On Mon, 30 May 2011 16:54:53 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> On Mon, 30 May 2011 16:29:04 +0900
> KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> SRAT: Node 1 PXM 1 0-a0000
> SRAT: Node 1 PXM 1 100000-c8000000
> SRAT: Node 1 PXM 1 100000000-438000000
> SRAT: Node 3 PXM 3 438000000-838000000
> SRAT: Node 5 PXM 5 838000000-c38000000
> SRAT: Node 7 PXM 7 c38000000-1038000000
>
> Initmem setup node 1 0000000000000000-0000000438000000
> NODE_DATA [0000000437fd9000 - 0000000437ffffff]
> Initmem setup node 3 0000000438000000-0000000838000000
> NODE_DATA [0000000837fd9000 - 0000000837ffffff]
> Initmem setup node 5 0000000838000000-0000000c38000000
> NODE_DATA [0000000c37fd9000 - 0000000c37ffffff]
> Initmem setup node 7 0000000c38000000-0000001038000000
> NODE_DATA [0000001037fd7000 - 0000001037ffdfff]
> [ffffea000ec40000-ffffea000edfffff] potential offnode page_structs
> [ffffea001cc40000-ffffea001cdfffff] potential offnode page_structs
> [ffffea002ac40000-ffffea002adfffff] potential offnode page_structs
> ==
>
> Hmm..there are four nodes 1,3,5,7 but....no memory on node 0 hmm ?
>
I think I found a reason and this is a possible fix. But need to be tested.
And suggestion for better fix rather than this band-aid is appreciated.
==
>From b95edcf43619312f72895476c3e6ef46079bb05f Mon Sep 17 00:00:00 2001
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Date: Mon, 30 May 2011 16:49:59 +0900
Subject: [PATCH][BUGFIX] fallbacks at page_cgroup allocation.
Under SPARSEMEM, the page_struct is allocated per section.
Then, pfn_valid() for the whole section is "true" and there are page
structs. But, it's not related to valid range of [start_pfn, end_pfn)
and some page structs may not be initialized collectly because
it's not a valid pages.
(memmap_init_zone() skips a page which is not correct in
early_node_map[] and page->flags is initialized to be 0.)
In this case, a page->flags can be '0'. Assume a case where
node 0 has no memory....
page_cgroup is allocated onto the node
- page_to_nid(head of section pfn)
Head's pfn will be valid (struct page exists) but page->flags is 0 and contains
node_id:0. This causes allocation onto NODE_DATA(0) and cause panic.
This patch makes page_cgroup to use alloc_pages_exact() only
when NID is N_NORMAL_MEMORY.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
---
mm/page_cgroup.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index 74ccff6..3b0c8f2 100644
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -134,7 +134,10 @@ static void *__meminit alloc_page_cgroup(size_t size, int nid)
{
void *addr = NULL;
- addr = alloc_pages_exact_nid(nid, size, GFP_KERNEL | __GFP_NOWARN);
+ if (node_state(nid, N_NORMAL_MEMORY))
+ addr = alloc_pages_exact_nid(nid, size, GFP_KERNEL | __GFP_NOWARN);
+ if (!addr)
+ addr = alloc_pages_exact(size, GFP_KERNEL | __GFP_NOWARN);
if (addr)
return addr;
--
1.7.4.1
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxxx For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>