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-rw-r--r--mm/page_alloc.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 4c847cc57caf..33b1a4762a7b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2836,7 +2836,8 @@ static void setup_zone_migrate_reserve(struct zone *zone)
{
unsigned long start_pfn, pfn, end_pfn;
struct page *page;
- unsigned long reserve, block_migratetype;
+ unsigned long block_migratetype;
+ int reserve;
/* Get the start pfn, end pfn and the number of blocks to reserve */
start_pfn = zone->zone_start_pfn;
@@ -2844,6 +2845,15 @@ static void setup_zone_migrate_reserve(struct zone *zone)
reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >>
pageblock_order;
+ /*
+ * Reserve blocks are generally in place to help high-order atomic
+ * allocations that are short-lived. A min_free_kbytes value that
+ * would result in more than 2 reserve blocks for atomic allocations
+ * is assumed to be in place to help anti-fragmentation for the
+ * future allocation of hugepages at runtime.
+ */
+ reserve = min(2, reserve);
+
for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
if (!pfn_valid(pfn))
continue;