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diff -purN git2/arch/arm/include/asm/memory.h git/arch/arm/include/asm/memory.h
--- git2/arch/arm/include/asm/memory.h 2009-06-08 06:42:26.000000000 +0530
+++ git/arch/arm/include/asm/memory.h 2009-08-17 11:58:07.000000000 +0530
@@ -204,7 +204,6 @@ static inline __deprecated void *bus_to_
*
* page_to_pfn(page) convert a struct page * to a PFN number
* pfn_to_page(pfn) convert a _valid_ PFN number to struct page *
- * pfn_valid(pfn) indicates whether a PFN number is valid
*
* virt_to_page(k) convert a _valid_ virtual address to struct page *
* virt_addr_valid(k) indicates whether a virtual address is valid
@@ -213,10 +212,6 @@ static inline __deprecated void *bus_to_
#define ARCH_PFN_OFFSET PHYS_PFN_OFFSET
-#ifndef CONFIG_SPARSEMEM
-#define pfn_valid(pfn) ((pfn) >= PHYS_PFN_OFFSET && (pfn) < (PHYS_PFN_OFFSET + max_mapnr))
-#endif
-
#define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
#define virt_addr_valid(kaddr) ((unsigned long)(kaddr) >= PAGE_OFFSET && (unsigned long)(kaddr) < (unsigned long)high_memory)
@@ -233,18 +228,6 @@ static inline __deprecated void *bus_to_
#define arch_pfn_to_nid(pfn) PFN_TO_NID(pfn)
#define arch_local_page_offset(pfn, nid) LOCAL_MAP_NR((pfn) << PAGE_SHIFT)
-#define pfn_valid(pfn) \
- ({ \
- unsigned int nid = PFN_TO_NID(pfn); \
- int valid = nid < MAX_NUMNODES; \
- if (valid) { \
- pg_data_t *node = NODE_DATA(nid); \
- valid = (pfn - node->node_start_pfn) < \
- node->node_spanned_pages; \
- } \
- valid; \
- })
-
#define virt_to_page(kaddr) \
(ADDR_TO_MAPBASE(kaddr) + LOCAL_MAP_NR(kaddr))
diff -purN git2/arch/arm/include/asm/page.h git/arch/arm/include/asm/page.h
--- git2/arch/arm/include/asm/page.h 2009-06-08 06:42:26.000000000 +0530
+++ git/arch/arm/include/asm/page.h 2009-08-17 11:58:07.000000000 +0530
@@ -186,6 +186,10 @@ typedef unsigned long pgprot_t;
typedef struct page *pgtable_t;
+#ifndef CONFIG_SPARSEMEM
+extern int pfn_valid(unsigned long);
+#endif
+
#include <asm/memory.h>
#endif /* !__ASSEMBLY__ */
diff -purN git2/arch/arm/Kconfig git/arch/arm/Kconfig
--- git2/arch/arm/Kconfig 2009-07-20 05:07:12.000000000 +0530
+++ git/arch/arm/Kconfig 2009-08-17 12:08:37.000000000 +0530
@@ -272,6 +272,7 @@ config ARCH_EP93XX
select HAVE_CLK
select COMMON_CLKDEV
select ARCH_REQUIRE_GPIOLIB
+ select ARCH_HAS_HOLES_MEMORYMODEL
help
This enables support for the Cirrus EP93xx series of CPUs.
@@ -569,6 +570,7 @@ config ARCH_OMAP
select ARCH_REQUIRE_GPIOLIB
select GENERIC_TIME
select GENERIC_CLOCKEVENTS
+ select ARCH_HAS_HOLES_MEMORYMODEL
help
Support for TI's OMAP platform (OMAP1 and OMAP2).
@@ -891,10 +893,9 @@ config OABI_COMPAT
UNPREDICTABLE (in fact it can be predicted that it won't work
at all). If in doubt say Y.
