8148507: [JVMCI] mitigate deadlocks related to JVMCI compiler under -Xbatch
Reviewed-by: twisti, dholmes
--- a/hotspot/src/share/vm/compiler/compileBroker.cpp Mon Feb 08 18:52:03 2016 +0100
+++ b/hotspot/src/share/vm/compiler/compileBroker.cpp Mon Feb 08 18:52:03 2016 +0100
@@ -545,7 +545,7 @@
c1_count = JVMCIHostThreads;
}
- if (!UseInterpreter) {
+ if (!UseInterpreter || !BackgroundCompilation) {
// Force initialization of JVMCI compiler otherwise JVMCI
// compilations will not block until JVMCI is initialized
ResourceMark rm;
@@ -1346,49 +1346,55 @@
}
#if INCLUDE_JVMCI
-// The number of milliseconds to wait before checking if the
-// JVMCI compiler thread is blocked.
-static const long BLOCKING_JVMCI_COMPILATION_WAIT_TIMESLICE = 500;
+// The number of milliseconds to wait before checking if
+// JVMCI compilation has made progress.
+static const long JVMCI_COMPILATION_PROGRESS_WAIT_TIMESLICE = 500;
-// The number of successive times the above check is allowed to
-// see a blocked JVMCI compiler thread before unblocking the
-// thread waiting for the compilation to finish.
-static const int BLOCKING_JVMCI_COMPILATION_WAIT_TO_UNBLOCK_ATTEMPTS = 5;
+// The number of JVMCI compilation progress checks that must fail
+// before unblocking a thread waiting for a blocking compilation.
+static const int JVMCI_COMPILATION_PROGRESS_WAIT_ATTEMPTS = 5;
/**
* Waits for a JVMCI compiler to complete a given task. This thread
- * waits until either the task completes or it sees the JVMCI compiler
- * thread is blocked for N consecutive milliseconds where N is
- * BLOCKING_JVMCI_COMPILATION_WAIT_TIMESLICE *
- * BLOCKING_JVMCI_COMPILATION_WAIT_TO_UNBLOCK_ATTEMPTS.
+ * waits until either the task completes or it sees no JVMCI compilation
+ * progress for N consecutive milliseconds where N is
+ * JVMCI_COMPILATION_PROGRESS_WAIT_TIMESLICE *
+ * JVMCI_COMPILATION_PROGRESS_WAIT_ATTEMPTS.
*
* @return true if this thread needs to free/recycle the task
*/
-bool CompileBroker::wait_for_jvmci_completion(CompileTask* task, JavaThread* thread) {
+bool CompileBroker::wait_for_jvmci_completion(JVMCICompiler* jvmci, CompileTask* task, JavaThread* thread) {
MutexLocker waiter(task->lock(), thread);
- int consecutively_blocked = 0;
- while (task->lock()->wait(!Mutex::_no_safepoint_check_flag, BLOCKING_JVMCI_COMPILATION_WAIT_TIMESLICE)) {
+ int progress_wait_attempts = 0;
+ int methods_compiled = jvmci->methods_compiled();
+ while (!task->is_complete() && !is_compilation_disabled_forever() &&
+ task->lock()->wait(!Mutex::_no_safepoint_check_flag, JVMCI_COMPILATION_PROGRESS_WAIT_TIMESLICE)) {
CompilerThread* jvmci_compiler_thread = task->jvmci_compiler_thread();
+
+ bool progress;
if (jvmci_compiler_thread != NULL) {
- JavaThreadState state;
- {
- // A JVMCI compiler thread should not disappear at this point
- // but let's be extra safe.
- MutexLocker mu(Threads_lock, thread);
- state = jvmci_compiler_thread->thread_state();
- }
- if (state == _thread_blocked) {
- if (++consecutively_blocked == BLOCKING_JVMCI_COMPILATION_WAIT_TO_UNBLOCK_ATTEMPTS) {
- if (PrintCompilation) {
- task->print(tty, "wait for blocking compilation timed out");
- }
- break;
+ // If the JVMCI compiler thread is not blocked, we deem it to be making progress.
+ progress = jvmci_compiler_thread->thread_state() != _thread_blocked;
+ } else {
+ // Still waiting on JVMCI compiler queue. This thread may be holding a lock
+ // that all JVMCI compiler threads are blocked on. We use the counter for
+ // successful JVMCI compilations to determine whether JVMCI compilation
+ // is still making progress through the JVMCI compiler queue.
