1 files changed, 11 insertions, 2 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 81e18ceef579..3d974cb2a1a1 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -46,6 +46,7 @@
 #include <linux/stop_machine.h>
 #include <linux/sort.h>
 #include <linux/pfn.h>
+#include <xen/xen.h>
 #include <linux/backing-dev.h>
 #include <linux/fault-inject.h>
 #include <linux/page-isolation.h>
@@ -347,6 +348,9 @@ static inline bool update_defer_init(pg_data_t *pgdat,
         /* Always populate low zones for address-constrained allocations */
         if (zone_end < pgdat_end_pfn(pgdat))
                 return true;
+        /* Xen PV domains need page structures early */
+        if (xen_pv_domain())
+                return true;
         (*nr_initialised)++;
         if ((*nr_initialised > pgdat->static_init_pgcnt) &&
             (pfn & (PAGES_PER_SECTION - 1)) == 0) {
@@ -5355,9 +5359,14 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
                         /*
                          * Skip to the pfn preceding the next valid one (or
                          * end_pfn), such that we hit a valid pfn (or end_pfn)
-                         * on our next iteration of the loop.
+                         * on our next iteration of the loop. Note that it needs
+                         * to be pageblock aligned even when the region itself
+                         * is not. move_freepages_block() can shift ahead of
+                         * the valid region but still depends on correct page
+                         * metadata.
                          */
-                        pfn = memblock_next_valid_pfn(pfn, end_pfn) - 1;
+                        pfn = (memblock_next_valid_pfn(pfn, end_pfn) &
+                                        ~(pageblock_nr_pages-1)) - 1;
 #endif
                         continue;
                 }