hotplug memory remove: generic __remove_pages() support

Generic helper function to remove section mappings and sysfs entries for the
section of the memory we are removing.  offline_pages() correctly adjusted
zone and marked the pages reserved.

TODO: Yasunori Goto is working on patches to free up allocations from bootmem.

Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Acked-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 8fee7a45736b..aca9c65f8d08 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -8,6 +8,7 @@
 struct page;
 struct zone;
 struct pglist_data;
+struct mem_section;
 
 #ifdef CONFIG_MEMORY_HOTPLUG
 /*
@@ -64,9 +65,11 @@ extern int offline_pages(unsigned long, unsigned long, unsigned long);
 /* reasonably generic interface to expand the physical pages in a zone  */
 extern int __add_pages(struct zone *zone, unsigned long start_pfn,
         unsigned long nr_pages);
+extern int __remove_pages(struct zone *zone, unsigned long start_pfn,
+        unsigned long nr_pages);
 
 /*
- * Walk thorugh all memory which is registered as resource.
+ * Walk through all memory which is registered as resource.
  * arg is (start_pfn, nr_pages, private_arg_pointer)
  */
 extern int walk_memory_resource(unsigned long start_pfn,
@@ -176,5 +179,6 @@ extern int arch_add_memory(int nid, u64 start, u64 size);
 extern int remove_memory(u64 start, u64 size);
 extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn,
                                                                 int nr_pages);
+extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms);
 
 #endif /* __LINUX_MEMORY_HOTPLUG_H */