rt: Rename rust_scheduler to rust_task_thread

1 files changed, 372 insertions, 0 deletions

diff --git a/src/rt/rust_task_thread.cpp b/src/rt/rust_task_thread.cpp
new file mode 100644
index 00000000000..774e71f24aa
--- /dev/null
+++ b/src/rt/rust_task_thread.cpp
@@ -0,0 +1,372 @@
+
+#include <stdarg.h>
+#include <cassert>
+#include <pthread.h>
+#include "rust_internal.h"
+#include "rust_util.h"
+#include "globals.h"
+
+#ifndef _WIN32
+pthread_key_t rust_task_thread::task_key;
+#else
+DWORD rust_task_thread::task_key;
+#endif
+
+bool rust_task_thread::tls_initialized = false;
+
+rust_task_thread::rust_task_thread(rust_kernel *kernel,
+                               rust_srv *srv,
+                               int id) :
+    ref_count(1),
+    _log(srv, this),
+    log_lvl(log_debug),
+    srv(srv),
+    // TODO: calculate a per scheduler name.
+    name("main"),
+    newborn_tasks(this, "newborn"),
+    running_tasks(this, "running"),
+    blocked_tasks(this, "blocked"),
+    dead_tasks(this, "dead"),
+    cache(this),
+    kernel(kernel),
+    id(id),
+    min_stack_size(kernel->env->min_stack_size),
+    env(kernel->env),
+    should_exit(false)
+{
+    LOGPTR(this, "new dom", (uintptr_t)this);
+    isaac_init(this, &rctx);
+#ifndef __WIN32__
+    pthread_attr_init(&attr);
+    pthread_attr_setstacksize(&attr, 1024 * 1024);
+    pthread_attr_setdetachstate(&attr, true);
+#endif
+
+    if (!tls_initialized)
+        init_tls();
+}
+
+rust_task_thread::~rust_task_thread() {
+    DLOG(this, dom, "~rust_task_thread %s @0x%" PRIxPTR, name, (uintptr_t)this);
+
+    newborn_tasks.delete_all();
+    running_tasks.delete_all();
+    blocked_tasks.delete_all();
+    dead_tasks.delete_all();
+#ifndef __WIN32__
+    pthread_attr_destroy(&attr);
+#endif
+}
+
+void
+rust_task_thread::activate(rust_task *task) {
+    task->ctx.next = &c_context;
+    DLOG(this, task, "descheduling...");
+    lock.unlock();
+    task->ctx.swap(c_context);
+    lock.lock();
+    DLOG(this, task, "task has returned");
+}
+
+void
+rust_task_thread::log(rust_task* task, uint32_t level, char const *fmt, ...) {
+    char buf[BUF_BYTES];
+    va_list args;
+    va_start(args, fmt);
+    vsnprintf(buf, sizeof(buf), fmt, args);
+    _log.trace_ln(task, level, buf);
+    va_end(args);
+}
+
+void
+rust_task_thread::fail() {
+    log(NULL, log_err, "domain %s @0x%" PRIxPTR " root task failed",
+        name, this);
+    kernel->fail();
+}
+
+void
+rust_task_thread::kill_all_tasks() {
+    I(this, !lock.lock_held_by_current_thread());
+    scoped_lock with(lock);
+
+    for (size_t i = 0; i < running_tasks.length(); i++) {
+        // We don't want the failure of these tasks to propagate back
+        // to the kernel again since we're already failing everything
+        running_tasks[i]->unsupervise();
+        running_tasks[i]->kill();
+    }
+
+    for (size_t i = 0; i < blocked_tasks.length(); i++) {
+        blocked_tasks[i]->unsupervise();
+        blocked_tasks[i]->kill();
+    }
+}
+
+size_t
+rust_task_thread::number_of_live_tasks() {
+    return running_tasks.length() + blocked_tasks.length();
+}
+
+/**
+ * Delete any dead tasks.
