8255384: Remove special_runtime_exit_condition() check from SS::block()

Reviewed-by: dholmes, rrich, dcubed
This commit is contained in:
Patricio Chilano Mateo 2020-11-16 17:21:13 +00:00
parent f611fdfee8
commit 3675653c20
6 changed files with 30 additions and 57 deletions

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@ -102,11 +102,14 @@
There really shouldn't be any handles remaining to trash but this is cheap There really shouldn't be any handles remaining to trash but this is cheap
in relation to a safepoint. in relation to a safepoint.
*/ */
#define SAFEPOINT \ #define SAFEPOINT \
{ \ { \
/* zap freed handles rather than GC'ing them */ \ /* zap freed handles rather than GC'ing them */ \
HandleMarkCleaner __hmc(THREAD); \ HandleMarkCleaner __hmc(THREAD); \
CALL_VM(SafepointMechanism::process_if_requested(THREAD), handle_exception); \ if (SafepointMechanism::should_process(THREAD)) { \
CALL_VM(SafepointMechanism::process_if_requested_with_exit_check(THREAD, true /* check asyncs */), \
handle_exception); \
} \
} }
/* /*

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@ -737,29 +737,6 @@ void SafepointSynchronize::block(JavaThread *thread) {
guarantee(thread->safepoint_state()->get_safepoint_id() == InactiveSafepointCounter, guarantee(thread->safepoint_state()->get_safepoint_id() == InactiveSafepointCounter,
"The safepoint id should be set only in block path"); "The safepoint id should be set only in block path");
// Check for pending. async. exceptions or suspends - except if the
// thread was blocked inside the VM. has_special_runtime_exit_condition()
// is called last since it grabs a lock and we only want to do that when
// we must.
//
// Note: we never deliver an async exception at a polling point as the
// compiler may not have an exception handler for it. The polling
// code will notice the async and deoptimize and the exception will
// be delivered. (Polling at a return point is ok though). Sure is
// a lot of bother for a deprecated feature...
//
// We don't deliver an async exception if the thread state is
// _thread_in_native_trans so JNI functions won't be called with
// a surprising pending exception. If the thread state is going back to java,
// async exception is checked in check_special_condition_for_native_trans().
if (state != _thread_blocked_trans &&
state != _thread_in_vm_trans &&
thread->has_special_runtime_exit_condition()) {
thread->handle_special_runtime_exit_condition(
!thread->is_at_poll_safepoint() && (state != _thread_in_native_trans));
}
// cross_modify_fence is done by SafepointMechanism::process_if_requested // cross_modify_fence is done by SafepointMechanism::process_if_requested
// which is the only caller here. // which is the only caller here.
} }
@ -955,12 +932,7 @@ void ThreadSafepointState::handle_polling_page_exception() {
StackWatermarkSet::after_unwind(self); StackWatermarkSet::after_unwind(self);
// Process pending operation // Process pending operation
SafepointMechanism::process_if_requested(self); SafepointMechanism::process_if_requested_with_exit_check(self, true /* check asyncs */);
// We have to wait if we are here because of a handshake for object deoptimization.
if (self->is_obj_deopt_suspend()) {
self->wait_for_object_deoptimization();
}
self->check_and_handle_async_exceptions();
// restore oop result, if any // restore oop result, if any
if (return_oop) { if (return_oop) {
@ -970,17 +942,18 @@ void ThreadSafepointState::handle_polling_page_exception() {
// This is a safepoint poll. Verify the return address and block. // This is a safepoint poll. Verify the return address and block.
else { else {
set_at_poll_safepoint(true);
// verify the blob built the "return address" correctly // verify the blob built the "return address" correctly
assert(real_return_addr == caller_fr.pc(), "must match"); assert(real_return_addr == caller_fr.pc(), "must match");
set_at_poll_safepoint(true);
// Process pending operation // Process pending operation
SafepointMechanism::process_if_requested(self); // We never deliver an async exception at a polling point as the
// We have to wait if we are here because of a handshake for object deoptimization. // compiler may not have an exception handler for it. The polling
if (self->is_obj_deopt_suspend()) { // code will notice the pending async exception, deoptimize and
self->wait_for_object_deoptimization(); // the exception will be delivered. (Polling at a return point
} // is ok though). Sure is a lot of bother for a deprecated feature...
SafepointMechanism::process_if_requested_with_exit_check(self, false /* check asyncs */);
set_at_poll_safepoint(false); set_at_poll_safepoint(false);
// If we have a pending async exception deoptimize the frame // If we have a pending async exception deoptimize the frame

