Refactored the runtime to view coroutines as a component of tasks, instead of tasks as a component of coroutines.

12 files changed, 386 insertions, 550 deletions

diff --git a/src/libstd/rt/comm.rs b/src/libstd/rt/comm.rs
index dd27c03ff51..7608bc89e02 100644
--- a/src/libstd/rt/comm.rs
+++ b/src/libstd/rt/comm.rs
@@ -20,7 +20,8 @@ use cast;
 use util;
 use ops::Drop;
 use kinds::Owned;
-use rt::sched::{Scheduler, Coroutine};
+use rt::sched::{Scheduler};
+use rt::task::Task;
 use rt::local::Local;
 use unstable::atomics::{AtomicUint, AtomicOption, SeqCst};
 use unstable::sync::UnsafeAtomicRcBox;
@@ -136,7 +137,7 @@ impl<T> ChanOne<T> {
                 }
                 task_as_state => {
                     // Port is blocked. Wake it up.
-                    let recvr: ~Coroutine = cast::transmute(task_as_state);
+                    let recvr: ~Task = cast::transmute(task_as_state);
                     let mut sched = Local::take::<Scheduler>();
                     rtdebug!("rendezvous send");
                     sched.metrics.rendezvous_sends += 1;
@@ -192,7 +193,7 @@ impl<T> PortOne<T> {
                         // NB: We have to drop back into the scheduler event loop here
                         // instead of switching immediately back or we could end up
                         // triggering infinite recursion on the scheduler's stack.
-                        let task: ~Coroutine = cast::transmute(task_as_state);
+                        let task: ~Task = cast::transmute(task_as_state);
                         sched.enqueue_task(task);
                     }
                     _ => util::unreachable()
@@ -257,7 +258,7 @@ impl<T> Drop for ChanOneHack<T> {
                 task_as_state => {
                     // The port is blocked waiting for a message we will never send. Wake it.
                     assert!((*this.packet()).payload.is_none());
-                    let recvr: ~Coroutine = cast::transmute(task_as_state);
+                    let recvr: ~Task = cast::transmute(task_as_state);
                     let sched = Local::take::<Scheduler>();
                     sched.schedule_task(recvr);
                 }
@@ -554,6 +555,8 @@ mod test {
                 { let _c = chan; }
                 port.recv();
             };
+            // What is our res?
+            rtdebug!("res is: %?", res.is_err());
             assert!(res.is_err());
         }
     }
@@ -905,4 +908,5 @@ mod test {
             }
         }
     }
+
 }
diff --git a/src/libstd/rt/join_latch.rs b/src/libstd/rt/join_latch.rs
index ad5cf2eb378..79c0d5da9a4 100644
--- a/src/libstd/rt/join_latch.rs
+++ b/src/libstd/rt/join_latch.rs
@@ -643,3 +643,4 @@ mod test {
         }
     }
 }
+
diff --git a/src/libstd/rt/local.rs b/src/libstd/rt/local.rs
index 6df1ffaa453..374933ab281 100644
--- a/src/libstd/rt/local.rs
+++ b/src/libstd/rt/local.rs
@@ -13,6 +13,7 @@ use rt::sched::Scheduler;
 use rt::task::Task;
 use rt::local_ptr;
 use rt::rtio::{EventLoop, IoFactoryObject};
+//use borrow::to_uint;
 
 pub trait Local {
     fn put(value: ~Self);
@@ -32,6 +33,7 @@ impl Local for Scheduler {
         let res_ptr: *mut Option<T> = &mut res;
         unsafe {
             do local_ptr::borrow |sched| {
+//                rtdebug!("successfully unsafe borrowed sched pointer");
                 let result = f(sched);
                 *res_ptr = Some(result);
             }
@@ -51,9 +53,12 @@ impl Local for Task {
     fn exists() -> bool { rtabort!("unimpl") }
     fn borrow<T>(f: &fn(&mut Task) -> T) -> T {
         do Local::borrow::<Scheduler, T> |sched| {
+//            rtdebug!("sched about to grab current_task");
             match sched.current_task {
                 Some(~ref mut task) => {
-                    f(&mut *task.task)
+//                    rtdebug!("current task pointer: %x", to_uint(task));
+//                    rtdebug!("current task heap pointer: %x", to_uint(&task.heap));
+                    f(task)
                 }
                 None => {
                     rtabort!("no scheduler")
@@ -64,7 +69,7 @@ impl Local for Task {
     unsafe fn unsafe_borrow() -> *mut Task {
         match (*Local::unsafe_borrow::<Scheduler>()).current_task {
             Some(~ref mut task) => {
-                let s: *mut Task = &mut *task.task;
+                let s: *mut Task = &mut *task;
                 return s;
             }
             None => {
diff --git a/src/libstd/rt/mod.rs b/src/libstd/rt/mod.rs
index bbf1cf0d9b7..aae194ae548 100644
--- a/src/libstd/rt/mod.rs
+++ b/src/libstd/rt/mod.rs
@@ -67,7 +67,7 @@ use iter::Times;
 use iterator::IteratorUtil;
 use option::Some;
 use ptr::RawPtr;
-use rt::sched::{Scheduler, Coroutine, Shutdown};
+use rt::sched::{Scheduler, Shutdown};
 use rt::sleeper_list::SleeperList;
 use rt::task::Task;
 use rt::thread::Thread;
@@ -268,10 +268,9 @@ pub fn run(main: ~fn()) -> int {
 
     // Create and enqueue the main task.
     let main_cell = Cell::new(main);
-    let mut new_task = ~Task::new_root();
-    new_task.on_exit = Some(on_exit);
-    let main_task = ~Coroutine::with_task(&mut scheds[0].stack_pool,
-                                          new_task, main_cell.take());
+    let mut main_task = ~Task::new_root(&mut scheds[0].stack_pool,
+                                    main_cell.take());
+    main_task.on_exit = Some(on_exit);
     scheds[0].enqueue_task(main_task);
 
     // Run each scheduler in a thread.
@@ -348,7 +347,7 @@ pub fn context() -> RuntimeContext {
 #[test]
 fn test_context() {
     use unstable::run_in_bare_thread;
-    use self::sched::{Scheduler, Coroutine};
+    use self::sched::{Scheduler};
     use rt::local::Local;
     use rt::test::new_test_uv_sched;
 
@@ -356,7 +355,7 @@ fn test_context() {
     do run_in_bare_thread {
         assert_eq!(context(), GlobalContext);
         let mut sched = ~new_test_uv_sched();
-        let task = ~do Coroutine::new_root(&mut sched.stack_pool) {
+        let task = ~do Task::new_root(&mut sched.stack_pool) {
             assert_eq!(context(), TaskContext);
             let sched = Local::take::<Scheduler>();
             do sched.deschedule_running_task_and_then() |sched, task| {
diff --git a/src/libstd/rt/sched.rs b/src/libstd/rt/sched.rs
index bbe4aa25e29..ed5cce4b35c 100644
--- a/src/libstd/rt/sched.rs
+++ b/src/libstd/rt/sched.rs
@@ -16,19 +16,15 @@ use clone::Clone;
 
 use super::sleeper_list::SleeperList;
 use super::work_queue::WorkQueue;
-use super::stack::{StackPool, StackSegment};
+use super::stack::{StackPool};
 use super::rtio::{EventLoop, EventLoopObject, RemoteCallbackObject};
 use super::context::Context;
-use super::task::Task;
+use super::task::{Task, AnySched, Sched};
 use super::message_queue::MessageQueue;
 use rt::local_ptr;
 use rt::local::Local;
 use rt::rtio::RemoteCallback;
 use rt::metrics::SchedMetrics;
-
-//use to_str::ToStr;
-
-/// To allow for using pointers as scheduler ids
 use borrow::{to_uint};
 
