ion: move shrinker out of heaps

Every heap that uses deferred frees is going to need a shrinker
to shrink the freelist under memory pressure.  Rather than
requiring each heap to implement a shrinker, automatically
register a shrinker if the deferred free flag is set.
The system heap also needs to shrink its page pools, so add
a shrink function to the heap ops that will be called after
shrinking the freelists.

Change-Id: Icda722d683426fadb8ddd1c8e9499264ab682c57
Signed-off-by: Colin Cross <ccross@android.com>

1 files changed, 17 insertions, 47 deletions

diff --git a/drivers/staging/android/ion/ion_system_heap.c b/drivers/staging/android/ion/ion_system_heap.c
index 5bccf9e2c93..4a87fcf5326 100644
--- a/drivers/staging/android/ion/ion_system_heap.c
+++ b/drivers/staging/android/ion/ion_system_heap.c
@@ -227,60 +227,34 @@ static void ion_system_heap_unmap_dma(struct ion_heap *heap,
 	return;
 }
 
-static struct ion_heap_ops system_heap_ops = {
-	.allocate = ion_system_heap_allocate,
-	.free = ion_system_heap_free,
-	.map_dma = ion_system_heap_map_dma,
-	.unmap_dma = ion_system_heap_unmap_dma,
-	.map_kernel = ion_heap_map_kernel,
-	.unmap_kernel = ion_heap_unmap_kernel,
-	.map_user = ion_heap_map_user,
-};
-
-static int ion_system_heap_shrink(struct shrinker *shrinker,
-				  struct shrink_control *sc) {
-
-	struct ion_heap *heap = container_of(shrinker, struct ion_heap,
-					     shrinker);
-	struct ion_system_heap *sys_heap = container_of(heap,
-							struct ion_system_heap,
-							heap);
+static int ion_system_heap_shrink(struct ion_heap *heap, gfp_t gfp_mask,
+					int nr_to_scan)
+{
+	struct ion_system_heap *sys_heap;
 	int nr_total = 0;
-	int nr_freed = 0;
 	int i;
 
-	if (sc->nr_to_scan == 0)
-		goto end;
-
-	/* shrink the free list first, no point in zeroing the memory if
-	   we're just going to reclaim it */
-	nr_freed += ion_heap_freelist_drain(heap, sc->nr_to_scan * PAGE_SIZE) /
-		PAGE_SIZE;
-
-	if (nr_freed >= sc->nr_to_scan)
-		goto end;
+	sys_heap = container_of(heap, struct ion_system_heap, heap);
 
 	for (i = 0; i < num_orders; i++) {
 		struct ion_page_pool *pool = sys_heap->pools[i];
-
-		nr_freed += ion_page_pool_shrink(pool, sc->gfp_mask,
-						 sc->nr_to_scan);
-		if (nr_freed >= sc->nr_to_scan)
-			break;
+		nr_total += ion_page_pool_shrink(pool, gfp_mask, nr_to_scan);
 	}
 
-end:
-	/* total number of items is whatever the page pools are holding
-	   plus whatever's in the freelist */
-	for (i = 0; i < num_orders; i++) {
-		struct ion_page_pool *pool = sys_heap->pools[i];
-		nr_total += ion_page_pool_shrink(pool, sc->gfp_mask, 0);
-	}
-	nr_total += ion_heap_freelist_size(heap) / PAGE_SIZE;
 	return nr_total;
-
 }
 
+static struct ion_heap_ops system_heap_ops = {
+	.allocate = ion_system_heap_allocate,
+	.free = ion_system_heap_free,
+	.map_dma = ion_system_heap_map_dma,
+	.unmap_dma = ion_system_heap_unmap_dma,
+	.map_kernel = ion_heap_map_kernel,
+	.unmap_kernel = ion_heap_unmap_kernel,
+	.map_user = ion_heap_map_user,
+	.shrink = ion_system_heap_shrink,
+};
+
 static int ion_system_heap_debug_show(struct ion_heap *heap, struct seq_file *s,
 				      void *unused)
 {
@@ -328,10 +302,6 @@ struct ion_heap *ion_system_heap_create(struct ion_platform_heap *unused)
 		heap->pools[i] = pool;
 	}
 
-	heap->heap.shrinker.shrink = ion_system_heap_shrink;
-	heap->heap.shrinker.seeks = DEFAULT_SEEKS;
-	heap->heap.shrinker.batch = 0;
-	register_shrinker(&heap->heap.shrinker);
 	heap->heap.debug_show = ion_system_heap_debug_show;
 	return &heap->heap;
 err_create_pool: