rust/src/rt/rust_sched_loop.cpp

397 lines
10 KiB
C++

#include "rust_sched_loop.h"
#include "rust_util.h"
#include "rust_scheduler.h"
#ifndef _WIN32
pthread_key_t rust_sched_loop::task_key;
#else
DWORD rust_sched_loop::task_key;
#endif
const size_t C_STACK_SIZE = 1024*1024;
bool rust_sched_loop::tls_initialized = false;
rust_sched_loop::rust_sched_loop(rust_scheduler *sched,int id) :
_log(this),
id(id),
should_exit(false),
cached_c_stack(NULL),
dead_task(NULL),
pump_signal(NULL),
kernel(sched->kernel),
sched(sched),
log_lvl(log_debug),
min_stack_size(kernel->env->min_stack_size),
local_region(kernel->env, false),
// TODO: calculate a per scheduler name.
name("main")
{
LOGPTR(this, "new dom", (uintptr_t)this);
isaac_init(kernel, &rctx, NULL);
if (!tls_initialized)
init_tls();
}
void
rust_sched_loop::activate(rust_task *task) {
lock.must_have_lock();
task->ctx.next = &c_context;
DLOG(this, task, "descheduling...");
lock.unlock();
prepare_c_stack(task);
task->ctx.swap(c_context);
task->cleanup_after_turn();
unprepare_c_stack();
lock.lock();
DLOG(this, task, "task has returned");
}
void
rust_sched_loop::fail() {
_log.log(NULL, log_err, "domain %s @0x%" PRIxPTR " root task failed",
name, this);
kernel->fail();
}
void
rust_sched_loop::kill_all_tasks() {
std::vector<rust_task*> all_tasks;
{
scoped_lock with(lock);
for (size_t i = 0; i < running_tasks.length(); i++) {
all_tasks.push_back(running_tasks[i]);
}
for (size_t i = 0; i < blocked_tasks.length(); i++) {
all_tasks.push_back(blocked_tasks[i]);
}
}
while (!all_tasks.empty()) {
rust_task *task = all_tasks.back();
all_tasks.pop_back();
// We don't want the failure of these tasks to propagate back
// to the kernel again since we're already failing everything
task->unsupervise();
task->kill();
}
}
size_t
rust_sched_loop::number_of_live_tasks() {
return running_tasks.length() + blocked_tasks.length();
}
/**
* Delete any dead tasks.
*/
void
rust_sched_loop::reap_dead_tasks() {
lock.must_have_lock();
if (dead_task == NULL) {
return;
}
// Dereferencing the task will probably cause it to be released
// from the scheduler, which may end up trying to take this lock
lock.unlock();
dead_task->delete_all_stacks();
// Deref the task, which may cause it to request us to release it
dead_task->deref();
dead_task = NULL;
lock.lock();
}
void
rust_sched_loop::release_task(rust_task *task) {
// Nobody should have a ref to the task at this point
assert(task->get_ref_count() == 0);
// Now delete the task, which will require using this thread's
// memory region.
delete task;
// Now release the task from the scheduler, which may trigger this
// thread to exit
sched->release_task();
}
/**
* 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_sched_loop::schedule_task() {
lock.must_have_lock();
assert(this);
// FIXME: in the face of failing tasks, this is not always right.
