Mon, 30 Jun 2008 17:04:59 -0700
6618726: Introduce -XX:+UnlockExperimentalVMOptions flag
Summary: experimental() flags will protect features of an experimental nature that are not supported in the regular product build. Made UseG1GC an experimental flag.
Reviewed-by: jmasa, kamg, coleenp
1 /*
2 * Copyright 1997-2007 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 class ThreadSafepointState;
26 class ThreadProfiler;
28 class JvmtiThreadState;
29 class JvmtiGetLoadedClassesClosure;
30 class ThreadStatistics;
31 class ConcurrentLocksDump;
32 class ParkEvent ;
34 class ciEnv;
35 class CompileThread;
36 class CompileLog;
37 class CompileTask;
38 class CompileQueue;
39 class CompilerCounters;
40 class vframeArray;
42 class DeoptResourceMark;
43 class jvmtiDeferredLocalVariableSet;
45 class GCTaskQueue;
46 class ThreadClosure;
47 class IdealGraphPrinter;
49 // Class hierarchy
50 // - Thread
51 // - VMThread
52 // - JavaThread
53 // - WatcherThread
55 class Thread: public ThreadShadow {
56 friend class VMStructs;
57 private:
58 // Exception handling
59 // (Note: _pending_exception and friends are in ThreadShadow)
60 //oop _pending_exception; // pending exception for current thread
61 // const char* _exception_file; // file information for exception (debugging only)
62 // int _exception_line; // line information for exception (debugging only)
64 // Support for forcing alignment of thread objects for biased locking
65 void* _real_malloc_address;
66 public:
67 void* operator new(size_t size);
68 void operator delete(void* p);
69 private:
71 // ***************************************************************
72 // Suspend and resume support
73 // ***************************************************************
74 //
75 // VM suspend/resume no longer exists - it was once used for various
76 // things including safepoints but was deprecated and finally removed
77 // in Java 7. Because VM suspension was considered "internal" Java-level
78 // suspension was considered "external", and this legacy naming scheme
79 // remains.
80 //
81 // External suspend/resume requests come from JVM_SuspendThread,
82 // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI
83 // ResumeThread. External
84 // suspend requests cause _external_suspend to be set and external
85 // resume requests cause _external_suspend to be cleared.
86 // External suspend requests do not nest on top of other external
87 // suspend requests. The higher level APIs reject suspend requests
88 // for already suspended threads.
89 //
90 // The external_suspend
91 // flag is checked by has_special_runtime_exit_condition() and java thread
92 // will self-suspend when handle_special_runtime_exit_condition() is
93 // called. Most uses of the _thread_blocked state in JavaThreads are
94 // considered the same as being externally suspended; if the blocking
95 // condition lifts, the JavaThread will self-suspend. Other places
96 // where VM checks for external_suspend include:
97 // + mutex granting (do not enter monitors when thread is suspended)
98 // + state transitions from _thread_in_native
99 //
100 // In general, java_suspend() does not wait for an external suspend
101 // request to complete. When it returns, the only guarantee is that
102 // the _external_suspend field is true.
103 //
104 // wait_for_ext_suspend_completion() is used to wait for an external
105 // suspend request to complete. External suspend requests are usually
106 // followed by some other interface call that requires the thread to
107 // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into
108 // the interface that requires quiescence, we give the JavaThread a
109 // chance to self-suspend before we need it to be quiescent. This
110 // improves overall suspend/query performance.
111 //
112 // _suspend_flags controls the behavior of java_ suspend/resume.
113 // It must be set under the protection of SR_lock. Read from the flag is
114 // OK without SR_lock as long as the value is only used as a hint.
115 // (e.g., check _external_suspend first without lock and then recheck
116 // inside SR_lock and finish the suspension)
117 //
118 // _suspend_flags is also overloaded for other "special conditions" so
119 // that a single check indicates whether any special action is needed
120 // eg. for async exceptions.
121 // -------------------------------------------------------------------
122 // Notes:
123 // 1. The suspend/resume logic no longer uses ThreadState in OSThread
124 // but we still update its value to keep other part of the system (mainly
125 // JVMTI) happy. ThreadState is legacy code (see notes in
126 // osThread.hpp).
127 //
128 // 2. It would be more natural if set_external_suspend() is private and
129 // part of java_suspend(), but that probably would affect the suspend/query
130 // performance. Need more investigation on this.
131 //
133 // suspend/resume lock: used for self-suspend
134 Monitor* _SR_lock;
136 protected:
137 enum SuspendFlags {
138 // NOTE: avoid using the sign-bit as cc generates different test code
139 // when the sign-bit is used, and sometimes incorrectly - see CR 6398077
141 _external_suspend = 0x20000000U, // thread is asked to self suspend
142 _ext_suspended = 0x40000000U, // thread has self-suspended
143 _deopt_suspend = 0x10000000U, // thread needs to self suspend for deopt
145 _has_async_exception = 0x00000001U // there is a pending async exception
146 };
148 // various suspension related flags - atomically updated
149 // overloaded for async exception checking in check_special_condition_for_native_trans.
150 volatile uint32_t _suspend_flags;
152 private:
153 int _num_nested_signal;
155 public:
156 void enter_signal_handler() { _num_nested_signal++; }
157 void leave_signal_handler() { _num_nested_signal--; }
158 bool is_inside_signal_handler() const { return _num_nested_signal > 0; }
160 private:
161 // Debug tracing
162 static void trace(const char* msg, const Thread* const thread) PRODUCT_RETURN;
164 // Active_handles points to a block of handles
165 JNIHandleBlock* _active_handles;
167 // One-element thread local free list
168 JNIHandleBlock* _free_handle_block;
170 // Point to the last handle mark
171 HandleMark* _last_handle_mark;
173 // The parity of the last strong_roots iteration in which this thread was
174 // claimed as a task.
175 jint _oops_do_parity;
177 public:
178 void set_last_handle_mark(HandleMark* mark) { _last_handle_mark = mark; }
179 HandleMark* last_handle_mark() const { return _last_handle_mark; }
180 private:
182 // debug support for checking if code does allow safepoints or not
183 // GC points in the VM can happen because of allocation, invoking a VM operation, or blocking on
184 // mutex, or blocking on an object synchronizer (Java locking).
185 // If !allow_safepoint(), then an assertion failure will happen in any of the above cases
186 // If !allow_allocation(), then an assertion failure will happen during allocation
187 // (Hence, !allow_safepoint() => !allow_allocation()).
188 //
189 // The two classes No_Safepoint_Verifier and No_Allocation_Verifier are used to set these counters.
190 //
191 NOT_PRODUCT(int _allow_safepoint_count;) // If 0, thread allow a safepoint to happen
192 debug_only (int _allow_allocation_count;) // If 0, the thread is allowed to allocate oops.
194 // Record when GC is locked out via the GC_locker mechanism
195 CHECK_UNHANDLED_OOPS_ONLY(int _gc_locked_out_count;)
197 friend class No_Alloc_Verifier;
198 friend class No_Safepoint_Verifier;
199 friend class Pause_No_Safepoint_Verifier;
200 friend class ThreadLocalStorage;
201 friend class GC_locker;
203 // In order for all threads to be able to use fast locking, we need to know the highest stack
204 // address of where a lock is on the stack (stacks normally grow towards lower addresses). This
205 // variable is initially set to NULL, indicating no locks are used by the thread. During the thread's
206 // execution, it will be set whenever locking can happen, i.e., when we call out to Java code or use
207 // an ObjectLocker. The value is never decreased, hence, it will over the lifetime of a thread
208 // approximate the real stackbase.
209 address _highest_lock; // Highest stack address where a JavaLock exist
211 ThreadLocalAllocBuffer _tlab; // Thread-local eden
213 int _vm_operation_started_count; // VM_Operation support
214 int _vm_operation_completed_count; // VM_Operation support
216 ObjectMonitor* _current_pending_monitor; // ObjectMonitor this thread
217 // is waiting to lock
218 bool _current_pending_monitor_is_from_java; // locking is from Java code
220 // ObjectMonitor on which this thread called Object.wait()
221 ObjectMonitor* _current_waiting_monitor;
223 // Private thread-local objectmonitor list - a simple cache organized as a SLL.
224 public:
225 ObjectMonitor * omFreeList ;
226 int omFreeCount ; // length of omFreeList
227 int omFreeProvision ; // reload chunk size
229 public:
230 enum {
231 is_definitely_current_thread = true
232 };
234 // Constructor
235 Thread();
236 virtual ~Thread();
238 // initializtion
239 void initialize_thread_local_storage();
241 // thread entry point
242 virtual void run();
244 // Testers
245 virtual bool is_VM_thread() const { return false; }
246 virtual bool is_Java_thread() const { return false; }
247 // Remove this ifdef when C1 is ported to the compiler interface.
