/
task.rs
595 lines (522 loc) · 18.9 KB
/
task.rs
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Language-level runtime services that should reasonably expected
//! to be available 'everywhere'. Local heaps, GC, unwinding,
//! local storage, and logging. Even a 'freestanding' Rust would likely want
//! to implement this.
use borrow;
use cast::transmute;
use cleanup;
use libc::{c_void, uintptr_t};
use ptr;
use prelude::*;
use option::{Option, Some, None};
use rt::env;
use rt::kill::Death;
use rt::local::Local;
use rt::logging::StdErrLogger;
use super::local_heap::LocalHeap;
use rt::sched::{Scheduler, SchedHandle};
use rt::stack::{StackSegment, StackPool};
use rt::context::Context;
use unstable::finally::Finally;
use task::spawn::Taskgroup;
use cell::Cell;
// The Task struct represents all state associated with a rust
// task. There are at this point two primary "subtypes" of task,
// however instead of using a subtype we just have a "task_type" field
// in the struct. This contains a pointer to another struct that holds
// the type-specific state.
pub struct Task {
heap: LocalHeap,
gc: GarbageCollector,
storage: LocalStorage,
logger: StdErrLogger,
unwinder: Unwinder,
taskgroup: Option<Taskgroup>,
death: Death,
destroyed: bool,
// FIXME(#6874/#7599) use StringRef to save on allocations
name: Option<~str>,
coroutine: Option<Coroutine>,
sched: Option<~Scheduler>,
task_type: TaskType
}
pub enum TaskType {
GreenTask(Option<~SchedHome>),
SchedTask
}
/// A coroutine is nothing more than a (register context, stack) pair.
pub struct Coroutine {
/// The segment of stack on which the task is currently running or
/// if the task is blocked, on which the task will resume
/// execution.
priv current_stack_segment: StackSegment,
/// Always valid if the task is alive and not running.
saved_context: Context
}
/// Some tasks have a deciated home scheduler that they must run on.
pub enum SchedHome {
AnySched,
Sched(SchedHandle)
}
pub struct GarbageCollector;
pub struct LocalStorage(*c_void, Option<extern "Rust" fn(*c_void)>);
pub struct Unwinder {
unwinding: bool,
}
impl Task {
// A helper to build a new task using the dynamically found
// scheduler and task. Only works in GreenTask context.
pub fn build_homed_child(stack_size: Option<uint>, f: ~fn(), home: SchedHome) -> ~Task {
let f = Cell::new(f);
let home = Cell::new(home);
do Local::borrow::<Task, ~Task> |running_task| {
let mut sched = running_task.sched.take_unwrap();
let new_task = ~running_task.new_child_homed(&mut sched.stack_pool,
stack_size,
home.take(),
f.take());
running_task.sched = Some(sched);
new_task
}
}
pub fn build_child(stack_size: Option<uint>, f: ~fn()) -> ~Task {
Task::build_homed_child(stack_size, f, AnySched)
}
pub fn build_homed_root(stack_size: Option<uint>, f: ~fn(), home: SchedHome) -> ~Task {
let f = Cell::new(f);
let home = Cell::new(home);
do Local::borrow::<Task, ~Task> |running_task| {
let mut sched = running_task.sched.take_unwrap();
let new_task = ~Task::new_root_homed(&mut sched.stack_pool,
stack_size,
home.take(),
f.take());
running_task.sched = Some(sched);
new_task
}
}
pub fn build_root(stack_size: Option<uint>, f: ~fn()) -> ~Task {
Task::build_homed_root(stack_size, f, AnySched)
}
pub fn new_sched_task() -> Task {
Task {
heap: LocalHeap::new(),
gc: GarbageCollector,
storage: LocalStorage(ptr::null(), None),
logger: StdErrLogger,
unwinder: Unwinder { unwinding: false },
taskgroup: None,
