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Linked failure: Make joining a taskgroup O(1)

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This commit is contained in:
Ben Blum 2012-07-18 15:58:59 -04:00
parent e0ea67a2a6
commit c936ae515b
1 changed files with 33 additions and 20 deletions
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53
src/libcore/task.rs
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@ -584,7 +584,8 @@ type rust_closure = libc::c_void;
/* linked failure */
type taskgroup_arc = arc::exclusive<option<dvec::dvec<option<*rust_task>>>>;
type taskgroup_arc =
arc::exclusive<option<(dvec::dvec<option<*rust_task>>,dvec::dvec<uint>)>>;
class taskgroup {
// FIXME (#2816): Change dvec to an O(1) data structure (and change 'me'
@ -594,9 +595,6 @@ class taskgroup {
let me: *rust_task;
let my_pos: uint;
// let parent_group: taskgroup_arc; // FIXME (#1868) (bblum)
// FIXME (#1868) XXX bblum: add a list of empty slots to get runtime back
// Indicates whether this is the main (root) taskgroup. If so, failure
// here should take down the entire runtime.
let is_main: bool;
new(-tasks: taskgroup_arc, me: *rust_task, my_pos: uint, is_main: bool) {
self.tasks = tasks;
@ -621,18 +619,24 @@ fn enlist_in_taskgroup(group_arc: taskgroup_arc,
me: *rust_task) -> option<uint> {
do group_arc.with |_c, state| {
// If 'none', the group was failing. Can't enlist.
do state.map |tasks| {
let mut newstate = none;
*state <-> newstate;
if newstate.is_some() {
let (tasks,empty_slots) = option::unwrap(newstate);
// Try to find an empty slot.
alt tasks.position(|x| x == none) {
some(empty_index) {
tasks.set_elt(empty_index, some(me));
empty_index
}
none {
tasks.push(some(me));
tasks.len() - 1
}
}
let slotno = if empty_slots.len() > 0 {
let empty_index = empty_slots.pop();
assert tasks[empty_index] == none;
tasks.set_elt(empty_index, some(me));
empty_index
} else {
tasks.push(some(me));
tasks.len() - 1
};
*state = some((tasks,empty_slots));
some(slotno)
} else {
none
}
}
}
@ -640,10 +644,15 @@ fn enlist_in_taskgroup(group_arc: taskgroup_arc,
// NB: Runs in destructor/post-exit context. Can't 'fail'.
fn leave_taskgroup(group_arc: taskgroup_arc, me: *rust_task, index: uint) {
do group_arc.with |_c, state| {
let mut newstate = none;
*state <-> newstate;
// If 'none', already failing and we've already gotten a kill signal.
do state.map |tasks| {
if newstate.is_some() {
let (tasks,empty_slots) = option::unwrap(newstate);
assert tasks[index] == some(me);
tasks.set_elt(index, none);
empty_slots.push(index);
*state = some((tasks,empty_slots));
};
};
}
@ -664,7 +673,8 @@ fn kill_taskgroup(group_arc: taskgroup_arc, me: *rust_task, index: uint,
// Might already be none, if somebody is failing simultaneously.
// That's ok; only one task needs to do the dirty work. (Might also
// see 'none' if somebody already failed and we got a kill signal.)
do newstate.map |tasks| {
if newstate.is_some() {
let (tasks,_empty_slots) = option::unwrap(newstate);
// First remove ourself (killing ourself won't do much good). This
// is duplicated here to avoid having to lock twice.
assert tasks[index] == some(me);
@ -679,7 +689,9 @@ fn kill_taskgroup(group_arc: taskgroup_arc, me: *rust_task, index: uint,
if is_main {
rustrt::rust_task_kill_all(me);
}
};
// Do NOT restore state to some(..)! It stays none to indicate
// that the whole taskgroup is failing, to forbid new spawns.
}
// (note: multiple tasks may reach this point)
};
}
@ -700,7 +712,8 @@ fn share_parent_taskgroup() -> (taskgroup_arc, bool) {
}
none {
// Main task, doing first spawn ever.
let tasks = arc::exclusive(some(dvec::from_elem(some(me))));
let tasks = arc::exclusive(some((dvec::from_elem(some(me)),
dvec::dvec())));
let group = @taskgroup(tasks.clone(), me, 0, true);
unsafe { local_set(me, taskgroup_key(), group); }
// Tell child task it's also in the main group.
@ -715,7 +728,7 @@ fn spawn_raw(opts: task_opts, +f: fn~()) {
share_parent_taskgroup()
} else {
// Detached from the parent group; create a new (non-main) one.
(arc::exclusive(some(dvec::from_elem(none))), false)
(arc::exclusive(some((dvec::dvec(),dvec::dvec()))), false)
};
unsafe {