm1]# cat /opt/mem_control/group_1/memory.usage
286
// Memory is limited to 512 GiB. try "dd" 1GiB (page size is 16KB)
 
[root at drpq test-2.6.23-rc4-mm1]# dd if=/dev/zero of=/tmp/tmpfile bs=1024 count=1048576
Killed
[root at drpq test-2.6.23-rc4-mm1]# ls
Killed
//above are caused by OOM.
[root at drpq test-2.6.23-rc4-mm1]# cat /opt/mem_control/group_1/memory.usage
32763
[root at drpq test-2.6.23-rc4-mm1]# cat /opt/mem_control/group_1/memory.limit
32768
// fully filled by page cache. no reclaim run.
==

The reason  this happens is  because I used kernelcore= boot option, i.e
ZONE_MOVABLE. Seems try_to_free_mem_container_pages() ignores ZONE_MOVABLE.

Quick fix is attached, but Mel's one-zonelist-pernode patch may change this.
I'll continue to watch.

Thanks,
-Kame
==
Now, there is ZONE_MOVABLE...

page cache and user pages are allocated from gfp_zone(GFP_HIGHUSER_MOVABLE)

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
---
 mm/vmscan.c |    9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

Index: linux-2.6.23-rc4-mm1.bak/mm/vmscan.c
===================================================================
--- linux-2.6.23-rc4-mm1.bak.orig/mm/vmscan.c
+++ linux-2.6.23-rc4-mm1.bak/mm/vmscan.c
@@ -1351,12 +1351,6 @@ unsigned long try_to_free_pages(struct z
 
 #ifdef CONFIG_CONTAINER_MEM_CONT
 
-#ifdef CONFIG_HIGHMEM
-#define ZONE_USERPAGES ZONE_HIGHMEM
-#else
-#define ZONE_USERPAGES ZONE_NORMAL
-#endif
-
 unsigned long try_to_free_mem_container_pages(struct mem_container *mem_cont)
 {
 	struct scan_control sc = {
@@ -1371,9 +1365,10 @@ unsigned long try_to_free_mem_container_
 	};
 	int node;
 	struct zone **zones;
+	int target_zone = gfp_zone(GFP_HIGHUSER_MOVABLE);
 
 	for_each_online_node(node) {
-		zones = NODE_DATA(node)->node_zonelists[ZONE_USERPAGES].zones;
+		zones = NODE_DATA(node)->node_zonelists[target_zone].zones;
 		if (do_try_to_free_pages(zones, sc.gfp_mask, &sc))
 			return 1;
 	}






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