death: Death::new(),
destroyed: false,
coroutine: Some(Coroutine::empty()),
name: None,
sched: None,
task_type: SchedTask
}
}
pub fn new_root(stack_pool: &mut StackPool,
stack_size: Option<uint>,
start: ~fn()) -> Task {
Task::new_root_homed(stack_pool, stack_size, AnySched, start)
}
pub fn new_child(&mut self,
stack_pool: &mut StackPool,
stack_size: Option<uint>,
start: ~fn()) -> Task {
self.new_child_homed(stack_pool, stack_size, AnySched, start)
}
pub fn new_root_homed(stack_pool: &mut StackPool,
stack_size: Option<uint>,
home: SchedHome,
start: ~fn()) -> Task {
Task {
heap: LocalHeap::new(),
gc: GarbageCollector,
storage: LocalStorage(ptr::null(), None),
logger: StdErrLogger,
unwinder: Unwinder { unwinding: false },
taskgroup: None,
death: Death::new(),
destroyed: false,
name: None,
coroutine: Some(Coroutine::new(stack_pool, stack_size, start)),
sched: None,
task_type: GreenTask(Some(~home))
}
}
pub fn new_child_homed(&mut self,
stack_pool: &mut StackPool,
stack_size: Option<uint>,
home: SchedHome,
start: ~fn()) -> Task {
Task {
heap: LocalHeap::new(),
gc: GarbageCollector,
storage: LocalStorage(ptr::null(), None),
logger: StdErrLogger,
unwinder: Unwinder { unwinding: false },
taskgroup: None,
// FIXME(#7544) make watching optional
death: self.death.new_child(),
destroyed: false,
name: None,
coroutine: Some(Coroutine::new(stack_pool, stack_size, start)),
sched: None,
task_type: GreenTask(Some(~home))
}
}
pub fn give_home(&mut self, new_home: SchedHome) {
match self.task_type {
GreenTask(ref mut home) => {
*home = Some(~new_home);
}
SchedTask => {
rtabort!("type error: used SchedTask as GreenTask");
}
}
}
pub fn take_unwrap_home(&mut self) -> SchedHome {
match self.task_type {
GreenTask(ref mut home) => {
let out = home.take_unwrap();
return *out;
}
SchedTask => {
rtabort!("type error: used SchedTask as GreenTask");
}
}
}
pub fn run(&mut self, f: &fn()) {
rtdebug!("run called on task: %u", borrow::to_uint(self));
// The only try/catch block in the world. Attempt to run the task's
// client-specified code and catch any failures.
do self.unwinder.try {
// Run the task main function, then do some cleanup.
do f.finally {
// Destroy task-local storage. This may run user dtors.
match self.storage {
LocalStorage(ptr, Some(ref dtor)) => {
(*dtor)(ptr)
}
_ => ()
}
// FIXME #8302: Dear diary. I'm so tired and confused.
// There's some interaction in rustc between the box
// annihilator and the TLS dtor by which TLS is
// accessed from annihilated box dtors *after* TLS is
// destroyed. Somehow setting TLS back to null, as the
// old runtime did, makes this work, but I don't currently
// understand how. I would expect that, if the annihilator
// reinvokes TLS while TLS is uninitialized, that
// TLS would be reinitialized but never destroyed,
// but somehow this works. I have no idea what's going
// on but this seems to make things magically work. FML.
self.storage = LocalStorage(ptr::null(), None);
// Destroy remaining boxes. Also may run user dtors.
unsafe { cleanup::annihilate(); }
}
}
// NB. We pass the taskgroup into death so that it can be dropped while
// the unkillable counter is set. This is necessary for when the
// taskgroup destruction code drops references on KillHandles, which
// might require using unkillable (to synchronize with an unwrapper).
self.death.collect_failure(!self.unwinder.unwinding, self.taskgroup.take());
self.destroyed = true;
}
// New utility functions for homes.
