memory-hotplug: implement register_page_bootmem_info_section of sparse-vmemmap

For removing memmap region of sparse-vmemmap which is allocated bootmem,
memmap region of sparse-vmemmap needs to be registered by
get_page_bootmem().  So the patch searches pages of virtual mapping and
registers the pages by get_page_bootmem().

NOTE: register_page_bootmem_memmap() is not implemented for ia64,
      ppc, s390, and sparc.  So introduce CONFIG_HAVE_BOOTMEM_INFO_NODE
      and revert register_page_bootmem_info_node() when platform doesn't
      support it.

      It's implemented by adding a new Kconfig option named
      CONFIG_HAVE_BOOTMEM_INFO_NODE, which will be automatically selected
      by memory-hotplug feature fully supported archs(currently only on
      x86_64).

      Since we have 2 config options called MEMORY_HOTPLUG and
      MEMORY_HOTREMOVE used for memory hot-add and hot-remove separately,
      and codes in function register_page_bootmem_info_node() are only
      used for collecting infomation for hot-remove, so reside it under
      MEMORY_HOTREMOVE.

      Besides page_isolation.c selected by MEMORY_ISOLATION under
      MEMORY_HOTPLUG is also such case, move it too.

[mhocko@suse.cz: put register_page_bootmem_memmap inside CONFIG_MEMORY_HOTPLUG_SPARSE]
[linfeng@cn.fujitsu.com: introduce CONFIG_HAVE_BOOTMEM_INFO_NODE and revert register_page_bootmem_info_node()]
[mhocko@suse.cz: remove the arch specific functions without any implementation]
[linfeng@cn.fujitsu.com: mm/Kconfig: move auto selects from MEMORY_HOTPLUG to MEMORY_HOTREMOVE as needed]
[rientjes@google.com: fix defined but not used warning]
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Wu Jianguo <wujianguo@huawei.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Lin Feng <linfeng@cn.fujitsu.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 40 insertions, 5 deletions

diff --git a/mm/Kconfig b/mm/Kconfig
index 0b23db9a8791..2c7aea7106f9 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -162,10 +162,16 @@ config MOVABLE_NODE
           Say Y here if you want to hotplug a whole node.
           Say N here if you want kernel to use memory on all nodes evenly.
 
+#
+# Only be set on architectures that have completely implemented memory hotplug
+# feature. If you are not sure, don't touch it.
+#
+config HAVE_BOOTMEM_INFO_NODE
+        def_bool n
+
 # eventually, we can have this option just 'select SPARSEMEM'
 config MEMORY_HOTPLUG
         bool "Allow for memory hot-add"
-        select MEMORY_ISOLATION
         depends on SPARSEMEM || X86_64_ACPI_NUMA
         depends on HOTPLUG && ARCH_ENABLE_MEMORY_HOTPLUG
         depends on (IA64 || X86 || PPC_BOOK3S_64 || SUPERH || S390)
@@ -176,6 +182,8 @@ config MEMORY_HOTPLUG_SPARSE
 
 config MEMORY_HOTREMOVE
         bool "Allow for memory hot remove"
+        select MEMORY_ISOLATION
+        select HAVE_BOOTMEM_INFO_NODE if X86_64
         depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
         depends on MIGRATION
 
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 942b43f6d736..6c90d222ec0a 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -91,9 +91,8 @@ 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,
-                             unsigned long type)
+void get_page_bootmem(unsigned long info,  struct page *page,
+                      unsigned long type)
 {
         page->lru.next = (struct list_head *) type;
         SetPagePrivate(page);
@@ -128,6 +127,8 @@ void __ref put_page_bootmem(struct page *page)
 
 }
 
+#ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
+#ifndef CONFIG_SPARSEMEM_VMEMMAP
 static void register_page_bootmem_info_section(unsigned long start_pfn)
 {
         unsigned long *usemap, mapsize, section_nr, i;
@@ -161,6 +162,32 @@ static void register_page_bootmem_info_section(unsigned long start_pfn)
                 get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
 
 }
+#else /* CONFIG_SPARSEMEM_VMEMMAP */
+static void register_page_bootmem_info_section(unsigned long start_pfn)
+{
+        unsigned long *usemap, mapsize, section_nr, i;
+        struct mem_section *ms;
+        struct page *page, *memmap;
+
+        if (!pfn_valid(start_pfn))
+                return;
+
+        section_nr = pfn_to_section_nr(start_pfn);
+        ms = __nr_to_section(section_nr);
+
+        memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
+
+        register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
+
+        usemap = __nr_to_section(section_nr)->pageblock_flags;
+        page = virt_to_page(usemap);
+
+        mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
+
+        for (i = 0; i < mapsize; i++, page++)
+                get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
+}
+#endif /* !CONFIG_SPARSEMEM_VMEMMAP */
 
 void register_page_bootmem_info_node(struct pglist_data *pgdat)
 {
@@ -203,7 +230,7 @@ void register_page_bootmem_info_node(struct pglist_data *pgdat)
                         register_page_bootmem_info_section(pfn);
         }
 }
-#endif /* !CONFIG_SPARSEMEM_VMEMMAP */
+#endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
 
 static void grow_zone_span(struct zone *zone, unsigned long start_pfn,
                            unsigned long end_pfn)