/* Context switching within the JVM. */
-/* Copyright (c) 2009-2018. The SimGrid Team. All rights reserved. */
+/* Copyright (c) 2009-2021. The SimGrid Team. All rights reserved. */
/* This program is free software; you can redistribute it and/or modify it
* under the terms of the license (GNU LGPL) which comes with this package. */
#include "JavaContext.hpp"
#include "jxbt_utilities.hpp"
+#include "simgrid/Exception.hpp"
#include "src/simix/smx_private.hpp"
-#include "xbt/ex.hpp"
#include <functional>
#include <utility>
return new JavaContextFactory();
}
-JavaContextFactory::JavaContextFactory(): ContextFactory("JavaContextFactory")
+JavaContextFactory::JavaContextFactory() : ContextFactory()
{
+ xbt_assert(xbt::binary_name == "java");
}
JavaContextFactory::~JavaContextFactory()=default;
-JavaContext* JavaContextFactory::self()
+Context* JavaContextFactory::create_context(std::function<void()>&& code, actor::ActorImpl* actor)
{
- return static_cast<JavaContext*>(xbt_os_thread_get_extra_data());
-}
-
-JavaContext* JavaContextFactory::create_context(
- std::function<void()> code,
- void_pfn_smxprocess_t cleanup, smx_actor_t process)
-{
- return this->new_context<JavaContext>(std::move(code), cleanup, process);
+ return this->new_context<JavaContext>(std::move(code), actor);
}
void JavaContextFactory::run_all()
{
- for (smx_actor_t const& process : simgrid::simix::process_get_runnable()) {
- static_cast<JavaContext*>(process->context)->resume();
- }
+ SerialThreadContext::run_all();
}
-JavaContext::JavaContext(std::function<void()> code,
- void_pfn_smxprocess_t cleanup_func,
- smx_actor_t process)
- : Context(std::move(code), cleanup_func, process)
+JavaContext::JavaContext(std::function<void()>&& code, smx_actor_t actor)
+ : SerialThreadContext(std::move(code), actor, false /* not maestro */)
{
- static int thread_amount=0;
- thread_amount++;
-
- /* If the user provided a function for the process then use it otherwise is the context for maestro */
- if (has_code()) {
- this->jprocess = nullptr;
- this->begin = xbt_os_sem_init(0);
- this->end = xbt_os_sem_init(0);
-
- try {
- this->thread = xbt_os_thread_create(
- nullptr, JavaContext::wrapper, this, nullptr);
- }
- catch (xbt_ex& ex) {
- char* str = bprintf(
- "Failed to create context #%d. You may want to switch to Java coroutines to increase your limits (error: %s)."
- "See the Install section of simgrid-java documentation (in doc/install.html) for more on coroutines.",
- thread_amount, ex.what());
- xbt_ex new_exception(XBT_THROW_POINT, str);
- new_exception.category = ex.category;
- new_exception.value = ex.value;
- std::throw_with_nested(std::move(new_exception));
- }
- } else {
- this->thread = nullptr;
- xbt_os_thread_set_extra_data(this);
- }
+ /* ThreadContext already does all we need */
}
-JavaContext::~JavaContext()
+void JavaContext::start_hook()
{
- if (this->thread) {
- // We are not in maestro context
- xbt_os_thread_join(this->thread, nullptr);
- xbt_os_sem_destroy(this->begin);
- xbt_os_sem_destroy(this->end);
- }
-}
+ Context::set_current(this); // We need to attach it also for maestro, in contrary to our ancestor
-void* JavaContext::wrapper(void *data)
-{
- JavaContext* context = static_cast<JavaContext*>(data);
- xbt_os_thread_set_extra_data(context);
//Attach the thread to the JVM
-
JNIEnv *env;
XBT_ATTRIB_UNUSED jint error = __java_vm->AttachCurrentThread((void**)&env, nullptr);
xbt_assert((error == JNI_OK), "The thread could not be attached to the JVM");
- context->jenv = env;
- //Wait for the first scheduling round to happen.
