From a7612150ff79e353e647224a1ea0ac617064726a Mon Sep 17 00:00:00 2001
From: Rick Yiu <rickyiu@google.com>
Date: Thu, 19 Dec 2019 16:57:22 +0800
Subject: [PATCH] Implement the ThreadPrioritySetter interface

Implement the ThreadPrioritySetter interface and register it in
runtime.

Bug: 139521784
Test: CtsLibcoreTestCases, device boot to home, thread priority set
      as expected.
Change-Id: Iee33a26c0b25386dd10a51a14284cab71e71edb2
---
 .../com/android/internal/os/RuntimeInit.java  | 31 +++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/core/java/com/android/internal/os/RuntimeInit.java b/core/java/com/android/internal/os/RuntimeInit.java
index fa823c4bf2f61..f14145b35db70 100644
--- a/core/java/com/android/internal/os/RuntimeInit.java
+++ b/core/java/com/android/internal/os/RuntimeInit.java
@@ -35,6 +35,7 @@ import com.android.internal.logging.AndroidConfig;
 import com.android.server.NetworkManagementSocketTagger;
 
 import dalvik.system.RuntimeHooks;
+import dalvik.system.ThreadPrioritySetter;
 import dalvik.system.VMRuntime;
 
 import libcore.content.type.MimeMap;
@@ -204,6 +205,7 @@ public class RuntimeInit {
      */
     public static void preForkInit() {
         if (DEBUG) Slog.d(TAG, "Entered preForkInit.");
+        RuntimeHooks.setThreadPrioritySetter(new RuntimeThreadPrioritySetter());
         RuntimeInit.enableDdms();
         // TODO(b/142019040#comment13): Decide whether to load the default instance eagerly, i.e.
         // MimeMap.setDefault(DefaultMimeMapFactory.create());
@@ -216,6 +218,35 @@ public class RuntimeInit {
         MimeMap.setDefaultSupplier(DefaultMimeMapFactory::create);
     }
 
+    private static class RuntimeThreadPrioritySetter implements ThreadPrioritySetter {
+        // Should remain consistent with kNiceValues[] in system/libartpalette/palette_android.cc
+        private static final int[] NICE_VALUES = {
+            Process.THREAD_PRIORITY_LOWEST,  // 1 (MIN_PRIORITY)
+            Process.THREAD_PRIORITY_BACKGROUND + 6,
+            Process.THREAD_PRIORITY_BACKGROUND + 3,
+            Process.THREAD_PRIORITY_BACKGROUND,
+            Process.THREAD_PRIORITY_DEFAULT,  // 5 (NORM_PRIORITY)
+            Process.THREAD_PRIORITY_DEFAULT - 2,
+            Process.THREAD_PRIORITY_DEFAULT - 4,
+            Process.THREAD_PRIORITY_URGENT_DISPLAY + 3,
+            Process.THREAD_PRIORITY_URGENT_DISPLAY + 2,
+            Process.THREAD_PRIORITY_URGENT_DISPLAY  // 10 (MAX_PRIORITY)
+        };
+
+        @Override
+        public void setPriority(int priority) {
+            // Check NICE_VALUES[] length first.
+            if (NICE_VALUES.length != (1 + Thread.MAX_PRIORITY - Thread.MIN_PRIORITY)) {
+                throw new AssertionError("Unexpected NICE_VALUES.length=" + NICE_VALUES.length);
+            }
+            // Priority should be in the range of MIN_PRIORITY (1) to MAX_PRIORITY (10).
+            if (priority < Thread.MIN_PRIORITY || priority > Thread.MAX_PRIORITY) {
+                throw new IllegalArgumentException("Priority out of range: " + priority);
+            }
+            Process.setThreadPriority(NICE_VALUES[priority - Thread.MIN_PRIORITY]);
+        }
+    }
+
     @UnsupportedAppUsage
     protected static final void commonInit() {
         if (DEBUG) Slog.d(TAG, "Entered RuntimeInit!");