mm/memory-failure.c: move set_migratetype_isolate() outside get_any_page()

Chen Gong pointed out that set/unset_migratetype_isolate() was done in
different functions in mm/memory-failure.c, which makes the code less
readable/maintainable.  So this patch does it in soft_offline_page().

With this patch, we get to hold lock_memory_hotplug() longer but it's
not a problem because races between memory hotplug and soft offline are
very rare.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Chen, Gong <gong.chen@linux.intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index bf3351b..f9d78ec 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1422,19 +1422,6 @@ static int __get_any_page(struct page *p, unsigned long pfn, int flags)
        if (flags & MF_COUNT_INCREASED)
                return 1;
 
-       /*
-        * The lock_memory_hotplug prevents a race with memory hotplug.
-        * This is a big hammer, a better would be nicer.
-        */
-       lock_memory_hotplug();
-
-       /*
-        * Isolate the page, so that it doesn't get reallocated if it
-        * was free. This flag should be kept set until the source page
-        * is freed and PG_hwpoison on it is set.
-        */
-       if (get_pageblock_migratetype(p) != MIGRATE_ISOLATE)
-               set_migratetype_isolate(p, true);
        /*
         * When the target page is a free hugepage, just remove it
         * from free hugepage list.
@@ -1455,7 +1442,6 @@ static int __get_any_page(struct page *p, unsigned long pfn, int flags)
                /* Not a free page */
                ret = 1;
        }
-       unlock_memory_hotplug();
        return ret;
 }
 
@@ -1654,15 +1640,28 @@ int soft_offline_page(struct page *page, int flags)
                }
        }
 
+       /*
+        * The lock_memory_hotplug prevents a race with memory hotplug.
+        * This is a big hammer, a better would be nicer.
+        */
+       lock_memory_hotplug();
+
+       /*
+        * Isolate the page, so that it doesn't get reallocated if it
+        * was free. This flag should be kept set until the source page
+        * is freed and PG_hwpoison on it is set.
+        */
+       if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
+               set_migratetype_isolate(page, true);
+
        ret = get_any_page(page, pfn, flags);
-       if (ret < 0)
-               goto unset;
-       if (ret) { /* for in-use pages */
+       unlock_memory_hotplug();
+       if (ret > 0) { /* for in-use pages */
                if (PageHuge(page))
                        ret = soft_offline_huge_page(page, flags);
                else
                        ret = __soft_offline_page(page, flags);
-       } else { /* for free pages */
+       } else if (ret == 0) { /* for free pages */
                if (PageHuge(page)) {
                        set_page_hwpoison_huge_page(hpage);
                        dequeue_hwpoisoned_huge_page(hpage);
@@ -1673,7 +1672,6 @@ int soft_offline_page(struct page *page, int flags)
                        atomic_long_inc(&num_poisoned_pages);
                }
        }
-unset:
        unset_migratetype_isolate(page, MIGRATE_MOVABLE);
        return ret;
 }