On Thu, 5 Feb 2009 10:39:25 +0000
Mel Gorman <mel@xxxxxxxxx> wrote:
> ====
> If a PFN is not in early_node_map[] then the struct page for it is not
> initialised. If there are holes within a MAX_ORDER_NR_PAGES range of
> pages, then PG_reserved will not be set. Code that walks PFNs within
> MAX_ORDER_NR_PAGES will then use uninitialised struct pages.
>
> To avoid any problems, this patch initialises holes within a MAX_ORDER_NR_PAGES
> that valid memmap exists but is otherwise unused.
> ====
>
Thank you, I use this text.
==
If PFN is not in early_node_map[] then struct page for it is not initialized.
If there are holes within a MAX_ORDER_NE_PAGES range of pages, then PG_reserved
will not be set. Code that walks PFNs within MAX_ORDER_NR_PAGES will the use
uninitialized struct pages.
To avoid any problems, this patch initializes holes within a MAX_ORDER_NR_PAGES
that valid memmap exists but is otherwise unused.
Changelog:
- renamed variable from "tmp" to "actual_nid"
Reported-by: David Miller <davem@xxxxxxxxxxxxxx>
Acked-by: Mel Gorman <mel@xxxxxxxxx>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
---
include/linux/mmzone.h | 6 ------
mm/page_alloc.c | 13 +++++++++++--
2 files changed, 11 insertions(+), 8 deletions(-)
Index: linux-2.6.28-rc3/mm/page_alloc.c
===================================================================
--- linux-2.6.28-rc3.orig/mm/page_alloc.c
+++ linux-2.6.28-rc3/mm/page_alloc.c
@@ -2632,9 +2632,18 @@ void __meminit memmap_init_zone(unsigned
* exist on hotplugged memory.
*/
if (context == MEMMAP_EARLY) {
+ int nid_from_node_memory_map;
+
if (!early_pfn_valid(pfn))
continue;
- if (!early_pfn_in_nid(pfn, nid))
+ /*
+ * early_pfn_to_nid() returns -1 if the page doesn't
+ * exist in early_node_map[]. Initialize it in force
+ * and set PG_reserved at el.
+ */
+ nid_from_node_memory_map = early_pfn_to_nid(pfn);
+ if (nid_from_node_memory_map > -1 &&
+ nid_from_node_memory_map != nid)
continue;
}
page = pfn_to_page(pfn);
@@ -3001,7 +3010,7 @@ int __meminit early_pfn_to_nid(unsigned
return early_node_map[i].nid;
}
- return 0;
+ return -1;
}
#endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
Index: linux-2.6.28-rc3/include/linux/mmzone.h
===================================================================
--- linux-2.6.28-rc3.orig/include/linux/mmzone.h
+++ linux-2.6.28-rc3/include/linux/mmzone.h
@@ -1070,12 +1070,6 @@ void sparse_init(void);
#define sparse_index_init(_sec, _nid) do {} while (0)
#endif /* CONFIG_SPARSEMEM */
-#ifdef CONFIG_NODES_SPAN_OTHER_NODES
-#define early_pfn_in_nid(pfn, nid) (early_pfn_to_nid(pfn) == (nid))
-#else
-#define early_pfn_in_nid(pfn, nid) (1)
-#endif
-
#ifndef early_pfn_valid
#define early_pfn_valid(pfn) (1)
#endif
--
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