pub fn is_home_no_tls(&self, sched: &~Scheduler) -> bool {
match self.task_type {
GreenTask(Some(~AnySched)) => { false }
GreenTask(Some(~Sched(SchedHandle { sched_id: ref id, _}))) => {
*id == sched.sched_id()
}
GreenTask(None) => {
rtabort!("task without home");
}
SchedTask => {
// Awe yea
rtabort!("type error: expected: GreenTask, found: SchedTask");
}
}
}
pub fn homed(&self) -> bool {
match self.task_type {
GreenTask(Some(~AnySched)) => { false }
GreenTask(Some(~Sched(SchedHandle { _ }))) => { true }
GreenTask(None) => {
rtabort!("task without home");
}
SchedTask => {
rtabort!("type error: expected: GreenTask, found: SchedTask");
}
}
}
// Grab both the scheduler and the task from TLS and check if the
// task is executing on an appropriate scheduler.
pub fn on_appropriate_sched() -> bool {
do Local::borrow::<Task,bool> |task| {
let sched_id = task.sched.get_ref().sched_id();
let sched_run_anything = task.sched.get_ref().run_anything;
match task.task_type {
GreenTask(Some(~AnySched)) => {
rtdebug!("anysched task in sched check ****");
sched_run_anything
}
GreenTask(Some(~Sched(SchedHandle { sched_id: ref id, _ }))) => {
rtdebug!("homed task in sched check ****");
*id == sched_id
}
GreenTask(None) => {
rtabort!("task without home");
}
SchedTask => {
rtabort!("type error: expected: GreenTask, found: SchedTask");
}
}
}
}
}
impl Drop for Task {
fn drop(&self) {
rtdebug!("called drop for a task: %u", borrow::to_uint(self));
rtassert!(self.destroyed)
}
}
// Coroutines represent nothing more than a context and a stack
// segment.
impl Coroutine {
pub fn new(stack_pool: &mut StackPool, stack_size: Option<uint>, start: ~fn()) -> Coroutine {
let stack_size = match stack_size {
Some(size) => size,
None => env::min_stack()
};
let start = Coroutine::build_start_wrapper(start);
let mut stack = stack_pool.take_segment(stack_size);
let initial_context = Context::new(start, &mut stack);
Coroutine {
current_stack_segment: stack,
saved_context: initial_context
}
}
pub fn empty() -> Coroutine {
Coroutine {
current_stack_segment: StackSegment::new(0),
saved_context: Context::empty()
}
}
fn build_start_wrapper(start: ~fn()) -> ~fn() {
let start_cell = Cell::new(start);
let wrapper: ~fn() = || {
// First code after swap to this new context. Run our
// cleanup job.
unsafe {
// Again - might work while safe, or it might not.
do Local::borrow::<Scheduler,()> |sched| {
(sched).run_cleanup_job();
}
// To call the run method on a task we need a direct
// reference to it. The task is in TLS, so we can
// simply unsafe_borrow it to get this reference. We
// need to still have the task in TLS though, so we
// need to unsafe_borrow.
let task = Local::unsafe_borrow::<Task>();
do (*task).run {
// N.B. Removing `start` from the start wrapper
// closure by emptying a cell is critical for
// correctness. The ~Task pointer, and in turn the
// closure used to initialize the first call
// frame, is destroyed in the scheduler context,
// not task context. So any captured closures must
// not contain user-definable dtors that expect to
// be in task context. By moving `start` out of
// the closure, all the user code goes our of
// scope while the task is still running.
let start = start_cell.take();
start();
};
}
// We remove the sched from the Task in TLS right now.
let sched = Local::take::<Scheduler>();
// ... allowing us to give it away when performing a
// scheduling operation.
sched.terminate_current_task()
};
return wrapper;
}
/// Destroy coroutine and try to reuse stack segment.