- xbt_os_sem_acquire(context->begin);
- //Create the "Process" object if needed.
- (*context)();
- context->stop();
- return nullptr;
+ this->jenv_ = env;
}
-void JavaContext::stop()
+void JavaContext::stop_hook()
{
- /* I was asked to die (either with kill() or because of a failed element) */
- if (this->iwannadie) {
- this->iwannadie = 0;
- JNIEnv *env = get_current_thread_env();
- XBT_DEBUG("Gonna launch Killed Error");
- // When the process wants to stop before its regular end, we should cut its call stack quickly.
- // The easiest way to do so is to raise an exception that will be catched in its top calling level.
- //
- // For that, we raise a ProcessKilledError that is catched in Process::run() (in msg/Process.java)
- //
- // Throwing a Java exception to stop the actor may be an issue for pure C actors
- // (as the ones created for the VM migration). The Java exception will not be catched anywhere.
- // Bad things happen currently if these actors get killed, unfortunately.
- jxbt_throw_by_name(env, "org/simgrid/msg/ProcessKilledError",
- std::string("Process ") + this->process()->get_cname() + " killed from file JavaContext.cpp");
-
- // (remember that throwing a java exception from C does not break the C execution path.
- // Instead, it marks the exception to be raised when returning to the Java world and
- // continues to execute the C function until it ends or returns).
-
- // Once the Java stack is marked to be unrolled, a C cancel_error is raised to kill the simcall
- // on which the killed actor is blocked (if any).
- // Not doing so would prevent the actor to notice that it's dead, leading to segfaults when it wakes up.
- // This is dangerous: if the killed actor is not actually blocked, the cancel_error will not get catched.
- // But it should be OK in most cases:
- // - If I kill myself, I must do so with Process.kill().
- // The binding of this function in jmsg_process.cpp adds a try/catch around the MSG_process_kill() leading to us
- // - If I kill someone else that is blocked, the cancel_error will unblock it.
- //
- // A problem remains probably if I kill a process that is ready_to_run in the same scheduling round.
- // I guess that this will kill the whole simulation because the victim does not catch the exception.
- // The only solution I see to that problem would be to completely rewrite the process killing sequence
- // (also in C) so that it's based on regular C++ exceptions that would be catched anyway.
- // In other words, we need to do in C++ what we do in Java for sake of uniformity.
- //
- // Plus, C++ RAII would work in that case, too.
-
- XBT_DEBUG("Trigger a cancel error at the C level");
- THROWF(cancel_error, 0, "process cancelled");
- } else {
- Context::stop();
- /* detach the thread and kills it */
- JNIEnv *env = this->jenv;
- env->DeleteGlobalRef(this->jprocess);
- XBT_ATTRIB_UNUSED jint error = __java_vm->DetachCurrentThread();
- xbt_assert((error == JNI_OK), "The thread couldn't be detached.");
- xbt_os_sem_release(this->end);
- xbt_os_thread_exit(nullptr);
- }
-}
-
-void JavaContext::suspend()
-{
- xbt_os_sem_release(this->end);
- xbt_os_sem_acquire(this->begin);
-}
-
-// FIXME: inline those functions
-void JavaContext::resume()
-{
- xbt_os_sem_release(this->begin);
- xbt_os_sem_acquire(this->end);
+ JNIEnv* env = this->jenv_;
+ env->DeleteGlobalRef(this->jprocess_);
+ jint error = __java_vm->DetachCurrentThread();
+ if (error != JNI_OK) {
+ /* This is probably a Java thread, ie an actor not created from the XML (and thus from the C++),
+ * but from Java with something like new Process().start().
+ *
+ * We should not even try to detach such threads. Instead, we throw a Java exception that will raise up
+ * until run_jprocess(), IIUC.
+ */
+ jxbt_throw_by_name(env, "org/simgrid/msg/ProcessKilledError", "Process killed");
+ XBT_DEBUG("Cannot detach the current thread");
+ }
}
}}} // namespace simgrid::kernel::context