248 virtual bool is_Compiler_thread() const { return false; }
249 virtual bool is_hidden_from_external_view() const { return false; }
250 virtual bool is_jvmti_agent_thread() const { return false; }
251 // True iff the thread can perform GC operations at a safepoint.
252 // Generally will be true only of VM thread and parallel GC WorkGang
253 // threads.
254 virtual bool is_GC_task_thread() const { return false; }
255 virtual bool is_Watcher_thread() const { return false; }
256 virtual bool is_ConcurrentGC_thread() const { return false; }
258 virtual char* name() const { return (char*)"Unknown thread"; }
260 // Returns the current thread
261 static inline Thread* current();
263 // Common thread operations
264 static void set_priority(Thread* thread, ThreadPriority priority);
265 static ThreadPriority get_priority(const Thread* const thread);
266 static void start(Thread* thread);
267 static void interrupt(Thread* thr);
268 static bool is_interrupted(Thread* thr, bool clear_interrupted);
270 Monitor* SR_lock() const { return _SR_lock; }
272 bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; }
274 void set_suspend_flag(SuspendFlags f) {
275 assert(sizeof(jint) == sizeof(_suspend_flags), "size mismatch");
276 uint32_t flags;
277 do {
278 flags = _suspend_flags;
279 }
280 while (Atomic::cmpxchg((jint)(flags | f),
281 (volatile jint*)&_suspend_flags,
282 (jint)flags) != (jint)flags);
283 }
284 void clear_suspend_flag(SuspendFlags f) {
285 assert(sizeof(jint) == sizeof(_suspend_flags), "size mismatch");
286 uint32_t flags;
287 do {
288 flags = _suspend_flags;
289 }
290 while (Atomic::cmpxchg((jint)(flags & ~f),
291 (volatile jint*)&_suspend_flags,
292 (jint)flags) != (jint)flags);
293 }
295 void set_has_async_exception() {
296 set_suspend_flag(_has_async_exception);
297 }
298 void clear_has_async_exception() {
299 clear_suspend_flag(_has_async_exception);
300 }
302 // Support for Unhandled Oop detection
303 #ifdef CHECK_UNHANDLED_OOPS
304 private:
305 UnhandledOops *_unhandled_oops;
306 public:
307 UnhandledOops* unhandled_oops() { return _unhandled_oops; }
308 // Mark oop safe for gc. It may be stack allocated but won't move.
309 void allow_unhandled_oop(oop *op) {
310 if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
311 }
312 // Clear oops at safepoint so crashes point to unhandled oop violator
313 void clear_unhandled_oops() {
314 if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
315 }
316 bool is_gc_locked_out() { return _gc_locked_out_count > 0; }
317 #endif // CHECK_UNHANDLED_OOPS
319 public:
320 // Installs a pending exception to be inserted later
321 static void send_async_exception(oop thread_oop, oop java_throwable);
323 // Resource area
324 ResourceArea* resource_area() const { return _resource_area; }
325 void set_resource_area(ResourceArea* area) { _resource_area = area; }
327 OSThread* osthread() const { return _osthread; }
328 void set_osthread(OSThread* thread) { _osthread = thread; }
330 // JNI handle support
331 JNIHandleBlock* active_handles() const { return _active_handles; }
332 void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
333 JNIHandleBlock* free_handle_block() const { return _free_handle_block; }
334 void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
336 // Internal handle support
337 HandleArea* handle_area() const { return _handle_area; }
338 void set_handle_area(HandleArea* area) { _handle_area = area; }
340 // Thread-Local Allocation Buffer (TLAB) support
341 ThreadLocalAllocBuffer& tlab() { return _tlab; }
342 void initialize_tlab() {
343 if (UseTLAB) {
344 tlab().initialize();
345 }
346 }
348 // VM operation support
349 int vm_operation_ticket() { return ++_vm_operation_started_count; }
350 int vm_operation_completed_count() { return _vm_operation_completed_count; }
351 void increment_vm_operation_completed_count() { _vm_operation_completed_count++; }
353 // For tracking the heavyweight monitor the thread is pending on.
354 ObjectMonitor* current_pending_monitor() {
355 return _current_pending_monitor;
356 }
357 void set_current_pending_monitor(ObjectMonitor* monitor) {
358 _current_pending_monitor = monitor;
359 }
360 void set_current_pending_monitor_is_from_java(bool from_java) {
361 _current_pending_monitor_is_from_java = from_java;
362 }
363 bool current_pending_monitor_is_from_java() {
364 return _current_pending_monitor_is_from_java;
365 }
367 // For tracking the ObjectMonitor on which this thread called Object.wait()
368 ObjectMonitor* current_waiting_monitor() {
369 return _current_waiting_monitor;
370 }
371 void set_current_waiting_monitor(ObjectMonitor* monitor) {
372 _current_waiting_monitor = monitor;
373 }
375 // GC support
376 // Apply "f->do_oop" to all root oops in "this".
377 void oops_do(OopClosure* f);
379 // Handles the parallel case for the method below.
380 private:
381 bool claim_oops_do_par_case(int collection_parity);
382 public:
383 // Requires that "collection_parity" is that of the current strong roots
384 // iteration. If "is_par" is false, sets the parity of "this" to
385 // "collection_parity", and returns "true". If "is_par" is true,
386 // uses an atomic instruction to set the current threads parity to
387 // "collection_parity", if it is not already. Returns "true" iff the
388 // calling thread does the update, this indicates that the calling thread
389 // has claimed the thread's stack as a root groop in the current
390 // collection.
391 bool claim_oops_do(bool is_par, int collection_parity) {
392 if (!is_par) {
393 _oops_do_parity = collection_parity;
394 return true;
395 } else {
396 return claim_oops_do_par_case(collection_parity);
397 }
398 }
400 // Sweeper support
401 void nmethods_do();
403 // Fast-locking support
404 address highest_lock() const { return _highest_lock; }
405 void update_highest_lock(address base) { if (base > _highest_lock) _highest_lock = base; }
407 // Tells if adr belong to this thread. This is used
408 // for checking if a lock is owned by the running thread.
409 // Warning: the method can only be used on the running thread
410 // Fast lock support uses these methods
411 virtual bool lock_is_in_stack(address adr) const;
412 virtual bool is_lock_owned(address adr) const;
414 // Check if address is in the stack of the thread (not just for locks).
415 bool is_in_stack(address adr) const;
417 // Sets this thread as starting thread. Returns failure if thread
418 // creation fails due to lack of memory, too many threads etc.
419 bool set_as_starting_thread();
421 protected:
422 // OS data associated with the thread
423 OSThread* _osthread; // Platform-specific thread information
425 // Thread local resource area for temporary allocation within the VM
426 ResourceArea* _resource_area;
428 // Thread local handle area for allocation of handles within the VM
429 HandleArea* _handle_area;
431 // Support for stack overflow handling, get_thread, etc.
432 address _stack_base;
433 size_t _stack_size;
434 uintptr_t _self_raw_id; // used by get_thread (mutable)
435 int _lgrp_id;
437 public:
438 // Stack overflow support
439 address stack_base() const { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
441 void set_stack_base(address base) { _stack_base = base; }
442 size_t stack_size() const { return _stack_size; }
443 void set_stack_size(size_t size) { _stack_size = size; }
444 void record_stack_base_and_size();
446 int lgrp_id() const { return _lgrp_id; }
447 void set_lgrp_id(int value) { _lgrp_id = value; }
449 // Printing
450 void print_on(outputStream* st) const;
451 void print() const { print_on(tty); }
452 virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
454 // Debug-only code
456 #ifdef ASSERT
457 private:
458 // Deadlock detection support for Mutex locks. List of locks own by thread.
