3 files changed, 96 insertions, 7 deletions

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index c4c8f2e1dd15..d7d77d4a402c 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -63,6 +63,20 @@ void unregister_memory_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL(unregister_memory_notifier);
 
+static ATOMIC_NOTIFIER_HEAD(memory_isolate_chain);
+
+int register_memory_isolate_notifier(struct notifier_block *nb)
+{
+        return atomic_notifier_chain_register(&memory_isolate_chain, nb);
+}
+EXPORT_SYMBOL(register_memory_isolate_notifier);
+
+void unregister_memory_isolate_notifier(struct notifier_block *nb)
+{
+        atomic_notifier_chain_unregister(&memory_isolate_chain, nb);
+}
+EXPORT_SYMBOL(unregister_memory_isolate_notifier);
+
 /*
  * register_memory - Setup a sysfs device for a memory block
  */
@@ -157,6 +171,11 @@ int memory_notify(unsigned long val, void *v)
         return blocking_notifier_call_chain(&memory_chain, val, v);
 }
 
+int memory_isolate_notify(unsigned long val, void *v)
+{
+        return atomic_notifier_call_chain(&memory_isolate_chain, val, v);
+}
+
 /*
  * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
  * OK to have direct references to sparsemem variables in here.
diff --git a/include/linux/memory.h b/include/linux/memory.h
index 37fa19b34ef5..1adfe779eb99 100644
--- a/include/linux/memory.h
+++ b/include/linux/memory.h
@@ -50,6 +50,19 @@ struct memory_notify {
         int status_change_nid;
 };
 
+/*
+ * During pageblock isolation, count the number of pages within the
+ * range [start_pfn, start_pfn + nr_pages) which are owned by code
+ * in the notifier chain.
+ */
+#define MEM_ISOLATE_COUNT       (1<<0)
+
+struct memory_isolate_notify {
+        unsigned long start_pfn;        /* Start of range to check */
+        unsigned int nr_pages;          /* # pages in range to check */
+        unsigned int pages_found;       /* # pages owned found by callbacks */
+};
+
 struct notifier_block;
 struct mem_section;
 
@@ -76,14 +89,28 @@ static inline int memory_notify(unsigned long val, void *v)
 {
         return 0;
 }
+static inline int register_memory_isolate_notifier(struct notifier_block *nb)
+{
+        return 0;
+}
+static inline void unregister_memory_isolate_notifier(struct notifier_block *nb)
+{
+}
+static inline int memory_isolate_notify(unsigned long val, void *v)
+{
+        return 0;
+}
 #else
 extern int register_memory_notifier(struct notifier_block *nb);
 extern void unregister_memory_notifier(struct notifier_block *nb);
+extern int register_memory_isolate_notifier(struct notifier_block *nb);
+extern void unregister_memory_isolate_notifier(struct notifier_block *nb);
 extern int register_new_memory(int, struct mem_section *);
 extern int unregister_memory_section(struct mem_section *);
 extern int memory_dev_init(void);
 extern int remove_memory_block(unsigned long, struct mem_section *, int);
 extern int memory_notify(unsigned long val, void *v);
+extern int memory_isolate_notify(unsigned long val, void *v);
 extern struct memory_block *find_memory_block(struct mem_section *);
 #define CONFIG_MEM_BLOCK_SIZE   (PAGES_PER_SECTION<<PAGE_SHIFT)
 enum mem_add_context { BOOT, HOTPLUG };
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 74af449b1f1d..998eacc1e4c3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -48,6 +48,7 @@
 #include <linux/page_cgroup.h>
 #include <linux/debugobjects.h>
 #include <linux/kmemleak.h>
+#include <linux/memory.h>
 #include <trace/events/kmem.h>
 
 #include <asm/tlbflush.h>
@@ -5008,23 +5009,65 @@ void set_pageblock_flags_group(struct page *page, unsigned long flags,
 int set_migratetype_isolate(struct page *page)
 {
         struct zone *zone;
-        unsigned long flags;
+        struct page *curr_page;
+        unsigned long flags, pfn, iter;
+        unsigned long immobile = 0;
+        struct memory_isolate_notify arg;
+        int notifier_ret;
         int ret = -EBUSY;
         int zone_idx;
 
         zone = page_zone(page);
         zone_idx = zone_idx(zone);
+
         spin_lock_irqsave(&zone->lock, flags);
+        if (get_pageblock_migratetype(page) == MIGRATE_MOVABLE ||
+            zone_idx == ZONE_MOVABLE) {
+                ret = 0;
+                goto out;
+        }
+
+        pfn = page_to_pfn(page);
+        arg.start_pfn = pfn;
+        arg.nr_pages = pageblock_nr_pages;
+        arg.pages_found = 0;
+
         /*
-         * In future, more migrate types will be able to be isolation target.
+         * It may be possible to isolate a pageblock even if the
+         * migratetype is not MIGRATE_MOVABLE. The memory isolation
+         * notifier chain is used by balloon drivers to return the
+         * number of pages in a range that are held by the balloon
+         * driver to shrink memory. If all the pages are accounted for
+         * by balloons, are free, or on the LRU, isolation can continue.
+         * Later, for example, when memory hotplug notifier runs, these
+         * pages reported as "can be isolated" should be isolated(freed)
+         * by the balloon driver through the memory notifier chain.
          */
-        if (get_pageblock_migratetype(page) != MIGRATE_MOVABLE &&
-            zone_idx != ZONE_MOVABLE)
+        notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
+        notifier_ret = notifier_to_errno(notifier_ret);
+        if (notifier_ret || !arg.pages_found)
                 goto out;
-        set_pageblock_migratetype(page, MIGRATE_ISOLATE);
-        move_freepages_block(zone, page, MIGRATE_ISOLATE);
-        ret = 0;
+
+        for (iter = pfn; iter < (pfn + pageblock_nr_pages); iter++) {
+                if (!pfn_valid_within(pfn))
+                        continue;
+
+                curr_page = pfn_to_page(iter);
+                if (!page_count(curr_page) || PageLRU(curr_page))
+                        continue;
+
+                immobile++;
+        }
+
+        if (arg.pages_found == immobile)
+                ret = 0;
+
 out:
+        if (!ret) {
+                set_pageblock_migratetype(page, MIGRATE_ISOLATE);
+                move_freepages_block(zone, page, MIGRATE_ISOLATE);
+        }
+
         spin_unlock_irqrestore(&zone->lock, flags);
         if (!ret)
                 drain_all_pages();