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8234086: VM operation can be simplified

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Reviewed-by: kbarrett, dholmes, dcubed
This commit is contained in:
Robbin Ehn 2019-11-29 12:09:25 +01:00
parent 6230791e9e
commit 3d7d54b145
14 changed files with 75 additions and 159 deletions
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50
src/hotspot/share/runtime/vmOperations.hpp
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@ -128,15 +128,8 @@
template(GTestExecuteAtSafepoint) \
template(JFROldObject) \
class VM_Operation: public CHeapObj<mtInternal> {
class VM_Operation : public StackObj {
public:
enum Mode {
_safepoint, // blocking, safepoint, vm_op C-heap allocated
_no_safepoint, // blocking, no safepoint, vm_op C-Heap allocated
_concurrent, // non-blocking, no safepoint, vm_op C-Heap allocated
_async_safepoint // non-blocking, safepoint, vm_op C-Heap allocated
};
enum VMOp_Type {
VM_OPS_DO(VM_OP_ENUM)
VMOp_Terminating
@ -152,8 +145,7 @@ class VM_Operation: public CHeapObj<mtInternal> {
static const char* _names[];
public:
VM_Operation() { _calling_thread = NULL; _next = NULL; _prev = NULL; }
virtual ~VM_Operation() {}
VM_Operation() : _calling_thread(NULL), _timestamp(0), _next(NULL), _prev(NULL) {}
// VM operation support (used by VM thread)
Thread* calling_thread() const { return _calling_thread; }
@ -174,10 +166,7 @@ class VM_Operation: public CHeapObj<mtInternal> {
// completes. If doit_prologue() returns false the VM operation is cancelled.
virtual void doit() = 0;
virtual bool doit_prologue() { return true; };
virtual void doit_epilogue() {}; // Note: Not called if mode is: _concurrent
// Type test
virtual bool is_methodCompiler() const { return false; }
virtual void doit_epilogue() {};
// Linking
VM_Operation *next() const { return _next; }
@ -187,28 +176,12 @@ class VM_Operation: public CHeapObj<mtInternal> {
// Configuration. Override these appropriately in subclasses.
virtual VMOp_Type type() const = 0;
virtual Mode evaluation_mode() const { return _safepoint; }
virtual bool allow_nested_vm_operations() const { return false; }
virtual bool is_cheap_allocated() const { return false; }
virtual void oops_do(OopClosure* f) { /* do nothing */ };
// CAUTION: <don't hang yourself with following rope>
// If you override these methods, make sure that the evaluation
// of these methods is race-free and non-blocking, since these
// methods may be evaluated either by the mutators or by the
// vm thread, either concurrently with mutators or with the mutators
// stopped. In other words, taking locks is verboten, and if there
// are any races in evaluating the conditions, they'd better be benign.
virtual bool evaluate_at_safepoint() const {
return evaluation_mode() == _safepoint ||
evaluation_mode() == _async_safepoint;
}
virtual bool evaluate_concurrently() const {
return evaluation_mode() == _concurrent ||
evaluation_mode() == _async_safepoint;
}
static const char* mode_to_string(Mode mode);
// An operation can either be done inside a safepoint
// or concurrently with Java threads running.
virtual bool evaluate_at_safepoint() const { return true; }
// Debugging
virtual void print_on_error(outputStream* st) const;
@ -254,8 +227,6 @@ class VM_ThreadStop: public VM_Operation {
void doit();
// We deoptimize if top-most frame is compiled - this might require a C2I adapter to be generated
bool allow_nested_vm_operations() const { return true; }
Mode evaluation_mode() const { return _async_safepoint; }
bool is_cheap_allocated() const { return true; }
// GC support
void oops_do(OopClosure* f) {
@ -297,14 +268,6 @@ class VM_ICBufferFull: public VM_ForceSafepoint {
VMOp_Type type() const { return VMOp_ICBufferFull; }
};
// empty asynchronous vm op, when forcing a safepoint to scavenge monitors
class VM_ScavengeMonitors: public VM_ForceSafepoint {
public:
VMOp_Type type() const { return VMOp_ScavengeMonitors; }
Mode evaluation_mode() const { return _async_safepoint; }
bool is_cheap_allocated() const { return true; }
};
// Base class for invoking parts of a gtest in a safepoint.
// Derived classes provide the doit method.
// Typically also need to transition the gtest thread from native to VM.
@ -498,7 +461,6 @@ class VM_PrintCompileQueue: public VM_Operation {
public:
VM_PrintCompileQueue(outputStream* st) : _out(st) {}
VMOp_Type type() const { return VMOp_PrintCompileQueue; }
Mode evaluation_mode() const { return _safepoint; }
void doit();
};