3 files changed, 175 insertions, 0 deletions

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index f6167f2fd7fb..322e8048463e 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -13,6 +13,7 @@
 #include <linux/init.h>
 #include <linux/seqlock.h>
 #include <linux/nodemask.h>
+#include <linux/pageblock-flags.h>
 #include <asm/atomic.h>
 #include <asm/page.h>
 
@@ -222,6 +223,14 @@ struct zone {
 #endif
         struct free_area        free_area[MAX_ORDER];
 
+#ifndef CONFIG_SPARSEMEM
+        /*
+         * Flags for a MAX_ORDER_NR_PAGES block. See pageblock-flags.h.
+         * In SPARSEMEM, this map is stored in struct mem_section
+         */
+        unsigned long           *pageblock_flags;
+#endif /* CONFIG_SPARSEMEM */
+
 
         ZONE_PADDING(_pad1_)
 
@@ -720,6 +729,9 @@ extern struct zone *next_zone(struct zone *zone);
 #define PAGES_PER_SECTION       (1UL << PFN_SECTION_SHIFT)
 #define PAGE_SECTION_MASK       (~(PAGES_PER_SECTION-1))
 
+#define SECTION_BLOCKFLAGS_BITS \
+                ((SECTION_SIZE_BITS - (MAX_ORDER-1)) * NR_PAGEBLOCK_BITS)
+
 #if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS
 #error Allocator MAX_ORDER exceeds SECTION_SIZE
 #endif
@@ -739,6 +751,7 @@ struct mem_section {
          * before using it wrong.
          */
         unsigned long section_mem_map;
+        DECLARE_BITMAP(pageblock_flags, SECTION_BLOCKFLAGS_BITS);
 };
 
 #ifdef CONFIG_SPARSEMEM_EXTREME
diff --git a/include/linux/pageblock-flags.h b/include/linux/pageblock-flags.h
new file mode 100644
index 000000000000..96b623f9b4db
--- /dev/null
+++ b/include/linux/pageblock-flags.h
@@ -0,0 +1,51 @@
+/*
+ * Macros for manipulating and testing flags related to a
+ * MAX_ORDER_NR_PAGES block of pages.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation version 2 of the License
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2006
+ *
+ * Original author, Mel Gorman
+ * Major cleanups and reduction of bit operations, Andy Whitcroft
+ */
+#ifndef PAGEBLOCK_FLAGS_H
+#define PAGEBLOCK_FLAGS_H
+
+#include <linux/types.h>
+
+/* Macro to aid the definition of ranges of bits */
+#define PB_range(name, required_bits) \
+        name, name ## _end = (name + required_bits) - 1
+
+/* Bit indices that affect a whole block of pages */
+enum pageblock_bits {
+        NR_PAGEBLOCK_BITS
+};
+
+/* Forward declaration */
+struct page;
+
+/* Declarations for getting and setting flags. See mm/page_alloc.c */
+unsigned long get_pageblock_flags_group(struct page *page,
+                                        int start_bitidx, int end_bitidx);
+void set_pageblock_flags_group(struct page *page, unsigned long flags,
+                                        int start_bitidx, int end_bitidx);
+
+#define get_pageblock_flags(page) \
+                        get_pageblock_flags_group(page, 0, NR_PAGEBLOCK_BITS-1)
+#define set_pageblock_flags(page) \
+                        set_pageblock_flags_group(page, 0, NR_PAGEBLOCK_BITS-1)
+
+#endif  /* PAGEBLOCK_FLAGS_H */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e69f19e841e5..332f46d70d2d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2931,6 +2931,41 @@ static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
                                                         realtotalpages);
 }
 
