# HG changeset patch # User shade # Date 1544715924 -3600 # Thu Dec 13 16:45:24 2018 +0100 # Node ID a9fbf30c7b36109a8d10c5cab8b66256caa65d44 # Parent 3e04374c6b3bb3bc9216cd4e45279057c5b29289 8181143: Introduce diagnostic flag to abort VM on too long VM operations Reviewed-by: rkennke, zgu, dholmes, stuefe, rehn diff --git a/src/hotspot/share/runtime/globals.hpp b/src/hotspot/share/runtime/globals.hpp --- a/src/hotspot/share/runtime/globals.hpp +++ b/src/hotspot/share/runtime/globals.hpp @@ -513,6 +513,13 @@ diagnostic(bool, AbortVMOnSafepointTimeout, false, \ "Abort upon failure to reach safepoint (see SafepointTimeout)") \ \ + diagnostic(bool, AbortVMOnVMOperationTimeout, false, \ + "Abort upon failure to complete VM operation promptly") \ + \ + diagnostic(intx, AbortVMOnVMOperationTimeoutDelay, 1000, \ + "Delay in milliseconds for option AbortVMOnVMOperationTimeout") \ + range(0, max_intx) \ + \ /* 50 retries * (5 * current_retry_count) millis = ~6.375 seconds */ \ /* typically, at most a few retries are needed */ \ product(intx, SuspendRetryCount, 50, \ diff --git a/src/hotspot/share/runtime/vmThread.cpp b/src/hotspot/share/runtime/vmThread.cpp --- a/src/hotspot/share/runtime/vmThread.cpp +++ b/src/hotspot/share/runtime/vmThread.cpp @@ -28,6 +28,7 @@ #include "jfr/jfrEvents.hpp" #include "jfr/support/jfrThreadId.hpp" #include "logging/log.hpp" +#include "logging/logStream.hpp" #include "logging/logConfiguration.hpp" #include "memory/resourceArea.hpp" #include "oops/method.hpp" @@ -197,6 +198,32 @@ drain_list_oops_do(f); } +//------------------------------------------------------------------------------------------------------------------ +// Timeout machinery + +void VMOperationTimeoutTask::task() { + assert(AbortVMOnVMOperationTimeout, "only if enabled"); + if (is_armed()) { + jlong delay = (os::javaTimeMillis() - _arm_time); + if (delay > AbortVMOnVMOperationTimeoutDelay) { + fatal("VM operation took too long: " SIZE_FORMAT " ms (timeout: " SIZE_FORMAT " ms)", + delay, AbortVMOnVMOperationTimeoutDelay); + } + } +} + +bool VMOperationTimeoutTask::is_armed() { + return OrderAccess::load_acquire(&_armed) != 0; +} + +void VMOperationTimeoutTask::arm() { + _arm_time = os::javaTimeMillis(); + OrderAccess::release_store_fence(&_armed, 1); +} + +void VMOperationTimeoutTask::disarm() { + OrderAccess::release_store_fence(&_armed, 0); +} //------------------------------------------------------------------------------------------------------------------ // Implementation of VMThread stuff @@ -209,12 +236,28 @@ VMOperationQueue* VMThread::_vm_queue = NULL; PerfCounter* VMThread::_perf_accumulated_vm_operation_time = NULL; const char* VMThread::_no_op_reason = NULL; +VMOperationTimeoutTask* VMThread::_timeout_task = NULL; void VMThread::create() { assert(vm_thread() == NULL, "we can only allocate one VMThread"); _vm_thread = new VMThread(); + if (AbortVMOnVMOperationTimeout) { + // Make sure we call the timeout task frequently enough, but not too frequent. + // Try to make the interval 10% of the timeout delay, so that we miss the timeout + // by those 10% at max. Periodic task also expects it to fit min/max intervals. + size_t interval = (size_t)AbortVMOnVMOperationTimeoutDelay / 10; + interval = interval / PeriodicTask::interval_gran * PeriodicTask::interval_gran; + interval = MAX2(interval, PeriodicTask::min_interval); + interval = MIN2(interval, PeriodicTask::max_interval); + + _timeout_task = new VMOperationTimeoutTask(interval); + _timeout_task->enroll(); + } else { + assert(_timeout_task == NULL, "sanity"); + } + // Create VM operation queue _vm_queue = new VMOperationQueue(); guarantee(_vm_queue != NULL, "just checking"); @@ -497,6 +540,11 @@ _vm_queue->set_drain_list(safepoint_ops); // ensure ops can be scanned SafepointSynchronize::begin(); + + if (_timeout_task != NULL) { + _timeout_task->arm(); + } + evaluate_operation(_cur_vm_operation); // now process all queued safepoint ops, iteratively draining // the queue until there are none left @@ -538,6 +586,10 @@ _vm_queue->set_drain_list(NULL); + if (_timeout_task != NULL) { + _timeout_task->disarm(); + } + // Complete safepoint synchronization SafepointSynchronize::end(); diff --git a/src/hotspot/share/runtime/vmThread.hpp b/src/hotspot/share/runtime/vmThread.hpp --- a/src/hotspot/share/runtime/vmThread.hpp +++ b/src/hotspot/share/runtime/vmThread.hpp @@ -27,6 +27,7 @@ #include "runtime/perfData.hpp" #include "runtime/thread.hpp" +#include "runtime/task.hpp" #include "runtime/vm_operations.hpp" // @@ -84,6 +85,26 @@ }; +// VM operation timeout handling: warn or abort the VM when VM operation takes +// too long. Periodic tasks do not participate in safepoint protocol, and therefore +// can fire when application threads are stopped. + +class VMOperationTimeoutTask : public PeriodicTask { +private: + volatile int _armed; + jlong _arm_time; + +public: + VMOperationTimeoutTask(size_t interval_time) : + PeriodicTask(interval_time), _armed(0), _arm_time(0) {} + + virtual void task(); + + bool is_armed(); + void arm(); + void disarm(); +}; + // // A single VMThread (the primordial thread) spawns all other threads // and is itself used by other threads to offload heavy vm operations @@ -101,6 +122,8 @@ static const char* _no_op_reason; + static VMOperationTimeoutTask* _timeout_task; + static bool no_op_safepoint_needed(bool check_time); void evaluate_operation(VM_Operation* op); diff --git a/test/hotspot/jtreg/runtime/Safepoint/TestAbortOnVMOperationTimeout.java b/test/hotspot/jtreg/runtime/Safepoint/TestAbortOnVMOperationTimeout.java new file mode 100644 --- /dev/null +++ b/test/hotspot/jtreg/runtime/Safepoint/TestAbortOnVMOperationTimeout.java @@ -0,0 +1,81 @@ +/* + * Copyright (c) 2018, Red Hat, Inc. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + */ + +import jdk.test.lib.*; +import jdk.test.lib.process.*; + +/* + * @test TestAbortOnVMOperationTimeout + * @bug 8181143 + * @summary Check abort on VM timeout is working + * @library /test/lib + * @modules java.base/jdk.internal.misc + * java.management + */ + +public class TestAbortOnVMOperationTimeout { + + public static void main(String[] args) throws Exception { + if (args.length > 0) { + Object[] arr = new Object[10_000_000]; + for (int i = 0; i < arr.length; i++) { + arr[i] = new Object(); + } + return; + } + + // These should definitely pass: more than a minute is enough for Serial to act. + // The values are deliberately non-round to trip off periodic task granularity. + for (int delay : new int[]{63423, 12388131}) { + testWith(delay, true); + } + + // These should fail: Serial is not very fast. Traversing 10M objects in 5 ms + // means less than 0.5 ns per object, which is not doable. + for (int delay : new int[]{0, 1, 5}) { + testWith(delay, false); + } + } + + public static void testWith(int delay, boolean shouldPass) throws Exception { + ProcessBuilder pb = ProcessTools.createJavaProcessBuilder( + "-XX:+UnlockDiagnosticVMOptions", + "-XX:+AbortVMOnVMOperationTimeout", + "-XX:AbortVMOnVMOperationTimeoutDelay=" + delay, + "-Xmx256m", + "-XX:+UseSerialGC", + "-XX:-CreateCoredumpOnCrash", + "TestAbortOnVMOperationTimeout", + "foo" + ); + + OutputAnalyzer output = new OutputAnalyzer(pb.start()); + if (shouldPass) { + output.shouldHaveExitValue(0); + } else { + output.shouldMatch("VM operation took too long"); + output.shouldNotHaveExitValue(0); + } + } +} +