memory-hotplug: introduce new arch_remove_memory() for removing page table

For removing memory, we need to remove page tables.  But it depends on
architecture.  So the patch introduce arch_remove_memory() for removing
page table.  Now it only calls __remove_pages().

Note: __remove_pages() for some archtecuture is not implemented
      (I don't know how to implement it for s390).

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.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: Wu Jianguo <wujianguo@huawei.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

9 files changed, 97 insertions, 0 deletions

diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index b755ea92aea7..20bc967c7209 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -688,6 +688,24 @@ int arch_add_memory(int nid, u64 start, u64 size)
 
         return ret;
 }
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+        unsigned long start_pfn = start >> PAGE_SHIFT;
+        unsigned long nr_pages = size >> PAGE_SHIFT;
+        struct zone *zone;
+        int ret;
+
+        zone = page_zone(pfn_to_page(start_pfn));
+        ret = __remove_pages(zone, start_pfn, nr_pages);
+        if (ret)
+                pr_warn("%s: Problem encountered in __remove_pages() as"
+                        " ret=%d\n", __func__,  ret);
+
+        return ret;
+}
+#endif
 #endif
 
 /*
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 0dba5066c22a..09c64518b4d0 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -133,6 +133,18 @@ int arch_add_memory(int nid, u64 start, u64 size)
 
         return __add_pages(nid, zone, start_pfn, nr_pages);
 }
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+        unsigned long start_pfn = start >> PAGE_SHIFT;
+        unsigned long nr_pages = size >> PAGE_SHIFT;
+        struct zone *zone;
+
+        zone = page_zone(pfn_to_page(start_pfn));
+        return __remove_pages(zone, start_pfn, nr_pages);
+}
+#endif
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 /*
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index ae672f41c464..49ce6bb2c641 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -228,4 +228,16 @@ int arch_add_memory(int nid, u64 start, u64 size)
                 vmem_remove_mapping(start, size);
         return rc;
 }
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+        /*
+         * There is no hardware or firmware interface which could trigger a
+         * hot memory remove on s390. So there is nothing that needs to be
+         * implemented.
+         */
+        return -EBUSY;
+}
+#endif
 #endif /* CONFIG_MEMORY_HOTPLUG */
diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
index 82cc576fab15..105794037143 100644
--- a/arch/sh/mm/init.c
+++ b/arch/sh/mm/init.c
@@ -558,4 +558,21 @@ int memory_add_physaddr_to_nid(u64 addr)
 EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
 #endif
 
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+        unsigned long start_pfn = start >> PAGE_SHIFT;
+        unsigned long nr_pages = size >> PAGE_SHIFT;
+        struct zone *zone;
+        int ret;
+
+        zone = page_zone(pfn_to_page(start_pfn));
+        ret = __remove_pages(zone, start_pfn, nr_pages);
+        if (unlikely(ret))
+                pr_warn("%s: Failed, __remove_pages() == %d\n", __func__,
+                        ret);
+
+        return ret;
+}
+#endif
 #endif /* CONFIG_MEMORY_HOTPLUG */
diff --git a/arch/tile/mm/init.c b/arch/tile/mm/init.c
index ef29d6c5e10e..2749515a0547 100644
--- a/arch/tile/mm/init.c
+++ b/arch/tile/mm/init.c
@@ -935,6 +935,14 @@ int remove_memory(u64 start, u64 size)
 {
         return -EINVAL;
 }
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+        /* TODO */
+        return -EBUSY;
+}
+#endif
 #endif
 
 struct kmem_cache *pgd_cache;
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index b299724f6e34..2d19001151d5 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -862,6 +862,18 @@ int arch_add_memory(int nid, u64 start, u64 size)
 
         return __add_pages(nid, zone, start_pfn, nr_pages);
 }
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int arch_remove_memory(u64 start, u64 size)
+{
+        unsigned long start_pfn = start >> PAGE_SHIFT;
+        unsigned long nr_pages = size >> PAGE_SHIFT;
+        struct zone *zone;
+
+        zone = page_zone(pfn_to_page(start_pfn));
+        return __remove_pages(zone, start_pfn, nr_pages);
+}
+#endif
 #endif
 
 /*
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 3eba7f429880..b6dd1c480b30 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -707,6 +707,21 @@ int arch_add_memory(int nid, u64 start, u64 size)
 }
 EXPORT_SYMBOL_GPL(arch_add_memory);
 
+#ifdef CONFIG_MEMORY_HOTREMOVE
+int __ref arch_remove_memory(u64 start, u64 size)
+{
+        unsigned long start_pfn = start >> PAGE_SHIFT;
+        unsigned long nr_pages = size >> PAGE_SHIFT;
+        struct zone *zone;
+        int ret;
+
+        zone = page_zone(pfn_to_page(start_pfn));
+        ret = __remove_pages(zone, start_pfn, nr_pages);
+        WARN_ON_ONCE(ret);
+
+        return ret;
+}
+#endif
 #endif /* CONFIG_MEMORY_HOTPLUG */
 
 static struct kcore_list kcore_vsyscall;
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 8dd0950a6a7a..31a563bbd936 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -96,6 +96,7 @@ extern void __online_page_free(struct page *page);
 
 #ifdef CONFIG_MEMORY_HOTREMOVE
 extern bool is_pageblock_removable_nolock(struct page *page);
+extern int arch_remove_memory(u64 start, u64 size);
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 
 /* reasonably generic interface to expand the physical pages in a zone  */
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index a776dbf3fa00..942b43f6d736 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1513,6 +1513,8 @@ repeat:
         /* remove memmap entry */
         firmware_map_remove(start, start + size, "System RAM");
 
+        arch_remove_memory(start, size);
+
         unlock_memory_hotplug();
 
         return 0;