In future parts, TaskQueue will require extra initialization to be performed
which cannot happen in a constructor, as it takes references to the TaskQueue
object itself, which will require the introduction of a helper method. This
patch switches all callers of the TaskQueue constructor to use the new method.
Differential Revision: https://phabricator.services.mozilla.com/D142604
This makes the behaviour of TaskQueue more in-line with nsThread, which may be
useful when converting code to using taskqueue instead of threads.
Differential Revision: https://phabricator.services.mozilla.com/D129838
The Runnable markers in the profilers are handy, but miss many types of
runnables. This includes most of those that wrap another runnable and run that
at a (possibly) later time.
AbstractThread, TaskDispatcher and TaskQueue does this for e.g. tail dispatched
tasks.
TaskQueueWrapper does this when wrapping webrtc tasks (and Mozilla Runnables) to
be run in a Mozilla TaskQueue with some overhead on the stack.
DelayedRunnable wraps a runnable to be run after a timeout.
It would perhaps be better in many cases to ignore the intermediate runnables,
but I haven't seen a straight forward way to achieve this.
More detailed data could be added on a case by case basis, for instance the
delay for a DelayedRunnable (incl. actual vs. target delay) or the scope of a
task in which a tail-dispatched runnable was dispatched. But this is also true
for the status quo (for instance the time from dispatch to run) so I leave these
ideas as future work.
Differential Revision: https://phabricator.services.mozilla.com/D135027
The Runnable markers in the profilers are handy, but miss many types of
runnables. This includes most of those that wrap another runnable and run that
at a (possibly) later time.
AbstractThread, TaskDispatcher and TaskQueue does this for e.g. tail dispatched
tasks.
TaskQueueWrapper does this when wrapping webrtc tasks (and Mozilla Runnables) to
be run in a Mozilla TaskQueue with some overhead on the stack.
DelayedRunnable wraps a runnable to be run after a timeout.
It would perhaps be better in many cases to ignore the intermediate runnables,
but I haven't seen a straight forward way to achieve this.
More detailed data could be added on a case by case basis, for instance the
delay for a DelayedRunnable (incl. actual vs. target delay) or the scope of a
task in which a tail-dispatched runnable was dispatched. But this is also true
for the status quo (for instance the time from dispatch to run) so I leave these
ideas as future work.
Differential Revision: https://phabricator.services.mozilla.com/D135027
It looks like we can do a mostly direct swap from `std::Queue` to `mozilla::Queue` without needing to expose any new API, so that's what I've done here.
Differential Revision: https://phabricator.services.mozilla.com/D123523
DelayedDispatch, in all current implementations, will set up a timer sync and
then Dispatch() a runnable. Since the timer is set up before the Dispatch, there
is a theoretical chance that the timer fires and dispatches a TimerEvent to the
target thread before DelayedDispatch managed to do so. When this happens the
internal DelayedDispatch runnable exits early, i.e., in practice it never runs.
The chance increases dramatically if the Dispatch() to the target in question is
tail dispatched, since the time between DelayedDispatch and the tail could be
non-trivial.
This patch removes the assert that checks that all DelayedRunnables that have
run have also been scheduled, since per the above no such guarantee exists.
Differential Revision: https://phabricator.services.mozilla.com/D112876
This assertion currently only happens on debug builds, but attempts to dispatch delayed runnables after we have started or finished cancelling all delayed runnables in a TaskQueue may be causing shutdown hangs.
Differential Revision: https://phabricator.services.mozilla.com/D113839
DelayedDispatch, in all current implementations, will set up a timer sync and
then Dispatch() a runnable. Since the timer is set up before the Dispatch, there
is a theoretical chance that the timer fires and dispatches a TimerEvent to the
target thread before DelayedDispatch managed to do so. When this happens the
internal DelayedDispatch runnable exits early, i.e., in practice it never runs.
The chance increases dramatically if the Dispatch() to the target in question is
tail dispatched, since the time between DelayedDispatch and the tail could be
non-trivial.
This patch removes the assert that checks that all DelayedRunnables that have
run have also been scheduled, since per the above no such guarantee exists.
