--- 9e0826ea7bbe759dfb2356d13bdfb038cc3e0869
+++ c4a5bfef1848b97ca2668d09d58d4e42ff22831c
@@ -454,8 +454,8 @@ out:
 }
 EXPORT_SYMBOL(add_to_page_cache_locked);
 
-int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
-				pgoff_t offset, gfp_t gfp_mask)
+int __add_to_page_cache_lru(struct page *page, struct address_space *mapping,
+				pgoff_t offset, gfp_t gfp_mask, int tail)
 {
 	int ret;
 
@@ -471,12 +471,19 @@ int add_to_page_cache_lru(struct page *p
 	ret = add_to_page_cache(page, mapping, offset, gfp_mask);
 	if (ret == 0) {
 		if (page_is_file_cache(page))
-			lru_cache_add_file(page);
+			lru_cache_add_file(page, tail);
 		else
 			lru_cache_add_anon(page);
 	}
 	return ret;
 }
+
+int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
+				pgoff_t offset, gfp_t gfp_mask)
+{
+	return __add_to_page_cache_lru(page, mapping, offset, gfp_mask, 0);
+}
+
 EXPORT_SYMBOL_GPL(add_to_page_cache_lru);
 
 #ifdef CONFIG_NUMA
@@ -970,6 +977,28 @@ static void shrink_readahead_size_eio(st
 	ra->ra_pages /= 4;
 }
 
+static inline int nr_mapped(void)
+{
+	return global_page_state(NR_FILE_MAPPED) +
+		global_page_state(NR_ANON_PAGES);
+}
+
+/*
+ * This examines how large in pages a file size is and returns 1 if it is
+ * more than half the unmapped ram. Avoid doing read_page_state which is
+ * expensive unless we already know it is likely to be large enough.
+ */
+static int large_isize(unsigned long nr_pages)
+{
+	if (nr_pages * 6 > vm_total_pages) {
+		 unsigned long unmapped_ram = vm_total_pages - nr_mapped();
+
+		if (nr_pages * 2 > unmapped_ram)
+			return 1;
+	}
+	return 0;
+}
+
 /**
  * do_generic_file_read - generic file read routine
  * @filp:	the file to read
@@ -994,7 +1023,7 @@ static void do_generic_file_read(struct
 	pgoff_t prev_index;
 	unsigned long offset;      /* offset into pagecache page */
 	unsigned int prev_offset;
-	int error;
+	int error, tail = 0;
 
 	index = *ppos >> PAGE_CACHE_SHIFT;
 	prev_index = ra->prev_pos >> PAGE_CACHE_SHIFT;
@@ -1005,7 +1034,7 @@ static void do_generic_file_read(struct
 	for (;;) {
 		struct page *page;
 		pgoff_t end_index;
-		loff_t isize;
+		loff_t isize = 0;
 		unsigned long nr, ret;
 
 		cond_resched();
@@ -1179,8 +1208,16 @@ no_cached_page:
 			desc->error = -ENOMEM;
 			goto out;
 		}
-		error = add_to_page_cache_lru(page, mapping,
-						index, GFP_KERNEL);
+		/*
+		 * If we know the file is large we add the pages read to the
+		 * end of the lru as we're unlikely to be able to cache the
+		 * whole file in ram so make those pages the first to be
+		 * dropped if not referenced soon.
+		 */
+		if (large_isize(end_index))
+			tail = 1;
+		error = __add_to_page_cache_lru(page, mapping,
+						index, GFP_KERNEL, tail);
 		if (error) {
 			page_cache_release(page);
 			if (error == -EEXIST)