+ progress = jvmci->methods_compiled() != methods_compiled;
+ }
+
+ if (!progress) {
+ if (++progress_wait_attempts == JVMCI_COMPILATION_PROGRESS_WAIT_ATTEMPTS) {
+ if (PrintCompilation) {
+ task->print(tty, "wait for blocking compilation timed out");
}
- } else {
- consecutively_blocked = 0;
+ break;
}
} else {
- // Still waiting on JVMCI compiler queue
+ progress_wait_attempts = 0;
+ if (jvmci_compiler_thread == NULL) {
+ methods_compiled = jvmci->methods_compiled();
+ }
}
}
task->clear_waiter();
@@ -1413,8 +1419,9 @@
methodHandle method(thread, task->method());
bool free_task;
#if INCLUDE_JVMCI
- if (compiler(task->comp_level())->is_jvmci()) {
- free_task = wait_for_jvmci_completion(task, thread);
+ AbstractCompiler* comp = compiler(task->comp_level());
+ if (comp->is_jvmci()) {
+ free_task = wait_for_jvmci_completion((JVMCICompiler*) comp, task, thread);
} else
#endif
{
--- a/hotspot/src/share/vm/compiler/compileBroker.hpp Mon Feb 08 18:52:03 2016 +0100
+++ b/hotspot/src/share/vm/compiler/compileBroker.hpp Mon Feb 08 18:52:03 2016 +0100
@@ -32,6 +32,9 @@
#include "runtime/perfData.hpp"
#include "trace/tracing.hpp"
#include "utilities/stack.hpp"
+#if INCLUDE_JVMCI
+#include "jvmci/jvmciCompiler.hpp"
+#endif
class nmethod;
class nmethodLocker;
@@ -234,7 +237,7 @@
bool blocking);
static void wait_for_completion(CompileTask* task);
#if INCLUDE_JVMCI
- static bool wait_for_jvmci_completion(CompileTask* task, JavaThread* thread);
+ static bool wait_for_jvmci_completion(JVMCICompiler* comp, CompileTask* task, JavaThread* thread);
#endif
static void invoke_compiler_on_method(CompileTask* task);
--- a/hotspot/src/share/vm/jvmci/jvmciCompiler.cpp Mon Feb 08 18:52:03 2016 +0100
+++ b/hotspot/src/share/vm/jvmci/jvmciCompiler.cpp Mon Feb 08 18:52:03 2016 +0100
@@ -38,7 +38,7 @@
JVMCICompiler::JVMCICompiler() : AbstractCompiler(jvmci) {
_bootstrapping = false;
- _methodsCompiled = 0;
+ _methods_compiled = 0;
assert(_instance == NULL, "only one instance allowed");
_instance = this;
}
@@ -99,7 +99,7 @@
} while (first_round && qsize == 0);
first_round = false;
if (PrintBootstrap) {
- while (z < (_methodsCompiled / 100)) {
+ while (z < (_methods_compiled / 100)) {
++z;
tty->print_raw(".");
}
@@ -107,7 +107,7 @@
} while (qsize != 0);
if (PrintBootstrap) {
- tty->print_cr(" in " JLONG_FORMAT " ms (compiled %d methods)", os::javaTimeMillis() - start, _methodsCompiled);
+ tty->print_cr(" in " JLONG_FORMAT " ms (compiled %d methods)", os::javaTimeMillis() - start, _methods_compiled);
}
_bootstrapping = false;
}
@@ -176,7 +176,7 @@
env->set_failure("no nmethod produced", true);
} else {
env->task()->set_num_inlined_bytecodes(CompilationRequestResult::inlinedBytecodes(result_object));
- _methodsCompiled++;
+ Atomic::inc(&_methods_compiled);
}
}
} else {
--- a/hotspot/src/share/vm/jvmci/jvmciCompiler.hpp Mon Feb 08 18:52:03 2016 +0100
+++ b/hotspot/src/share/vm/jvmci/jvmciCompiler.hpp Mon Feb 08 18:52:03 2016 +0100
@@ -33,10 +33,10 @@
bool _bootstrapping;
/**
- * Number of methods compiled by JVMCI. This is not synchronized
- * so may not be 100% accurate.
+ * Number of methods successfully compiled by a call to
+ * JVMCICompiler::compile_method().
*/
- volatile int _methodsCompiled;
+ volatile int _methods_compiled;
static JVMCICompiler* _instance;
@@ -80,8 +80,11 @@
// Print compilation timers and statistics
virtual void print_timers();
- // Print compilation statistics
- void reset_compilation_stats();
+ /**
+ * Gets the number of methods that have been successfully compiled by
+ * a call to JVMCICompiler::compile_method().
+ */
+ int methods_compiled() { return _methods_compiled; }
// Print compilation timers and statistics
static void print_compilation_timers();