[PATCH] architecture hooks for mem_map initialization

From: Christoph Hellwig <hch@lst.de>

This patch is from the IA64 tree, with minor cleanups from me.

Split out initialization of pgdat->node_mem_map into a separate function
and allow architectures to override it.  This is needed for HP IA64
machines that have a virtually mapped memory map to support big
memory holes without having to use discontigmem.

(memmap_init_zone is non-static to allow the IA64 code to use it -
 I did that instead of passing it's address into the arch hook as
 it is done currently in the IA64 tree)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5f4bf646e1876ab1dcf61516b62a324d5868bf1a..ede6c5ff418127d5e8ff0bad73d427e1b3f55fbb 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -486,6 +486,8 @@ extern void free_area_init(unsigned long * zones_size);
 extern void free_area_init_node(int nid, pg_data_t *pgdat, struct page *pmap,
        unsigned long * zones_size, unsigned long zone_start_pfn, 
        unsigned long *zholes_size);
+extern void memmap_init_zone(struct page *, unsigned long, int,
+       unsigned long, unsigned long);
 extern void mem_init(void);
 extern void show_mem(void);
 extern void si_meminfo(struct sysinfo * val);

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index f2e5ffc3de3272c8584b6d541a926b592e901632..906770cf8a4d0fa24c2223f022f454bcc332d338 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1141,6 +1141,35 @@ static void __init calculate_zone_bitmap(struct pglist_data *pgdat,
        memset(pgdat->valid_addr_bitmap, 0, size);
 }
 
+/*
+ * Initially all pages are reserved - free ones are freed
+ * up by free_all_bootmem() once the early boot process is
+ * done. Non-atomic initialization, single-pass.
+ */
+void __init memmap_init_zone(struct page *start, unsigned long size, int nid,
+               unsigned long zone, unsigned long start_pfn)
+{
+       struct page *page;
+
+       for (page = start; page < (start + size); page++) {
+               set_page_zone(page, nid * MAX_NR_ZONES + zone);
+               set_page_count(page, 0);
+               SetPageReserved(page);
+               INIT_LIST_HEAD(&page->list);
+#ifdef WANT_PAGE_VIRTUAL
+               /* The shift won't overflow because ZONE_NORMAL is below 4G. */
+               if (zone != ZONE_HIGHMEM)
+                       set_page_address(page, __va(start_pfn << PAGE_SHIFT));
+#endif
+               start_pfn++;
+       }
+}
+
+#ifndef __HAVE_ARCH_MEMMAP_INIT
+#define memmap_init(start, size, nid, zone, start_pfn) \
+       memmap_init_zone((start), (size), (nid), (zone), (start_pfn))
+#endif
+
 /*
  * Set up the zone data structures:
  *   - mark all pages reserved
@@ -1151,7 +1180,6 @@ static void __init free_area_init_core(struct pglist_data *pgdat,
                unsigned long *zones_size, unsigned long *zholes_size)
 {
        unsigned long i, j;
-       unsigned long local_offset;
        const unsigned long zone_required_alignment = 1UL << (MAX_ORDER-1);
        int cpu, nid = pgdat->node_id;
        struct page *lmem_map = pgdat->node_mem_map;
@@ -1160,7 +1188,6 @@ static void __init free_area_init_core(struct pglist_data *pgdat,
        pgdat->nr_zones = 0;
        init_waitqueue_head(&pgdat->kswapd_wait);
        
-       local_offset = 0;                /* offset within lmem_map */
        for (j = 0; j < MAX_NR_ZONES; j++) {
                struct zone *zone = pgdat->node_zones + j;
                unsigned long mask;
@@ -1246,36 +1273,17 @@ static void __init free_area_init_core(struct pglist_data *pgdat,
                zone->pages_low = mask*2;
                zone->pages_high = mask*3;
 
-               zone->zone_mem_map = lmem_map + local_offset;
+               zone->zone_mem_map = lmem_map;
                zone->zone_start_pfn = zone_start_pfn;
 
                if ((zone_start_pfn) & (zone_required_alignment-1))
                        printk("BUG: wrong zone alignment, it will crash\n");
 
-               /*
-                * Initially all pages are reserved - free ones are freed
-                * up by free_all_bootmem() once the early boot process is
-                * done. Non-atomic initialization, single-pass.
-                */
-               for (i = 0; i < size; i++) {
-                       struct page *page = lmem_map + local_offset + i;
-                       set_page_zone(page, nid * MAX_NR_ZONES + j);
-                       set_page_count(page, 0);
-                       SetPageReserved(page);
-                       INIT_LIST_HEAD(&page->list);
-#ifdef WANT_PAGE_VIRTUAL
-                       if (j != ZONE_HIGHMEM)
-                               /*
-                                * The shift left won't overflow because the
-                                * ZONE_NORMAL is below 4G.
-                                */
-                               set_page_address(page,
-                                       __va(zone_start_pfn << PAGE_SHIFT));
-#endif
-                       zone_start_pfn++;
-               }
+               memmap_init(lmem_map, size, nid, j, zone_start_pfn);
+
+               zone_start_pfn += size;
+               lmem_map += size;
 
-               local_offset += size;
                for (i = 0; ; i++) {
                        unsigned long bitmap_size;