Adding async operations; first step towards tossing libeio out.

2 files changed, 201 insertions, 0 deletions

diff --git a/src/Async.cc b/src/Async.cc
new file mode 100644
index 0000000..829c677
--- /dev/null
+++ b/src/Async.cc
@@ -0,0 +1,171 @@
+#include "Async.h"
+
+namespace {
+
+class AsyncStopper : public Balau::AsyncOperation {
+  public:
+    virtual bool needsSynchronousCallback() { return false; }
+    virtual void done() { delete this; }
+};
+
+};
+
+void Balau::AsyncManager::setIdleReadyCallback(void (*callback)(void *), void * param) {
+    while (!m_ready);
+    TLS * tls = getTLS();
+    tls->idleReadyCallback = callback;
+    tls->idleReadyParam = param;
+}
+
+void Balau::AsyncManager::queueOp(AsyncOperation * op) {
+    if (m_stopperPushed) {
+        Printer::elog(E_ASYNC, "AsyncManager's queue has been stopped; running operation %p on this thread instead.", op);
+        op->run();
+        op->finalize();
+        return;
+    }
+    while (!m_ready);
+    TLS * tls = getTLS();
+    Printer::elog(E_ASYNC, "Queuing operation at %p", op);
+    if (op->needsSynchronousCallback()) {
+        Printer::elog(E_ASYNC, "Operation at %p needs synchronous callback, copying values; idleQueue = %p; idleReadyCallback = %p; idleReadyParam = %p", &tls->idleQueue, tls->idleReadyCallback, tls->idleReadyParam);
+        op->m_idleQueue = &tls->idleQueue;
+        op->m_idleReadyCallback = tls->idleReadyCallback;
+        op->m_idleReadyParam = tls->idleReadyParam;
+    }
+    if (op->needsMainQueue())
+        m_queue.push(op);
+    else
+        m_finished.push(op);
+}
+
+void Balau::AsyncManager::checkIdle() {
+    if (m_numFinishersIdle > m_maxIdle)
+        killOneFinisher();
+    if (m_numFinishersIdle < m_minIdle)
+        startOneFinisher();
+    joinStoppedFinishers();
+}
+
+void Balau::AsyncManager::killOneFinisher() {
+    Printer::elog(E_ASYNC, "Too many workers idle (%i / %i), killing one.", m_numFinishersIdle, m_maxIdle);
+    m_finished.push(new AsyncStopper());
+}
+
+void Balau::AsyncManager::startOneFinisher() {
+    AsyncFinishWorker * worker = new AsyncFinishWorker(this, &m_finished);
+    Printer::elog(E_ASYNC, "Not enough workers idle (%i / %i), starting one at %p.", m_numFinishersIdle, m_minIdle, worker);
+    m_workers.push_back(worker);
+    m_numFinishers++;
+    worker->threadStart();
+}
+
+void Balau::AsyncManager::joinStoppedFinishers() {
+    for (auto i = m_workers.begin(); i != m_workers.end(); i++) {
+        AsyncFinishWorker * worker = *i;
+        if (!worker->m_stopped)
+            continue;
+        Printer::elog(E_ASYNC, "Joining stopped worker at %p", worker);
+        m_numFinishers--;
+        m_workers.erase(i);
+        worker->join();
+        delete worker;
+        break;
+    }
+}
+
+void * Balau::AsyncManager::proc() {
+    Printer::elog(E_ASYNC, "AsyncManager thread starting up");
+    m_tlsManager.init();
+    m_ready = true;
+    while (!m_stopping) {
+        checkIdle();
+        AsyncOperation * op = m_queue.pop();
+        Printer::elog(E_ASYNC, "AsyncManager got an operation at %p", op);
+        if (dynamic_cast<AsyncStopper *>(op)) {
+            Printer::elog(E_ASYNC, "AsyncManager got a stopper operation");
+            m_stopping = true;
+        }
+        Printer::elog(E_ASYNC, "AsyncManager running operation at %p", op);
+        op->run();
+        if (op->needsFinishWorker()) {
+            Printer::elog(E_ASYNC, "AsyncManager pushing operation at %p in the finisher's queue", op);
+            m_finished.push(op);
+        } else {
+            Printer::elog(E_ASYNC, "AsyncManager finalizing operation at %p", op);
+            op->finalize();
+        }
+    }
+    stopAllWorkers();
+
+    while (Atomic::Prefetch::Decrement(&m_numTLSes)) {
+        TLS * tls = m_TLSes.pop();
+        while (!tls->idleQueue.isEmpty());
+    }
+
+    return NULL;
+}
+
+void * Balau::AsyncFinishWorker::proc() {
+    Printer::elog(E_ASYNC, "AsyncFinishWorker thread starting up");
+    AsyncOperation * op;
+    while (!m_stopping) {
+        m_async->incIdle();
+        op = m_queue->pop();
+        m_async->decIdle();
+        Printer::elog(E_ASYNC, "AsyncFinishWorker got operation at %p", op);
+        if (dynamic_cast<AsyncStopper *>(op)) {
+            Printer::elog(E_ASYNC, "AsyncFinishWorker got a stopper operation");
+            m_stopping = true;
+        }
+        op->finalize();
+    }
+
+    m_stopped = true;
+    Printer::elog(E_ASYNC, "AsyncFinishWorker thread stopping");
+
+    return NULL;
+}
+
+void Balau::AsyncOperation::finalize() {
+    Printer::elog(E_ASYNC, "AsyncOperation::finalize() is finishing operation %p", this);
+    finish();
+    if (needsSynchronousCallback()) {
+        Printer::elog(E_ASYNC, "AsyncOperation::finalize() is pushing operation %p to its idle queue", this);
+        bool wasEmpty = m_idleQueue->isEmpty();
+        m_idleQueue->push(this);
+        Printer::elog(E_ASYNC, "AsyncOperation::finalize() has pushed operation %p to its idle queue; wasEmpty = %s; callback = %p", this, wasEmpty ? "true" : "false", m_idleReadyCallback);
+        if (wasEmpty && m_idleReadyCallback) {
+            Printer::elog(E_ASYNC, "AsyncOperation::finalize() is calling ready callback to wake up main loop");
+            m_idleReadyCallback(m_idleReadyParam);
+        }
+    } else {
+        Printer::elog(E_ASYNC, "AsyncOperation::finalize() is wrapping up operation %p", this);
+        done();
+    }
+}
+
+void Balau::AsyncManager::idle() {
+    Printer::elog(E_ASYNC, "AsyncManager::idle() is running");
+    while (!m_ready);
+    AsyncOperation * op;
+    TLS * tls = getTLS();
+    while ((op = tls->idleQueue.pop(false))) {
+        Printer::elog(E_ASYNC, "AsyncManager::idle() is wrapping up operation %p", op);
+        op->done();
+    }
+}
+
+void Balau::AsyncManager::threadExit() {
+    Printer::elog(E_ASYNC, "AsyncManager thread is being asked to stop; creating stopper");
+    if (Atomic::CmpXChgBool(&m_stopperPushed, true, false))
+        m_queue.push(new AsyncStopper());
+}
+
+void Balau::AsyncManager::stopAllWorkers() {
+    Printer::elog(E_ASYNC, "AsyncManager thread is being stopping and joining %i workers", m_numFinishers);
+    for (int i = 0; i < m_numFinishers; i++)
+        m_finished.push(new AsyncStopper());
+    for (auto worker : m_workers)
+        worker->join();
+}
diff --git a/src/TaskMan.cc b/src/TaskMan.cc
index 17f0a40..49c326a 100644
--- a/src/TaskMan.cc
+++ b/src/TaskMan.cc
@@ -1,8 +1,24 @@
+#include "Async.h"
 #include "TaskMan.h"
 #include "Task.h"
 #include "Main.h"
 #include "Local.h"
 
