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src/share/vm/runtime/safepoint.hpp@b985cbb00e68 (annotated)

src/share/vm/runtime/safepoint.hpp

Mon, 12 Aug 2019 18:30:40 +0300

author

apetushkov

date

Mon, 12 Aug 2019 18:30:40 +0300

changeset 9858

b985cbb00e68

parent 6680

78bbf4d43a14

child 9896

1b8c45b8216a

permissions

-rw-r--r--

8223147: JFR Backport
8199712: Flight Recorder
8203346: JFR: Inconsistent signature of jfr_add_string_constant
8195817: JFR.stop should require name of recording
8195818: JFR.start should increase autogenerated name by one
8195819: Remove recording=x from jcmd JFR.check output
8203921: JFR thread sampling is missing fixes from JDK-8194552
8203929: Limit amount of data for JFR.dump
8203664: JFR start failure after AppCDS archive created with JFR StartFlightRecording
8003209: JFR events for network utilization
8207392: [PPC64] Implement JFR profiling
8202835: jfr/event/os/TestSystemProcess.java fails on missing events
Summary: Backport JFR from JDK11. Initial integration
Reviewed-by: neugens

duke@435	1	/*
drchase@6680	2	* Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
trims@1907	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907	20	* or visit www.oracle.com if you need additional information or have any
trims@1907	21	* questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
stefank@2314	25	#ifndef SHARE_VM_RUNTIME_SAFEPOINT_HPP
stefank@2314	26	#define SHARE_VM_RUNTIME_SAFEPOINT_HPP
stefank@2314	27
stefank@2314	28	#include "asm/assembler.hpp"
stefank@2314	29	#include "code/nmethod.hpp"
stefank@2314	30	#include "memory/allocation.hpp"
stefank@2314	31	#include "runtime/extendedPC.hpp"
never@3494	32	#include "runtime/mutexLocker.hpp"
stefank@2314	33	#include "runtime/os.hpp"
stefank@2314	34	#include "utilities/ostream.hpp"
stefank@2314	35
duke@435	36	//
duke@435	37	// Safepoint synchronization
duke@435	38	////
duke@435	39	// The VMThread or CMS_thread uses the SafepointSynchronize::begin/end
duke@435	40	// methods to enter/exit a safepoint region. The begin method will roll
duke@435	41	// all JavaThreads forward to a safepoint.
duke@435	42	//
duke@435	43	// JavaThreads must use the ThreadSafepointState abstraction (defined in
duke@435	44	// thread.hpp) to indicate that that they are at a safepoint.
duke@435	45	//
duke@435	46	// The Mutex/Condition variable and ObjectLocker classes calls the enter/
duke@435	47	// exit safepoint methods, when a thread is blocked/restarted. Hence, all mutex exter/
duke@435	48	// exit points *must* be at a safepoint.
duke@435	49
duke@435	50
duke@435	51	class ThreadSafepointState;
duke@435	52	class SnippetCache;
duke@435	53	class nmethod;
duke@435	54
duke@435	55	//
duke@435	56	// Implements roll-forward to safepoint (safepoint synchronization)
duke@435	57	//
duke@435	58	class SafepointSynchronize : AllStatic {
duke@435	59	public:
duke@435	60	enum SynchronizeState {
duke@435	61	_not_synchronized = 0, // Threads not synchronized at a safepoint
duke@435	62	// Keep this value 0. See the coment in do_call_back()
duke@435	63	_synchronizing = 1, // Synchronizing in progress
duke@435	64	_synchronized = 2 // All Java threads are stopped at a safepoint. Only VM thread is running
duke@435	65	};
duke@435	66
duke@435	67	enum SafepointingThread {
duke@435	68	_null_thread = 0,
duke@435	69	_vm_thread = 1,
duke@435	70	_other_thread = 2
duke@435	71	};
duke@435	72
duke@435	73	enum SafepointTimeoutReason {
duke@435	74	_spinning_timeout = 0,
duke@435	75	_blocking_timeout = 1
duke@435	76	};
duke@435	77
duke@435	78	typedef struct {
xlu@1726	79	float _time_stamp; // record when the current safepoint occurs in seconds
duke@435	80	int _vmop_type; // type of VM operation triggers the safepoint
duke@435	81	int _nof_total_threads; // total number of Java threads
duke@435	82	int _nof_initial_running_threads; // total number of initially seen running threads
duke@435	83	int _nof_threads_wait_to_block; // total number of threads waiting for to block
duke@435	84	bool _page_armed; // true if polling page is armed, false otherwise
duke@435	85	int _nof_threads_hit_page_trap; // total number of threads hitting the page trap
duke@435	86	jlong _time_to_spin; // total time in millis spent in spinning