459 Monitor *_owned_locks;
460 // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
461 // thus the friendship
462 friend class Mutex;
463 friend class Monitor;
465 public:
466 void print_owned_locks_on(outputStream* st) const;
467 void print_owned_locks() const { print_owned_locks_on(tty); }
468 Monitor * owned_locks() const { return _owned_locks; }
469 bool owns_locks() const { return owned_locks() != NULL; }
470 bool owns_locks_but_compiled_lock() const;
472 // Deadlock detection
473 bool allow_allocation() { return _allow_allocation_count == 0; }
474 #endif
476 void check_for_valid_safepoint_state(bool potential_vm_operation) PRODUCT_RETURN;
478 private:
479 volatile int _jvmti_env_iteration_count;
481 public:
482 void entering_jvmti_env_iteration() { ++_jvmti_env_iteration_count; }
483 void leaving_jvmti_env_iteration() { --_jvmti_env_iteration_count; }
484 bool is_inside_jvmti_env_iteration() { return _jvmti_env_iteration_count > 0; }
486 // Code generation
487 static ByteSize exception_file_offset() { return byte_offset_of(Thread, _exception_file ); }
488 static ByteSize exception_line_offset() { return byte_offset_of(Thread, _exception_line ); }
489 static ByteSize active_handles_offset() { return byte_offset_of(Thread, _active_handles ); }
491 static ByteSize stack_base_offset() { return byte_offset_of(Thread, _stack_base ); }
492 static ByteSize stack_size_offset() { return byte_offset_of(Thread, _stack_size ); }
493 static ByteSize omFreeList_offset() { return byte_offset_of(Thread, omFreeList); }
495 #define TLAB_FIELD_OFFSET(name) \
496 static ByteSize tlab_##name##_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::name##_offset(); }
498 TLAB_FIELD_OFFSET(start)
499 TLAB_FIELD_OFFSET(end)
500 TLAB_FIELD_OFFSET(top)
501 TLAB_FIELD_OFFSET(pf_top)
502 TLAB_FIELD_OFFSET(size) // desired_size
503 TLAB_FIELD_OFFSET(refill_waste_limit)
504 TLAB_FIELD_OFFSET(number_of_refills)
505 TLAB_FIELD_OFFSET(fast_refill_waste)
506 TLAB_FIELD_OFFSET(slow_allocations)
508 #undef TLAB_FIELD_OFFSET
510 public:
511 volatile intptr_t _Stalled ;
512 volatile int _TypeTag ;
513 ParkEvent * _ParkEvent ; // for synchronized()
514 ParkEvent * _SleepEvent ; // for Thread.sleep
515 ParkEvent * _MutexEvent ; // for native internal Mutex/Monitor
516 ParkEvent * _MuxEvent ; // for low-level muxAcquire-muxRelease
517 int NativeSyncRecursion ; // diagnostic
519 volatile int _OnTrap ; // Resume-at IP delta
520 jint _hashStateW ; // Marsaglia Shift-XOR thread-local RNG
521 jint _hashStateX ; // thread-specific hashCode generator state
522 jint _hashStateY ;
523 jint _hashStateZ ;
524 void * _schedctl ;
526 intptr_t _ScratchA, _ScratchB ; // Scratch locations for fast-path sync code
527 static ByteSize ScratchA_offset() { return byte_offset_of(Thread, _ScratchA ); }
528 static ByteSize ScratchB_offset() { return byte_offset_of(Thread, _ScratchB ); }
530 volatile jint rng [4] ; // RNG for spin loop
532 // Low-level leaf-lock primitives used to implement synchronization
533 // and native monitor-mutex infrastructure.
534 // Not for general synchronization use.
535 static void SpinAcquire (volatile int * Lock, const char * Name) ;
536 static void SpinRelease (volatile int * Lock) ;
537 static void muxAcquire (volatile intptr_t * Lock, const char * Name) ;
538 static void muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) ;
539 static void muxRelease (volatile intptr_t * Lock) ;
541 };
543 // Inline implementation of Thread::current()
544 // Thread::current is "hot" it's called > 128K times in the 1st 500 msecs of
545 // startup.
546 // ThreadLocalStorage::thread is warm -- it's called > 16K times in the same
547 // period. This is inlined in thread_<os_family>.inline.hpp.
549 inline Thread* Thread::current() {
550 #ifdef ASSERT
551 // This function is very high traffic. Define PARANOID to enable expensive
552 // asserts.
553 #ifdef PARANOID
554 // Signal handler should call ThreadLocalStorage::get_thread_slow()
555 Thread* t = ThreadLocalStorage::get_thread_slow();
556 assert(t != NULL && !t->is_inside_signal_handler(),
557 "Don't use Thread::current() inside signal handler");
558 #endif
559 #endif
560 Thread* thread = ThreadLocalStorage::thread();
561 assert(thread != NULL, "just checking");
562 return thread;
563 }
565 // Name support for threads. non-JavaThread subclasses with multiple
566 // uniquely named instances should derive from this.
567 class NamedThread: public Thread {
568 friend class VMStructs;
569 enum {
570 max_name_len = 64
571 };
572 private:
573 char* _name;
574 public:
575 NamedThread();
576 ~NamedThread();
577 // May only be called once per thread.
578 void set_name(const char* format, ...);
579 virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; }
580 };
582 // Worker threads are named and have an id of an assigned work.
583 class WorkerThread: public NamedThread {
584 private:
585 uint _id;
586 public:
587 WorkerThread() : _id(0) { }
588 void set_id(uint work_id) { _id = work_id; }
589 uint id() const { return _id; }
590 };
592 // A single WatcherThread is used for simulating timer interrupts.
593 class WatcherThread: public Thread {
594 friend class VMStructs;
595 public:
596 virtual void run();
598 private:
599 static WatcherThread* _watcher_thread;
601 static bool _should_terminate;
602 public:
603 enum SomeConstants {
604 delay_interval = 10 // interrupt delay in milliseconds
605 };
607 // Constructor
608 WatcherThread();
610 // Tester
611 bool is_Watcher_thread() const { return true; }
613 // Printing
614 char* name() const { return (char*)"VM Periodic Task Thread"; }
615 void print_on(outputStream* st) const;
616 void print() const { print_on(tty); }
618 // Returns the single instance of WatcherThread
619 static WatcherThread* watcher_thread() { return _watcher_thread; }
621 // Create and start the single instance of WatcherThread, or stop it on shutdown
622 static void start();
623 static void stop();
624 };
627 class CompilerThread;
629 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
631 class JavaThread: public Thread {
632 friend class VMStructs;
633 private:
634 JavaThread* _next; // The next thread in the Threads list
635 oop _threadObj; // The Java level thread object
637 #ifdef ASSERT
638 private:
639 int _java_call_counter;
641 public:
642 int java_call_counter() { return _java_call_counter; }
643 void inc_java_call_counter() { _java_call_counter++; }
644 void dec_java_call_counter() {
645 assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
646 _java_call_counter--;
647 }
648 private: // restore original namespace restriction
649 #endif // ifdef ASSERT
651 #ifndef PRODUCT
652 public:
653 enum {
654 jump_ring_buffer_size = 16
655 };
656 private: // restore original namespace restriction
657 #endif
659 JavaFrameAnchor _anchor; // Encapsulation of current java frame and it state
661 ThreadFunction _entry_point;
663 JNIEnv _jni_environment;
665 // Deopt support
666 DeoptResourceMark* _deopt_mark; // Holds special ResourceMark for deoptimization
668 intptr_t* _must_deopt_id; // id of frame that needs to be deopted once we
669 // transition out of native
671 vframeArray* _vframe_array_head; // Holds the heap of the active vframeArrays
672 vframeArray* _vframe_array_last; // Holds last vFrameArray we popped
673 // Because deoptimization is lazy we must save jvmti requests to set locals
674 // in compiled frames until we deoptimize and we have an interpreter frame.
675 // This holds the pointer to array (yeah like there might be more than one) of
676 // description of compiled vframes that have locals that need to be updated.
677 GrowableArray<jvmtiDeferredLocalVariableSet*>* _deferred_locals_updates;
679 // Handshake value for fixing 6243940. We need a place for the i2c
680 // adapter to store the callee methodOop. This value is NEVER live
681 // across a gc point so it does NOT have to be gc'd
682 // The handshake is open ended since we can't be certain that it will
683 // be NULLed. This is because we rarely ever see the race and end up
684 // in handle_wrong_method which is the backend of the handshake. See
685 // code in i2c adapters and handle_wrong_method.
687 methodOop _callee_target;
689 // Oop results of VM runtime calls
690 oop _vm_result; // Used to pass back an oop result into Java code, GC-preserved
691 oop _vm_result_2; // Used to pass back an oop result into Java code, GC-preserved
693 MonitorChunk* _monitor_chunks; // Contains the off stack monitors
694 // allocated during deoptimization
695 // and by JNI_MonitorEnter/Exit
697 // Async. requests support
698 enum AsyncRequests {
699 _no_async_condition = 0,
700 _async_exception,
701 _async_unsafe_access_error
702 };
703 AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request
704 oop _pending_async_exception;
706 // Safepoint support
707 public: // Expose _thread_state for SafeFetchInt()
708 volatile JavaThreadState _thread_state;
709 private:
710 ThreadSafepointState *_safepoint_state; // Holds information about a thread during a safepoint
711 address _saved_exception_pc; // Saved pc of instruction where last implicit exception happened
713 // JavaThread termination support
714 enum TerminatedTypes {
715 _not_terminated = 0xDEAD - 2,
716 _thread_exiting, // JavaThread::exit() has been called for this thread
717 _thread_terminated, // JavaThread is removed from thread list
718 _vm_exited // JavaThread is still executing native code, but VM is terminated
719 // only VM_Exit can set _vm_exited
720 };
722 // In general a JavaThread's _terminated field transitions as follows:
723 //
724 // _not_terminated => _thread_exiting => _thread_terminated
725 //
726 // _vm_exited is a special value to cover the case of a JavaThread
727 // executing native code after the VM itself is terminated.
