1 files changed, 71 insertions, 9 deletions

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 833f854eabe5..89fee2dcb039 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -62,9 +62,9 @@ static void release_memory_resource(struct resource *res)
 
 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
 #ifndef CONFIG_SPARSEMEM_VMEMMAP
-static void get_page_bootmem(unsigned long info,  struct page *page, int magic)
+static void get_page_bootmem(unsigned long info,  struct page *page, int type)
 {
-        atomic_set(&page->_mapcount, magic);
+        atomic_set(&page->_mapcount, type);
         SetPagePrivate(page);
         set_page_private(page, info);
         atomic_inc(&page->_count);
@@ -72,10 +72,10 @@ static void get_page_bootmem(unsigned long info,  struct page *page, int magic)
 
 void put_page_bootmem(struct page *page)
 {
-        int magic;
+        int type;
 
-        magic = atomic_read(&page->_mapcount);
-        BUG_ON(magic >= -1);
+        type = atomic_read(&page->_mapcount);
+        BUG_ON(type >= -1);
 
         if (atomic_dec_return(&page->_count) == 1) {
                 ClearPagePrivate(page);
@@ -86,7 +86,7 @@ void put_page_bootmem(struct page *page)
 
 }
 
-void register_page_bootmem_info_section(unsigned long start_pfn)
+static void register_page_bootmem_info_section(unsigned long start_pfn)
 {
         unsigned long *usemap, mapsize, section_nr, i;
         struct mem_section *ms;
@@ -119,7 +119,7 @@ void register_page_bootmem_info_section(unsigned long start_pfn)
         mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
 
         for (i = 0; i < mapsize; i++, page++)
-                get_page_bootmem(section_nr, page, MIX_INFO);
+                get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
 
 }
 
@@ -429,7 +429,9 @@ int online_pages(unsigned long pfn, unsigned long nr_pages)
 
         if (need_zonelists_rebuild)
                 build_all_zonelists();
-        vm_total_pages = nr_free_pagecache_pages();
+        else
+                vm_total_pages = nr_free_pagecache_pages();
+
         writeback_set_ratelimit();
 
         if (onlined_pages)
@@ -455,7 +457,7 @@ static pg_data_t *hotadd_new_pgdat(int nid, u64 start)
         /* we can use NODE_DATA(nid) from here */
 
         /* init node's zones as empty zones, we don't have any present pages.*/
-        free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size);
+        free_area_init_node(nid, zones_size, start_pfn, zholes_size);
 
         return pgdat;
 }
@@ -521,6 +523,66 @@ EXPORT_SYMBOL_GPL(add_memory);
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
 /*
+ * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
+ * set and the size of the free page is given by page_order(). Using this,
+ * the function determines if the pageblock contains only free pages.
+ * Due to buddy contraints, a free page at least the size of a pageblock will
+ * be located at the start of the pageblock
+ */
+static inline int pageblock_free(struct page *page)
+{
+        return PageBuddy(page) && page_order(page) >= pageblock_order;
+}
+
+/* Return the start of the next active pageblock after a given page */
+static struct page *next_active_pageblock(struct page *page)
+{
+        int pageblocks_stride;
+
+        /* Ensure the starting page is pageblock-aligned */
+        BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
+
+        /* Move forward by at least 1 * pageblock_nr_pages */
+        pageblocks_stride = 1;
+
+        /* If the entire pageblock is free, move to the end of free page */
+        if (pageblock_free(page))
+                pageblocks_stride += page_order(page) - pageblock_order;
+
+        return page + (pageblocks_stride * pageblock_nr_pages);
+}
+
+/* Checks if this range of memory is likely to be hot-removable. */
+int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
+{
+        int type;
+        struct page *page = pfn_to_page(start_pfn);
+        struct page *end_page = page + nr_pages;
+
+        /* Check the starting page of each pageblock within the range */
+        for (; page < end_page; page = next_active_pageblock(page)) {
+                type = get_pageblock_migratetype(page);
+
+                /*
+                 * A pageblock containing MOVABLE or free pages is considered
+                 * removable
+                 */
+                if (type != MIGRATE_MOVABLE && !pageblock_free(page))
+                        return 0;
+
+                /*
+                 * A pageblock starting with a PageReserved page is not
+                 * considered removable.
+                 */
+                if (PageReserved(page))
+                        return 0;
+        }
+
+        /* All pageblocks in the memory block are likely to be hot-removable */
+        return 1;
+}
+
+/*
  * Confirm all pages in a range [start, end) is belongs to the same zone.
  */
 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)