duke@435	87	jlong _time_to_wait_to_block; // total time in millis spent in waiting for to block
xlu@1726	88	jlong _time_to_do_cleanups; // total time in millis spent in performing cleanups
duke@435	89	jlong _time_to_sync; // total time in millis spent in getting to _synchronized
duke@435	90	jlong _time_to_exec_vmop; // total time in millis spent in vm operation itself
duke@435	91	} SafepointStats;
duke@435	92
duke@435	93	private:
duke@435	94	static volatile SynchronizeState _state; // Threads might read this flag directly, without acquireing the Threads_lock
xlu@1726	95	static volatile int _waiting_to_block; // number of threads we are waiting for to block
never@3494	96	static int _current_jni_active_count; // Counts the number of active critical natives during the safepoint
duke@435	97
duke@435	98	// This counter is used for fast versions of jni_Get<Primitive>Field.
duke@435	99	// An even value means there is no ongoing safepoint operations.
duke@435	100	// The counter is incremented ONLY at the beginning and end of each
duke@435	101	// safepoint. The fact that Threads_lock is held throughout each pair of
duke@435	102	// increments (at the beginning and end of each safepoint) guarantees
duke@435	103	// race freedom.
duke@435	104	public:
duke@435	105	static volatile int _safepoint_counter;
duke@435	106	private:
xlu@1726	107	static long _end_of_last_safepoint; // Time of last safepoint in milliseconds
duke@435	108
duke@435	109	// statistics
xlu@1726	110	static jlong _safepoint_begin_time; // time when safepoint begins
xlu@1726	111	static SafepointStats* _safepoint_stats; // array of SafepointStats struct
xlu@1726	112	static int _cur_stat_index; // current index to the above array
xlu@1726	113	static julong _safepoint_reasons[]; // safepoint count for each VM op
xlu@1726	114	static julong _coalesced_vmop_count; // coalesced vmop count
xlu@1726	115	static jlong _max_sync_time; // maximum sync time in nanos
xlu@1726	116	static jlong _max_vmop_time; // maximum vm operation time in nanos
xlu@1726	117	static float _ts_of_current_safepoint; // time stamp of current safepoint in seconds
duke@435	118
duke@435	119	static void begin_statistics(int nof_threads, int nof_running);
duke@435	120	static void update_statistics_on_spin_end();
duke@435	121	static void update_statistics_on_sync_end(jlong end_time);
xlu@1726	122	static void update_statistics_on_cleanup_end(jlong end_time);
duke@435	123	static void end_statistics(jlong end_time);
duke@435	124	static void print_statistics();
duke@435	125	inline static void inc_page_trap_count() {
duke@435	126	Atomic::inc(&_safepoint_stats[_cur_stat_index]._nof_threads_hit_page_trap);
duke@435	127	}
duke@435	128
duke@435	129	// For debug long safepoint
duke@435	130	static void print_safepoint_timeout(SafepointTimeoutReason timeout_reason);
duke@435	131
duke@435	132	public:
duke@435	133
duke@435	134	// Main entry points
duke@435	135
duke@435	136	// Roll all threads forward to safepoint. Must be called by the
duke@435	137	// VMThread or CMS_thread.
duke@435	138	static void begin();
duke@435	139	static void end(); // Start all suspended threads again...
duke@435	140
duke@435	141	static bool safepoint_safe(JavaThread *thread, JavaThreadState state);
duke@435	142
never@3500	143	static void check_for_lazy_critical_native(JavaThread *thread, JavaThreadState state);
never@3500	144
duke@435	145	// Query
duke@435	146	inline static bool is_at_safepoint() { return _state == _synchronized; }
duke@435	147	inline static bool is_synchronizing() { return _state == _synchronizing; }
apetushkov@9858	148	inline static int safepoint_counter() { return _safepoint_counter; }
duke@435	149
duke@435	150	inline static bool do_call_back() {
duke@435	151	return (_state != _not_synchronized);
duke@435	152	}
duke@435	153
never@3494	154	inline static void increment_jni_active_count() {
never@3494	155	assert_locked_or_safepoint(Safepoint_lock);
never@3494	156	_current_jni_active_count++;
never@3494	157	}
never@3494	158
duke@435	159	// Called when a thread volantary blocks
duke@435	160	static void block(JavaThread *thread);
duke@435	161	static void signal_thread_at_safepoint() { _waiting_to_block--; }
duke@435	162
