[PATCH] x86_64: Support memory hotadd without sparsemem

Memory hotadd doesn't need SPARSEMEM, but can be handled by just preallocating
mem_maps. This only needs some untangling of ifdefs to enable the necessary
code even without SPARSEMEM.

Originally from Keith Mannthey, hacked by AK.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 34 insertions, 2 deletions

diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index e5f7f1c34462..492161168402 100644
--- a/arch/x86_64/mm/init.c
+++ b/arch/x86_64/mm/init.c
@@ -507,9 +507,8 @@ void __init clear_kernel_mapping(unsigned long address, unsigned long size)
 
 /*
  * Memory hotplug specific functions
- * These are only for non-NUMA machines right now.
  */
-#ifdef CONFIG_MEMORY_HOTPLUG
+#if defined(CONFIG_ACPI_HOTPLUG_MEMORY) || defined(CONFIG_ACPI_HOTPLUG_MEMORY_MODULE)
 
 void online_page(struct page *page)
 {
@@ -520,6 +519,39 @@ void online_page(struct page *page)
         num_physpages++;
 }
 
+#ifndef CONFIG_MEMORY_HOTPLUG
+/*
+ * Memory Hotadd without sparsemem. The mem_maps have been allocated in advance,
+ * just online the pages.
+ */
+int __add_pages(struct zone *z, unsigned long start_pfn, unsigned long nr_pages)
+{
+        int err = -EIO;
+        unsigned long pfn;
+        unsigned long total = 0, mem = 0;
+        for (pfn = start_pfn; pfn < start_pfn + nr_pages; pfn++) {
+                unsigned long addr = pfn << PAGE_SHIFT;
+                if (pfn_valid(pfn) && e820_mapped(addr, addr+1, E820_RAM)) {
+                        online_page(pfn_to_page(pfn));
+                        err = 0;
+                        mem++;
+                }
+                total++;
+        }
+        if (!err) {
+                z->spanned_pages += total;
+                z->present_pages += mem;
+                z->zone_pgdat->node_spanned_pages += total;
+                z->zone_pgdat->node_present_pages += mem;
+        }
+        return err;
+}
+#endif
+
+/*
+ * Memory is added always to NORMAL zone. This means you will never get
+ * additional DMA/DMA32 memory.
+ */
 int add_memory(u64 start, u64 size)
 {
         struct pglist_data *pgdat = NODE_DATA(0);