728 TerminatedTypes _terminated;
729 // suspend/resume support
730 volatile bool _suspend_equivalent; // Suspend equivalent condition
731 jint _in_deopt_handler; // count of deoptimization
732 // handlers thread is in
733 volatile bool _doing_unsafe_access; // Thread may fault due to unsafe access
734 bool _do_not_unlock_if_synchronized; // Do not unlock the receiver of a synchronized method (since it was
735 // never locked) when throwing an exception. Used by interpreter only.
737 // Flag to mark a JNI thread in the process of attaching - See CR 6404306
738 // This flag is never set true other than at construction, and in that case
739 // is shortly thereafter set false
740 volatile bool _is_attaching;
742 public:
743 // State of the stack guard pages for this thread.
744 enum StackGuardState {
745 stack_guard_unused, // not needed
746 stack_guard_yellow_disabled,// disabled (temporarily) after stack overflow
747 stack_guard_enabled // enabled
748 };
750 private:
752 StackGuardState _stack_guard_state;
754 // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
755 // used to temp. parsing values into and out of the runtime system during exception handling for compiled
756 // code)
757 volatile oop _exception_oop; // Exception thrown in compiled code
758 volatile address _exception_pc; // PC where exception happened
759 volatile address _exception_handler_pc; // PC for handler of exception
760 volatile int _exception_stack_size; // Size of frame where exception happened
762 // support for compilation
763 bool _is_compiling; // is true if a compilation is active inthis thread (one compilation per thread possible)
765 // support for JNI critical regions
766 jint _jni_active_critical; // count of entries into JNI critical region
768 // For deadlock detection.
769 int _depth_first_number;
771 // JVMTI PopFrame support
772 // This is set to popframe_pending to signal that top Java frame should be popped immediately
773 int _popframe_condition;
775 #ifndef PRODUCT
776 int _jmp_ring_index;
777 struct {
778 // We use intptr_t instead of address so debugger doesn't try and display strings
779 intptr_t _target;
780 intptr_t _instruction;
781 const char* _file;
782 int _line;
783 } _jmp_ring[ jump_ring_buffer_size ];
784 #endif /* PRODUCT */
786 #ifndef SERIALGC
787 // Support for G1 barriers
789 ObjPtrQueue _satb_mark_queue; // Thread-local log for SATB barrier.
790 // Set of all such queues.
791 static SATBMarkQueueSet _satb_mark_queue_set;
793 DirtyCardQueue _dirty_card_queue; // Thread-local log for dirty cards.
794 // Set of all such queues.
795 static DirtyCardQueueSet _dirty_card_queue_set;
796 #endif // !SERIALGC
798 friend class VMThread;
799 friend class ThreadWaitTransition;
800 friend class VM_Exit;
802 void initialize(); // Initialized the instance variables
804 public:
805 // Constructor
806 JavaThread(bool is_attaching = false); // for main thread and JNI attached threads
807 JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
808 ~JavaThread();
810 #ifdef ASSERT
811 // verify this JavaThread hasn't be published in the Threads::list yet
812 void verify_not_published();
813 #endif
815 //JNI functiontable getter/setter for JVMTI jni function table interception API.
816 void set_jni_functions(struct JNINativeInterface_* functionTable) {
817 _jni_environment.functions = functionTable;
818 }
819 struct JNINativeInterface_* get_jni_functions() {
820 return (struct JNINativeInterface_ *)_jni_environment.functions;
821 }
823 // Executes Shutdown.shutdown()
824 void invoke_shutdown_hooks();
826 // Cleanup on thread exit
827 enum ExitType {
828 normal_exit,
829 jni_detach
830 };
831 void exit(bool destroy_vm, ExitType exit_type = normal_exit);
833 void cleanup_failed_attach_current_thread();
835 // Testers
836 virtual bool is_Java_thread() const { return true; }
838 // compilation
839 void set_is_compiling(bool f) { _is_compiling = f; }
840 bool is_compiling() const { return _is_compiling; }
842 // Thread chain operations
843 JavaThread* next() const { return _next; }
844 void set_next(JavaThread* p) { _next = p; }
846 // Thread oop. threadObj() can be NULL for initial JavaThread
847 // (or for threads attached via JNI)
848 oop threadObj() const { return _threadObj; }
849 void set_threadObj(oop p) { _threadObj = p; }
851 ThreadPriority java_priority() const; // Read from threadObj()
853 // Prepare thread and add to priority queue. If a priority is
854 // not specified, use the priority of the thread object. Threads_lock
855 // must be held while this function is called.
856 void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
858 void set_saved_exception_pc(address pc) { _saved_exception_pc = pc; }
859 address saved_exception_pc() { return _saved_exception_pc; }
862 ThreadFunction entry_point() const { return _entry_point; }
864 // Allocates a new Java level thread object for this thread. thread_name may be NULL.
865 void allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS);
867 // Last frame anchor routines
869 JavaFrameAnchor* frame_anchor(void) { return &_anchor; }
871 // last_Java_sp
872 bool has_last_Java_frame() const { return _anchor.has_last_Java_frame(); }
873 intptr_t* last_Java_sp() const { return _anchor.last_Java_sp(); }
875 // last_Java_pc
877 address last_Java_pc(void) { return _anchor.last_Java_pc(); }
879 // Safepoint support
880 JavaThreadState thread_state() const { return _thread_state; }
881 void set_thread_state(JavaThreadState s) { _thread_state=s; }
882 ThreadSafepointState *safepoint_state() const { return _safepoint_state; }
883 void set_safepoint_state(ThreadSafepointState *state) { _safepoint_state = state; }
884 bool is_at_poll_safepoint() { return _safepoint_state->is_at_poll_safepoint(); }
886 // thread has called JavaThread::exit() or is terminated
887 bool is_exiting() { return _terminated == _thread_exiting || is_terminated(); }
888 // thread is terminated (no longer on the threads list); we compare
889 // against the two non-terminated values so that a freed JavaThread
890 // will also be considered terminated.
891 bool is_terminated() { return _terminated != _not_terminated && _terminated != _thread_exiting; }
892 void set_terminated(TerminatedTypes t) { _terminated = t; }
893 // special for Threads::remove() which is static:
894 void set_terminated_value() { _terminated = _thread_terminated; }
895 void block_if_vm_exited();
897 bool doing_unsafe_access() { return _doing_unsafe_access; }
898 void set_doing_unsafe_access(bool val) { _doing_unsafe_access = val; }
900 bool do_not_unlock_if_synchronized() { return _do_not_unlock_if_synchronized; }
901 void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
904 // Suspend/resume support for JavaThread
906 private:
907 void set_ext_suspended() { set_suspend_flag (_ext_suspended); }
908 void clear_ext_suspended() { clear_suspend_flag(_ext_suspended); }
910 public:
911 void java_suspend();
912 void java_resume();
913 int java_suspend_self();
915 void check_and_wait_while_suspended() {
916 assert(JavaThread::current() == this, "sanity check");
918 bool do_self_suspend;
919 do {
920 // were we externally suspended while we were waiting?
921 do_self_suspend = handle_special_suspend_equivalent_condition();
922 if (do_self_suspend) {
923 // don't surprise the thread that suspended us by returning
924 java_suspend_self();
925 set_suspend_equivalent();
926 }
927 } while (do_self_suspend);
928 }
929 static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread);
930 // Check for async exception in addition to safepoint and suspend request.
931 static void check_special_condition_for_native_trans(JavaThread *thread);
933 bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits);
934 bool is_ext_suspend_completed_with_lock(uint32_t *bits) {
935 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
936 // Warning: is_ext_suspend_completed() may temporarily drop the
937 // SR_lock to allow the thread to reach a stable thread state if
938 // it is currently in a transient thread state.
939 return is_ext_suspend_completed(false /*!called_by_wait */,
940 SuspendRetryDelay, bits);
941 }
943 // We cannot allow wait_for_ext_suspend_completion() to run forever or
944 // we could hang. SuspendRetryCount and SuspendRetryDelay are normally
945 // passed as the count and delay parameters. Experiments with specific
946 // calls to wait_for_ext_suspend_completion() can be done by passing
947 // other values in the code. Experiments with all calls can be done
948 // via the appropriate -XX options.
