The patch titled
FLATMEM: relax requirement for memory to start at pfn 0
has been added to the -mm tree. Its filename is
flatmem-relax-requirement-for-memory-to-start-at-pfn-0.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: FLATMEM: relax requirement for memory to start at pfn 0
From: Andy Whitcroft <apw@xxxxxxxxxxxx>
The FLATMEM memory model assumes that memory is in one contigious area
based at pfn 0. If we initialise node 0 to start at any other offset we
will incorrectly map pfn's to the wrong struct page *. The key to the
memory model is the contigious nature of the memory not the location of it.
Relax the requirement for the area to start at 0.
Signed-off-by: Andy Whitcroft <apw@xxxxxxxxxxxx>
Acked-by: Mel Gorman <mel@xxxxxxxxx>
Cc: Dave Hansen <haveblue@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
mm/page_alloc.c | 17 +++++++++++++----
1 files changed, 13 insertions(+), 4 deletions(-)
diff -puN mm/page_alloc.c~flatmem-relax-requirement-for-memory-to-start-at-pfn-0 mm/page_alloc.c
--- 25/mm/page_alloc.c~flatmem-relax-requirement-for-memory-to-start-at-pfn-0 Fri May 19 13:51:18 2006
+++ 25-akpm/mm/page_alloc.c Fri May 19 13:51:18 2006
@@ -2199,15 +2199,16 @@ static void __meminit free_area_init_cor
static void __init alloc_node_mem_map(struct pglist_data *pgdat)
{
+#ifdef CONFIG_FLAT_NODE_MEM_MAP
+ struct page *map = pgdat->node_mem_map;
+
/* Skip empty nodes */
if (!pgdat->node_spanned_pages)
return;
-#ifdef CONFIG_FLAT_NODE_MEM_MAP
/* ia64 gets its own node_mem_map, before this, without bootmem */
- if (!pgdat->node_mem_map) {
+ if (!map) {
unsigned long size, start, end;
- struct page *map;
/*
* The zone's endpoints aren't required to be MAX_ORDER
@@ -2222,13 +2223,21 @@ static void __init alloc_node_mem_map(st
if (!map)
map = alloc_bootmem_node(pgdat, size);
pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
+
+ /*
+ * With FLATMEM the global mem_map is used. This is assumed
+ * to be based at pfn 0 such that 'pfn = page* - mem_map'
+ * is true. Adjust map relative to node_mem_map to
+ * maintain this relationship.
+ */
+ map -= pgdat->node_start_pfn;
}
#ifdef CONFIG_FLATMEM
/*
* With no DISCONTIG, the global mem_map is just set as node 0's
*/
if (pgdat == NODE_DATA(0))
- mem_map = NODE_DATA(0)->node_mem_map;
+ mem_map = map;
#endif
#endif /* CONFIG_FLAT_NODE_MEM_MAP */
}
_
Patches currently in -mm which might be from apw@xxxxxxxxxxxx are
origin.patch
sparsemem-incorrectly-calculates-section-number.patch
zone-init-check-and-report-unaligned-zone-boundaries.patch
zone-init-check-and-report-unaligned-zone-boundaries-fix-v2.patch
x86-align-highmem-zone-boundaries-with-numa.patch
zone-allow-unaligned-zone-boundaries.patch
zone-allow-unaligned-zone-boundaries-spelling-fix.patch
pg_uncached-is-ia64-only.patch
squash-duplicate-page_to_pfn-and-pfn_to_page.patch
align-the-node_mem_map-endpoints-to-a-max_order-boundary.patch
flatmem-relax-requirement-for-memory-to-start-at-pfn-0.patch
introduce-mechanism-for-registering-active-regions-of-memory.patch
have-power-use-add_active_range-and-free_area_init_nodes.patch
have-x86-use-add_active_range-and-free_area_init_nodes.patch
have-x86_64-use-add_active_range-and-free_area_init_nodes.patch
have-ia64-use-add_active_range-and-free_area_init_nodes.patch
sparsemem-record-nid-during-memory-present.patch
-
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