-config ARCH_FLATMEM_HAS_HOLES
+config ARCH_HAS_HOLES_MEMORYMODEL
bool
- default y
- depends on FLATMEM
+ default n
# Discontigmem is deprecated
config ARCH_DISCONTIGMEM_ENABLE
diff -purN git2/arch/arm/mm/init.c git/arch/arm/mm/init.c
--- git2/arch/arm/mm/init.c 2009-06-08 06:42:27.000000000 +0530
+++ git/arch/arm/mm/init.c 2009-08-17 12:03:16.000000000 +0530
@@ -15,7 +15,7 @@
#include <linux/mman.h>
#include <linux/nodemask.h>
#include <linux/initrd.h>
-
+#include <linux/sort.h>
#include <asm/mach-types.h>
#include <asm/sections.h>
#include <asm/setup.h>
@@ -333,12 +333,40 @@ static void __init bootmem_free_node(int
free_area_init_node(node, zone_size, start_pfn, zhole_size);
}
+#ifndef CONFIG_SPARSEMEM
+int pfn_valid(unsigned long pfn)
+{
+ struct meminfo *mi = &meminfo;
+ unsigned int mid, left = 0, right = mi->nr_banks;
+
+ while ((mid = (right - left) / 2) > 0) {
+ struct membank *bank = &mi->bank[mid];
+
+ if (pfn < bank_pfn_start(bank))
+ right = mid;
+ else if (pfn >= bank_pfn_end(bank))
+ left = mid + 1;
+ else
+ return 1;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(pfn_valid);
+#endif
+
+static int __init meminfo_cmp(const void *_a, const void *_b) {
+ const struct membank *a = _a, *b = _b;
+ long cmp = bank_pfn_start(b) - bank_pfn_start(a);
+ return cmp < 0 ? -1 : cmp > 0 ? 1 : 0; }
+
void __init bootmem_init(void)
{
struct meminfo *mi = &meminfo;
unsigned long memend_pfn = 0;
int node, initrd_node;
+ sort(&mi->bank, mi->nr_banks, sizeof(mi->bank[0]), meminfo_cmp, NULL);
+
/*
* Locate which node contains the ramdisk image, if any.
*/
diff -purN git2/include/linux/mmzone.h git/include/linux/mmzone.h
--- git2/include/linux/mmzone.h 2009-06-08 06:42:40.000000000 +0530
+++ git/include/linux/mmzone.h 2009-08-17 11:57:17.000000000 +0530
@@ -1095,6 +1095,32 @@ unsigned long __init node_memmap_size_by
#define pfn_valid_within(pfn) (1)
#endif
+#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
+/*
+ * pfn_valid() is meant to be able to tell if a given PFN has valid memmap
+ * associated with it or not. In FLATMEM, it is expected that holes always
+ * have valid memmap as long as there is valid PFNs either side of the hole.
+ * In SPARSEMEM, it is assumed that a valid section has a memmap for the
+ * entire section.
+ *
+ * However, an ARM, and maybe other embedded architectures in the future
+ * free memmap backing holes to save memory on the assumption the memmap is
+ * never used. The page_zone linkages are then broken even though pfn_valid()
+ * returns true. A walker of the full memmap must then do this additional
+ * check to ensure the memmap they are looking at is sane by making sure
+ * the zone and PFN linkages are still valid. This is expensive, but walkers
+ * of the full memmap are extremely rare.
+ */
+int memmap_valid_within(unsigned long pfn,
+ struct page *page, struct zone *zone);
+#else
+static inline int memmap_valid_within(unsigned long pfn,
+ struct page *page, struct zone *zone)
+{
+ return 1;
+}
+#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
+
#endif /* !__GENERATING_BOUNDS.H */
#endif /* !__ASSEMBLY__ */
#endif /* _LINUX_MMZONE_H */
diff -purN git2/mm/mmzone.c git/mm/mmzone.c
--- git2/mm/mmzone.c 2009-06-08 06:42:41.000000000 +0530
+++ git/mm/mmzone.c 2009-08-17 11:57:17.000000000 +0530
@@ -6,6 +6,7 @@
#include <linux/stddef.h>
+#include <linux/mm.h>
#include <linux/mmzone.h>
#include <linux/module.h>
@@ -72,3 +73,17 @@ struct zoneref *next_zones_zonelist(stru
*zone = zonelist_zone(z);
return z;
}
+
+#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
+int memmap_valid_within(unsigned long pfn,
+ struct page *page, struct zone *zone)
+{
+ if (page_to_pfn(page) != pfn)
+ return 0;
+
+ if (page_zone(page) != zone)
+ return 0;
+
+ return 1;
+}
+#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
diff -purN git2/mm/vmstat.c git/mm/vmstat.c
--- git2/mm/vmstat.c 2009-06-08 06:42:41.000000000 +0530
+++ git/mm/vmstat.c 2009-08-17 11:57:17.000000000 +0530
@@ -516,22 +516,11 @@ static void pagetypeinfo_showblockcount_
continue;
page = pfn_to_page(pfn);
-#ifdef CONFIG_ARCH_FLATMEM_HAS_HOLES
- /*
- * Ordinarily, memory holes in flatmem still have a valid
- * memmap for the PFN range. However, an architecture for
- * embedded systems (e.g. ARM) can free up the memmap backing
- * holes to save memory on the assumption the memmap is
- * never used. The page_zone linkages are then broken even
- * though pfn_valid() returns true. Skip the page if the
- * linkages are broken. Even if this test passed, the impact
- * is that the counters for the movable type are off but
- * fragmentation monitoring is likely meaningless on small
- * systems.
- */
- if (page_zone(page) != zone)
+
+ /* Watch for unexpected holes punched in the memmap */
+ if (!memmap_valid_within(pfn, page, zone))
continue;
-#endif
+
mtype = get_pageblock_migratetype(page);
if (mtype < MIGRATE_TYPES)
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