949 bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits);
951 void set_external_suspend() { set_suspend_flag (_external_suspend); }
952 void clear_external_suspend() { clear_suspend_flag(_external_suspend); }
954 void set_deopt_suspend() { set_suspend_flag (_deopt_suspend); }
955 void clear_deopt_suspend() { clear_suspend_flag(_deopt_suspend); }
956 bool is_deopt_suspend() { return (_suspend_flags & _deopt_suspend) != 0; }
958 bool is_external_suspend() const {
959 return (_suspend_flags & _external_suspend) != 0;
960 }
961 // Whenever a thread transitions from native to vm/java it must suspend
962 // if external|deopt suspend is present.
963 bool is_suspend_after_native() const {
964 return (_suspend_flags & (_external_suspend | _deopt_suspend) ) != 0;
965 }
967 // external suspend request is completed
968 bool is_ext_suspended() const {
969 return (_suspend_flags & _ext_suspended) != 0;
970 }
972 // legacy method that checked for either external suspension or vm suspension
973 bool is_any_suspended() const {
974 return is_ext_suspended();
975 }
977 bool is_external_suspend_with_lock() const {
978 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
979 return is_external_suspend();
980 }
982 // Special method to handle a pending external suspend request
983 // when a suspend equivalent condition lifts.
984 bool handle_special_suspend_equivalent_condition() {
985 assert(is_suspend_equivalent(),
986 "should only be called in a suspend equivalence condition");
987 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
988 bool ret = is_external_suspend();
989 if (!ret) {
990 // not about to self-suspend so clear suspend equivalence
991 clear_suspend_equivalent();
992 }
993 // implied else:
994 // We have a pending external suspend request so we leave the
995 // suspend_equivalent flag set until java_suspend_self() sets
996 // the ext_suspended flag and clears the suspend_equivalent
997 // flag. This insures that wait_for_ext_suspend_completion()
998 // will return consistent values.
999 return ret;
1000 }
1002 bool is_any_suspended_with_lock() const {
1003 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1004 return is_any_suspended();
1005 }
1006 // utility methods to see if we are doing some kind of suspension
1007 bool is_being_ext_suspended() const {
1008 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1009 return is_ext_suspended() || is_external_suspend();
1010 }
1012 bool is_suspend_equivalent() const { return _suspend_equivalent; }
1014 void set_suspend_equivalent() { _suspend_equivalent = true; };
1015 void clear_suspend_equivalent() { _suspend_equivalent = false; };
1017 // Thread.stop support
1018 void send_thread_stop(oop throwable);
1019 AsyncRequests clear_special_runtime_exit_condition() {
1020 AsyncRequests x = _special_runtime_exit_condition;
1021 _special_runtime_exit_condition = _no_async_condition;
1022 return x;
1023 }
1025 // Are any async conditions present?
1026 bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); }
1028 void check_and_handle_async_exceptions(bool check_unsafe_error = true);
1030 // these next two are also used for self-suspension and async exception support
1031 void handle_special_runtime_exit_condition(bool check_asyncs = true);
1033 // Return true if JavaThread has an asynchronous condition or
1034 // if external suspension is requested.
1035 bool has_special_runtime_exit_condition() {
1036 // We call is_external_suspend() last since external suspend should
1037 // be less common. Because we don't use is_external_suspend_with_lock
1038 // it is possible that we won't see an asynchronous external suspend
1039 // request that has just gotten started, i.e., SR_lock grabbed but
1040 // _external_suspend field change either not made yet or not visible
1041 // yet. However, this is okay because the request is asynchronous and
1042 // we will see the new flag value the next time through. It's also
1043 // possible that the external suspend request is dropped after
1044 // we have checked is_external_suspend(), we will recheck its value
1045 // under SR_lock in java_suspend_self().
1046 return (_special_runtime_exit_condition != _no_async_condition) ||
1047 is_external_suspend() || is_deopt_suspend();
1048 }
1050 void set_pending_unsafe_access_error() { _special_runtime_exit_condition = _async_unsafe_access_error; }
1052 void set_pending_async_exception(oop e) {
1053 _pending_async_exception = e;
1054 _special_runtime_exit_condition = _async_exception;
1055 set_has_async_exception();
1056 }
1058 // Fast-locking support
1059 bool is_lock_owned(address adr) const;
1061 // Accessors for vframe array top
1062 // The linked list of vframe arrays are sorted on sp. This means when we
1063 // unpack the head must contain the vframe array to unpack.
1064 void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
1065 vframeArray* vframe_array_head() const { return _vframe_array_head; }
1067 // Side structure for defering update of java frame locals until deopt occurs
1068 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred_locals() const { return _deferred_locals_updates; }
1069 void set_deferred_locals(GrowableArray<jvmtiDeferredLocalVariableSet *>* vf) { _deferred_locals_updates = vf; }
1071 // These only really exist to make debugging deopt problems simpler
1073 void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
1074 vframeArray* vframe_array_last() const { return _vframe_array_last; }
1076 // The special resourceMark used during deoptimization
1078 void set_deopt_mark(DeoptResourceMark* value) { _deopt_mark = value; }
1079 DeoptResourceMark* deopt_mark(void) { return _deopt_mark; }
1081 intptr_t* must_deopt_id() { return _must_deopt_id; }
1082 void set_must_deopt_id(intptr_t* id) { _must_deopt_id = id; }
1083 void clear_must_deopt_id() { _must_deopt_id = NULL; }
1085 methodOop callee_target() const { return _callee_target; }
1086 void set_callee_target (methodOop x) { _callee_target = x; }
1088 // Oop results of vm runtime calls
1089 oop vm_result() const { return _vm_result; }
1090 void set_vm_result (oop x) { _vm_result = x; }
1092 oop vm_result_2() const { return _vm_result_2; }
1093 void set_vm_result_2 (oop x) { _vm_result_2 = x; }
1095 // Exception handling for compiled methods
1096 oop exception_oop() const { return _exception_oop; }
1097 int exception_stack_size() const { return _exception_stack_size; }
1098 address exception_pc() const { return _exception_pc; }
1099 address exception_handler_pc() const { return _exception_handler_pc; }
1101 void set_exception_oop(oop o) { _exception_oop = o; }
1102 void set_exception_pc(address a) { _exception_pc = a; }
1103 void set_exception_handler_pc(address a) { _exception_handler_pc = a; }
1104 void set_exception_stack_size(int size) { _exception_stack_size = size; }
1106 // Stack overflow support
1107 inline size_t stack_available(address cur_sp);
1108 address stack_yellow_zone_base()
1109 { return (address)(stack_base() - (stack_size() - (stack_red_zone_size() + stack_yellow_zone_size()))); }
1110 size_t stack_yellow_zone_size()
1111 { return StackYellowPages * os::vm_page_size(); }
1112 address stack_red_zone_base()
1113 { return (address)(stack_base() - (stack_size() - stack_red_zone_size())); }
1114 size_t stack_red_zone_size()
1115 { return StackRedPages * os::vm_page_size(); }
1116 bool in_stack_yellow_zone(address a)
1117 { return (a <= stack_yellow_zone_base()) && (a >= stack_red_zone_base()); }
1118 bool in_stack_red_zone(address a)
1119 { return (a <= stack_red_zone_base()) && (a >= (address)((intptr_t)stack_base() - stack_size())); }
1121 void create_stack_guard_pages();
1122 void remove_stack_guard_pages();
1124 void enable_stack_yellow_zone();
1125 void disable_stack_yellow_zone();
1126 void enable_stack_red_zone();
1127 void disable_stack_red_zone();
1129 inline bool stack_yellow_zone_disabled();
1130 inline bool stack_yellow_zone_enabled();
1132 // Attempt to reguard the stack after a stack overflow may have occurred.
1133 // Returns true if (a) guard pages are not needed on this thread, (b) the
1134 // pages are already guarded, or (c) the pages were successfully reguarded.
1135 // Returns false if there is not enough stack space to reguard the pages, in
1136 // which case the caller should unwind a frame and try again. The argument
1137 // should be the caller's (approximate) sp.
1138 bool reguard_stack(address cur_sp);
1139 // Similar to above but see if current stackpoint is out of the guard area
1140 // and reguard if possible.