 /// The Scheduler is responsible for coordinating execution of Coroutines
@@ -41,7 +37,7 @@ use borrow::{to_uint};
 pub struct Scheduler {
     /// A queue of available work. Under a work-stealing policy there
     /// is one per Scheduler.
-    priv work_queue: WorkQueue<~Coroutine>,
+    priv work_queue: WorkQueue<~Task>,
     /// The queue of incoming messages from other schedulers.
     /// These are enqueued by SchedHandles after which a remote callback
     /// is triggered to handle the message.
@@ -66,7 +62,7 @@ pub struct Scheduler {
     /// Always valid when a task is executing, otherwise not
     priv saved_context: Context,
     /// The currently executing task
-    current_task: Option<~Coroutine>,
+    current_task: Option<~Task>,
     /// An action performed after a context switch on behalf of the
     /// code running before the context switch
     priv cleanup_job: Option<CleanupJob>,
@@ -81,33 +77,15 @@ pub struct SchedHandle {
     sched_id: uint
 }
 
-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,
-    /// These are always valid when the task is not running, unless
-    /// the task is dead
-    priv saved_context: Context,
-    /// The heap, GC, unwinding, local storage, logging
-    task: ~Task,
-}
-
-// A scheduler home is either a handle to the home scheduler, or an
-// explicit "AnySched".
-pub enum SchedHome {
-    AnySched,
-    Sched(SchedHandle)
-}
-
 pub enum SchedMessage {
     Wake,
     Shutdown,
-    PinnedTask(~Coroutine)
+    PinnedTask(~Task)
 }
 
 enum CleanupJob {
     DoNothing,
-    GiveTask(~Coroutine, UnsafeTaskReceiver)
+    GiveTask(~Task, UnsafeTaskReceiver)
 }
 
 impl Scheduler {
@@ -116,7 +94,7 @@ impl Scheduler {
     pub fn sched_id(&self) -> uint { to_uint(self) }
 
     pub fn new(event_loop: ~EventLoopObject,
-               work_queue: WorkQueue<~Coroutine>,
+               work_queue: WorkQueue<~Task>,
                sleeper_list: SleeperList)
         -> Scheduler {
 
@@ -125,7 +103,7 @@ impl Scheduler {
     }
 
     pub fn new_special(event_loop: ~EventLoopObject,
-                       work_queue: WorkQueue<~Coroutine>,
+                       work_queue: WorkQueue<~Task>,
                        sleeper_list: SleeperList,
                        run_anything: bool)
         -> Scheduler {
@@ -253,7 +231,7 @@ impl Scheduler {
     /// Pushes the task onto the work stealing queue and tells the
     /// event loop to run it later. Always use this instead of pushing
     /// to the work queue directly.
-    pub fn enqueue_task(&mut self, task: ~Coroutine) {
+    pub fn enqueue_task(&mut self, task: ~Task) {
 
         // We don't want to queue tasks that belong on other threads,
         // so we send them home at enqueue time.
@@ -307,7 +285,7 @@ impl Scheduler {
                 rtdebug!("recv BiasedTask message in sched: %u",
                          this.sched_id());
                 let mut task = task;
-                task.task.home = Some(Sched(this.make_handle()));
+                task.home = Some(Sched(this.make_handle()));
                 this.resume_task_immediately(task);
                 return true;
             }
@@ -349,9 +327,9 @@ impl Scheduler {
     }
 
     /// Given an input Coroutine sends it back to its home scheduler.
-    fn send_task_home(task: ~Coroutine) {
+    fn send_task_home(task: ~Task) {
         let mut task = task;
-        let mut home = task.task.home.swap_unwrap();
+        let mut home = task.home.swap_unwrap();
         match home {
             Sched(ref mut home_handle) => {
                 home_handle.send(PinnedTask(task));
@@ -377,7 +355,7 @@ impl Scheduler {
         match this.work_queue.pop() {
             Some(task) => {
                 let action_id = {
-                    let home = &task.task.home;
+                    let home = &task.home;
                     match home {
                         &Some(Sched(ref home_handle))
                         if home_handle.sched_id != this.sched_id() => {
@@ -440,14 +418,15 @@ impl Scheduler {
         rtdebug!("ending running task");
 
         do self.deschedule_running_task_and_then |sched, dead_task| {
-            let dead_task = Cell::new(dead_task);
-            dead_task.take().recycle(&mut sched.stack_pool);
+            let mut dead_task = dead_task;
+            let coroutine = dead_task.coroutine.swap_unwrap();
+            coroutine.recycle(&mut sched.stack_pool);
         }
 
         rtabort!("control reached end of task");
     }
 
-    pub fn schedule_task(~self, task: ~Coroutine) {
+    pub fn schedule_task(~self, task: ~Task) {
         assert!(self.in_task_context());
 
         // is the task home?
@@ -478,7 +457,7 @@ impl Scheduler {
 
     // Core scheduling ops
 
-    pub fn resume_task_immediately(~self, task: ~Coroutine) {
+    pub fn resume_task_immediately(~self, task: ~Task) {
         let mut this = self;
         assert!(!this.in_task_context());
 
@@ -521,7 +500,7 @@ impl Scheduler {
     /// This passes a Scheduler pointer to the fn after the context switch
     /// in order to prevent that fn from performing further scheduling operations.
     /// Doing further scheduling could easily result in infinite recursion.
-    pub fn deschedule_running_task_and_then(~self, f: &fn(&mut Scheduler, ~Coroutine)) {
+    pub fn deschedule_running_task_and_then(~self, f: &fn(&mut Scheduler, ~Task)) {
         let mut this = self;
         assert!(this.in_task_context());
 
@@ -530,8 +509,8 @@ impl Scheduler {
 
         unsafe {
             let blocked_task = this.current_task.swap_unwrap();
-            let f_fake_region = transmute::<&fn(&mut Scheduler, ~Coroutine),
-                                            &fn(&mut Scheduler, ~Coroutine)>(f);
+            let f_fake_region = transmute::<&fn(&mut Scheduler, ~Task),
+                                            &fn(&mut Scheduler, ~Task)>(f);
             let f_opaque = ClosureConverter::from_fn(f_fake_region);
             this.enqueue_cleanup_job(GiveTask(blocked_task, f_opaque));
         }
@@ -553,8 +532,8 @@ impl Scheduler {
     /// Switch directly to another task, without going through the scheduler.
     /// You would want to think hard about doing this, e.g. if there are
     /// pending I/O events it would be a bad idea.
-    pub fn switch_running_tasks_and_then(~self, next_task: ~Coroutine,
-                                         f: &fn(&mut Scheduler, ~Coroutine)) {
+    pub fn switch_running_tasks_and_then(~self, next_task: ~Task,
+                                         f: &fn(&mut Scheduler, ~Task)) {
         let mut this = self;
         assert!(this.in_task_context());
 