+ */
+void
+rust_task_thread::reap_dead_tasks() {
+    I(this, lock.lock_held_by_current_thread());
+    if (dead_tasks.length() == 0) {
+        return;
+    }
+
+    // First make a copy of the dead_task list with the lock held
+    size_t dead_tasks_len = dead_tasks.length();
+    rust_task **dead_tasks_copy = (rust_task**)
+        srv->malloc(sizeof(rust_task*) * dead_tasks_len);
+    for (size_t i = 0; i < dead_tasks_len; ++i) {
+        dead_tasks_copy[i] = dead_tasks.pop_value();
+    }
+
+    // Now unlock again because we have to actually free the dead tasks,
+    // and that may end up wanting to lock the kernel lock. We have
+    // a kernel lock -> scheduler lock locking order that we need
+    // to maintain.
+    lock.unlock();
+
+    for (size_t i = 0; i < dead_tasks_len; ++i) {
+        rust_task *task = dead_tasks_copy[i];
+        if (task) {
+            task->deref();
+            int live_tasks = sync::decrement(kernel->live_tasks);
+            if (live_tasks == 0) {
+                // There are no more tasks and there never will be.
+                // Tell all the schedulers to exit.
+                kernel->exit_schedulers();
+            }
+        }
+    }
+    srv->free(dead_tasks_copy);
+
+    lock.lock();
+}
+
+/**
+ * Schedules a running task for execution. Only running tasks can be
+ * activated.  Blocked tasks have to be unblocked before they can be
+ * activated.
+ *
+ * Returns NULL if no tasks can be scheduled.
+ */
+rust_task *
+rust_task_thread::schedule_task() {
+    I(this, this);
+    // FIXME: in the face of failing tasks, this is not always right.
+    // I(this, n_live_tasks() > 0);
+    if (running_tasks.length() > 0) {
+        size_t k = isaac_rand(&rctx);
+        // Look around for a runnable task, starting at k.
+        for(size_t j = 0; j < running_tasks.length(); ++j) {
+            size_t  i = (j + k) % running_tasks.length();
+            return (rust_task *)running_tasks[i];
+        }
+    }
+    return NULL;
+}
+
+void
+rust_task_thread::log_state() {
+    if (log_rt_task < log_debug) return;
+
+    if (!running_tasks.is_empty()) {
+        log(NULL, log_debug, "running tasks:");
+        for (size_t i = 0; i < running_tasks.length(); i++) {
+            log(NULL, log_debug, "\t task: %s @0x%" PRIxPTR,
+                running_tasks[i]->name,
+                running_tasks[i]);
+        }
+    }
+
+    if (!blocked_tasks.is_empty()) {
+        log(NULL, log_debug, "blocked tasks:");
+        for (size_t i = 0; i < blocked_tasks.length(); i++) {
+            log(NULL, log_debug, "\t task: %s @0x%" PRIxPTR ", blocked on: 0x%"
+                PRIxPTR " '%s'",
+                blocked_tasks[i]->name, blocked_tasks[i],
+                blocked_tasks[i]->cond, blocked_tasks[i]->cond_name);
+        }
+    }
+
+    if (!dead_tasks.is_empty()) {
+        log(NULL, log_debug, "dead tasks:");
+        for (size_t i = 0; i < dead_tasks.length(); i++) {
+            log(NULL, log_debug, "\t task: %s 0x%" PRIxPTR,
+                dead_tasks[i]->name, dead_tasks[i]);
+        }
+    }
+}
+/**
+ * Starts the main scheduler loop which performs task scheduling for this
+ * domain.
+ *
+ * Returns once no more tasks can be scheduled and all task ref_counts
+ * drop to zero.