1141 bool reguard_stack(void);
1143 // Misc. accessors/mutators
1144 void set_do_not_unlock(void) { _do_not_unlock_if_synchronized = true; }
1145 void clr_do_not_unlock(void) { _do_not_unlock_if_synchronized = false; }
1146 bool do_not_unlock(void) { return _do_not_unlock_if_synchronized; }
1148 #ifndef PRODUCT
1149 void record_jump(address target, address instr, const char* file, int line);
1150 #endif /* PRODUCT */
1152 // For assembly stub generation
1153 static ByteSize threadObj_offset() { return byte_offset_of(JavaThread, _threadObj ); }
1154 #ifndef PRODUCT
1155 static ByteSize jmp_ring_index_offset() { return byte_offset_of(JavaThread, _jmp_ring_index ); }
1156 static ByteSize jmp_ring_offset() { return byte_offset_of(JavaThread, _jmp_ring ); }
1157 #endif /* PRODUCT */
1158 static ByteSize jni_environment_offset() { return byte_offset_of(JavaThread, _jni_environment ); }
1159 static ByteSize last_Java_sp_offset() {
1160 return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
1161 }
1162 static ByteSize last_Java_pc_offset() {
1163 return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
1164 }
1165 static ByteSize frame_anchor_offset() {
1166 return byte_offset_of(JavaThread, _anchor);
1167 }
1168 static ByteSize callee_target_offset() { return byte_offset_of(JavaThread, _callee_target ); }
1169 static ByteSize vm_result_offset() { return byte_offset_of(JavaThread, _vm_result ); }
1170 static ByteSize vm_result_2_offset() { return byte_offset_of(JavaThread, _vm_result_2 ); }
1171 static ByteSize thread_state_offset() { return byte_offset_of(JavaThread, _thread_state ); }
1172 static ByteSize saved_exception_pc_offset() { return byte_offset_of(JavaThread, _saved_exception_pc ); }
1173 static ByteSize osthread_offset() { return byte_offset_of(JavaThread, _osthread ); }
1174 static ByteSize exception_oop_offset() { return byte_offset_of(JavaThread, _exception_oop ); }
1175 static ByteSize exception_pc_offset() { return byte_offset_of(JavaThread, _exception_pc ); }
1176 static ByteSize exception_handler_pc_offset() { return byte_offset_of(JavaThread, _exception_handler_pc); }
1177 static ByteSize exception_stack_size_offset() { return byte_offset_of(JavaThread, _exception_stack_size); }
1178 static ByteSize stack_guard_state_offset() { return byte_offset_of(JavaThread, _stack_guard_state ); }
1179 static ByteSize suspend_flags_offset() { return byte_offset_of(JavaThread, _suspend_flags ); }
1181 static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
1183 #ifndef SERIALGC
1184 static ByteSize satb_mark_queue_offset() { return byte_offset_of(JavaThread, _satb_mark_queue); }
1185 static ByteSize dirty_card_queue_offset() { return byte_offset_of(JavaThread, _dirty_card_queue); }
1186 #endif // !SERIALGC
1188 // Returns the jni environment for this thread
1189 JNIEnv* jni_environment() { return &_jni_environment; }
1191 static JavaThread* thread_from_jni_environment(JNIEnv* env) {
1192 JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
1193 // Only return NULL if thread is off the thread list; starting to
1194 // exit should not return NULL.
1195 if (thread_from_jni_env->is_terminated()) {
1196 thread_from_jni_env->block_if_vm_exited();
1197 return NULL;
1198 } else {
1199 return thread_from_jni_env;
1200 }
1201 }
1203 // JNI critical regions. These can nest.
1204 bool in_critical() { return _jni_active_critical > 0; }
1205 void enter_critical() { assert(Thread::current() == this,
1206 "this must be current thread");
1207 _jni_active_critical++; }
1208 void exit_critical() { assert(Thread::current() == this,
1209 "this must be current thread");
1210 _jni_active_critical--;
1211 assert(_jni_active_critical >= 0,
1212 "JNI critical nesting problem?"); }
1214 // For deadlock detection
1215 int depth_first_number() { return _depth_first_number; }
1216 void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1218 private:
1219 void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
1221 public:
1222 MonitorChunk* monitor_chunks() const { return _monitor_chunks; }
1223 void add_monitor_chunk(MonitorChunk* chunk);
1224 void remove_monitor_chunk(MonitorChunk* chunk);
1225 bool in_deopt_handler() const { return _in_deopt_handler > 0; }
1226 void inc_in_deopt_handler() { _in_deopt_handler++; }
1227 void dec_in_deopt_handler() {
1228 assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1229 if (_in_deopt_handler > 0) { // robustness
1230 _in_deopt_handler--;
1231 }
1232 }
1234 private:
1235 void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1237 public:
1239 // Frame iteration; calls the function f for all frames on the stack
1240 void frames_do(void f(frame*, const RegisterMap*));
1242 // Memory operations
1243 void oops_do(OopClosure* f);
1245 // Sweeper operations
1246 void nmethods_do();
1248 // Memory management operations
1249 void gc_epilogue();
1250 void gc_prologue();
1252 // Misc. operations
1253 char* name() const { return (char*)get_thread_name(); }
1254 void print_on(outputStream* st) const;
1255 void print() const { print_on(tty); }
1256 void print_value();
1257 void print_thread_state_on(outputStream* ) const PRODUCT_RETURN;
1258 void print_thread_state() const PRODUCT_RETURN;
1259 void print_on_error(outputStream* st, char* buf, int buflen) const;
1260 void verify();
1261 const char* get_thread_name() const;
1262 private:
1263 // factor out low-level mechanics for use in both normal and error cases
1264 const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
1265 public:
1266 const char* get_threadgroup_name() const;
1267 const char* get_parent_name() const;
1269 // Accessing frames
1270 frame last_frame() {
1271 _anchor.make_walkable(this);
1272 return pd_last_frame();
1273 }
1274 javaVFrame* last_java_vframe(RegisterMap* reg_map);
1276 // Returns method at 'depth' java or native frames down the stack
1277 // Used for security checks
1278 klassOop security_get_caller_class(int depth);
1280 // Print stack trace in external format
1281 void print_stack_on(outputStream* st);
1282 void print_stack() { print_stack_on(tty); }
1284 // Print stack traces in various internal formats
1285 void trace_stack() PRODUCT_RETURN;
1286 void trace_stack_from(vframe* start_vf) PRODUCT_RETURN;
1287 void trace_frames() PRODUCT_RETURN;
1289 // Returns the number of stack frames on the stack
1290 int depth() const;
1292 // Function for testing deoptimization
1293 void deoptimize();
1294 void make_zombies();
1296 void deoptimized_wrt_marked_nmethods();
1298 // Profiling operation (see fprofile.cpp)
1299 public:
1300 bool profile_last_Java_frame(frame* fr);
1302 private:
1303 ThreadProfiler* _thread_profiler;
1304 private:
1305 friend class FlatProfiler; // uses both [gs]et_thread_profiler.
1306 friend class FlatProfilerTask; // uses get_thread_profiler.
1307 friend class ThreadProfilerMark; // uses get_thread_profiler.
1308 ThreadProfiler* get_thread_profiler() { return _thread_profiler; }
1309 ThreadProfiler* set_thread_profiler(ThreadProfiler* tp) {
1310 ThreadProfiler* result = _thread_profiler;
1311 _thread_profiler = tp;
1312 return result;
1313 }
1315 // Static operations
1316 public:
1317 // Returns the running thread as a JavaThread
1318 static inline JavaThread* current();
1320 // Returns the active Java thread. Do not use this if you know you are calling
1321 // from a JavaThread, as it's slower than JavaThread::current. If called from
1322 // the VMThread, it also returns the JavaThread that instigated the VMThread's
1323 // operation. You may not want that either.
1324 static JavaThread* active();
1326 inline CompilerThread* as_CompilerThread();
1328 public:
1329 virtual void run();
1330 void thread_main_inner();
1332 private:
1333 // PRIVILEGED STACK
1334 PrivilegedElement* _privileged_stack_top;
1335 GrowableArray<oop>* _array_for_gc;
1336 public:
1338 // Returns the privileged_stack information.
1339 PrivilegedElement* privileged_stack_top() const { return _privileged_stack_top; }
1340 void set_privileged_stack_top(PrivilegedElement *e) { _privileged_stack_top = e; }
1341 void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; }
1343 public:
1344 // Thread local information maintained by JVMTI.
1345 void set_jvmti_thread_state(JvmtiThreadState *value) { _jvmti_thread_state = value; }
1346 JvmtiThreadState *jvmti_thread_state() const { return _jvmti_thread_state; }
1347 static ByteSize jvmti_thread_state_offset() { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1348 void set_jvmti_get_loaded_classes_closure(JvmtiGetLoadedClassesClosure* value) { _jvmti_get_loaded_classes_closure = value; }
1349 JvmtiGetLoadedClassesClosure* get_jvmti_get_loaded_classes_closure() const { return _jvmti_get_loaded_classes_closure; }
1351 // JVMTI PopFrame support
1352 // Setting and clearing popframe_condition
1353 // All of these enumerated values are bits. popframe_pending
1354 // indicates that a PopFrame() has been requested and not yet been
1355 // completed. popframe_processing indicates that that PopFrame() is in
1356 // the process of being completed. popframe_force_deopt_reexecution_bit
1357 // indicates that special handling is required when returning to a
1358 // deoptimized caller.