// assert(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_sched_loop::log_state() {
if (log_rt_task < log_debug) return;
if (!running_tasks.is_empty()) {
_log.log(NULL, log_debug, "running tasks:");
for (size_t i = 0; i < running_tasks.length(); i++) {
_log.log(NULL, log_debug, "\t task: %s @0x%" PRIxPTR,
running_tasks[i]->name,
running_tasks[i]);
}
}
if (!blocked_tasks.is_empty()) {
_log.log(NULL, log_debug, "blocked tasks:");
for (size_t i = 0; i < blocked_tasks.length(); i++) {
_log.log(NULL, log_debug, "\t task: %s @0x%" PRIxPTR
", blocked on: 0x%" PRIxPTR " '%s'",
blocked_tasks[i]->name, blocked_tasks[i],
blocked_tasks[i]->get_cond(),
blocked_tasks[i]->get_cond_name());
}
}
}
void
rust_sched_loop::on_pump_loop(rust_signal *signal) {
assert(pump_signal == NULL);
assert(signal != NULL);
pump_signal = signal;
}
void
rust_sched_loop::pump_loop() {
assert(pump_signal != NULL);
pump_signal->signal();
}
rust_sched_loop_state
rust_sched_loop::run_single_turn() {
DLOG(this, task,
"scheduler %d resuming ...", id);
lock.lock();
if (!should_exit) {
assert(dead_task == NULL && "Tasks should only die after running");
DLOG(this, dom, "worker %d, number_of_live_tasks = %d",
id, number_of_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.unlock();
return sched_loop_state_block;
}
assert(scheduled_task->running());
DLOG(this, task,
"activating task %s 0x%" PRIxPTR
", state: %s",
scheduled_task->name,
(uintptr_t)scheduled_task,
state_name(scheduled_task->get_state()));
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', worker id=%d" PRIxPTR,
scheduled_task->name,
(uintptr_t)scheduled_task,
state_name(scheduled_task->get_state()),
id);
reap_dead_tasks();
lock.unlock();
return sched_loop_state_keep_going;
} else {
assert(running_tasks.is_empty() && "Should have no running tasks");
assert(blocked_tasks.is_empty() && "Should have no blocked tasks");
assert(dead_task == NULL && "Should have no dead tasks");
DLOG(this, dom, "finished main-loop %d", id);
lock.unlock();
assert(!extra_c_stack);
if (cached_c_stack) {
destroy_stack(kernel->region(), cached_c_stack);
cached_c_stack = NULL;
}
sched->release_task_thread();
return sched_loop_state_exit;
}
}
rust_task *
rust_sched_loop::create_task(rust_task *spawner, const char *name) {
rust_task *task =
new (this->kernel, "rust_task")
rust_task (this, task_state_newborn,
spawner, name, kernel->env->min_stack_size);
DLOG(this, task, "created task: " PTR ", spawner: %s, name: %s",
task, spawner ? spawner->name : "null", name);
task->id = kernel->generate_task_id();
return task;
}
rust_task_list *
rust_sched_loop::state_list(rust_task_state state) {
switch (state) {
case task_state_running:
return &running_tasks;
case task_state_blocked:
return &blocked_tasks;
default:
return NULL;
}
}
const char *
rust_sched_loop::state_name(rust_task_state state) {
switch (state) {
case task_state_newborn:
return "newborn";
case task_state_running:
return "running";
case task_state_blocked:
return "blocked";
case task_state_dead:
return "dead";
default:
assert(false);
return "";
}
}
void
rust_sched_loop::transition(rust_task *task,
rust_task_state src, rust_task_state dst,
rust_cond *cond, const char* cond_name) {
scoped_lock with(lock);
DLOG(this, task,
"task %s " PTR " state change '%s' -> '%s' while in '%s'",
name, (uintptr_t)this, state_name(src), state_name(dst),
state_name(task->get_state()));
assert(task->get_state() == src);
rust_task_list *src_list = state_list(src);
if (src_list) {
src_list->remove(task);
}
rust_task_list *dst_list = state_list(dst);
if (dst_list) {
dst_list->append(task);
}
if (dst == task_state_dead) {
assert(dead_task == NULL);
dead_task = task;
}
task->set_state(dst, cond, cond_name);
pump_loop();
}
#ifndef _WIN32
void
rust_sched_loop::init_tls() {
int result = pthread_key_create(&task_key, NULL);
assert(!result && "Couldn't create the TLS key!");
tls_initialized = true;
}
void
rust_sched_loop::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();
}
#else
void
rust_sched_loop::init_tls() {
task_key = TlsAlloc();
assert(task_key != TLS_OUT_OF_INDEXES && "Couldn't create the TLS key!");
tls_initialized = true;
}
void
rust_sched_loop::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();
}
#endif
void
rust_sched_loop::exit() {
scoped_lock with(lock);
DLOG(this, dom, "Requesting exit for thread %d", id);
should_exit = true;
pump_loop();
}
// Before activating each task, make sure we have a C stack available.
// It needs to be allocated ahead of time (while we're on our own
// stack), because once we're on the Rust stack we won't have enough
// room to do the allocation
void
rust_sched_loop::prepare_c_stack(rust_task *task) {
assert(!extra_c_stack);
if (!cached_c_stack && !task->have_c_stack()) {
cached_c_stack = create_stack(kernel->region(), C_STACK_SIZE);
}
}
void
rust_sched_loop::unprepare_c_stack() {
if (extra_c_stack) {
destroy_stack(kernel->region(), extra_c_stack);
extra_c_stack = NULL;
}
}
//
// Local Variables:
// mode: C++
// fill-column: 70;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End:
//