From ab45cf3da3ec9305c348e2d097483dc83cf9fda2 Mon Sep 17 00:00:00 2001
From: John Reck <jreck@google.com>
Date: Tue, 19 Oct 2021 11:35:14 -0400
Subject: [PATCH] Fix SurfaceTexture listener performance

Attaching & detaching threads from JavaVM isn't cheap. There's
no reason to do a detach anyway, so just don't. This avoids
subsequent callbacks needing to re-attach.

This aligns SurfaceTexture to the common pattern elsewhere
in the platform for attaching as a daemon if it's not a java
thread.

Fixes: 26842782
Test: make
Change-Id: I9bebe288dc8896c1f2c47cc1b02409526926cef7
---
 core/jni/android_graphics_SurfaceTexture.cpp | 29 ++++----------------
 1 file changed, 5 insertions(+), 24 deletions(-)

diff --git a/core/jni/android_graphics_SurfaceTexture.cpp b/core/jni/android_graphics_SurfaceTexture.cpp
index 0909ce7ff23b1..2f12289621607 100644
--- a/core/jni/android_graphics_SurfaceTexture.cpp
+++ b/core/jni/android_graphics_SurfaceTexture.cpp
@@ -147,8 +147,7 @@ public:
     virtual void onFrameAvailable(const BufferItem& item);
 
 private:
-    static JNIEnv* getJNIEnv(bool* needsDetach);
-    static void detachJNI();
+    static JNIEnv* getJNIEnv();
 
     jobject mWeakThiz;
     jclass mClazz;
@@ -160,58 +159,40 @@ JNISurfaceTextureContext::JNISurfaceTextureContext(JNIEnv* env,
     mClazz((jclass)env->NewGlobalRef(clazz))
 {}
 
-JNIEnv* JNISurfaceTextureContext::getJNIEnv(bool* needsDetach) {
-    *needsDetach = false;
+JNIEnv* JNISurfaceTextureContext::getJNIEnv() {
     JNIEnv* env = AndroidRuntime::getJNIEnv();
     if (env == NULL) {
         JavaVMAttachArgs args = {
             JNI_VERSION_1_4, "JNISurfaceTextureContext", NULL };
         JavaVM* vm = AndroidRuntime::getJavaVM();
-        int result = vm->AttachCurrentThread(&env, (void*) &args);
+        int result = vm->AttachCurrentThreadAsDaemon(&env, (void*)&args);
         if (result != JNI_OK) {
             ALOGE("thread attach failed: %#x", result);
             return NULL;
         }
-        *needsDetach = true;
     }
     return env;
 }
 
-void JNISurfaceTextureContext::detachJNI() {
-    JavaVM* vm = AndroidRuntime::getJavaVM();
-    int result = vm->DetachCurrentThread();
-    if (result != JNI_OK) {
-        ALOGE("thread detach failed: %#x", result);
-    }
-}
-
 JNISurfaceTextureContext::~JNISurfaceTextureContext()
 {
-    bool needsDetach = false;
-    JNIEnv* env = getJNIEnv(&needsDetach);
+    JNIEnv* env = getJNIEnv();
     if (env != NULL) {
         env->DeleteGlobalRef(mWeakThiz);
         env->DeleteGlobalRef(mClazz);
     } else {
         ALOGW("leaking JNI object references");
     }
-    if (needsDetach) {
-        detachJNI();
-    }
 }
 
 void JNISurfaceTextureContext::onFrameAvailable(const BufferItem& /* item */)
 {
-    bool needsDetach = false;
-    JNIEnv* env = getJNIEnv(&needsDetach);
+    JNIEnv* env = getJNIEnv();
     if (env != NULL) {
         env->CallStaticVoidMethod(mClazz, fields.postEvent, mWeakThiz);
     } else {
         ALOGW("onFrameAvailable event will not posted");
     }
-    if (needsDetach) {
-        detachJNI();
-    }
 }
 
 // ----------------------------------------------------------------------------