btrfs: ensure that a DUP or RAID1 block group has exactly two stripes

[linux-2.6-block.git] / mm / page_alloc.c

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 35fdde041f5c1ed50cf1c14a8ffdafeeced3475c..0b9f577b1a2aee9f2b959f2d717e936802cbfc75 100644 (file)
--- 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,
@@ -4675,11 +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;
        }
 
@@ -4695,10 +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;
        }