--- a/hotspot/src/share/vm/logging/log.cpp Tue Mar 15 15:43:04 2016 -0400
+++ b/hotspot/src/share/vm/logging/log.cpp Tue Mar 15 20:37:35 2016 +0000
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2016, Oracle and/or its affiliates. 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
@@ -136,4 +136,27 @@
LogConfiguration::parse_log_arguments("stdout", saved_config, NULL, NULL, log.error_stream());
os::free(saved_config);
}
+
+static int Test_logconfiguration_subscribe_triggered = 0;
+
+static void Test_logconfiguration_subscribe_helper() {
+ Test_logconfiguration_subscribe_triggered++;
+}
+
+void Test_logconfiguration_subscribe() {
+ ResourceMark rm;
+ LogHandle(logging) log;
+
+ LogConfiguration::register_update_listener(&Test_logconfiguration_subscribe_helper);
+
+ LogConfiguration::parse_log_arguments("stdout", "logging=trace", NULL, NULL, log.error_stream());
+ assert(Test_logconfiguration_subscribe_triggered == 1, "subscription not triggered (1)");
+
+ LogConfiguration::configure_stdout(LogLevel::Debug, true, LOG_TAGS(gc));
+ assert(Test_logconfiguration_subscribe_triggered == 2, "subscription not triggered (2)");
+
+ LogConfiguration::disable_logging();
+ assert(Test_logconfiguration_subscribe_triggered == 3, "subscription not triggered (3)");
+}
+
#endif // PRODUCT
--- a/hotspot/src/share/vm/logging/logConfiguration.cpp Tue Mar 15 15:43:04 2016 -0400
+++ b/hotspot/src/share/vm/logging/logConfiguration.cpp Tue Mar 15 20:37:35 2016 +0000
@@ -40,6 +40,9 @@
LogOutput** LogConfiguration::_outputs = NULL;
size_t LogConfiguration::_n_outputs = 0;
+LogConfiguration::UpdateListenerFunction* LogConfiguration::_listener_callbacks = NULL;
+size_t LogConfiguration::_n_listener_callbacks = 0;
+
// Stack object to take the lock for configuring the logging.
// Should only be held during the critical parts of the configuration
// (when calling configure_output or reading/modifying the outputs array).
@@ -254,6 +257,7 @@
for (size_t i = 0; i < _n_outputs; i++) {
disable_output(i);
}
+ notify_update_listeners();
}
void LogConfiguration::configure_stdout(LogLevelType level, bool exact_match, ...) {
@@ -282,6 +286,7 @@
// Apply configuration to stdout (output #0), with the same decorators as before.
ConfigurationLock cl;
configure_output(0, expr, LogOutput::Stdout->decorators());
+ notify_update_listeners();
}
bool LogConfiguration::parse_command_line_arguments(const char* opts) {
@@ -373,6 +378,7 @@
}
}
configure_output(idx, expr, decorators);
+ notify_update_listeners();
return true;
}
@@ -471,3 +477,20 @@
}
}
+void LogConfiguration::register_update_listener(UpdateListenerFunction cb) {
+ assert(cb != NULL, "Should not register NULL as listener");
+ ConfigurationLock cl;
+ size_t idx = _n_listener_callbacks++;
+ _listener_callbacks = REALLOC_C_HEAP_ARRAY(UpdateListenerFunction,
+ _listener_callbacks,
+ _n_listener_callbacks,
+ mtLogging);
+ _listener_callbacks[idx] = cb;
+}
+
+void LogConfiguration::notify_update_listeners() {
+ assert(ConfigurationLock::current_thread_has_lock(), "notify_update_listeners must be called in ConfigurationLock scope (lock held)");
+ for (size_t i = 0; i < _n_listener_callbacks; i++) {
+ _listener_callbacks[i]();
+ }
+}
--- a/hotspot/src/share/vm/logging/logConfiguration.hpp Tue Mar 15 15:43:04 2016 -0400
+++ b/hotspot/src/share/vm/logging/logConfiguration.hpp Tue Mar 15 20:37:35 2016 +0000
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2015, 2016, Oracle and/or its affiliates. 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
@@ -37,10 +37,26 @@
// kept implicitly in the LogTagSets and their LogOutputLists. During configuration the tagsets
// are iterated over and updated accordingly.
class LogConfiguration : public AllStatic {
+ public:
+ // Function for listeners
+ typedef void (*UpdateListenerFunction)(void);
+
+ // Register callback for config change.
+ // The callback is always called with ConfigurationLock held,
+ // hence doing log reconfiguration from the callback will deadlock.
+ // The main Java thread may call this callback if there is an early registration
+ // else the attach listener JavaThread, started via diagnostic command, will be executing thread.
+ // The main purpose of this callback is to see if a loglevel have been changed.
+ // There is no way to unregister.
+ static void register_update_listener(UpdateListenerFunction cb);
+
private:
static LogOutput** _outputs;
static size_t _n_outputs;
+ static UpdateListenerFunction* _listener_callbacks;
+ static size_t _n_listener_callbacks;
+
// Create a new output. Returns NULL if failed.
static LogOutput* new_output(char* name, const char* options, outputStream* errstream);
@@ -60,6 +76,9 @@
// Configure output (add or update existing configuration) to log on tag-level combination using specified decorators.
static void configure_output(size_t idx, const LogTagLevelExpression& tag_level_expression, const LogDecorators& decorators);
+ // This should be called after any configuration change while still holding ConfigurationLock
+ static void notify_update_listeners();
+
public:
// Initialization and finalization of log configuration, to be run at vm startup and shutdown respectively.
static void initialize(jlong vm_start_time);
--- a/hotspot/src/share/vm/utilities/internalVMTests.cpp Tue Mar 15 15:43:04 2016 -0400
+++ b/hotspot/src/share/vm/utilities/internalVMTests.cpp Tue Mar 15 20:37:35 2016 +0000
@@ -69,6 +69,7 @@
run_unit_test(JSON_test);
run_unit_test(Test_log_length);
run_unit_test(Test_configure_stdout);
+ run_unit_test(Test_logconfiguration_subscribe);
run_unit_test(DirectivesParser_test);
run_unit_test(Test_TempNewSymbol);
#if INCLUDE_VM_STRUCTS