@@ -563,8 +542,8 @@ impl Scheduler {
 
         let old_running_task = this.current_task.swap_unwrap();
         let f_fake_region = unsafe {
-            transmute::<&fn(&mut Scheduler, ~Coroutine),
-                        &fn(&mut Scheduler, ~Coroutine)>(f)
+            transmute::<&fn(&mut Scheduler, ~Task),
+                        &fn(&mut Scheduler, ~Task)>(f)
         };
         let f_opaque = ClosureConverter::from_fn(f_fake_region);
         this.enqueue_cleanup_job(GiveTask(old_running_task, f_opaque));
@@ -631,12 +610,22 @@ impl Scheduler {
         // because borrowck thinks the three patterns are conflicting
         // borrows
         unsafe {
-            let last_task = transmute::<Option<&Coroutine>, Option<&mut Coroutine>>(last_task);
+            let last_task = transmute::<Option<&Task>, Option<&mut Task>>(last_task);
             let last_task_context = match last_task {
-                Some(t) => Some(&mut t.saved_context), None => None
+                Some(t) => {
+                    Some(&mut t.coroutine.get_mut_ref().saved_context)
+                }
+                None => {
+                    None
+                }
             };
             let next_task_context = match self.current_task {
-                Some(ref mut t) => Some(&mut t.saved_context), None => None
+                Some(ref mut t) => {
+                    Some(&mut t.coroutine.get_mut_ref().saved_context)
+                }
+                None => {
+                    None
+                }
             };
             // XXX: These transmutes can be removed after snapshot
             return (transmute(&mut self.saved_context),
@@ -661,186 +650,34 @@ impl SchedHandle {
     }
 }
 
-impl Coroutine {
-
-    /// This function checks that a coroutine is running "home".
-    pub fn is_home(&self) -> bool {
-        rtdebug!("checking if coroutine is home");
-        do Local::borrow::<Scheduler,bool> |sched| {
-            match self.task.home {
-                Some(AnySched) => { false }
-                Some(Sched(SchedHandle { sched_id: ref id, _ })) => {
-                    *id == sched.sched_id()
-                }
-                None => { rtabort!("error: homeless task!"); }
-            }
-        }
-    }
-
-    /// Without access to self, but with access to the "expected home
-    /// id", see if we are home.
-    fn is_home_using_id(id: uint) -> bool {
-        rtdebug!("checking if coroutine is home using id");
-        do Local::borrow::<Scheduler,bool> |sched| {
-            if sched.sched_id() == id {
-                true
-            } else {
-                false
-            }
-        }
-    }
-
-    /// Check if this coroutine has a home
-    fn homed(&self) -> bool {
-        rtdebug!("checking if this coroutine has a home");
-        match self.task.home {
-            Some(AnySched) => { false }
-            Some(Sched(_)) => { true }
-            None => { rtabort!("error: homeless task!");
-                    }
-        }
-    }
-
-    /// A version of is_home that does not need to use TLS, it instead
-    /// takes local scheduler as a parameter.
-    fn is_home_no_tls(&self, sched: &~Scheduler) -> bool {
-        rtdebug!("checking if coroutine is home without tls");
-        match self.task.home {
-            Some(AnySched) => { true }
-            Some(Sched(SchedHandle { sched_id: ref id, _})) => {
-                *id == sched.sched_id()
-            }
-            None => { rtabort!("error: homeless task!"); }
-        }
-    }
-
-    /// Check TLS for the scheduler to see if we are on a special
-    /// scheduler.
-    pub fn on_special() -> bool {
-        rtdebug!("checking if coroutine is executing on special sched");
-        do Local::borrow::<Scheduler,bool>() |sched| {
-            !sched.run_anything
-        }
-    }
-
-    // Created new variants of "new" that takes a home scheduler
-    // parameter. The original with_task now calls with_task_homed
-    // using the AnySched paramter.
-
-    pub fn new_homed(stack_pool: &mut StackPool, home: SchedHome, start: ~fn()) -> Coroutine {
-        Coroutine::with_task_homed(stack_pool, ~Task::new_root(), start, home)
-    }
-
-    pub fn new_root(stack_pool: &mut StackPool, start: ~fn()) -> Coroutine {
-        Coroutine::with_task(stack_pool, ~Task::new_root(), start)
-    }
-
-    pub fn with_task_homed(stack_pool: &mut StackPool,
-                           task: ~Task,
-                           start: ~fn(),
-                           home: SchedHome) -> Coroutine {
-
-        static MIN_STACK_SIZE: uint = 1000000; // XXX: Too much stack
-
-        let start = Coroutine::build_start_wrapper(start);
-        let mut stack = stack_pool.take_segment(MIN_STACK_SIZE);
-        // NB: Context holds a pointer to that ~fn
-        let initial_context = Context::new(start, &mut stack);
-        let mut crt = Coroutine {
-            current_stack_segment: stack,
-            saved_context: initial_context,
-            task: task,
-        };
-        crt.task.home = Some(home);
-        return crt;
-    }
-
-    pub fn with_task(stack_pool: &mut StackPool,
-                 task: ~Task,
-                 start: ~fn()) -> Coroutine {
-        Coroutine::with_task_homed(stack_pool,
-                                   task,
-                                   start,
-                                   AnySched)
-    }
-
-    fn build_start_wrapper(start: ~fn()) -> ~fn() {
-        // XXX: The old code didn't have this extra allocation
-        let start_cell = Cell::new(start);
-        let wrapper: ~fn() = || {
-            // This is the first code to execute after the initial
-            // context switch to the task. The previous context may
-            // have asked us to do some cleanup.
-            unsafe {
-                let sched = Local::unsafe_borrow::<Scheduler>();
-                (*sched).run_cleanup_job();
-
-                let sched = Local::unsafe_borrow::<Scheduler>();
-                let task = (*sched).current_task.get_mut_ref();
-                // FIXME #6141: shouldn't neet to put `start()` in
-                // another closure
-                let start_cell = Cell::new(start_cell.take());
-                do task.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 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 out of
-                    // scope while the task is still running.
-                    let start = start_cell.take();
-                    start();
-                };
-            }
-
-            let sched = Local::take::<Scheduler>();
-            sched.terminate_current_task();
-        };
-        return wrapper;
-    }
-
-    /// Destroy the task and try to reuse its components
-    pub fn recycle(~self, stack_pool: &mut StackPool) {
-        match self {
-            ~Coroutine {current_stack_segment, _} => {
-                stack_pool.give_segment(current_stack_segment);
-            }
-        }
-    }
-}
-
 // XXX: Some hacks to put a &fn in Scheduler without borrowck
 // complaining
 type UnsafeTaskReceiver = sys::Closure;
 trait ClosureConverter {
-    fn from_fn(&fn(&mut Scheduler, ~Coroutine)) -> Self;
-    fn to_fn(self) -> &fn(&mut Scheduler, ~Coroutine);
+    fn from_fn(&fn(&mut Scheduler, ~Task)) -> Self;
+    fn to_fn(self) -> &fn(&mut Scheduler, ~Task);
 }
 impl ClosureConverter for UnsafeTaskReceiver {
-    fn from_fn(f: &fn(&mut Scheduler, ~Coroutine)) -> UnsafeTaskReceiver { unsafe { transmute(f) } }
-    fn to_fn(self) -> &fn(&mut Scheduler, ~Coroutine) { unsafe { transmute(self) } }
+    fn from_fn(f: &fn(&mut Scheduler, ~Task)) -> UnsafeTaskReceiver { unsafe { transmute(f) } }
+    fn to_fn(self) -> &fn(&mut Scheduler, ~Task) { unsafe { transmute(self) } }
 }
 
+
 #[cfg(test)]
 mod test {
     use int;
     use cell::Cell;
-    use iterator::IteratorUtil;
     use unstable::run_in_bare_thread;
     use task::spawn;
     use rt::local::Local;
     use rt::test::*;
     use super::*;
     use rt::thread::Thread;
-    use ptr::to_uint;
-    use vec::MutableVector;
+    use borrow::to_uint;
+    use rt::task::{Task,Sched};
 
     // Confirm that a sched_id actually is the uint form of the
     // pointer to the scheduler struct.
-
     #[test]
     fn simple_sched_id_test() {
         do run_in_bare_thread {
@@ -851,7 +688,6 @@ mod test {
 
