8257831: Suspend with handshakes

Reviewed-by: dcubed, rrich, dholmes, pchilanomate, sspitsyn

Author: robehn

src/hotspot/os/aix/attachListener_aix.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2021, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012, 2018 SAP SE. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -440,10 +440,6 @@ void AixAttachOperation::complete(jint result, bufferedStream* st) {
   JavaThread* thread = JavaThread::current();
   ThreadBlockInVM tbivm(thread);
 
-  thread->set_suspend_equivalent();
-  // cleared by handle_special_suspend_equivalent_condition() or
-  // java_suspend_self() via check_and_wait_while_suspended()
-
   // write operation result
   char msg[32];
   sprintf(msg, "%d\n", result);
@@ -459,9 +455,6 @@ void AixAttachOperation::complete(jint result, bufferedStream* st) {
   // done
   ::close(this->socket());
 
-  // were we externally suspended while we were waiting?
-  thread->check_and_wait_while_suspended();
-
   delete this;
 }
 
@@ -472,15 +465,8 @@ AttachOperation* AttachListener::dequeue() {
   JavaThread* thread = JavaThread::current();
   ThreadBlockInVM tbivm(thread);
 
-  thread->set_suspend_equivalent();
-  // cleared by handle_special_suspend_equivalent_condition() or
-  // java_suspend_self() via check_and_wait_while_suspended()
-
   AttachOperation* op = AixAttachListener::dequeue();
 
-  // were we externally suspended while we were waiting?
-  thread->check_and_wait_while_suspended();
-
   return op;
 }
 
@@ -511,15 +497,8 @@ int AttachListener::pd_init() {
   JavaThread* thread = JavaThread::current();
   ThreadBlockInVM tbivm(thread);
 
-  thread->set_suspend_equivalent();
-  // cleared by handle_special_suspend_equivalent_condition() or
-  // java_suspend_self() via check_and_wait_while_suspended()
-
   int ret_code = AixAttachListener::init();
 
-  // were we externally suspended while we were waiting?
-  thread->check_and_wait_while_suspended();
-
   return ret_code;
 }
 

src/hotspot/os/bsd/attachListener_bsd.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2021, 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
@@ -409,10 +409,6 @@ void BsdAttachOperation::complete(jint result, bufferedStream* st) {
   JavaThread* thread = JavaThread::current();
   ThreadBlockInVM tbivm(thread);
 
-  thread->set_suspend_equivalent();
-  // cleared by handle_special_suspend_equivalent_condition() or
-  // java_suspend_self() via check_and_wait_while_suspended()
-
   // write operation result
   char msg[32];
   sprintf(msg, "%d\n", result);
@@ -427,9 +423,6 @@ void BsdAttachOperation::complete(jint result, bufferedStream* st) {
   // done
   ::close(this->socket());
 
-  // were we externally suspended while we were waiting?
-  thread->check_and_wait_while_suspended();
-
   delete this;
 }
 
@@ -440,15 +433,8 @@ AttachOperation* AttachListener::dequeue() {
   JavaThread* thread = JavaThread::current();
   ThreadBlockInVM tbivm(thread);
 
-  thread->set_suspend_equivalent();
-  // cleared by handle_special_suspend_equivalent_condition() or
-  // java_suspend_self() via check_and_wait_while_suspended()
-
   AttachOperation* op = BsdAttachListener::dequeue();
 
-  // were we externally suspended while we were waiting?
-  thread->check_and_wait_while_suspended();
-
   return op;
 }
 
@@ -479,15 +465,8 @@ int AttachListener::pd_init() {
   JavaThread* thread = JavaThread::current();
   ThreadBlockInVM tbivm(thread);
 
-  thread->set_suspend_equivalent();
-  // cleared by handle_special_suspend_equivalent_condition() or
-  // java_suspend_self() via check_and_wait_while_suspended()
-
   int ret_code = BsdAttachListener::init();
 
-  // were we externally suspended while we were waiting?
-  thread->check_and_wait_while_suspended();
-
   return ret_code;
 }
 

src/hotspot/os/linux/attachListener_linux.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2021, 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
@@ -409,10 +409,6 @@ void LinuxAttachOperation::complete(jint result, bufferedStream* st) {
   JavaThread* thread = JavaThread::current();
   ThreadBlockInVM tbivm(thread);
 