duke@435	163	// Exception handling for page polling
duke@435	164	static void handle_polling_page_exception(JavaThread *thread);
duke@435	165
duke@435	166	// VM Thread interface for determining safepoint rate
xlu@1726	167	static long last_non_safepoint_interval() {
xlu@1726	168	return os::javaTimeMillis() - _end_of_last_safepoint;
xlu@1726	169	}
iveresov@2138	170	static long end_of_last_safepoint() {
iveresov@2138	171	return _end_of_last_safepoint;
iveresov@2138	172	}
duke@435	173	static bool is_cleanup_needed();
duke@435	174	static void do_cleanup_tasks();
duke@435	175
duke@435	176	// debugging
duke@435	177	static void print_state() PRODUCT_RETURN;
drchase@6680	178	static void safepoint_msg(const char* format, ...) ATTRIBUTE_PRINTF(1, 2) PRODUCT_RETURN;
duke@435	179
duke@435	180	static void deferred_initialize_stat();
duke@435	181	static void print_stat_on_exit();
duke@435	182	inline static void inc_vmop_coalesced_count() { _coalesced_vmop_count++; }
duke@435	183
duke@435	184	static void set_is_at_safepoint() { _state = _synchronized; }
duke@435	185	static void set_is_not_at_safepoint() { _state = _not_synchronized; }
duke@435	186
duke@435	187	// assembly support
duke@435	188	static address address_of_state() { return (address)&_state; }
duke@435	189
duke@435	190	static address safepoint_counter_addr() { return (address)&_safepoint_counter; }
duke@435	191	};
duke@435	192
duke@435	193	// State class for a thread suspended at a safepoint
zgu@3900	194	class ThreadSafepointState: public CHeapObj<mtInternal> {
duke@435	195	public:
duke@435	196	// These states are maintained by VM thread while threads are being brought
duke@435	197	// to a safepoint. After SafepointSynchronize::end(), they are reset to
duke@435	198	// _running.
duke@435	199	enum suspend_type {
duke@435	200	_running = 0, // Thread state not yet determined (i.e., not at a safepoint yet)
duke@435	201	_at_safepoint = 1, // Thread at a safepoint (f.ex., when blocked on a lock)
duke@435	202	_call_back = 2 // Keep executing and wait for callback (if thread is in interpreted or vm)
duke@435	203	};
duke@435	204	private:
duke@435	205	volatile bool _at_poll_safepoint; // At polling page safepoint (NOT a poll return safepoint)
duke@435	206	// Thread has called back the safepoint code (for debugging)
duke@435	207	bool _has_called_back;
duke@435	208
duke@435	209	JavaThread * _thread;
duke@435	210	volatile suspend_type _type;
never@2082	211	JavaThreadState _orig_thread_state;
duke@435	212
duke@435	213
duke@435	214	public:
duke@435	215	ThreadSafepointState(JavaThread *thread);
duke@435	216
duke@435	217	// examine/roll-forward/restart
duke@435	218	void examine_state_of_thread();
duke@435	219	void roll_forward(suspend_type type);
duke@435	220	void restart();
duke@435	221
duke@435	222	// Query
duke@435	223	JavaThread* thread() const { return _thread; }
duke@435	224	suspend_type type() const { return _type; }
duke@435	225	bool is_running() const { return (_type==_running); }
never@2082	226	JavaThreadState orig_thread_state() const { return _orig_thread_state; }
duke@435	227
duke@435	228	// Support for safepoint timeout (debugging)
duke@435	229	bool has_called_back() const { return _has_called_back; }
duke@435	230	void set_has_called_back(bool val) { _has_called_back = val; }
duke@435	231	bool is_at_poll_safepoint() { return _at_poll_safepoint; }
duke@435	232	void set_at_poll_safepoint(bool val) { _at_poll_safepoint = val; }
duke@435	233
duke@435	234	void handle_polling_page_exception();
duke@435	235
duke@435	236	// debugging
duke@435	237	void print_on(outputStream* st) const;
duke@435	238	void print() const { print_on(tty); }
duke@435	239
duke@435	240	// Initialize
duke@435	241	static void create(JavaThread *thread);
duke@435	242	static void destroy(JavaThread *thread);
duke@435	243
drchase@6680	244	void safepoint_msg(const char* format, ...) ATTRIBUTE_PRINTF(2, 3) {
duke@435	245	if (ShowSafepointMsgs) {
duke@435	246	va_list ap;
duke@435	247	va_start(ap, format);
duke@435	248	tty->vprint_cr(format, ap);
duke@435	249	va_end(ap);
duke@435	250	}
duke@435	251	}
duke@435	252	};
duke@435	253
iveresov@2138	254
stefank@2314	255
stefank@2314	256	#endif // SHARE_VM_RUNTIME_SAFEPOINT_HPP