     // Compare two scheduler ids that are different, this should never
     // fail but may catch a mistake someday.
-
     #[test]
     fn compare_sched_id_test() {
         do run_in_bare_thread {
@@ -863,7 +699,6 @@ mod test {
 
     // A simple test to check if a homed task run on a single
     // scheduler ends up executing while home.
-
     #[test]
     fn test_home_sched() {
         do run_in_bare_thread {
@@ -874,8 +709,8 @@ mod test {
             let sched_handle = sched.make_handle();
             let sched_id = sched.sched_id();
 
-            let task = ~do Coroutine::new_homed(&mut sched.stack_pool,
-                                                Sched(sched_handle)) {
+            let task = ~do Task::new_root_homed(&mut sched.stack_pool,
+                                                 Sched(sched_handle)) {
                 unsafe { *task_ran_ptr = true };
                 let sched = Local::take::<Scheduler>();
                 assert!(sched.sched_id() == sched_id);
@@ -888,7 +723,6 @@ mod test {
     }
 
     // A test for each state of schedule_task
-
     #[test]
     fn test_schedule_home_states() {
 
@@ -898,7 +732,6 @@ mod test {
         use rt::work_queue::WorkQueue;
 
         do run_in_bare_thread {
-//            let nthreads = 2;
 
             let sleepers = SleeperList::new();
             let work_queue = WorkQueue::new();
@@ -924,33 +757,33 @@ mod test {
             let t1_handle = special_sched.make_handle();
             let t4_handle = special_sched.make_handle();
 
-            let t1f = ~do Coroutine::new_homed(&mut special_sched.stack_pool,
-                                            Sched(t1_handle)) {
-                let is_home = Coroutine::is_home_using_id(special_id);
+            let t1f = ~do Task::new_root_homed(&mut special_sched.stack_pool,
+                                               Sched(t1_handle)) || {
+                let is_home = Task::is_home_using_id(special_id);
                 rtdebug!("t1 should be home: %b", is_home);
                 assert!(is_home);
             };
             let t1f = Cell::new(t1f);
 
-            let t2f = ~do Coroutine::new_root(&mut normal_sched.stack_pool) {
-                let on_special = Coroutine::on_special();
+            let t2f = ~do Task::new_root(&mut normal_sched.stack_pool) {
+                let on_special = Task::on_special();
                 rtdebug!("t2 should not be on special: %b", on_special);
                 assert!(!on_special);
             };
             let t2f = Cell::new(t2f);
 
-            let t3f = ~do Coroutine::new_root(&mut normal_sched.stack_pool) {
+            let t3f = ~do Task::new_root(&mut normal_sched.stack_pool) {
                 // not on special
-                let on_special = Coroutine::on_special();
+                let on_special = Task::on_special();
                 rtdebug!("t3 should not be on special: %b", on_special);
                 assert!(!on_special);
             };
             let t3f = Cell::new(t3f);
 
-            let t4f = ~do Coroutine::new_homed(&mut special_sched.stack_pool,
-                                            Sched(t4_handle)) {
+            let t4f = ~do Task::new_root_homed(&mut special_sched.stack_pool,
+                                          Sched(t4_handle)) {
                 // is home
-                let home = Coroutine::is_home_using_id(special_id);
+                let home = Task::is_home_using_id(special_id);
                 rtdebug!("t4 should be home: %b", home);
                 assert!(home);
             };
@@ -988,7 +821,7 @@ mod test {
             let t4 = Cell::new(t4);
 
             // build a main task that runs our four tests
-            let main_task = ~do Coroutine::new_root(&mut normal_sched.stack_pool) {
+            let main_task = ~do Task::new_root(&mut normal_sched.stack_pool) {
                 // the two tasks that require a normal start location
                 t2.take()();
                 t4.take()();
@@ -997,7 +830,7 @@ mod test {
             };
 
             // task to run the two "special start" tests
-            let special_task = ~do Coroutine::new_homed(
+            let special_task = ~do Task::new_root_homed(
                 &mut special_sched.stack_pool,
                 Sched(special_handle2.take())) {
                 t1.take()();
@@ -1027,91 +860,7 @@ mod test {
         }
     }
 
-    // The following test is a bit of a mess, but it trys to do
-    // something tricky so I'm not sure how to get around this in the
-    // short term.
-
-    // A number of schedulers are created, and then a task is created
-    // and assigned a home scheduler. It is then "started" on a
-    // different scheduler. The scheduler it is started on should
-    // observe that the task is not home, and send it home.
-
-    // This test is light in that it does very little.
-
-    #[test]
-    fn test_transfer_task_home() {
-
-        use rt::uv::uvio::UvEventLoop;
-        use rt::sched::Shutdown;
-        use rt::sleeper_list::SleeperList;
-        use rt::work_queue::WorkQueue;
-        use uint;
-        use container::Container;
-        use vec::OwnedVector;
-
-        do run_in_bare_thread {
-
-            static N: uint = 8;
-
-            let sleepers = SleeperList::new();
-            let work_queue = WorkQueue::new();
-
-            let mut handles = ~[];
-            let mut scheds = ~[];
-
-            for uint::range(0, N) |_| {
-                let loop_ = ~UvEventLoop::new();
-                let mut sched = ~Scheduler::new(loop_,
-                                                work_queue.clone(),
-                                                sleepers.clone());
-                let handle = sched.make_handle();
-                rtdebug!("sched id: %u", handle.sched_id);
-                handles.push(handle);
-                scheds.push(sched);
-            };
-
-            let handles = Cell::new(handles);
-
-            let home_handle = scheds[6].make_handle();
-            let home_id = home_handle.sched_id;
-            let home = Sched(home_handle);
-
-            let main_task = ~do Coroutine::new_homed(&mut scheds[1].stack_pool, home) {
-
-                // Here we check if the task is running on its home.
-                let sched = Local::take::<Scheduler>();
-                rtdebug!("run location scheduler id: %u, home: %u",
-                         sched.sched_id(),
-                         home_id);
-                assert!(sched.sched_id() == home_id);
-                Local::put::<Scheduler>(sched);
-
-                let mut handles = handles.take();
-                for handles.mut_iter().advance |handle| {
-                    handle.send(Shutdown);
-                }
-            };
-
-            scheds[0].enqueue_task(main_task);
-
-            let mut threads = ~[];
-
-            while !scheds.is_empty() {
-                let sched = scheds.pop();
-                let sched_cell = Cell::new(sched);
-                let thread = do Thread::start {
-                    let sched = sched_cell.take();
-                    sched.run();
-                };
-                threads.push(thread);
-            }
-
-            let _threads = threads;
-        }
-    }
-
     // Do it a lot
-
     #[test]
     fn test_stress_schedule_task_states() {
         let n = stress_factor() * 120;
@@ -1120,21 +869,6 @@ mod test {
         }
     }
 
