gpu: ion: Modify gfp flags in ion_system_heap

When allocations larger than order 4 are made, use _GFP_NORETRY
and __GFP_NO_KSWAPD so kswapd doesn't get kicked off to reclaim
these larger chunks.  For smaller allocaitons, these are
unnecessary, as the system should be able to reclaim these.
Signed-off-by: Rebecca Schultz Zavin <rebecca@android.com>
[jstultz: modified patch to apply to staging directory]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/android/ion/ion_system_heap.c

@@ -26,6 +26,11 @@
 #include "ion.h"
 #include "ion_priv.h"
 
+static unsigned int high_order_gfp_flags = (GFP_HIGHUSER | __GFP_ZERO |
+					    __GFP_NOWARN | __GFP_NORETRY |
+					    __GFP_NO_KSWAPD);
+static unsigned int low_order_gfp_flags  = (GFP_HIGHUSER | __GFP_ZERO |
+					 __GFP_NOWARN);
 static const unsigned int orders[] = {8, 4, 0};
 static const int num_orders = ARRAY_SIZE(orders);
 static int order_to_index(unsigned int order)
@@ -63,11 +68,15 @@ static struct page *alloc_buffer_page(struct ion_system_heap *heap,
 	struct ion_page_pool *pool = heap->pools[order_to_index(order)];
 	struct page *page;
 
-	if (!cached)
+	if (!cached) {
 		page = ion_page_pool_alloc(pool);
-	else
-		page = alloc_pages(GFP_HIGHUSER | __GFP_ZERO |
-				   __GFP_NOWARN | __GFP_NORETRY, order);
+	} else {
+		gfp_t gfp_flags = low_order_gfp_flags;
+
+		if (order > 4)
+			gfp_flags = high_order_gfp_flags;
+		page = alloc_pages(gfp_flags, order);
+	}
 	if (!page)
 		return 0;
 	if (split_pages)
@@ -342,9 +351,11 @@ struct ion_heap *ion_system_heap_create(struct ion_platform_heap *unused)
 		goto err_alloc_pools;
 	for (i = 0; i < num_orders; i++) {
 		struct ion_page_pool *pool;
-		pool = ion_page_pool_create(GFP_HIGHUSER | __GFP_ZERO |
-					   __GFP_NOWARN | __GFP_NORETRY,
-					   orders[i]);
+		gfp_t gfp_flags = low_order_gfp_flags;
+
+		if (orders[i] > 4)
+			gfp_flags = high_order_gfp_flags;
+		pool = ion_page_pool_create(gfp_flags, orders[i]);
 		if (!pool)
 			goto err_create_pool;
 		heap->pools[i] = pool;