+static Balau::AsyncManager s_async;
+
+namespace {
+
+class AsyncStarter : public Balau::AtStart, Balau::AtExit {
+  public:
+      AsyncStarter() : AtStart(1000), AtExit(0) { }
+    void doStart() {
+        s_async.threadStart();
+    }
+    void doExit() {
+        s_async.join();
+    }
+};
+
 class Stopper : public Balau::Task {
   public:
       Stopper(int code) : m_code(code) { }
@@ -12,6 +28,10 @@ class Stopper : public Balau::Task {
     int m_code;
 };
 
+};
+
+static AsyncStarter s_asyncStarter;
+
 void Stopper::Do() {
     getTaskMan()->stopMe(m_code);
 }
@@ -207,6 +227,8 @@ int Balau::TaskMan::mainLoop() {
         if (t->getStatus() == Task::STARTING)
             starting.insert(t);
 
+    s_async.setIdleReadyCallback(asyncIdleReady, this);
+
     do {
         bool noWait = false;
 
@@ -239,6 +261,9 @@ int Balau::TaskMan::mainLoop() {
         ev_run(m_loop, noWait || m_stopped ? EVRUN_NOWAIT : EVRUN_ONCE);
         Printer::elog(E_TASK, "TaskMan at %p Getting out of libev main loop", this);
 
+        // calling async's idle loop here
+        s_async.idle();
+
         // let's check what task got stopped, and signal them
         for (Task * t : stopped) {
             IAssert((t->getStatus() == Task::STOPPED) || (t->getStatus() == Task::FAULTED), "Task %p in stopped list but isn't stopped.", t);
@@ -316,6 +341,7 @@ int Balau::TaskMan::mainLoop() {
 
     } while (!m_stopped);
     Printer::elog(E_TASK, "TaskManager at %p stopping.", this);
+    s_async.setIdleReadyCallback(NULL, NULL);
     return m_stopCode;
 }
 
@@ -329,6 +355,10 @@ void Balau::TaskMan::registerTask(Balau::Task * t, Balau::Task * stick) {
     }
 }
 
+void Balau::TaskMan::registerAsyncOp(Balau::AsyncOperation * op) {
+    s_async.queueOp(op);
+}
+
 void Balau::TaskMan::addToPending(Balau::Task * t) {
     m_pendingAdd.push(t);
 }