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8130448: thread dump improvements, comment additions, new diagnostics inspired by 8077392

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Reviewed-by: dholmes, coleenp
This commit is contained in:
Daniel D. Daugherty 2015-07-14 09:33:20 -07:00
parent 055105c707
commit 0db4f21ce2
8 changed files with 136 additions and 75 deletions
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10
hotspot/src/cpu/x86/vm/macroAssembler_x86.cpp
View File

@ -1781,6 +1781,7 @@ void MacroAssembler::fast_lock(Register objReg, Register boxReg, Register tmpReg
cmpxchgptr(scrReg, Address(boxReg, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner)));
} else
if ((EmitSync & 128) == 0) { // avoid ST-before-CAS
// register juggle because we need tmpReg for cmpxchgptr below
movptr(scrReg, boxReg);
movptr(boxReg, tmpReg); // consider: LEA box, [tmp-2]
@ -1814,7 +1815,10 @@ void MacroAssembler::fast_lock(Register objReg, Register boxReg, Register tmpReg
}
cmpxchgptr(scrReg, Address(boxReg, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner)));
movptr(Address(scrReg, 0), 3); // box->_displaced_header = 3
// If we weren't able to swing _owner from NULL to the BasicLock
// then take the slow path.
jccb (Assembler::notZero, DONE_LABEL);
// update _owner from BasicLock to thread
get_thread (scrReg); // beware: clobbers ICCs
movptr(Address(boxReg, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner)), scrReg);
xorptr(boxReg, boxReg); // set icc.ZFlag = 1 to indicate success
@ -2083,6 +2087,9 @@ void MacroAssembler::fast_unlock(Register objReg, Register boxReg, Register tmpR
xorptr(boxReg, boxReg); // box is really EAX
if (os::is_MP()) { lock(); }
cmpxchgptr(rsp, Address(tmpReg, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner)));
// There's no successor so we tried to regrab the lock with the
// placeholder value. If that didn't work, then another thread
// grabbed the lock so we're done (and exit was a success).
jccb (Assembler::notEqual, LSuccess);
// Since we're low on registers we installed rsp as a placeholding in _owner.
// Now install Self over rsp. This is safe as we're transitioning from
@ -2190,6 +2197,9 @@ void MacroAssembler::fast_unlock(Register objReg, Register boxReg, Register tmpR
movptr(boxReg, (int32_t)NULL_WORD);
if (os::is_MP()) { lock(); }
cmpxchgptr(r15_thread, Address(tmpReg, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner)));
// There's no successor so we tried to regrab the lock.
// If that didn't work, then another thread grabbed the
// lock so we're done (and exit was a success).
jccb (Assembler::notEqual, LSuccess);
// Intentional fall-through into slow-path

28
hotspot/src/share/vm/oops/markOop.cpp
View File

@ -32,26 +32,32 @@ PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
void markOopDesc::print_on(outputStream* st) const {
if (is_marked()) {
st->print(" marked(" INTPTR_FORMAT ")", value());
} else if (has_monitor()) {
// have to check has_monitor() before is_locked()
st->print(" monitor(" INTPTR_FORMAT ")=", value());
ObjectMonitor* mon = monitor();
if (mon == NULL) {
st->print("NULL (this should never be seen!)");
} else {
st->print("{count=" INTPTR_FORMAT ",waiters=" INTPTR_FORMAT
",recursions=" INTPTR_FORMAT ",owner=" INTPTR_FORMAT "}",
mon->count(), mon->waiters(), mon->recursions(),
p2i(mon->owner()));
}
} else if (is_locked()) {
st->print(" locked(" INTPTR_FORMAT ")->", value());
if (is_neutral()) {
st->print("is_neutral");
if (has_no_hash()) st->print(" no_hash");
else st->print(" hash=" INTPTR_FORMAT, hash());
if (has_no_hash()) {
st->print(" no_hash");
} else {
st->print(" hash=" INTPTR_FORMAT, hash());
}
st->print(" age=%d", age());
} else if (has_bias_pattern()) {
st->print("is_biased");
JavaThread* jt = biased_locker();
st->print(" biased_locker=" INTPTR_FORMAT, p2i(jt));
} else if (has_monitor()) {
ObjectMonitor* mon = monitor();
if (mon == NULL)
st->print("monitor=NULL");
else {
BasicLock * bl = (BasicLock *) mon->owner();
st->print("monitor={count=" INTPTR_FORMAT ",waiters=" INTPTR_FORMAT ",recursions=" INTPTR_FORMAT ",owner=" INTPTR_FORMAT "}",
mon->count(), mon->waiters(), mon->recursions(), p2i(bl));
}
} else {
st->print("??");
}