+#ifndef CONFIG_SPARSEMEM
+/*
+ * Calculate the size of the zone->blockflags rounded to an unsigned long
+ * Start by making sure zonesize is a multiple of MAX_ORDER-1 by rounding up
+ * Then figure 1 NR_PAGEBLOCK_BITS worth of bits per MAX_ORDER-1, finally
+ * round what is now in bits to nearest long in bits, then return it in
+ * bytes.
+ */
+static unsigned long __init usemap_size(unsigned long zonesize)
+{
+        unsigned long usemapsize;
+
+        usemapsize = roundup(zonesize, MAX_ORDER_NR_PAGES);
+        usemapsize = usemapsize >> (MAX_ORDER-1);
+        usemapsize *= NR_PAGEBLOCK_BITS;
+        usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
+
+        return usemapsize / 8;
+}
+
+static void __init setup_usemap(struct pglist_data *pgdat,
+                                struct zone *zone, unsigned long zonesize)
+{
+        unsigned long usemapsize = usemap_size(zonesize);
+        zone->pageblock_flags = NULL;
+        if (usemapsize) {
+                zone->pageblock_flags = alloc_bootmem_node(pgdat, usemapsize);
+                memset(zone->pageblock_flags, 0, usemapsize);
+        }
+}
+#else
+static void inline setup_usemap(struct pglist_data *pgdat,
+                                struct zone *zone, unsigned long zonesize) {}
+#endif /* CONFIG_SPARSEMEM */
+
 /*
  * Set up the zone data structures:
  *   - mark all pages reserved
@@ -3011,6 +3046,7 @@ static void __meminit free_area_init_core(struct pglist_data *pgdat,
                 if (!size)
                         continue;
 
+                setup_usemap(pgdat, zone, size);
                 ret = init_currently_empty_zone(zone, zone_start_pfn,
                                                 size, MEMMAP_EARLY);
                 BUG_ON(ret);
@@ -3991,4 +4027,79 @@ EXPORT_SYMBOL(pfn_to_page);
 EXPORT_SYMBOL(page_to_pfn);
 #endif /* CONFIG_OUT_OF_LINE_PFN_TO_PAGE */
 
+/* Return a pointer to the bitmap storing bits affecting a block of pages */
+static inline unsigned long *get_pageblock_bitmap(struct zone *zone,
+                                                        unsigned long pfn)
+{
+#ifdef CONFIG_SPARSEMEM
+        return __pfn_to_section(pfn)->pageblock_flags;
+#else
+        return zone->pageblock_flags;
+#endif /* CONFIG_SPARSEMEM */
+}
+
+static inline int pfn_to_bitidx(struct zone *zone, unsigned long pfn)
+{
+#ifdef CONFIG_SPARSEMEM
+        pfn &= (PAGES_PER_SECTION-1);
+        return (pfn >> (MAX_ORDER-1)) * NR_PAGEBLOCK_BITS;
+#else
+        pfn = pfn - zone->zone_start_pfn;
+        return (pfn >> (MAX_ORDER-1)) * NR_PAGEBLOCK_BITS;
+#endif /* CONFIG_SPARSEMEM */
+}
+
+/**
+ * get_pageblock_flags_group - Return the requested group of flags for the MAX_ORDER_NR_PAGES block of pages
+ * @page: The page within the block of interest
+ * @start_bitidx: The first bit of interest to retrieve
+ * @end_bitidx: The last bit of interest
+ * returns pageblock_bits flags
+ */
+unsigned long get_pageblock_flags_group(struct page *page,
+                                        int start_bitidx, int end_bitidx)
+{
+        struct zone *zone;
+        unsigned long *bitmap;
+        unsigned long pfn, bitidx;
+        unsigned long flags = 0;
+        unsigned long value = 1;
+
+        zone = page_zone(page);
+        pfn = page_to_pfn(page);
+        bitmap = get_pageblock_bitmap(zone, pfn);
+        bitidx = pfn_to_bitidx(zone, pfn);
+
+        for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
+                if (test_bit(bitidx + start_bitidx, bitmap))
+                        flags |= value;
 
+        return flags;
+}
+
+/**
+ * set_pageblock_flags_group - Set the requested group of flags for a MAX_ORDER_NR_PAGES block of pages
+ * @page: The page within the block of interest
+ * @start_bitidx: The first bit of interest
+ * @end_bitidx: The last bit of interest
+ * @flags: The flags to set
+ */
+void set_pageblock_flags_group(struct page *page, unsigned long flags,
+                                        int start_bitidx, int end_bitidx)
+{
+        struct zone *zone;
+        unsigned long *bitmap;
+        unsigned long pfn, bitidx;
+        unsigned long value = 1;
+
+        zone = page_zone(page);
+        pfn = page_to_pfn(page);
+        bitmap = get_pageblock_bitmap(zone, pfn);
+        bitidx = pfn_to_bitidx(zone, pfn);
+
+        for (; start_bitidx <= end_bitidx; start_bitidx++, value <<= 1)
+                if (flags & value)
+                        __set_bit(bitidx + start_bitidx, bitmap);
+                else
+                        __clear_bit(bitidx + start_bitidx, bitmap);
+}