1359 enum PopCondition {
1360 popframe_inactive = 0x00,
1361 popframe_pending_bit = 0x01,
1362 popframe_processing_bit = 0x02,
1363 popframe_force_deopt_reexecution_bit = 0x04
1364 };
1365 PopCondition popframe_condition() { return (PopCondition) _popframe_condition; }
1366 void set_popframe_condition(PopCondition c) { _popframe_condition = c; }
1367 void set_popframe_condition_bit(PopCondition c) { _popframe_condition |= c; }
1368 void clear_popframe_condition() { _popframe_condition = popframe_inactive; }
1369 static ByteSize popframe_condition_offset() { return byte_offset_of(JavaThread, _popframe_condition); }
1370 bool has_pending_popframe() { return (popframe_condition() & popframe_pending_bit) != 0; }
1371 bool popframe_forcing_deopt_reexecution() { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1372 void clear_popframe_forcing_deopt_reexecution() { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
1373 #ifdef CC_INTERP
1374 bool pop_frame_pending(void) { return ((_popframe_condition & popframe_pending_bit) != 0); }
1375 void clr_pop_frame_pending(void) { _popframe_condition = popframe_inactive; }
1376 bool pop_frame_in_process(void) { return ((_popframe_condition & popframe_processing_bit) != 0); }
1377 void set_pop_frame_in_process(void) { _popframe_condition |= popframe_processing_bit; }
1378 void clr_pop_frame_in_process(void) { _popframe_condition &= ~popframe_processing_bit; }
1379 #endif
1381 private:
1382 // Saved incoming arguments to popped frame.
1383 // Used only when popped interpreted frame returns to deoptimized frame.
1384 void* _popframe_preserved_args;
1385 int _popframe_preserved_args_size;
1387 public:
1388 void popframe_preserve_args(ByteSize size_in_bytes, void* start);
1389 void* popframe_preserved_args();
1390 ByteSize popframe_preserved_args_size();
1391 WordSize popframe_preserved_args_size_in_words();
1392 void popframe_free_preserved_args();
1395 private:
1396 JvmtiThreadState *_jvmti_thread_state;
1397 JvmtiGetLoadedClassesClosure* _jvmti_get_loaded_classes_closure;
1399 // Used by the interpreter in fullspeed mode for frame pop, method
1400 // entry, method exit and single stepping support. This field is
1401 // only set to non-zero by the VM_EnterInterpOnlyMode VM operation.
1402 // It can be set to zero asynchronously (i.e., without a VM operation
1403 // or a lock) so we have to be very careful.
1404 int _interp_only_mode;
1406 public:
1407 // used by the interpreter for fullspeed debugging support (see above)
1408 static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1409 bool is_interp_only_mode() { return (_interp_only_mode != 0); }
1410 int get_interp_only_mode() { return _interp_only_mode; }
1411 void increment_interp_only_mode() { ++_interp_only_mode; }
1412 void decrement_interp_only_mode() { --_interp_only_mode; }
1414 private:
1415 ThreadStatistics *_thread_stat;
1417 public:
1418 ThreadStatistics* get_thread_stat() const { return _thread_stat; }
1420 // Return a blocker object for which this thread is blocked parking.
1421 oop current_park_blocker();
1423 private:
1424 static size_t _stack_size_at_create;
1426 public:
1427 static inline size_t stack_size_at_create(void) {
1428 return _stack_size_at_create;
1429 }
1430 static inline void set_stack_size_at_create(size_t value) {
1431 _stack_size_at_create = value;
1432 }
1434 #ifndef SERIALGC
1435 // SATB marking queue support
1436 ObjPtrQueue& satb_mark_queue() { return _satb_mark_queue; }
1437 static SATBMarkQueueSet& satb_mark_queue_set() {
1438 return _satb_mark_queue_set;
1439 }
1441 // Dirty card queue support
1442 DirtyCardQueue& dirty_card_queue() { return _dirty_card_queue; }
1443 static DirtyCardQueueSet& dirty_card_queue_set() {
1444 return _dirty_card_queue_set;
1445 }
1446 #endif // !SERIALGC
1448 // Machine dependent stuff
1449 #include "incls/_thread_pd.hpp.incl"
1451 public:
1452 void set_blocked_on_compilation(bool value) {
1453 _blocked_on_compilation = value;
1454 }
1456 bool blocked_on_compilation() {
1457 return _blocked_on_compilation;
1458 }
1459 protected:
1460 bool _blocked_on_compilation;
1463 // JSR166 per-thread parker
1464 private:
1465 Parker* _parker;
1466 public:
1467 Parker* parker() { return _parker; }
1469 // Biased locking support
1470 private:
1471 GrowableArray<MonitorInfo*>* _cached_monitor_info;
1472 public:
1473 GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; }
1474 void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; }
1476 // clearing/querying jni attach status
1477 bool is_attaching() const { return _is_attaching; }
1478 void set_attached() { _is_attaching = false; OrderAccess::fence(); }
1479 private:
1480 // This field is used to determine if a thread has claimed
1481 // a par_id: it is -1 if the thread has not claimed a par_id;
1482 // otherwise its value is the par_id that has been claimed.
1483 int _claimed_par_id;
1484 public:
1485 int get_claimed_par_id() { return _claimed_par_id; }
1486 void set_claimed_par_id(int id) { _claimed_par_id = id;}
1487 };
1489 // Inline implementation of JavaThread::current
1490 inline JavaThread* JavaThread::current() {
1491 Thread* thread = ThreadLocalStorage::thread();
1492 assert(thread != NULL && thread->is_Java_thread(), "just checking");
1493 return (JavaThread*)thread;
1494 }
1496 inline CompilerThread* JavaThread::as_CompilerThread() {
1497 assert(is_Compiler_thread(), "just checking");
1498 return (CompilerThread*)this;
1499 }
1501 inline bool JavaThread::stack_yellow_zone_disabled() {
1502 return _stack_guard_state == stack_guard_yellow_disabled;
1503 }
1505 inline bool JavaThread::stack_yellow_zone_enabled() {
1506 #ifdef ASSERT
1507 if (os::uses_stack_guard_pages()) {
1508 assert(_stack_guard_state != stack_guard_unused, "guard pages must be in use");
1509 }
1510 #endif
1511 return _stack_guard_state == stack_guard_enabled;
1512 }
1514 inline size_t JavaThread::stack_available(address cur_sp) {
1515 // This code assumes java stacks grow down
1516 address low_addr; // Limit on the address for deepest stack depth
1517 if ( _stack_guard_state == stack_guard_unused) {
1518 low_addr = stack_base() - stack_size();
1519 } else {
1520 low_addr = stack_yellow_zone_base();
1521 }
1522 return cur_sp > low_addr ? cur_sp - low_addr : 0;
1523 }
1525 // A JavaThread for low memory detection support
1526 class LowMemoryDetectorThread : public JavaThread {
1527 friend class VMStructs;
1528 public:
1529 LowMemoryDetectorThread(ThreadFunction entry_point) : JavaThread(entry_point) {};
1531 // Hide this thread from external view.
1532 bool is_hidden_from_external_view() const { return true; }
1533 };
1535 // A thread used for Compilation.
1536 class CompilerThread : public JavaThread {
1537 friend class VMStructs;
1538 private:
1539 CompilerCounters* _counters;
1541 ciEnv* _env;
1542 CompileLog* _log;
1543 CompileTask* _task;
1544 CompileQueue* _queue;
1546 public:
1548 static CompilerThread* current();
1550 CompilerThread(CompileQueue* queue, CompilerCounters* counters);
1552 bool is_Compiler_thread() const { return true; }
1553 // Hide this compiler thread from external view.
1554 bool is_hidden_from_external_view() const { return true; }
1556 CompileQueue* queue() { return _queue; }
1557 CompilerCounters* counters() { return _counters; }
1559 // Get/set the thread's compilation environment.
1560 ciEnv* env() { return _env; }
1561 void set_env(ciEnv* env) { _env = env; }
1563 // Get/set the thread's logging information
1564 CompileLog* log() { return _log; }
1565 void init_log(CompileLog* log) {
1566 // Set once, for good.