-    // The goal is that this is the high-stress test for making sure
-    // homing is working. It allocates RUST_RT_STRESS tasks that
-    // do nothing but assert that they are home at execution
-    // time. These tasks are queued to random schedulers, so sometimes
-    // they are home and sometimes not. It also runs RUST_RT_STRESS
-    // times.
-
-    #[test]
-    fn test_stress_homed_tasks() {
-        let n = stress_factor();
-        for int::range(0,n as int) |_| {
-            run_in_mt_newsched_task_random_homed();
-        }
-    }
-
     #[test]
     fn test_simple_scheduling() {
         do run_in_bare_thread {
@@ -1142,7 +876,7 @@ mod test {
             let task_ran_ptr: *mut bool = &mut task_ran;
 
             let mut sched = ~new_test_uv_sched();
-            let task = ~do Coroutine::new_root(&mut sched.stack_pool) {
+            let task = ~do Task::new_root(&mut sched.stack_pool) {
                 unsafe { *task_ran_ptr = true; }
             };
             sched.enqueue_task(task);
@@ -1160,7 +894,7 @@ mod test {
 
             let mut sched = ~new_test_uv_sched();
             for int::range(0, total) |_| {
-                let task = ~do Coroutine::new_root(&mut sched.stack_pool) {
+                let task = ~do Task::new_root(&mut sched.stack_pool) {
                     unsafe { *task_count_ptr = *task_count_ptr + 1; }
                 };
                 sched.enqueue_task(task);
@@ -1177,10 +911,10 @@ mod test {
             let count_ptr: *mut int = &mut count;
 
             let mut sched = ~new_test_uv_sched();
-            let task1 = ~do Coroutine::new_root(&mut sched.stack_pool) {
+            let task1 = ~do Task::new_root(&mut sched.stack_pool) {
                 unsafe { *count_ptr = *count_ptr + 1; }
                 let mut sched = Local::take::<Scheduler>();
-                let task2 = ~do Coroutine::new_root(&mut sched.stack_pool) {
+                let task2 = ~do Task::new_root(&mut sched.stack_pool) {
                     unsafe { *count_ptr = *count_ptr + 1; }
                 };
                 // Context switch directly to the new task
@@ -1205,7 +939,7 @@ mod test {
 
             let mut sched = ~new_test_uv_sched();
 
-            let start_task = ~do Coroutine::new_root(&mut sched.stack_pool) {
+            let start_task = ~do Task::new_root(&mut sched.stack_pool) {
                 run_task(count_ptr);
             };
             sched.enqueue_task(start_task);
@@ -1215,7 +949,7 @@ mod test {
 
             fn run_task(count_ptr: *mut int) {
                 do Local::borrow::<Scheduler, ()> |sched| {
-                    let task = ~do Coroutine::new_root(&mut sched.stack_pool) {
+                    let task = ~do Task::new_root(&mut sched.stack_pool) {
                         unsafe {
                             *count_ptr = *count_ptr + 1;
                             if *count_ptr != MAX {
@@ -1233,7 +967,7 @@ mod test {
     fn test_block_task() {
         do run_in_bare_thread {
             let mut sched = ~new_test_uv_sched();
-            let task = ~do Coroutine::new_root(&mut sched.stack_pool) {
+            let task = ~do Task::new_root(&mut sched.stack_pool) {
                 let sched = Local::take::<Scheduler>();
                 assert!(sched.in_task_context());
                 do sched.deschedule_running_task_and_then() |sched, task| {
@@ -1280,13 +1014,13 @@ mod test {
             let mut sched1 = ~new_test_uv_sched();
             let handle1 = sched1.make_handle();
             let handle1_cell = Cell::new(handle1);
-            let task1 = ~do Coroutine::new_root(&mut sched1.stack_pool) {
+            let task1 = ~do Task::new_root(&mut sched1.stack_pool) {
                 chan_cell.take().send(());
             };
             sched1.enqueue_task(task1);
 
             let mut sched2 = ~new_test_uv_sched();
-            let task2 = ~do Coroutine::new_root(&mut sched2.stack_pool) {
+            let task2 = ~do Task::new_root(&mut sched2.stack_pool) {
                 port_cell.take().recv();
                 // Release the other scheduler's handle so it can exit
                 handle1_cell.take();
@@ -1383,7 +1117,6 @@ mod test {
                 }
             }
         }
-
     }
 
     #[test]
@@ -1408,5 +1141,4 @@ mod test {
             }
         }
     }
-
-}
+}
\ No newline at end of file
diff --git a/src/libstd/rt/task.rs b/src/libstd/rt/task.rs
index 97c3b6a749b..333eaa53912 100644
--- a/src/libstd/rt/task.rs
+++ b/src/libstd/rt/task.rs
@@ -23,8 +23,11 @@ use option::{Option, Some, None};
 use rt::local::Local;
 use rt::logging::StdErrLogger;
 use super::local_heap::LocalHeap;
-use rt::sched::{SchedHome, AnySched};
+use rt::sched::{Scheduler, SchedHandle};
 use rt::join_latch::JoinLatch;
+use rt::stack::{StackSegment, StackPool};
+use rt::context::Context;
+use cell::Cell;
 
 pub struct Task {
     heap: LocalHeap,
@@ -35,7 +38,22 @@ pub struct Task {
     home: Option<SchedHome>,
     join_latch: Option<~JoinLatch>,
     on_exit: Option<~fn(bool)>,
-    destroyed: bool
+    destroyed: bool,
+    coroutine: Option<~Coroutine>
+}
+
+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
+}
+
+pub enum SchedHome {
+    AnySched,
+    Sched(SchedHandle)
 }
 
 pub struct GarbageCollector;
@@ -46,31 +64,50 @@ pub struct Unwinder {
 }
 
 impl Task {
-    pub fn new_root() -> Task {
+
+    pub fn new_root(stack_pool: &mut StackPool,
+                    start: ~fn()) -> Task {
+        Task::new_root_homed(stack_pool, AnySched, start)
+    }
+
+    pub fn new_child(&mut self,
+                     stack_pool: &mut StackPool,
+                     start: ~fn()) -> Task {
+        self.new_child_homed(stack_pool, AnySched, start)
+    }
+
+    pub fn new_root_homed(stack_pool: &mut StackPool,
+                          home: SchedHome,
+                          start: ~fn()) -> Task {
         Task {
             heap: LocalHeap::new(),
             gc: GarbageCollector,
             storage: LocalStorage(ptr::null(), None),
             logger: StdErrLogger,
             unwinder: Unwinder { unwinding: false },
-            home: Some(AnySched),
+            home: Some(home),
             join_latch: Some(JoinLatch::new_root()),
             on_exit: None,
-            destroyed: false
+            destroyed: false,
+            coroutine: Some(~Coroutine::new(stack_pool, start))
         }
     }
 
-    pub fn new_child(&mut self) -> Task {
+    pub fn new_child_homed(&mut self,
+                           stack_pool: &mut StackPool,
+                           home: SchedHome,
+                           start: ~fn()) -> Task {
         Task {
             heap: LocalHeap::new(),
             gc: GarbageCollector,
             storage: LocalStorage(ptr::null(), None),
             logger: StdErrLogger,
-            home: Some(AnySched),
+            home: Some(home),
             unwinder: Unwinder { unwinding: false },
             join_latch: Some(self.join_latch.get_mut_ref().new_child()),
             on_exit: None,
-            destroyed: false
+            destroyed: false,
+            coroutine: Some(~Coroutine::new(stack_pool, start))
         }
     }
 
