Change return type to int

Author: kkHAIKE

arthas-vmtool/src/main/java/arthas/VmTool.java

@@ -117,9 +117,9 @@ public Class<?>[] getAllLoadedClasses() {
     }
 
     @Override
-    public boolean mallocTrim() {
+    public int mallocTrim() {
         return mallocTrim0();
     }
 
-    private static synchronized native boolean mallocTrim0();
+    private static synchronized native int mallocTrim0();
 }

arthas-vmtool/src/main/java/arthas/VmToolMXBean.java

@@ -61,5 +61,5 @@ public interface VmToolMXBean {
     /**
      * glibc 释放空闲内存
      */
-    public boolean mallocTrim();
+    public int mallocTrim();
 }

arthas-vmtool/src/main/native/src/jni-library.cpp

@@ -210,12 +210,10 @@ JNIEXPORT jobjectArray JNICALL Java_arthas_VmTool_getAllLoadedClasses0
 }
 
 extern "C"
-JNIEXPORT jboolean JNICALL Java_arthas_VmTool_mallocTrim0
+JNIEXPORT jint JNICALL Java_arthas_VmTool_mallocTrim0
         (JNIEnv *env, jclass thisClass) {
 #ifdef __GLIBC__
-    if (!::malloc_trim(0)) {
-        return JNI_FALSE;
-    }
+    return ::malloc_trim(0);
 #endif
-    return JNI_TRUE;
+    return -1;
 }

core/src/main/java/com/taobao/arthas/core/command/monitor200/VmToolCommand.java

@@ -241,9 +241,10 @@ public void process(final CommandProcess process) {
 
                 return;
             } else if (VmToolAction.mallocTrim.equals(action)) {
-                boolean result = vmToolInstance().mallocTrim();
+                int result = vmToolInstance().mallocTrim();
                 process.write("\n");
-                process.end(result ? 0 : -1, "mallocTrim result: " + result);
+                process.end(result == 1 ? 0 : -1, "mallocTrim result: " +
+                    (result == 1 ? "true" : (result == 0 ? "false" : "not supported")));
                 return;
             }