1567 assert(_log == NULL, "set only once");
1568 _log = log;
1569 }
1571 #ifndef PRODUCT
1572 private:
1573 IdealGraphPrinter *_ideal_graph_printer;
1574 public:
1575 IdealGraphPrinter *ideal_graph_printer() { return _ideal_graph_printer; }
1576 void set_ideal_graph_printer(IdealGraphPrinter *n) { _ideal_graph_printer = n; }
1577 #endif
1579 // Get/set the thread's current task
1580 CompileTask* task() { return _task; }
1581 void set_task(CompileTask* task) { _task = task; }
1582 };
1584 inline CompilerThread* CompilerThread::current() {
1585 return JavaThread::current()->as_CompilerThread();
1586 }
1589 // The active thread queue. It also keeps track of the current used
1590 // thread priorities.
1591 class Threads: AllStatic {
1592 friend class VMStructs;
1593 private:
1594 static JavaThread* _thread_list;
1595 static int _number_of_threads;
1596 static int _number_of_non_daemon_threads;
1597 static int _return_code;
1599 public:
1600 // Thread management
1601 // force_daemon is a concession to JNI, where we may need to add a
1602 // thread to the thread list before allocating its thread object
1603 static void add(JavaThread* p, bool force_daemon = false);
1604 static void remove(JavaThread* p);
1605 static bool includes(JavaThread* p);
1606 static JavaThread* first() { return _thread_list; }
1607 static void threads_do(ThreadClosure* tc);
1609 // Initializes the vm and creates the vm thread
1610 static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
1611 static void convert_vm_init_libraries_to_agents();
1612 static void create_vm_init_libraries();
1613 static void create_vm_init_agents();
1614 static void shutdown_vm_agents();
1615 static bool destroy_vm();
1616 // Supported VM versions via JNI
1617 // Includes JNI_VERSION_1_1
1618 static jboolean is_supported_jni_version_including_1_1(jint version);
1619 // Does not include JNI_VERSION_1_1
1620 static jboolean is_supported_jni_version(jint version);
1622 // Garbage collection
1623 static void follow_other_roots(void f(oop*));
1625 // Apply "f->do_oop" to all root oops in all threads.
1626 // This version may only be called by sequential code.
1627 static void oops_do(OopClosure* f);
1628 // This version may be called by sequential or parallel code.
1629 static void possibly_parallel_oops_do(OopClosure* f);
1630 // This creates a list of GCTasks, one per thread.
1631 static void create_thread_roots_tasks(GCTaskQueue* q);
1632 // This creates a list of GCTasks, one per thread, for marking objects.
1633 static void create_thread_roots_marking_tasks(GCTaskQueue* q);
1635 // Apply "f->do_oop" to roots in all threads that
1636 // are part of compiled frames
1637 static void compiled_frame_oops_do(OopClosure* f);
1639 static void convert_hcode_pointers();
1640 static void restore_hcode_pointers();
1642 // Sweeper
1643 static void nmethods_do();
1645 static void gc_epilogue();
1646 static void gc_prologue();
1648 // Verification
1649 static void verify();
1650 static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks);
1651 static void print(bool print_stacks, bool internal_format) {
1652 // this function is only used by debug.cpp
1653 print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */);
1654 }
1655 static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
1657 // Get Java threads that are waiting to enter a monitor. If doLock
1658 // is true, then Threads_lock is grabbed as needed. Otherwise, the
1659 // VM needs to be at a safepoint.
1660 static GrowableArray<JavaThread*>* get_pending_threads(int count,
1661 address monitor, bool doLock);
1663 // Get owning Java thread from the monitor's owner field. If doLock
1664 // is true, then Threads_lock is grabbed as needed. Otherwise, the
1665 // VM needs to be at a safepoint.
1666 static JavaThread *owning_thread_from_monitor_owner(address owner,
1667 bool doLock);
1669 // Number of threads on the active threads list
1670 static int number_of_threads() { return _number_of_threads; }
1671 // Number of non-daemon threads on the active threads list
1672 static int number_of_non_daemon_threads() { return _number_of_non_daemon_threads; }
1674 // Deoptimizes all frames tied to marked nmethods
1675 static void deoptimized_wrt_marked_nmethods();
1677 };
1680 // Thread iterator
1681 class ThreadClosure: public StackObj {
1682 public:
1683 virtual void do_thread(Thread* thread) = 0;
1684 };
1686 class SignalHandlerMark: public StackObj {
1687 private:
1688 Thread* _thread;
1689 public:
1690 SignalHandlerMark(Thread* t) {
1691 _thread = t;
1692 if (_thread) _thread->enter_signal_handler();
1693 }
1694 ~SignalHandlerMark() {
1695 if (_thread) _thread->leave_signal_handler();
1696 _thread = NULL;
1697 }
1698 };
1700 // ParkEvents are type-stable and immortal.
1701 //
1702 // Lifecycle: Once a ParkEvent is associated with a thread that ParkEvent remains
1703 // associated with the thread for the thread's entire lifetime - the relationship is
1704 // stable. A thread will be associated at most one ParkEvent. When the thread
1705 // expires, the ParkEvent moves to the EventFreeList. New threads attempt to allocate from
1706 // the EventFreeList before creating a new Event. Type-stability frees us from
1707 // worrying about stale Event or Thread references in the objectMonitor subsystem.
1708 // (A reference to ParkEvent is always valid, even though the event may no longer be associated
1709 // with the desired or expected thread. A key aspect of this design is that the callers of
1710 // park, unpark, etc must tolerate stale references and spurious wakeups).
1711 //
1712 // Only the "associated" thread can block (park) on the ParkEvent, although
1713 // any other thread can unpark a reachable parkevent. Park() is allowed to
1714 // return spuriously. In fact park-unpark a really just an optimization to
1715 // avoid unbounded spinning and surrender the CPU to be a polite system citizen.
1716 // A degenerate albeit "impolite" park-unpark implementation could simply return.
1717 // See http://blogs.sun.com/dave for more details.
1718 //
1719 // Eventually I'd like to eliminate Events and ObjectWaiters, both of which serve as
1720 // thread proxies, and simply make the THREAD structure type-stable and persistent.
1721 // Currently, we unpark events associated with threads, but ideally we'd just
1722 // unpark threads.
1723 //
1724 // The base-class, PlatformEvent, is platform-specific while the ParkEvent is
1725 // platform-independent. PlatformEvent provides park(), unpark(), etc., and
1726 // is abstract -- that is, a PlatformEvent should never be instantiated except
1727 // as part of a ParkEvent.
1728 // Equivalently we could have defined a platform-independent base-class that
1729 // exported Allocate(), Release(), etc. The platform-specific class would extend
1730 // that base-class, adding park(), unpark(), etc.
1731 //
1732 // A word of caution: The JVM uses 2 very similar constructs:
1733 // 1. ParkEvent are used for Java-level "monitor" synchronization.
1734 // 2. Parkers are used by JSR166-JUC park-unpark.
1735 //
1736 // We'll want to eventually merge these redundant facilities and use ParkEvent.
1739 class ParkEvent : public os::PlatformEvent {
1740 private:
1741 ParkEvent * FreeNext ;
1743 // Current association
1744 Thread * AssociatedWith ;
1745 intptr_t RawThreadIdentity ; // LWPID etc
1746 volatile int Incarnation ;
1748 // diagnostic : keep track of last thread to wake this thread.
1749 // this is useful for construction of dependency graphs.
1750 void * LastWaker ;
1752 public:
1753 // MCS-CLH list linkage and Native Mutex/Monitor
1754 ParkEvent * volatile ListNext ;
1755 ParkEvent * volatile ListPrev ;
1756 volatile intptr_t OnList ;
1757 volatile int TState ;
1758 volatile int Notified ; // for native monitor construct
1759 volatile int IsWaiting ; // Enqueued on WaitSet
1762 private:
1763 static ParkEvent * volatile FreeList ;
1764 static volatile int ListLock ;
1766 // It's prudent to mark the dtor as "private"
1767 // ensuring that it's not visible outside the package.
1768 // Unfortunately gcc warns about such usage, so
1769 // we revert to the less desirable "protected" visibility.
1770 // The other compilers accept private dtors.
1772 protected: // Ensure dtor is never invoked
1773 ~ParkEvent() { guarantee (0, "invariant") ; }
1775 ParkEvent() : PlatformEvent() {
1776 AssociatedWith = NULL ;
1777 FreeNext = NULL ;
1778 ListNext = NULL ;
1779 ListPrev = NULL ;
1780 OnList = 0 ;
1781 TState = 0 ;
1782 Notified = 0 ;
1783 IsWaiting = 0 ;
1784 }
1786 // We use placement-new to force ParkEvent instances to be
1787 // aligned on 256-byte address boundaries. This ensures that the least
1788 // significant byte of a ParkEvent address is always 0.
1790 void * operator new (size_t sz) ;
1791 void operator delete (void * a) ;
1793 public:
1794 static ParkEvent * Allocate (Thread * t) ;
1795 static void Release (ParkEvent * e) ;
1796 } ;