@@ -108,11 +145,11 @@ impl Task {
     /// called unsafely, without removing Task from
     /// thread-local-storage.
     fn destroy(&mut self) {
-        // This is just an assertion that `destroy` was called unsafely
-        // and this instance of Task is still accessible.
+
         do Local::borrow::<Task, ()> |task| {
             assert!(borrow::ref_eq(task, self));
         }
+
         match self.storage {
             LocalStorage(ptr, Some(ref dtor)) => {
                 (*dtor)(ptr)
@@ -125,12 +162,129 @@ impl Task {
 
         self.destroyed = true;
     }
+
+    /// Check if *task* is currently home.
+    pub fn is_home(&self) -> bool {
+        do Local::borrow::<Scheduler,bool> |sched| {
+            match self.home {
+                Some(AnySched) => { false }
+                Some(Sched(SchedHandle { sched_id: ref id, _ })) => {
+                    *id == sched.sched_id()
+                }
+                None => { rtabort!("task home of None") }
+            }
+        }
+    }
+
+    pub fn is_home_no_tls(&self, sched: &~Scheduler) -> bool {
+        match self.home {
+            Some(AnySched) => { false }
+            Some(Sched(SchedHandle { sched_id: ref id, _ })) => {
+                *id == sched.sched_id()
+            }
+            None => {rtabort!("task home of None") }
+        }
+    }
+
+    pub fn is_home_using_id(sched_id: uint) -> bool {
+        do Local::borrow::<Task,bool> |task| {
+            match task.home {
+                Some(Sched(SchedHandle { sched_id: ref id, _ })) => {
+                    *id == sched_id
+                }
+                Some(AnySched) => { false }
+                None => { rtabort!("task home of None") }
+            }
+        }
+    }
+
+    /// Check if this *task* has a home.
+    pub fn homed(&self) -> bool {
+        match self.home {
+            Some(AnySched) => { false }
+            Some(Sched(_)) => { true }
+            None => {
+                rtabort!("task home of None")
+            }
+        }
+    }
+
+    /// On a special scheduler?
+    pub fn on_special() -> bool {
+        do Local::borrow::<Scheduler,bool> |sched| {
+            sched.run_anything
+        }
+    }
+
 }
 
 impl Drop for Task {
     fn finalize(&self) { assert!(self.destroyed) }
 }
 
+// Coroutines represent nothing more than a context and a stack
+// segment.
+
+impl Coroutine {
+
+    pub fn new(stack_pool: &mut StackPool, start: ~fn()) -> Coroutine {
+        static MIN_STACK_SIZE: uint = 100000; // XXX: Too much stack
+
+        let start = Coroutine::build_start_wrapper(start);
+        let mut stack = stack_pool.take_segment(MIN_STACK_SIZE);
+        let initial_context = Context::new(start, &mut stack);
+        Coroutine {
+            current_stack_segment: stack,
+            saved_context: initial_context
+        }
+    }
+
+    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 {
+                let sched = Local::unsafe_borrow::<Scheduler>();
+                (*sched).run_cleanup_job();
+
+                let sched = Local::unsafe_borrow::<Scheduler>();
+                let task = (*sched).current_task.get_mut_ref();
+
+                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();
+                };
+            }
+
+            let sched = Local::take::<Scheduler>();
+            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;
 
@@ -209,8 +363,10 @@ mod 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());
         }
     }
diff --git a/src/libstd/rt/test.rs b/src/libstd/rt/test.rs
index b0e49684014..659c7eb4985 100644
--- a/src/libstd/rt/test.rs
+++ b/src/libstd/rt/test.rs
@@ -8,30 +8,27 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use cell::Cell;
 use uint;
 use option::{Some, None};
-use cell::Cell;
-use clone::Clone;
-use container::Container;
-use iterator::IteratorUtil;
-use vec::{OwnedVector, MutableVector};
-use result::{Result, Ok, Err};
-use unstable::run_in_bare_thread;
+use rt::sched::Scheduler;
 use super::io::net::ip::{IpAddr, Ipv4};
-use rt::comm::oneshot;
-use rt::task::Task;
-use rt::thread::Thread;
 use rt::local::Local;
-use rt::sched::{Scheduler, Coroutine};
-use rt::sleeper_list::SleeperList;
+use unstable::run_in_bare_thread;
+use rt::thread::Thread;
+use rt::task::Task;
+use rt::uv::uvio::UvEventLoop;
 use rt::work_queue::WorkQueue;
+use rt::sleeper_list::SleeperList;
+use rt::task::{Sched};
+use rt::comm::oneshot;
+use result::{Result, Ok, Err};
 
 pub fn new_test_uv_sched() -> Scheduler {
-    use rt::uv::uvio::UvEventLoop;
-    use rt::work_queue::WorkQueue;
-    use rt::sleeper_list::SleeperList;
 
-    let mut sched = Scheduler::new(~UvEventLoop::new(), WorkQueue::new(), SleeperList::new());
+    let mut sched = Scheduler::new(~UvEventLoop::new(),
+                                   WorkQueue::new(),
+                                   SleeperList::new());
     // Don't wait for the Shutdown message
     sched.no_sleep = true;
     return sched;
@@ -41,19 +38,15 @@ pub fn new_test_uv_sched() -> Scheduler {
 /// then waits for the scheduler to exit. Failure of the task
 /// will abort the process.
 pub fn run_in_newsched_task(f: ~fn()) {
-    use super::sched::*;
-    use unstable::run_in_bare_thread;
-
     let f = Cell::new(f);
 
     do run_in_bare_thread {
         let mut sched = ~new_test_uv_sched();
-        let mut new_task = ~Task::new_root();
         let on_exit: ~fn(bool) = |exit_status| rtassert!(exit_status);
-        new_task.on_exit = Some(on_exit);
-        let task = ~Coroutine::with_task(&mut sched.stack_pool,
-                                         new_task,
-                                         f.take());
+        let mut task = ~Task::new_root(&mut sched.stack_pool,
+                                       f.take());
+        rtdebug!("newsched_task: %x", to_uint(task));
+        task.on_exit = Some(on_exit);
         sched.enqueue_task(task);
         sched.run();
     }
@@ -65,7 +58,6 @@ pub fn run_in_newsched_task(f: ~fn()) {
 pub fn run_in_mt_newsched_task(f: ~fn()) {
     use os;
     use from_str::FromStr;
-    use rt::uv::uvio::UvEventLoop;
     use rt::sched::Shutdown;
     use rt::util;
 
@@ -90,7 +82,9 @@ pub fn run_in_mt_newsched_task(f: ~fn()) {
 
         for uint::range(0, nthreads) |_| {
             let loop_ = ~UvEventLoop::new();
-            let mut sched = ~Scheduler::new(loop_, work_queue.clone(), sleepers.clone());
+            let mut sched = ~Scheduler::new(loop_,
+                                            work_queue.clone(),
+                                            sleepers.clone());
             let handle = sched.make_handle();
 
             handles.push(handle);
@@ -99,9 +93,7 @@ pub fn run_in_mt_newsched_task(f: ~fn()) {
 
         let f_cell = Cell::new(f_cell.take());
         let handles = Cell::new(handles);
-        let mut new_task = ~Task::new_root();
         let on_exit: ~fn(bool) = |exit_status| {
-
             let mut handles = handles.take();
             // Tell schedulers to exit
             for handles.mut_iter().advance |handle| {
@@ -110,9 +102,9 @@ pub fn run_in_mt_newsched_task(f: ~fn()) {
 
             rtassert!(exit_status);
         };
-        new_task.on_exit = Some(on_exit);
-        let main_task = ~Coroutine::with_task(&mut scheds[0].stack_pool,
-                                              new_task, f_cell.take());
+        let mut main_task = ~Task::new_root(&mut scheds[0].stack_pool,
+                                        f_cell.take());
+        main_task.on_exit = Some(on_exit);
         scheds[0].enqueue_task(main_task);
 
         let mut threads = ~[];
@@ -134,144 +126,44 @@ pub fn run_in_mt_newsched_task(f: ~fn()) {
 
