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我们有一个通过 JMX 监控的服务。JVM 堆使用量正在增长，甚至主要收集都无法删除垃圾。检查堆会显示由 RMI 相关引用组成的垃圾（如果不是全部，主要是相关的类加载器）。缓解此问题的唯一方法是通过 JMX 发出显式 gc 调用（删除所有累积的垃圾）。我们的 gc 相关选项是：

-XX:+UseParNewGC
-XX:+UseConcMarkSweepGC
-XX:+CMSParallelRemarkEnabled
-XX:SurvivorRatio=8
-XX:MaxTenuringThreshold=1
-XX:CMSInitiatingOccupancyFraction=75
-XX:+UseCMSInitiatingOccupancyOnly

而且我们还没有触及： DisableExplicitGC 或 sun.rmi.dgc.server.gcInterval

我相信这个问题应该由 sun.misc.GC.Daemon 中的代码解决：

public void run() {
        for (;;) {
            long l;
            synchronized (lock) {

                l = latencyTarget;
                if (l == NO_TARGET) {
                    /* No latency target, so exit */
                    GC.daemon = null;
                    return;
                }

                long d = maxObjectInspectionAge();
                if (d >= l) {
                    /* Do a full collection.  There is a remote possibility
                     * that a full collection will occurr between the time
                     * we sample the inspection age and the time the GC
                     * actually starts, but this is sufficiently unlikely
                     * that it doesn't seem worth the more expensive JVM
                     * interface that would be required.
                     */
                    System.gc();
                    d = 0;
                }

                /* Wait for the latency period to expire,
                 * or for notification that the period has changed
                 */
                try {
                    lock.wait(l - d);
                } catch (InterruptedException x) {
                    continue;
                }
            }
        }
    }

由于某种原因，上面的 System.gc 没有被调用（已经通过查看 gc 日志进行了验证）。有人对如何解决这个问题有建议吗？

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