34
hotspot/src/share/vm/runtime/objectMonitor.cpp
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@ -1,5 +1,5 @@
/*
* Copyright (c) 1998, 2014, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1998, 2015, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -103,8 +103,10 @@
// The knob* variables are effectively final. Once set they should
// never be modified hence. Consider using __read_mostly with GCC.
int ObjectMonitor::Knob_ExitRelease = 0;
int ObjectMonitor::Knob_Verbose = 0;
int ObjectMonitor::Knob_VerifyInUse = 0;
int ObjectMonitor::Knob_VerifyMatch = 0;
int ObjectMonitor::Knob_SpinLimit = 5000; // derived by an external tool -
static int Knob_LogSpins = 0; // enable jvmstat tally for spins
static int Knob_HandOff = 0;
@ -251,24 +253,6 @@ static volatile int InitDone = 0;
// -----------------------------------------------------------------------------
// Enter support
bool ObjectMonitor::try_enter(Thread* THREAD) {
if (THREAD != _owner) {
if (THREAD->is_lock_owned ((address)_owner)) {
assert(_recursions == 0, "internal state error");
_owner = THREAD;
_recursions = 1;
return true;
}
if (Atomic::cmpxchg_ptr (THREAD, &_owner, NULL) != NULL) {
return false;
}
return true;
} else {
_recursions++;
return true;
}
}
void NOINLINE ObjectMonitor::enter(TRAPS) {
// The following code is ordered to check the most common cases first
// and to reduce RTS->RTO cache line upgrades on SPARC and IA32 processors.
@ -2272,7 +2256,7 @@ void ObjectWaiter::wait_reenter_end(ObjectMonitor * const mon) {
}
inline void ObjectMonitor::AddWaiter(ObjectWaiter* node) {
assert(node != NULL, "should not dequeue NULL node");
assert(node != NULL, "should not add NULL node");
assert(node->_prev == NULL, "node already in list");
assert(node->_next == NULL, "node already in list");
// put node at end of queue (circular doubly linked list)
@ -2407,8 +2391,8 @@ static int kvGetInt(char * kvList, const char * Key, int Default) {
char * v = kvGet(kvList, Key);
int rslt = v ? ::strtol(v, NULL, 0) : Default;
if (Knob_ReportSettings && v != NULL) {
::printf (" SyncKnob: %s %d(%d)\n", Key, rslt, Default) ;
::fflush(stdout);
tty->print_cr("INFO: SyncKnob: %s %d(%d)", Key, rslt, Default) ;
tty->flush();
}
return rslt;
}
@ -2442,8 +2426,10 @@ void ObjectMonitor::DeferredInitialize() {
#define SETKNOB(x) { Knob_##x = kvGetInt(knobs, #x, Knob_##x); }
SETKNOB(ReportSettings);
SETKNOB(ExitRelease);
SETKNOB(Verbose);
SETKNOB(VerifyInUse);
SETKNOB(VerifyMatch);
SETKNOB(FixedSpin);
SETKNOB(SpinLimit);
SETKNOB(SpinBase);
@ -2477,7 +2463,9 @@ void ObjectMonitor::DeferredInitialize() {
if (os::is_MP()) {
BackOffMask = (1 << Knob_SpinBackOff) - 1;
if (Knob_ReportSettings) ::printf("BackOffMask=%X\n", BackOffMask);
if (Knob_ReportSettings) {
tty->print_cr("INFO: BackOffMask=0x%X", BackOffMask);
}
// CONSIDER: BackOffMask = ROUNDUP_NEXT_POWER2 (ncpus-1)
} else {
Knob_SpinLimit = 0;

