1 files changed, 23 insertions, 17 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index cde5dac6229a..0b9f577b1a2a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2170,6 +2170,18 @@ static inline void boost_watermark(struct zone *zone)
 
         max_boost = mult_frac(zone->_watermark[WMARK_HIGH],
                         watermark_boost_factor, 10000);
+
+        /*
+         * high watermark may be uninitialised if fragmentation occurs
+         * very early in boot so do not boost. We do not fall
+         * through and boost by pageblock_nr_pages as failing
+         * allocations that early means that reclaim is not going
+         * to help and it may even be impossible to reclaim the
+         * boosted watermark resulting in a hang.
+         */
+        if (!max_boost)
+                return;
+
         max_boost = max(pageblock_nr_pages, max_boost);
 
         zone->watermark_boost = min(zone->watermark_boost + pageblock_nr_pages,
@@ -2214,7 +2226,7 @@ static void steal_suitable_fallback(struct zone *zone, struct page *page,
          */
         boost_watermark(zone);
         if (alloc_flags & ALLOC_KSWAPD)
-                wakeup_kswapd(zone, 0, 0, zone_idx(zone));
+                set_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
 
         /* We are not allowed to try stealing from the whole block */
         if (!whole_block)
@@ -3102,6 +3114,12 @@ struct page *rmqueue(struct zone *preferred_zone,
         local_irq_restore(flags);
 
 out:
+        /* Separate test+clear to avoid unnecessary atomics */
+        if (test_bit(ZONE_BOOSTED_WATERMARK, &zone->flags)) {
+                clear_bit(ZONE_BOOSTED_WATERMARK, &zone->flags);
+                wakeup_kswapd(zone, 0, 0, zone_idx(zone));
+        }
+
         VM_BUG_ON_PAGE(page && bad_range(zone, page), page);
         return page;
 
@@ -4669,11 +4687,11 @@ refill:
                 /* Even if we own the page, we do not use atomic_set().
                  * This would break get_page_unless_zero() users.
                  */
-                page_ref_add(page, size - 1);
+                page_ref_add(page, PAGE_FRAG_CACHE_MAX_SIZE);
 
                 /* reset page count bias and offset to start of new frag */
                 nc->pfmemalloc = page_is_pfmemalloc(page);
-                nc->pagecnt_bias = size;
+                nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
                 nc->offset = size;
         }
 
@@ -4689,10 +4707,10 @@ refill:
                 size = nc->size;
 #endif
                 /* OK, page count is 0, we can safely set it */
-                set_page_count(page, size);
+                set_page_count(page, PAGE_FRAG_CACHE_MAX_SIZE + 1);
 
                 /* reset page count bias and offset to start of new frag */
-                nc->pagecnt_bias = size;
+                nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1;
                 offset = size - fragsz;
         }
 
@@ -5695,18 +5713,6 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
                         cond_resched();
                 }
         }
-#ifdef CONFIG_SPARSEMEM
-        /*
-         * If the zone does not span the rest of the section then
-         * we should at least initialize those pages. Otherwise we
-         * could blow up on a poisoned page in some paths which depend
-         * on full sections being initialized (e.g. memory hotplug).
-         */
-        while (end_pfn % PAGES_PER_SECTION) {
-                __init_single_page(pfn_to_page(end_pfn), end_pfn, zone, nid);
-                end_pfn++;
-        }
-#endif
 }
 
 #ifdef CONFIG_ZONE_DEVICE