+ */
+void
+rust_task_thread::start_main_loop() {
+    lock.lock();
+
+    DLOG(this, dom, "started domain loop %d", id);
+
+    while (!should_exit) {
+        A(this, kernel->is_deadlocked() == false, "deadlock");
+
+        DLOG(this, dom, "worker %d, number_of_live_tasks = %d, total = %d",
+             id, number_of_live_tasks(), kernel->live_tasks);
+
+        rust_task *scheduled_task = schedule_task();
+
+        if (scheduled_task == NULL) {
+            log_state();
+            DLOG(this, task,
+                 "all tasks are blocked, scheduler id %d yielding ...",
+                 id);
+            lock.wait();
+            reap_dead_tasks();
+            DLOG(this, task,
+                 "scheduler %d resuming ...", id);
+            continue;
+        }
+
+        I(this, scheduled_task->running());
+
+        DLOG(this, task,
+             "activating task %s 0x%" PRIxPTR
+             ", sp=0x%" PRIxPTR
+             ", state: %s",
+             scheduled_task->name,
+             (uintptr_t)scheduled_task,
+             scheduled_task->user.rust_sp,
+             scheduled_task->state->name);
+
+        place_task_in_tls(scheduled_task);
+
+        DLOG(this, task,
+             "Running task %p on worker %d",
+             scheduled_task, id);
+        activate(scheduled_task);
+
+        DLOG(this, task,
+             "returned from task %s @0x%" PRIxPTR
+             " in state '%s', sp=0x%x, worker id=%d" PRIxPTR,
+             scheduled_task->name,
+             (uintptr_t)scheduled_task,
+             scheduled_task->state->name,
+             scheduled_task->user.rust_sp,
+             id);
+
+        reap_dead_tasks();
+    }
+
+    A(this, newborn_tasks.is_empty(), "Should have no newborn tasks");
+    A(this, running_tasks.is_empty(), "Should have no running tasks");
+    A(this, blocked_tasks.is_empty(), "Should have no blocked tasks");
+    A(this, dead_tasks.is_empty(), "Should have no dead tasks");
+
+    DLOG(this, dom, "finished main-loop %d", id);
+
+    lock.unlock();
+}
+
+rust_crate_cache *
+rust_task_thread::get_cache() {
+    return &cache;
+}
+
+rust_task *
+rust_task_thread::create_task(rust_task *spawner, const char *name,
+                            size_t init_stack_sz) {
+    rust_task *task =
+        new (this->kernel, "rust_task")
+        rust_task (this, &newborn_tasks, spawner, name, init_stack_sz);
+    DLOG(this, task, "created task: " PTR ", spawner: %s, name: %s",
+                        task, spawner ? spawner->name : "null", name);
+
+    {
+        scoped_lock with(lock);
+        newborn_tasks.append(task);
+    }
+
+    sync::increment(kernel->live_tasks);
+
+    return task;
+}
+
+void rust_task_thread::run() {
+    this->start_main_loop();
+}
+
+#ifndef _WIN32
+void
+rust_task_thread::init_tls() {
+    int result = pthread_key_create(&task_key, NULL);
+    assert(!result && "Couldn't create the TLS key!");
+    tls_initialized = true;
+}
+
+void
+rust_task_thread::place_task_in_tls(rust_task *task) {
+    int result = pthread_setspecific(task_key, task);
+    assert(!result && "Couldn't place the task in TLS!");
+    task->record_stack_limit();
+}
+
+rust_task *
+rust_task_thread::get_task() {
+    if (!tls_initialized)
+        return NULL;
+    rust_task *task = reinterpret_cast<rust_task *>
+        (pthread_getspecific(task_key));
+    assert(task && "Couldn't get the task from TLS!");
+    return task;
+}
+#else
+void
+rust_task_thread::init_tls() {
+    task_key = TlsAlloc();
+    assert(task_key != TLS_OUT_OF_INDEXES && "Couldn't create the TLS key!");
+    tls_initialized = true;
+}
+
+void
+rust_task_thread::place_task_in_tls(rust_task *task) {
+    BOOL result = TlsSetValue(task_key, task);
+    assert(result && "Couldn't place the task in TLS!");
+    task->record_stack_limit();
+}
+
+rust_task *
+rust_task_thread::get_task() {
+    if (!tls_initialized)
+        return NULL;
+    rust_task *task = reinterpret_cast<rust_task *>(TlsGetValue(task_key));
+    assert(task && "Couldn't get the task from TLS!");
+    return task;
+}
+#endif
+
+void
+rust_task_thread::exit() {
+    A(this, !lock.lock_held_by_current_thread(), "Shouldn't have lock");
+    scoped_lock with(lock);
+    should_exit = true;
+    lock.signal();
+}
+
+//
+// Local Variables:
+// mode: C++
+// fill-column: 70;
+// indent-tabs-mode: nil
+// c-basic-offset: 4
+// buffer-file-coding-system: utf-8-unix
+// End:
+//