Add Zygotehooks.indefiniteThreadSuspensionOK

Bug: 159631815
Bug: 174211442
Test: Boot AOSP with zygote that needs this
Change-Id: I5f0626a74e43c8b1ac69164ce64b625f0654a7e2

2 files changed, 17 insertions, 0 deletions

diff --git a/dalvik/src/main/java/dalvik/system/ZygoteHooks.java b/dalvik/src/main/java/dalvik/system/ZygoteHooks.java
index 7e8fe3651e..f05ea2cca6 100644
--- a/dalvik/src/main/java/dalvik/system/ZygoteHooks.java
+++ b/dalvik/src/main/java/dalvik/system/ZygoteHooks.java
@@ -153,6 +153,20 @@ public final class ZygoteHooks {
         Daemons.startPostZygoteFork();
     }
 
+    /**
+     * Is it safe to keep all ART daemon threads stopped indefinitely in the zygote?
+     * The answer may change from false to true dynamically, but not in the other
+     * direction.
+     */
+    @libcore.api.CorePlatformApi
+    public static boolean indefiniteThreadSuspensionOK() {
+        // TODO: Make this return true if we're done with JIT compilation.
+        //
+        // We only care about JIT compilation that affects other processes.
+        // The zygote itself doesn't run appreciable amounts of Java code when
+        // running single-threaded.
+        return !nativeZygoteJitEnabled();
+    }
 
     // Hook for SystemServer specific early initialization post-forking.
     private static native void nativePostForkSystemServer(int runtimeFlags);
@@ -165,6 +179,8 @@ public final class ZygoteHooks {
                                                    boolean isSystemServer, boolean isZygote,
                                                    String instructionSet);
 
+    private static native boolean nativeZygoteJitEnabled();
+
     /**
      * We must not fork until we're single-threaded again. Wait until /proc shows we're
      * down to just one thread.
diff --git a/mmodules/core_platform_api/api/platform/current-api.txt b/mmodules/core_platform_api/api/platform/current-api.txt
index 15a0a48d8c..104e479171 100644
--- a/mmodules/core_platform_api/api/platform/current-api.txt
+++ b/mmodules/core_platform_api/api/platform/current-api.txt
@@ -745,6 +745,7 @@ package dalvik.system {
 
   public final class ZygoteHooks {
     method public static void gcAndFinalize();
+    method public static boolean indefiniteThreadSuspensionOK();
     method public static void onBeginPreload();
     method public static void onEndPreload();
     method public static void postForkChild(int, boolean, boolean, String);