[PATCH] memory hotplug prep: break out zone initialization

If a zone is empty at boot-time and then hot-added to later, it needs to run
the same init code that would have been run on it at boot.

This patch breaks out zone table and per-cpu-pages functions for use by the
hotplug code.  You can almost see all of the free_area_init_core() function on
one page now.  :)

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 58 insertions, 40 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a2995a5d012c..9a2fa8110afc 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1875,6 +1875,60 @@ void __init setup_per_cpu_pageset()
 
 #endif
 
+static __devinit
+void zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
+{
+        int i;
+        struct pglist_data *pgdat = zone->zone_pgdat;
+
+        /*
+         * The per-page waitqueue mechanism uses hashed waitqueues
+         * per zone.
+         */
+        zone->wait_table_size = wait_table_size(zone_size_pages);
+        zone->wait_table_bits = wait_table_bits(zone->wait_table_size);
+        zone->wait_table = (wait_queue_head_t *)
+                alloc_bootmem_node(pgdat, zone->wait_table_size
+                                        * sizeof(wait_queue_head_t));
+
+        for(i = 0; i < zone->wait_table_size; ++i)
+                init_waitqueue_head(zone->wait_table + i);
+}
+
+static __devinit void zone_pcp_init(struct zone *zone)
+{
+        int cpu;
+        unsigned long batch = zone_batchsize(zone);
+
+        for (cpu = 0; cpu < NR_CPUS; cpu++) {
+#ifdef CONFIG_NUMA
+                /* Early boot. Slab allocator not functional yet */
+                zone->pageset[cpu] = &boot_pageset[cpu];
+                setup_pageset(&boot_pageset[cpu],0);
+#else
+                setup_pageset(zone_pcp(zone,cpu), batch);
+#endif
+        }
+        printk(KERN_DEBUG "  %s zone: %lu pages, LIFO batch:%lu\n",
+                zone->name, zone->present_pages, batch);
+}
+
+static __devinit void init_currently_empty_zone(struct zone *zone,
+                unsigned long zone_start_pfn, unsigned long size)
+{
+        struct pglist_data *pgdat = zone->zone_pgdat;
+
+        zone_wait_table_init(zone, size);
+        pgdat->nr_zones = zone_idx(zone) + 1;
+
+        zone->zone_mem_map = pfn_to_page(zone_start_pfn);
+        zone->zone_start_pfn = zone_start_pfn;
+
+        memmap_init(size, pgdat->node_id, zone_idx(zone), zone_start_pfn);
+
+        zone_init_free_lists(pgdat, zone, zone->spanned_pages);
+}
+
 /*
  * Set up the zone data structures:
  *   - mark all pages reserved
@@ -1884,8 +1938,8 @@ void __init setup_per_cpu_pageset()
 static void __init free_area_init_core(struct pglist_data *pgdat,
                 unsigned long *zones_size, unsigned long *zholes_size)
 {
-        unsigned long i, j;
-        int cpu, nid = pgdat->node_id;
+        unsigned long j;
+        int nid = pgdat->node_id;
         unsigned long zone_start_pfn = pgdat->node_start_pfn;
 
         pgdat->nr_zones = 0;
@@ -1895,7 +1949,6 @@ static void __init free_area_init_core(struct pglist_data *pgdat,
         for (j = 0; j < MAX_NR_ZONES; j++) {
                 struct zone *zone = pgdat->node_zones + j;
                 unsigned long size, realsize;
-                unsigned long batch;
 
                 realsize = size = zones_size[j];
                 if (zholes_size)
@@ -1915,19 +1968,7 @@ static void __init free_area_init_core(struct pglist_data *pgdat,
 
                 zone->temp_priority = zone->prev_priority = DEF_PRIORITY;
 
-                batch = zone_batchsize(zone);
-
-                for (cpu = 0; cpu < NR_CPUS; cpu++) {
-#ifdef CONFIG_NUMA
-                        /* Early boot. Slab allocator not functional yet */
-                        zone->pageset[cpu] = &boot_pageset[cpu];
-                        setup_pageset(&boot_pageset[cpu],0);
-#else
-                        setup_pageset(zone_pcp(zone,cpu), batch);
-#endif
-                }
-                printk(KERN_DEBUG "  %s zone: %lu pages, LIFO batch:%lu\n",
-                                zone_names[j], realsize, batch);
+                zone_pcp_init(zone);
                 INIT_LIST_HEAD(&zone->active_list);
                 INIT_LIST_HEAD(&zone->inactive_list);
                 zone->nr_scan_active = 0;
@@ -1938,32 +1979,9 @@ static void __init free_area_init_core(struct pglist_data *pgdat,
                 if (!size)
                         continue;
 
-                /*
-                 * The per-page waitqueue mechanism uses hashed waitqueues
-                 * per zone.
-                 */
-                zone->wait_table_size = wait_table_size(size);
-                zone->wait_table_bits =
-                        wait_table_bits(zone->wait_table_size);
-                zone->wait_table = (wait_queue_head_t *)
-                        alloc_bootmem_node(pgdat, zone->wait_table_size
-                                                * sizeof(wait_queue_head_t));
-
-                for(i = 0; i < zone->wait_table_size; ++i)
-                        init_waitqueue_head(zone->wait_table + i);
-
-                pgdat->nr_zones = j+1;
-
-                zone->zone_mem_map = pfn_to_page(zone_start_pfn);
-                zone->zone_start_pfn = zone_start_pfn;
-
-                memmap_init(size, nid, j, zone_start_pfn);
-
                 zonetable_add(zone, nid, j, zone_start_pfn, size);
-
+                init_currently_empty_zone(zone, zone_start_pfn, size);
                 zone_start_pfn += size;
-
-                zone_init_free_lists(pgdat, zone, zone->spanned_pages);
         }
 }