21
hotspot/src/share/vm/runtime/objectMonitor.hpp
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 1998, 2014, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1998, 2015, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -196,8 +196,10 @@ class ObjectMonitor {
static PerfCounter * _sync_Deflations;
static PerfLongVariable * _sync_MonExtant;
static int Knob_ExitRelease;
static int Knob_Verbose;
static int Knob_VerifyInUse;
static int Knob_VerifyMatch;
static int Knob_SpinLimit;
void* operator new (size_t size) throw() {
@ -317,7 +319,6 @@ class ObjectMonitor {
void print();
#endif
bool try_enter(TRAPS);
void enter(TRAPS);
void exit(bool not_suspended, TRAPS);
void wait(jlong millis, bool interruptable, TRAPS);
@ -354,14 +355,14 @@ class ObjectMonitor {
#undef TEVENT
#define TEVENT(nom) { if (SyncVerbose) FEVENT(nom); }
#define FEVENT(nom) \
{ \
static volatile int ctr = 0; \
int v = ++ctr; \
if ((v & (v - 1)) == 0) { \
::printf(#nom " : %d\n", v); \
::fflush(stdout); \
} \
#define FEVENT(nom) \
{ \
static volatile int ctr = 0; \
int v = ++ctr; \
if ((v & (v - 1)) == 0) { \
tty->print_cr("INFO: " #nom " : %d", v); \
tty->flush(); \
} \
}
#undef TEVENT

28
hotspot/src/share/vm/runtime/synchronizer.cpp
View File

@ -40,6 +40,7 @@
#include "runtime/stubRoutines.hpp"
#include "runtime/synchronizer.hpp"
#include "runtime/thread.inline.hpp"
#include "runtime/vframe.hpp"
#include "utilities/dtrace.hpp"
#include "utilities/events.hpp"
#include "utilities/preserveException.hpp"
@ -927,8 +928,9 @@ static void InduceScavenge(Thread * Self, const char * Whence) {
if (ForceMonitorScavenge == 0 && Atomic::xchg (1, &ForceMonitorScavenge) == 0) {
if (ObjectMonitor::Knob_Verbose) {
::printf ("Monitor scavenge - Induced STW @%s (%d)\n", Whence, ForceMonitorScavenge) ;
::fflush(stdout);
tty->print_cr("INFO: Monitor scavenge - Induced STW @%s (%d)",
Whence, ForceMonitorScavenge) ;
tty->flush();
}
// Induce a 'null' safepoint to scavenge monitors
// Must VM_Operation instance be heap allocated as the op will be enqueue and posted
@ -937,8 +939,9 @@ static void InduceScavenge(Thread * Self, const char * Whence) {
VMThread::execute(new VM_ForceAsyncSafepoint());
if (ObjectMonitor::Knob_Verbose) {
::printf ("Monitor scavenge - STW posted @%s (%d)\n", Whence, ForceMonitorScavenge) ;
::fflush(stdout);
tty->print_cr("INFO: Monitor scavenge - STW posted @%s (%d)",
Whence, ForceMonitorScavenge) ;
tty->flush();
}
}
}
@ -1603,10 +1606,11 @@ void ObjectSynchronizer::deflate_idle_monitors() {
// Consider: audit gFreeList to ensure that gMonitorFreeCount and list agree.
if (ObjectMonitor::Knob_Verbose) {
::printf("Deflate: InCirc=%d InUse=%d Scavenged=%d ForceMonitorScavenge=%d : pop=%d free=%d\n",
nInCirculation, nInuse, nScavenged, ForceMonitorScavenge,
gMonitorPopulation, gMonitorFreeCount);
::fflush(stdout);
tty->print_cr("INFO: Deflate: InCirc=%d InUse=%d Scavenged=%d "
"ForceMonitorScavenge=%d : pop=%d free=%d",
nInCirculation, nInuse, nScavenged, ForceMonitorScavenge,
gMonitorPopulation, gMonitorFreeCount);
tty->flush();
}
ForceMonitorScavenge = 0; // Reset
@ -1643,6 +1647,14 @@ class ReleaseJavaMonitorsClosure: public MonitorClosure {
ReleaseJavaMonitorsClosure(Thread* thread) : THREAD(thread) {}
void do_monitor(ObjectMonitor* mid) {
if (mid->owner() == THREAD) {
if (ObjectMonitor::Knob_VerifyMatch != 0) {
Handle obj((oop) mid->object());
tty->print("INFO: unexpected locked object:");
javaVFrame::print_locked_object_class_name(tty, obj, "locked");
fatal(err_msg("exiting JavaThread=" INTPTR_FORMAT
" unexpectedly owns ObjectMonitor=" INTPTR_FORMAT,
THREAD, mid));
}
(void)mid->complete_exit(CHECK);
}
}

