Parcel implicit ashmem copies of bitmaps as immutable

Bug: 400807118
Flag: com.android.graphics.hwui.flags.bitmap_parcel_ashmem_as_immutable
Change-Id: I8b82c78bb13ca70f2ead8eb0f8ba2438db12dca0

2 files changed, 35 insertions, 1 deletions

diff --git a/libs/hwui/aconfig/hwui_flags.aconfig b/libs/hwui/aconfig/hwui_flags.aconfig
index d3fc91b65829..b3badd0bd51d 100644
--- a/libs/hwui/aconfig/hwui_flags.aconfig
+++ b/libs/hwui/aconfig/hwui_flags.aconfig
@@ -203,4 +203,11 @@ flag {
   description: "Initialize GraphicBufferAllocater on ViewRootImpl init, to avoid blocking on init during buffer allocation, improving app launch latency."
   bug: "389908734"
   is_fixed_read_only: true
+}
+
+flag {
+  name: "bitmap_parcel_ashmem_as_immutable"
+  namespace: "system_performance"
+  description: "Whether to parcel implicit copies of bitmaps to ashmem as immutable"
+  bug: "400807118"
 }
\ No newline at end of file
diff --git a/libs/hwui/jni/Bitmap.cpp b/libs/hwui/jni/Bitmap.cpp
index 27d4ac7cef4b..104ece6582f5 100644
--- a/libs/hwui/jni/Bitmap.cpp
+++ b/libs/hwui/jni/Bitmap.cpp
@@ -28,8 +28,18 @@
 #include "SkRefCnt.h"
 #include "SkStream.h"
 #include "SkTypes.h"
+#include "android/binder_parcel.h"
 #include "android_nio_utils.h"
 
+#ifdef __ANDROID__
+#include <com_android_graphics_hwui_flags.h>
+namespace hwui_flags = com::android::graphics::hwui::flags;
+#else
+namespace hwui_flags {
+constexpr bool bitmap_parcel_ashmem_as_immutable() { return false; }
+}
+#endif
+
 #define DEBUG_PARCEL 0
 
 static jclass   gBitmap_class;
@@ -841,6 +851,23 @@ static jobject Bitmap_createFromParcel(JNIEnv* env, jobject, jobject parcel) {
 #endif
 }
 
+// Returns whether this bitmap should be written to the parcel as mutable.
+static bool shouldParcelAsMutable(SkBitmap& bitmap, AParcel* parcel) {
+    // If the bitmap is immutable, then parcel as immutable.
+    if (bitmap.isImmutable()) {
+        return false;
+    }
+
+    if (!hwui_flags::bitmap_parcel_ashmem_as_immutable()) {
+        return true;
+    }
+
+    // If we're going to copy the bitmap to ashmem and write that to the parcel,
+    // then parcel as immutable, since we won't be mutating the bitmap after
+    // writing it to the parcel.
+    return !shouldUseAshmem(parcel, bitmap.computeByteSize());
+}
+
 static jboolean Bitmap_writeToParcel(JNIEnv* env, jobject, jlong bitmapHandle, jint density,
                                      jobject parcel) {
 #ifdef __linux__ // Only Linux support parcel
@@ -855,7 +882,7 @@ static jboolean Bitmap_writeToParcel(JNIEnv* env, jobject, jlong bitmapHandle, j
     auto bitmapWrapper = reinterpret_cast<BitmapWrapper*>(bitmapHandle);
     bitmapWrapper->getSkBitmap(&bitmap);
 
-    p.writeInt32(!bitmap.isImmutable());
+    p.writeInt32(shouldParcelAsMutable(bitmap, p.get()));
     p.writeInt32(bitmap.colorType());
     p.writeInt32(bitmap.alphaType());
     SkColorSpace* colorSpace = bitmap.colorSpace();