 }
 
-// THIS IS AWFUL. Copy-pasted the above initialization function but
-// with a number of hacks to make it spawn tasks on a variety of
-// schedulers with a variety of homes using the new spawn.
-
-pub fn run_in_mt_newsched_task_random_homed() {
-    use libc;
-    use os;
-    use from_str::FromStr;
-    use rt::uv::uvio::UvEventLoop;
-    use rt::sched::Shutdown;
-
-    do run_in_bare_thread {
-        let nthreads = match os::getenv("RUST_TEST_THREADS") {
-            Some(nstr) => FromStr::from_str(nstr).get(),
-            None => unsafe {
-                // Using more threads than cores in test code to force
-                // the OS to preempt them frequently.  Assuming that
-                // this help stress test concurrent types.
-                rust_get_num_cpus() * 2
-            }
-        };
-
-        let sleepers = SleeperList::new();
-        let work_queue = WorkQueue::new();
-
-        let mut handles = ~[];
-        let mut scheds = ~[];
-
-        // create a few special schedulers, those with even indicies
-        // will be pinned-only
-        for uint::range(0, nthreads) |i| {
-            let special = (i % 2) == 0;
-            let loop_ = ~UvEventLoop::new();
-            let mut sched = ~Scheduler::new_special(
-                loop_, work_queue.clone(), sleepers.clone(), special);
-            let handle = sched.make_handle();
-            handles.push(handle);
-            scheds.push(sched);
-        }
-
-        // Schedule a pile o tasks
-        let n = 5*stress_factor();
-        for uint::range(0,n) |_i| {
-                rtdebug!("creating task: %u", _i);
-                let hf: ~fn() = || { assert!(true) };
-                spawntask_homed(&mut scheds, hf);
-            }
-
-        // Now we want another pile o tasks that do not ever run on a
-        // special scheduler, because they are normal tasks. Because
-        // we can we put these in the "main" task.
-
-        let n = 5*stress_factor();
-
-        let f: ~fn() = || {
-            for uint::range(0,n) |_| {
-                let f: ~fn()  = || {
-                    // Borrow the scheduler we run on and check if it is
-                    // privileged.
-                    do Local::borrow::<Scheduler,()> |sched| {
-                        assert!(sched.run_anything);
-                    };
-                };
-                spawntask_random(f);
-            };
-        };
-
-        let f_cell = Cell::new(f);
-        let handles = Cell::new(handles);
-
-        rtdebug!("creating main task");
-
-        let main_task = ~do Coroutine::new_root(&mut scheds[0].stack_pool) {
-            f_cell.take()();
-            let mut handles = handles.take();
-            // Tell schedulers to exit
-            for handles.mut_iter().advance |handle| {
-                handle.send(Shutdown);
-            }
-        };
-
-        rtdebug!("queuing main task")
-
-        scheds[0].enqueue_task(main_task);
-
-        let mut threads = ~[];
-
-        while !scheds.is_empty() {
-            let sched = scheds.pop();
-            let sched_cell = Cell::new(sched);
-            let thread = do Thread::start {
-                let sched = sched_cell.take();
-                rtdebug!("running sched: %u", sched.sched_id());
-                sched.run();
-            };
-
-            threads.push(thread);
-        }
-
-        rtdebug!("waiting on scheduler threads");
-
-        // Wait for schedulers
-        let _threads = threads;
-    }
-
-    extern {
-        fn rust_get_num_cpus() -> libc::uintptr_t;
-    }
-}
-
-
 /// Test tasks will abort on failure instead of unwinding
 pub fn spawntask(f: ~fn()) {
     use super::sched::*;
+    let f = Cell::new(f);
 
-    rtdebug!("spawntask taking the scheduler from TLS")
-    let task = do Local::borrow::<Task, ~Task>() |running_task| {
-        ~running_task.new_child()
+    let task = unsafe {
+        let sched = Local::unsafe_borrow::<Scheduler>();
+        rtdebug!("spawntask taking the scheduler from TLS");
+
+
+        do Local::borrow::<Task, ~Task>() |running_task| {
+            ~running_task.new_child(&mut (*sched).stack_pool, f.take())
+        }
     };
 
-    let mut sched = Local::take::<Scheduler>();
-    let task = ~Coroutine::with_task(&mut sched.stack_pool,
-                                     task, f);
+    rtdebug!("new task pointer: %x", to_uint(task));
+
+    let sched = Local::take::<Scheduler>();
     rtdebug!("spawntask scheduling the new task");
     sched.schedule_task(task);
 }
 
+
 /// Create a new task and run it right now. Aborts on failure
 pub fn spawntask_immediately(f: ~fn()) {
     use super::sched::*;
 
-    let task = do Local::borrow::<Task, ~Task>() |running_task| {
-        ~running_task.new_child()
+    let f = Cell::new(f);
+
+    let task = unsafe {
+        let sched = Local::unsafe_borrow::<Scheduler>();
+        do Local::borrow::<Task, ~Task>() |running_task| {
+            ~running_task.new_child(&mut (*sched).stack_pool,
+                                    f.take())
+        }
     };
 
-    let mut sched = Local::take::<Scheduler>();
-    let task = ~Coroutine::with_task(&mut sched.stack_pool,
-                                     task, f);
+    let sched = Local::take::<Scheduler>();
     do sched.switch_running_tasks_and_then(task) |sched, task| {
         sched.enqueue_task(task);
     }
@@ -280,15 +172,16 @@ pub fn spawntask_immediately(f: ~fn()) {
 /// Create a new task and run it right now. Aborts on failure
 pub fn spawntask_later(f: ~fn()) {
     use super::sched::*;
+    let f = Cell::new(f);
 
-    let task = do Local::borrow::<Task, ~Task>() |running_task| {
-        ~running_task.new_child()
+    let task = unsafe {
+        let sched = Local::unsafe_borrow::<Scheduler>();
+        do Local::borrow::<Task, ~Task>() |running_task| {
+            ~running_task.new_child(&mut (*sched).stack_pool, f.take())
+        }
     };
 
     let mut sched = Local::take::<Scheduler>();
-    let task = ~Coroutine::with_task(&mut sched.stack_pool,
-                                     task, f);
-
     sched.enqueue_task(task);
     Local::put(sched);
 }
@@ -298,13 +191,18 @@ pub fn spawntask_random(f: ~fn()) {
     use super::sched::*;
     use rand::{Rand, rng};
 
-    let task = do Local::borrow::<Task, ~Task>() |running_task| {
-        ~running_task.new_child()
+    let f = Cell::new(f);
+
+    let task = unsafe {
+        let sched = Local::unsafe_borrow::<Scheduler>();
+        do Local::borrow::<Task, ~Task>() |running_task| {
+            ~running_task.new_child(&mut (*sched).stack_pool,
+                                    f.take())
+
+        }
     };
 
     let mut sched = Local::take::<Scheduler>();
-    let task = ~Coroutine::with_task(&mut sched.stack_pool,
-                                     task, f);
 
     let mut rng = rng();
     let run_now: bool = Rand::rand(&mut rng);
@@ -343,33 +241,49 @@ pub fn spawntask_homed(scheds: &mut ~[~Scheduler], f: ~fn()) {
             f()
         };
 
-        ~Coroutine::with_task_homed(&mut sched.stack_pool,
-                                    ~Task::new_root(),
-                                    af,
-                                    Sched(handle))
+        ~Task::new_root_homed(&mut sched.stack_pool,
+                              Sched(handle),
+                              af)
     };
     let dest_sched = &mut scheds[rng.gen_int_range(0,scheds.len() as int)];
     // enqueue it for future execution
     dest_sched.enqueue_task(task);
 }
 
-/// Spawn a task and wait for it to finish, returning whether it completed successfully or failed
+/// Spawn a task and wait for it to finish, returning whether it
+/// completed successfully or failed
 pub fn spawntask_try(f: ~fn()) -> Result<(), ()> {
     use cell::Cell;
     use super::sched::*;
 