25
hotspot/src/share/vm/runtime/thread.cpp
View File

@ -1802,14 +1802,25 @@ void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
assert(!this->has_pending_exception(), "ensure_join should have cleared");
// 6282335 JNI DetachCurrentThread spec states that all Java monitors
// held by this thread must be released. A detach operation must only
// get here if there are no Java frames on the stack. Therefore, any
// owned monitors at this point MUST be JNI-acquired monitors which are
// pre-inflated and in the monitor cache.
// held by this thread must be released. The spec does not distinguish
// between JNI-acquired and regular Java monitors. We can only see
// regular Java monitors here if monitor enter-exit matching is broken.
//
// ensure_join() ignores IllegalThreadStateExceptions, and so does this.
if (exit_type == jni_detach && JNIDetachReleasesMonitors) {
assert(!this->has_last_Java_frame(), "detaching with Java frames?");
// Optionally release any monitors for regular JavaThread exits. This
// is provided as a work around for any bugs in monitor enter-exit
// matching. This can be expensive so it is not enabled by default.
// ObjectMonitor::Knob_ExitRelease is a superset of the
// JNIDetachReleasesMonitors option.
//
// ensure_join() ignores IllegalThreadStateExceptions, and so does
// ObjectSynchronizer::release_monitors_owned_by_thread().
if ((exit_type == jni_detach && JNIDetachReleasesMonitors) ||
ObjectMonitor::Knob_ExitRelease) {
// Sanity check even though JNI DetachCurrentThread() would have
// returned JNI_ERR if there was a Java frame. JavaThread exit
// should be done executing Java code by the time we get here.
assert(!this->has_last_Java_frame(),
"should not have a Java frame when detaching or exiting");
ObjectSynchronizer::release_monitors_owned_by_thread(this);
assert(!this->has_pending_exception(), "release_monitors should have cleared");
}

