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src/share/vm/runtime/sweeper.hpp@427b2fb1944f (annotated)

src/share/vm/runtime/sweeper.hpp

Wed, 31 Jan 2018 19:24:57 -0500

author

dbuck

date

Wed, 31 Jan 2018 19:24:57 -0500

changeset 9289

427b2fb1944f

parent 6680

78bbf4d43a14

child 6876

710a3c8b516e

permissions

-rw-r--r--

8189170: Add option to disable stack overflow checking in primordial thread for use with JNI_CreateJavaJVM
Reviewed-by: dcubed

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_SWEEPER_HPP
stefank@2314	26	#define SHARE_VM_RUNTIME_SWEEPER_HPP
stefank@2314	27
mgronlun@6131	28	#include "utilities/ticks.hpp"
duke@435	29	// An NmethodSweeper is an incremental cleaner for:
duke@435	30	// - cleanup inline caches
anoll@5792	31	// - reclamation of nmethods
anoll@5792	32	// Removing nmethods from the code cache includes two operations
anoll@5792	33	// 1) mark active nmethods
anoll@5792	34	// Is done in 'mark_active_nmethods()'. This function is called at a
anoll@5792	35	// safepoint and marks all nmethods that are active on a thread's stack.
anoll@5792	36	// 2) sweep nmethods
anoll@5792	37	// Is done in sweep_code_cache(). This function is the only place in the
anoll@5792	38	// sweeper where memory is reclaimed. Note that sweep_code_cache() is not
anoll@5792	39	// called at a safepoint. However, sweep_code_cache() stops executing if
anoll@5792	40	// another thread requests a safepoint. Consequently, 'mark_active_nmethods()'
anoll@5792	41	// and sweep_code_cache() cannot execute at the same time.
anoll@5792	42	// To reclaim memory, nmethods are first marked as 'not-entrant'. Methods can
anoll@5792	43	// be made not-entrant by (i) the sweeper, (ii) deoptimization, (iii) dependency
anoll@5792	44	// invalidation, and (iv) being replaced be a different method version (tiered
anoll@5792	45	// compilation). Not-entrant nmethod cannot be called by Java threads, but they
anoll@5792	46	// can still be active on the stack. To ensure that active nmethod are not reclaimed,
anoll@5792	47	// we have to wait until the next marking phase has completed. If a not-entrant
anoll@5792	48	// nmethod was NOT marked as active, it can be converted to 'zombie' state. To safely
anoll@5792	49	// remove the nmethod, all inline caches (IC) that point to the the nmethod must be
anoll@5792	50	// cleared. After that, the nmethod can be evicted from the code cache. Each nmethod's
anoll@5792	51	// state change happens during separate sweeps. It may take at least 3 sweeps before an
anoll@5792	52	// nmethod's space is freed. Sweeping is currently done by compiler threads between
anoll@5792	53	// compilations or at least each 5 sec (NmethodSweepCheckInterval) when the code cache
anoll@5792	54	// is full.
duke@435	55
duke@435	56	class NMethodSweeper : public AllStatic {
anoll@6207	57	static long _traversals; // Stack scan count, also sweep ID.
anoll@6207	58	static long _total_nof_code_cache_sweeps; // Total number of full sweeps of the code cache
anoll@6207	59	static long _time_counter; // Virtual time used to periodically invoke sweeper
anoll@6207	60	static long _last_sweep; // Value of _time_counter when the last sweep happened
anoll@6207	61	static nmethod* _current; // Current nmethod
anoll@6207	62	static int _seen; // Nof. nmethod we have currently processed in current pass of CodeCache
anoll@6207	63	static int _flushed_count; // Nof. nmethods flushed in current sweep
anoll@6207	64	static int _zombified_count; // Nof. nmethods made zombie in current sweep
anoll@6207	65	static int _marked_for_reclamation_count; // Nof. nmethods marked for reclaim in current sweep
never@1999	66
anoll@6207	67	static volatile int _sweep_fractions_left; // Nof. invocations left until we are completed with this pass
anoll@6207	68	static volatile int _sweep_started; // Flag to control conc sweeper
anoll@6207	69	static volatile bool _should_sweep; // Indicates if we should invoke the sweeper
anoll@6207	70	static volatile int _bytes_changed; // Counts the total nmethod size if the nmethod changed from:
anoll@6207	71	// 1) alive -> not_entrant
anoll@6207	72	// 2) not_entrant -> zombie
anoll@6207	73	// 3) zombie -> marked_for_reclamation
sla@5237	74	// Stat counters
anoll@6207	75	static long _total_nof_methods_reclaimed; // Accumulated nof methods flushed
anoll@6207	76	static long _total_nof_c2_methods_reclaimed; // Accumulated nof C2-compiled methods flushed
anoll@6207	77	static size_t _total_flushed_size; // Total size of flushed methods
anoll@6207	78	static int _hotness_counter_reset_val;
anoll@6207	79
anoll@6207	80	static Tickspan _total_time_sweeping; // Accumulated time sweeping
anoll@6207	81	static Tickspan _total_time_this_sweep; // Total time this sweep
anoll@6207	82	static Tickspan _peak_sweep_time; // Peak time for a full sweep
anoll@6207	83	static Tickspan _peak_sweep_fraction_time; // Peak time sweeping one fraction
sla@5237	84
anoll@5792	85	static int process_nmethod(nmethod *nm);
coleenp@4037	86	static void release_nmethod(nmethod* nm);
coleenp@4037	87
neliasso@5038	88	static bool sweep_in_progress();
anoll@5792	89	static void sweep_code_cache();
anoll@5792	90
duke@435	91	public:
sla@5237	92	static long traversal_count() { return _traversals; }
sla@5237	93	static int total_nof_methods_reclaimed() { return _total_nof_methods_reclaimed; }
mgronlun@6131	94	static const Tickspan total_time_sweeping() { return _total_time_sweeping; }
mgronlun@6131	95	static const Tickspan peak_sweep_time() { return _peak_sweep_time; }
mgronlun@6131	96	static const Tickspan peak_sweep_fraction_time() { return _peak_sweep_fraction_time; }
drchase@6680	97	static void log_sweep(const char* msg, const char* format = NULL, ...) ATTRIBUTE_PRINTF(2, 3);
anoll@5792	98
duke@435	99
never@2916	100	#ifdef ASSERT
johnc@5548	101	static bool is_sweeping(nmethod* which) { return _current == which; }
never@2916	102	// Keep track of sweeper activity in the ring buffer
never@2916	103	static void record_sweep(nmethod* nm, int line);
never@2916	104	static void report_events(int id, address entry);
never@2916	105	static void report_events();
never@2916	106	#endif
never@2916	107
anoll@5792	108	static void mark_active_nmethods(); // Invoked at the end of each safepoint
anoll@5792	109	static void possibly_sweep(); // Compiler threads call this to sweep
duke@435	110
anoll@5792	111	static int hotness_counter_reset_val();
anoll@6099	112	static void report_state_change(nmethod* nm);
anoll@6099	113	static void possibly_enable_sweeper();
anoll@6207	114	static void print(); // Printing/debugging
duke@435	115	};
stefank@2314	116
stefank@2314	117	#endif // SHARE_VM_RUNTIME_SWEEPER_HPP