pub fn recycle(self, stack_pool: &mut StackPool) {
match self {
Coroutine { current_stack_segment, _ } => {
stack_pool.give_segment(current_stack_segment);
}
}
}
}
// Just a sanity check to make sure we are catching a Rust-thrown exception
static UNWIND_TOKEN: uintptr_t = 839147;
impl Unwinder {
pub fn try(&mut self, f: &fn()) {
use unstable::raw::Closure;
unsafe {
let closure: Closure = transmute(f);
let code = transmute(closure.code);
let env = transmute(closure.env);
let token = rust_try(try_fn, code, env);
assert!(token == 0 || token == UNWIND_TOKEN);
}
extern fn try_fn(code: *c_void, env: *c_void) {
unsafe {
let closure: Closure = Closure {
code: transmute(code),
env: transmute(env),
};
let closure: &fn() = transmute(closure);
closure();
}
}
extern {
#[rust_stack]
fn rust_try(f: *u8, code: *c_void, data: *c_void) -> uintptr_t;
}
}
pub fn begin_unwind(&mut self) -> ! {
self.unwinding = true;
unsafe {
rust_begin_unwind(UNWIND_TOKEN);
return transmute(());
}
extern {
fn rust_begin_unwind(token: uintptr_t);
}
}
}
#[cfg(test)]
mod test {
use rt::test::*;
#[test]
fn local_heap() {
do run_in_newsched_task() {
let a = @5;
let b = a;
assert!(*a == 5);
assert!(*b == 5);
}
}
#[test]
fn tls() {
use local_data;
do run_in_newsched_task() {
static key: local_data::Key<@~str> = &local_data::Key;
local_data::set(key, @~"data");
assert!(*local_data::get(key, |k| k.map_move(|k| *k)).unwrap() == ~"data");
static key2: local_data::Key<@~str> = &local_data::Key;
local_data::set(key2, @~"data");
assert!(*local_data::get(key2, |k| k.map_move(|k| *k)).unwrap() == ~"data");
}
}
#[test]
fn unwind() {
do run_in_newsched_task() {
let result = spawntask_try(||());
rtdebug!("trying first assert");
assert!(result.is_ok());
let result = spawntask_try(|| fail!());
rtdebug!("trying second assert");
assert!(result.is_err());
}
}
#[test]
fn rng() {
do run_in_newsched_task() {
use rand::{rng, Rng};
let mut r = rng();
let _ = r.next();
}
}
#[test]
fn logging() {
do run_in_newsched_task() {
info!("here i am. logging in a newsched task");
}
}
#[test]
fn comm_oneshot() {
use comm::*;
do run_in_newsched_task {
let (port, chan) = oneshot();
chan.send(10);
assert!(port.recv() == 10);
}
}
#[test]
fn comm_stream() {
use comm::*;
do run_in_newsched_task() {
let (port, chan) = stream();
chan.send(10);
assert!(port.recv() == 10);
}
}
#[test]
fn comm_shared_chan() {
use comm::*;
do run_in_newsched_task() {
let (port, chan) = stream();
let chan = SharedChan::new(chan);
chan.send(10);
assert!(port.recv() == 10);
}
}
#[test]
fn linked_failure() {
do run_in_newsched_task() {
let res = do spawntask_try {
spawntask_random(|| fail!());
};
assert!(res.is_err());
}
}
#[test]
fn heap_cycles() {
use option::{Option, Some, None};
do run_in_newsched_task {
struct List {
next: Option<@mut List>,
}
let a = @mut List { next: None };
let b = @mut List { next: Some(a) };
a.next = Some(b);
}
}
// XXX: This is a copy of test_future_result in std::task.
// It can be removed once the scheduler is turned on by default.
#[test]
fn future_result() {
do run_in_newsched_task {
use option::{Some, None};
use task::*;
let mut result = None;
let mut builder = task();
builder.future_result(|r| result = Some(r));
do builder.spawn {}
assert_eq!(result.unwrap().recv(), Success);
result = None;
let mut builder = task();
builder.future_result(|r| result = Some(r));
builder.unlinked();
do builder.spawn {
fail!();
}
assert_eq!(result.unwrap().recv(), Failure);
}
}
}