+    let f = Cell::new(f);
+
     let (port, chan) = oneshot();
     let chan = Cell::new(chan);
-    let mut new_task = ~Task::new_root();
     let on_exit: ~fn(bool) = |exit_status| chan.take().send(exit_status);
+    let mut new_task = unsafe {
+        let sched = Local::unsafe_borrow::<Scheduler>();
+        do Local::borrow::<Task, ~Task> |_running_task| {
+
+            // I don't understand why using a child task here fails. I
+            // think the fail status is propogating back up the task
+            // tree and triggering a fail for the parent, which we
+            // aren't correctly expecting.
+
+            // ~running_task.new_child(&mut (*sched).stack_pool,
+            ~Task::new_root(&mut (*sched).stack_pool,
+                           f.take())
+        }
+    };
     new_task.on_exit = Some(on_exit);
-    let mut sched = Local::take::<Scheduler>();
-    let new_task = ~Coroutine::with_task(&mut sched.stack_pool,
-                                         new_task, f);
+
+    let sched = Local::take::<Scheduler>();
     do sched.switch_running_tasks_and_then(new_task) |sched, old_task| {
         sched.enqueue_task(old_task);
     }
 
+    rtdebug!("enqueued the new task, now waiting on exit_status");
+
     let exit_status = port.recv();
     if exit_status { Ok(()) } else { Err(()) }
 }
@@ -378,23 +292,27 @@ pub fn spawntask_try(f: ~fn()) -> Result<(), ()> {
 pub fn spawntask_thread(f: ~fn()) -> Thread {
     use rt::sched::*;
 
-    let task = do Local::borrow::<Task, ~Task>() |running_task| {
-        ~running_task.new_child()
+    let f = Cell::new(f);
+
+    let task = unsafe {
+        let sched = Local::unsafe_borrow::<Scheduler>();
+        do Local::borrow::<Task, ~Task>() |running_task| {
+            ~running_task.new_child(&mut (*sched).stack_pool,
+                                    f.take())
+        }
     };
 
     let task = Cell::new(task);
-    let f = Cell::new(f);
+
     let thread = do Thread::start {
         let mut sched = ~new_test_uv_sched();
-        let task = ~Coroutine::with_task(&mut sched.stack_pool,
-                                         task.take(),
-                                         f.take());
-        sched.enqueue_task(task);
+        sched.enqueue_task(task.take());
         sched.run();
     };
     return thread;
 }
 
+
 /// Get a port number, starting at 9600, for use in tests
 pub fn next_test_port() -> u16 {
     unsafe {
@@ -410,7 +328,8 @@ pub fn next_test_ip4() -> IpAddr {
     Ipv4(127, 0, 0, 1, next_test_port())
 }
 
-/// Get a constant that represents the number of times to repeat stress tests. Default 1.
+/// Get a constant that represents the number of times to repeat
+/// stress tests. Default 1.
 pub fn stress_factor() -> uint {
     use os::getenv;
 
diff --git a/src/libstd/rt/tube.rs b/src/libstd/rt/tube.rs
index 89f3d10b5e4..013eb438c36 100644
--- a/src/libstd/rt/tube.rs
+++ b/src/libstd/rt/tube.rs
@@ -16,14 +16,15 @@
 use option::*;
 use clone::Clone;
 use super::rc::RC;
-use rt::sched::{Scheduler, Coroutine};
+use rt::sched::Scheduler;
 use rt::{context, TaskContext, SchedulerContext};
 use rt::local::Local;
+use rt::task::Task;
 use vec::OwnedVector;
 use container::Container;
 
 struct TubeState<T> {
-    blocked_task: Option<~Coroutine>,
+    blocked_task: Option<~Task>,
     buf: ~[T]
 }
 
diff --git a/src/libstd/rt/uv/uvio.rs b/src/libstd/rt/uv/uvio.rs
index 298277b3df0..b1708e70733 100644
--- a/src/libstd/rt/uv/uvio.rs
+++ b/src/libstd/rt/uv/uvio.rs
@@ -29,7 +29,10 @@ use unstable::sync::{Exclusive, exclusive};
 #[cfg(test)] use container::Container;
 #[cfg(test)] use uint;
 #[cfg(test)] use unstable::run_in_bare_thread;
-#[cfg(test)] use rt::test::*;
+#[cfg(test)] use rt::test::{spawntask_immediately,
+                            next_test_ip4,
+                            run_in_newsched_task};
+
 
 pub struct UvEventLoop {
     uvio: UvIoFactory
diff --git a/src/libstd/task/mod.rs b/src/libstd/task/mod.rs
index 99858feab22..b0fc6b2884f 100644
--- a/src/libstd/task/mod.rs
+++ b/src/libstd/task/mod.rs
@@ -1182,3 +1182,4 @@ fn test_simple_newsched_spawn() {
         spawn(||())
     }
 }
+
diff --git a/src/libstd/task/spawn.rs b/src/libstd/task/spawn.rs
index 63eb768d1c9..aea8cda6a21 100644
--- a/src/libstd/task/spawn.rs
+++ b/src/libstd/task/spawn.rs
@@ -581,13 +581,20 @@ pub fn spawn_raw(opts: TaskOpts, f: ~fn()) {
 fn spawn_raw_newsched(mut opts: TaskOpts, f: ~fn()) {
     use rt::sched::*;
 
-    let mut task = if opts.linked {
-        do Local::borrow::<Task, ~Task>() |running_task| {
-            ~running_task.new_child()
+    let f = Cell::new(f);
+
+    let mut task = unsafe {
+        let sched = Local::unsafe_borrow::<Scheduler>();
+        rtdebug!("unsafe borrowed sched");
+
+        if opts.linked {
+            do Local::borrow::<Task, ~Task>() |running_task| {
+                ~running_task.new_child(&mut (*sched).stack_pool, f.take())
+            }
+        } else {
+            // An unlinked task is a new root in the task tree
+            ~Task::new_root(&mut (*sched).stack_pool, f.take())
         }
-    } else {
-        // An unlinked task is a new root in the task tree
-        ~Task::new_root()
     };
 
     if opts.notify_chan.is_some() {
@@ -601,9 +608,13 @@ fn spawn_raw_newsched(mut opts: TaskOpts, f: ~fn()) {
         task.on_exit = Some(on_exit);
     }
 
+    rtdebug!("spawn about to take scheduler");
+
     let mut sched = Local::take::<Scheduler>();
-    let task = ~Coroutine::with_task(&mut sched.stack_pool,
-                                     task, f);
+    rtdebug!("took sched in spawn");
+//    let task = ~Coroutine::with_task(&mut sched.stack_pool,
+//                                     task, f);
+//    let task = ~Task::new_root(&mut sched.stack_pool, f);
     sched.schedule_task(task);
 }
 
diff --git a/src/libstd/unstable/lang.rs b/src/libstd/unstable/lang.rs
index f750b31a466..3a071af5d4c 100644
--- a/src/libstd/unstable/lang.rs
+++ b/src/libstd/unstable/lang.rs
@@ -23,6 +23,7 @@ use option::{Option, Some, None};
 use io;
 use rt::global_heap;
 use rt::borrowck;
+use borrow::to_uint;
 
 #[allow(non_camel_case_types)]
 pub type rust_task = c_void;
@@ -90,6 +91,9 @@ pub unsafe fn local_malloc(td: *c_char, size: uintptr_t) -> *c_char {
         _ => {
             let mut alloc = ::ptr::null();
             do Local::borrow::<Task,()> |task| {
+                rtdebug!("task pointer: %x, heap pointer: %x",
+                         to_uint(task),
+                         to_uint(&task.heap));
                 alloc = task.heap.alloc(td as *c_void, size as uint) as *c_char;
             }
             return alloc;