60
hotspot/src/share/vm/runtime/vframe.cpp
View File

@ -144,7 +144,7 @@ GrowableArray<MonitorInfo*>* javaVFrame::locked_monitors() {
return result;
}
static void print_locked_object_class_name(outputStream* st, Handle obj, const char* lock_state) {
void javaVFrame::print_locked_object_class_name(outputStream* st, Handle obj, const char* lock_state) {
if (obj.not_null()) {
st->print("\t- %s <" INTPTR_FORMAT "> ", lock_state, (address)obj());
if (obj->klass() == SystemDictionary::Class_klass()) {
@ -160,17 +160,29 @@ static void print_locked_object_class_name(outputStream* st, Handle obj, const c
void javaVFrame::print_lock_info_on(outputStream* st, int frame_count) {
ResourceMark rm;
// If this is the first frame, and java.lang.Object.wait(...) then print out the receiver.
// If this is the first frame and it is java.lang.Object.wait(...)
// then print out the receiver. Locals are not always available,
// e.g., compiled native frames have no scope so there are no locals.
if (frame_count == 0) {
if (method()->name() == vmSymbols::wait_name() &&
method()->method_holder()->name() == vmSymbols::java_lang_Object()) {
const char *wait_state = "waiting on"; // assume we are waiting
// If earlier in the output we reported java.lang.Thread.State ==
// "WAITING (on object monitor)" and now we report "waiting on", then
// we are still waiting for notification or timeout. Otherwise if
// we earlier reported java.lang.Thread.State == "BLOCKED (on object
// monitor)", then we are actually waiting to re-lock the monitor.
// At this level we can't distinguish the two cases to report
// "waited on" rather than "waiting on" for the second case.
StackValueCollection* locs = locals();
if (!locs->is_empty()) {
StackValue* sv = locs->at(0);
if (sv->type() == T_OBJECT) {
Handle o = locs->at(0)->get_obj();
print_locked_object_class_name(st, o, "waiting on");
print_locked_object_class_name(st, o, wait_state);
}
} else {
st->print_cr("\t- %s <no object reference available>", wait_state);
}
} else if (thread()->current_park_blocker() != NULL) {
oop obj = thread()->current_park_blocker();
@ -179,8 +191,8 @@ void javaVFrame::print_lock_info_on(outputStream* st, int frame_count) {
}
}
// Print out all monitors that we have locked or are trying to lock
// Print out all monitors that we have locked, or are trying to lock,
// including re-locking after being notified or timing out in a wait().
GrowableArray<MonitorInfo*>* mons = monitors();
if (!mons->is_empty()) {
bool found_first_monitor = false;
@ -202,14 +214,14 @@ void javaVFrame::print_lock_info_on(outputStream* st, int frame_count) {
if (monitor->owner() != NULL) {
// the monitor is associated with an object, i.e., it is locked
// First, assume we have the monitor locked. If we haven't found an
// owned monitor before and this is the first frame, then we need to
// see if we have completed the lock or we are blocked trying to
// acquire it - we can only be blocked if the monitor is inflated
markOop mark = NULL;
const char *lock_state = "locked"; // assume we have the monitor locked
if (!found_first_monitor && frame_count == 0) {
// If this is the first frame and we haven't found an owned
// monitor before, then we need to see if we have completed
// the lock or if we are blocked trying to acquire it. Only
// an inflated monitor that is first on the monitor list in
// the first frame can block us on a monitor enter.
mark = monitor->owner()->mark();
if (mark->has_monitor() &&
( // we have marked ourself as pending on this monitor
@ -219,13 +231,33 @@ void javaVFrame::print_lock_info_on(outputStream* st, int frame_count) {
)) {
lock_state = "waiting to lock";
} else {
mark = NULL; // Disable printing below
// We own the monitor which is not as interesting so
// disable the extra printing below.
mark = NULL;
}
} else if (frame_count != 0) {
// This is not the first frame so we either own this monitor
// or we owned the monitor before and called wait(). Because
// wait() could have been called on any monitor in a lower
// numbered frame on the stack, we have to check all the
// monitors on the list for this frame.
mark = monitor->owner()->mark();
if (mark->has_monitor() &&
( // we have marked ourself as pending on this monitor
mark->monitor() == thread()->current_pending_monitor() ||
// we are not the owner of this monitor
!mark->monitor()->is_entered(thread())
)) {
lock_state = "waiting to re-lock in wait()";
} else {
// We own the monitor which is not as interesting so
// disable the extra printing below.
mark = NULL;
}
}
print_locked_object_class_name(st, monitor->owner(), lock_state);
if (Verbose && mark != NULL) {
// match with format above, replacing "-" with " ".
st->print("\t lockbits=");
if (ObjectMonitor::Knob_Verbose && mark != NULL) {
st->print("\t- lockbits=");
mark->print_on(st);
st->cr();
}

5
hotspot/src/share/vm/runtime/vframe.hpp
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -135,7 +135,8 @@ class javaVFrame: public vframe {
// Return an array of monitors locked by this frame in the youngest to oldest order
GrowableArray<MonitorInfo*>* locked_monitors();
// printing used during stack dumps
// printing used during stack dumps and diagnostics
static void print_locked_object_class_name(outputStream* st, Handle obj, const char* lock_state);
void print_lock_info_on(outputStream* st, int frame_count);
void print_lock_info(int frame_count) { print_lock_info_on(tty, frame_count); }