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@ -80,7 +80,7 @@ void SafepointMechanism::process(JavaThread *thread) {
// Any load in ::block must not pass the global poll load. // Any load in ::block must not pass the global poll load.
// Otherwise we might load an old safepoint counter (for example). // Otherwise we might load an old safepoint counter (for example).
OrderAccess::loadload(); OrderAccess::loadload();
SafepointSynchronize::block(thread); // Recursive SafepointSynchronize::block(thread);
} }
// The call to on_safepoint fixes the thread's oops and the first few frames. // The call to on_safepoint fixes the thread's oops and the first few frames.

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@ -83,6 +83,7 @@ public:
// Processes a pending requested operation. // Processes a pending requested operation.
static inline void process_if_requested(JavaThread* thread); static inline void process_if_requested(JavaThread* thread);
static inline void process_if_requested_with_exit_check(JavaThread* thread, bool check_asyncs);
// Compute what the poll values should be and install them. // Compute what the poll values should be and install them.
static void update_poll_values(JavaThread* thread); static void update_poll_values(JavaThread* thread);

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@ -80,6 +80,13 @@ void SafepointMechanism::process_if_requested(JavaThread *thread) {
process_if_requested_slow(thread); process_if_requested_slow(thread);
} }
void SafepointMechanism::process_if_requested_with_exit_check(JavaThread* thread, bool check_asyncs) {
process_if_requested(thread);
if (thread->has_special_runtime_exit_condition()) {
thread->handle_special_runtime_exit_condition(check_asyncs);
}
}
void SafepointMechanism::arm_local_poll(JavaThread* thread) { void SafepointMechanism::arm_local_poll(JavaThread* thread) {
thread->poll_data()->set_polling_word(_poll_word_armed_value); thread->poll_data()->set_polling_word(_poll_word_armed_value);
thread->poll_data()->set_polling_page(_poll_page_armed_value); thread->poll_data()->set_polling_page(_poll_page_armed_value);

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@ -2409,11 +2409,11 @@ void JavaThread::java_suspend_self_with_safepoint_check() {
// might return to _thread_in_Java and execute bytecodes for an arbitrary // might return to _thread_in_Java and execute bytecodes for an arbitrary
// long time. // long time.
set_thread_state_fence(state); set_thread_state_fence(state);
} while (is_external_suspend());
if (state != _thread_in_native) { if (state != _thread_in_native) {
SafepointMechanism::process_if_requested(this); SafepointMechanism::process_if_requested(this);
} }
} while (is_external_suspend());
} }
// Wait for another thread to perform object reallocation and relocking on behalf of // Wait for another thread to perform object reallocation and relocking on behalf of
@ -2493,20 +2493,9 @@ void JavaThread::verify_not_published() {
// directly and when thread state is _thread_in_native_trans // directly and when thread state is _thread_in_native_trans
void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) { void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
assert(thread->thread_state() == _thread_in_native_trans, "wrong state"); assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition"); assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
if (thread->is_external_suspend()) { SafepointMechanism::process_if_requested_with_exit_check(thread, false /* check asyncs */);
thread->java_suspend_self_with_safepoint_check();
} else {
SafepointMechanism::process_if_requested(thread);
}
if (thread->is_obj_deopt_suspend()) {
thread->wait_for_object_deoptimization();
}
JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(thread);)
} }
// Slow path when the native==>VM/Java barriers detect a safepoint is in // Slow path when the native==>VM/Java barriers detect a safepoint is in