-  thread->set_suspend_equivalent();
-  // cleared by handle_special_suspend_equivalent_condition() or
-  // java_suspend_self() via check_and_wait_while_suspended()
-
   // write operation result
   char msg[32];
   sprintf(msg, "%d\n", result);
@@ -427,9 +423,6 @@ void LinuxAttachOperation::complete(jint result, bufferedStream* st) {
   // done
   ::close(this->socket());
 
-  // were we externally suspended while we were waiting?
-  thread->check_and_wait_while_suspended();
-
   delete this;
 }
 
@@ -440,15 +433,8 @@ AttachOperation* AttachListener::dequeue() {
   JavaThread* thread = JavaThread::current();
   ThreadBlockInVM tbivm(thread);
 
-  thread->set_suspend_equivalent();
-  // cleared by handle_special_suspend_equivalent_condition() or
-  // java_suspend_self() via check_and_wait_while_suspended()
-
   AttachOperation* op = LinuxAttachListener::dequeue();
 
-  // were we externally suspended while we were waiting?
-  thread->check_and_wait_while_suspended();
-
   return op;
 }
 
@@ -479,15 +465,8 @@ int AttachListener::pd_init() {
   JavaThread* thread = JavaThread::current();
   ThreadBlockInVM tbivm(thread);
 
-  thread->set_suspend_equivalent();
-  // cleared by handle_special_suspend_equivalent_condition() or
-  // java_suspend_self() via check_and_wait_while_suspended()
-
   int ret_code = LinuxAttachListener::init();
 
-  // were we externally suspended while we were waiting?
-  thread->check_and_wait_while_suspended();
-
   return ret_code;
 }
 

src/hotspot/os/posix/os_posix.cpp

@@ -1664,8 +1664,6 @@ void Parker::park(bool isAbsolute, jlong time) {
   }
 
   OSThreadWaitState osts(jt->osthread(), false /* not Object.wait() */);
-  jt->set_suspend_equivalent();
-  // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
 
   assert(_cur_index == -1, "invariant");
   if (time == 0) {
@@ -1688,11 +1686,6 @@ void Parker::park(bool isAbsolute, jlong time) {
   // Paranoia to ensure our locked and lock-free paths interact
   // correctly with each other and Java-level accesses.
   OrderAccess::fence();
-
-  // If externally suspended while waiting, re-suspend
-  if (jt->handle_special_suspend_equivalent_condition()) {
-    jt->java_suspend_self();
-  }
 }
 
 void Parker::unpark() {

src/hotspot/os/posix/signals_posix.cpp

@@ -32,6 +32,7 @@
 #include "runtime/java.hpp"
 #include "runtime/os.hpp"
 #include "runtime/osThread.hpp"
+#include "runtime/semaphore.inline.hpp"
 #include "runtime/stubRoutines.hpp"
 #include "runtime/thread.hpp"
 #include "signals_posix.hpp"
@@ -369,27 +370,7 @@ static int check_pending_signals() {
         return i;
       }
     }
-    JavaThread *thread = JavaThread::current();
-    ThreadBlockInVM tbivm(thread);
-
-    bool threadIsSuspended;
-    do {
-      thread->set_suspend_equivalent();
-      // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
-      sig_semaphore->wait();
-
-      // were we externally suspended while we were waiting?
-      threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
-      if (threadIsSuspended) {
-        // The semaphore has been incremented, but while we were waiting
-        // another thread suspended us. We don't want to continue running
-        // while suspended because that would surprise the thread that
-        // suspended us.
-        sig_semaphore->signal();
-
-        thread->java_suspend_self();
-      }
-    } while (threadIsSuspended);
+    sig_semaphore->wait_with_safepoint_check(JavaThread::current());
   }
   ShouldNotReachHere();
   return 0; // Satisfy compiler
@@ -1555,10 +1536,6 @@ void PosixSignals::hotspot_sigmask(Thread* thread) {
 //      - sets target osthread state to continue
 //      - sends signal to end the sigsuspend loop in the SR_handler
 //
-//  Note that the SR_lock plays no role in this suspend/resume protocol,
-//  but is checked for NULL in SR_handler as a thread termination indicator.
-//  The SR_lock is, however, used by JavaThread::java_suspend()/java_resume() APIs.
-//
 //  Note that resume_clear_context() and suspend_save_context() are needed
 //  by SR_handler(), so that fetch_frame_from_context() works,
 //  which in part is used by:
@@ -1603,11 +1580,11 @@ static void SR_handler(int sig, siginfo_t* siginfo, ucontext_t* context) {
 
   // On some systems we have seen signal delivery get "stuck" until the signal
   // mask is changed as part of thread termination. Check that the current thread
-  // has not already terminated (via SR_lock()) - else the following assertion
+  // has not already terminated - else the following assertion
   // will fail because the thread is no longer a JavaThread as the ~JavaThread
   // destructor has completed.
 
-  if (thread->SR_lock() == NULL) {
+  if (thread->has_terminated()) {
     return;
   }
 

src/hotspot/os/windows/attachListener_windows.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2005, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2005, 2021, 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
@@ -310,10 +310,6 @@ void Win32AttachOperation::complete(jint result, bufferedStream* result_stream)
   JavaThread* thread = JavaThread::current();
   ThreadBlockInVM tbivm(thread);
 
-  thread->set_suspend_equivalent();
-  // cleared by handle_special_suspend_equivalent_condition() or
-  // java_suspend_self() via check_and_wait_while_suspended()
-
   HANDLE hPipe = open_pipe();
   int lastError = (int)::GetLastError();
   if (hPipe != INVALID_HANDLE_VALUE) {
@@ -351,9 +347,6 @@ void Win32AttachOperation::complete(jint result, bufferedStream* result_stream)
 
     ::ReleaseMutex(Win32AttachListener::mutex());
   }
-
-  // were we externally suspended while we were waiting?
-  thread->check_and_wait_while_suspended();
 }
 
 
@@ -363,15 +356,8 @@ AttachOperation* AttachListener::dequeue() {
   JavaThread* thread = JavaThread::current();
   ThreadBlockInVM tbivm(thread);
 
-  thread->set_suspend_equivalent();
-  // cleared by handle_special_suspend_equivalent_condition() or
-  // java_suspend_self() via check_and_wait_while_suspended()
-
   AttachOperation* op = Win32AttachListener::dequeue();
 
-  // were we externally suspended while we were waiting?
-  thread->check_and_wait_while_suspended();
-
   return op;
 }
 

src/hotspot/os/windows/os_windows.cpp

@@ -2207,28 +2207,7 @@ static int check_pending_signals() {
         return i;
       }
     }
-    JavaThread *thread = JavaThread::current();
-
-    ThreadBlockInVM tbivm(thread);
-
-    bool threadIsSuspended;
-    do {
-      thread->set_suspend_equivalent();
-      // cleared by handle_special_suspend_equivalent_condition() or java_suspend_self()
-      sig_sem->wait();
-
-      // were we externally suspended while we were waiting?
-      threadIsSuspended = thread->handle_special_suspend_equivalent_condition();
-      if (threadIsSuspended) {
-        // The semaphore has been incremented, but while we were waiting
-        // another thread suspended us. We don't want to continue running
-        // while suspended because that would surprise the thread that
-        // suspended us.
-        sig_sem->signal();
-
-        thread->java_suspend_self();
-      }
-    } while (threadIsSuspended);
+    sig_sem->wait_with_safepoint_check(JavaThread::current());
   }
   ShouldNotReachHere();
   return 0; // Satisfy compiler
@@ -5487,15 +5466,9 @@ void Parker::park(bool isAbsolute, jlong time) {
   } else {
     ThreadBlockInVM tbivm(thread);
     OSThreadWaitState osts(thread->osthread(), false /* not Object.wait() */);
-    thread->set_suspend_equivalent();
 
     WaitForSingleObject(_ParkHandle, time);
     ResetEvent(_ParkHandle);
-
-    // If externally suspended while waiting, re-suspend
-    if (thread->handle_special_suspend_equivalent_condition()) {
-      thread->java_suspend_self();
-    }
   }
 }
 

src/hotspot/share/logging/logTag.hpp

@@ -174,6 +174,7 @@
   LOG_TAG(stringtable) \
   LOG_TAG(subclass) \
   LOG_TAG(survivor) \
+  LOG_TAG(suspend) \
   LOG_TAG(sweep) \
   LOG_TAG(symboltable) \
   LOG_TAG(system) \