Differential Revision: https://phabricator.services.mozilla.com/D112876
Because DelayedRunnables are fire-and-forget, there is no way for a targeted
EventTarget to clean them up on shutdown. Thus if a timer fires after
EventTarget shutdown it will fail to dispatch the timer event, and avoid
releasing the timer callback because it's not on the targeted thread. This
causes a leak as there is a ref-cycle between nsTimerImpl::mCallback and
DelayedRunnable::mTimer.
This patch adds nsIDelayedRunnableObserver for a target to observe which
DelayedRunnables are relying on their timer to run them. This allows the target
to schedule a shutdown task to cancel those timers and release the runnables on
the target thread.
Supported DelayedRunnable targets with this patch are TaskQueues,
eventqueue-based nsThreads and XPCOMThreadWrappers that wrap a supported
nsThread.
An assertion makes sure at runtime that future new uses of DelayedRunnable
target nsIDelayedRunnableObserver-supported event targets.
Differential Revision: https://phabricator.services.mozilla.com/D109781
Because DelayedRunnables are fire-and-forget, there is no way for a targeted
EventTarget to clean them up on shutdown. Thus if a timer fires after
EventTarget shutdown it will fail to dispatch the timer event, and avoid
releasing the timer callback because it's not on the targeted thread. This
causes a leak as there is a ref-cycle between nsTimerImpl::mCallback and
DelayedRunnable::mTimer.
This patch adds nsIDelayedRunnableObserver for a target to observe which
DelayedRunnables are relying on their timer to run them. This allows the target
to schedule a shutdown task to cancel those timers and release the runnables on
the target thread.
Supported DelayedRunnable targets with this patch are TaskQueues,
eventqueue-based nsThreads and XPCOMThreadWrappers that wrap a supported
nsThread.
An assertion makes sure at runtime that future new uses of DelayedRunnable
target nsIDelayedRunnableObserver-supported event targets.
Differential Revision: https://phabricator.services.mozilla.com/D109781
In the future, we may want to extend GetCurrentThreadSerialEventTarget to return the actual nsISerialEventTarget used to dispatch the task.
Differential Revision: https://phabricator.services.mozilla.com/D80353
When TaskQueue was first conceived; it was only used with AbstractThreads and with tail dispatch.
By default, AbstractThread::Dispatch dropped the flags , as it was dispatching all tasks via the tail dispatcher.
It was an oversight, there's no use-case where we wouldn't want the dispatch flags to be carried forward.
It also simplifies the code and TaskQueue's use.
Depends on D80351
Differential Revision: https://phabricator.services.mozilla.com/D80352
We extract the dealing of direct tasks from the TailDispatcher object and move into to the existing nsThread and TaskQueue classes.
TaskQueue is made to work with do_QueryInterface.
We continue accessing the direct tasks dispatcher via the TailDispatcher for now, which itself will forward the dealing of such tasks to the underlying thread.
Differential Revision: https://phabricator.services.mozilla.com/D79093
This is in preparation for running the tail dispatcher off
nsIThreadObserver callbacks, which only work during regular
event processing.
Differential Revision: https://phabricator.services.mozilla.com/D72264
Makes TaskQueue's queue hold a struct with each runnable and its flags. When specified, flags will be stored and passed with NS_DISPATCH_AT_END when TaskQueue::Runner dispatches itself back to its event target.
Differential Revision: https://phabricator.services.mozilla.com/D56802
`TaskQueue` wraps an `nsIEventTarget` to provide "one runnable at a
time" execution policies regardless of the underlying implementation of
the wrapped `nsIEventTarget` (e.g. a thread pool). `TaskQueue` also
provides a `nsISerialEventTarget` wrapper, `EventTargetWrapper`, around
itself (!) for consumers who want to continue to provide a more
XPCOM-ish API.
One would think that dispatching tasks to `EventTargetWrapper` with a
given set of flags would pass that set of flags through, unchanged, to
the underlying event target of the wrapped `TaskQueue`.
This pass-through is not the case. `TaskQueue` supports a "tail
dispatch" mode of operation that is somewhat underdocumented. Roughly,
tail dispatch to a `TaskQueue` says (with several other conditions) that
dispatched tasks are held separately and not passed through to the
underlying event target. If a given `TaskQueue` supports tail dispatch
and the dispatcher also supports tail dispatch, any tasks dispatched to
said `TaskQueue` are silently converted to tail dispatched tasks. Since
tail dispatched tasks can't meaningfully have flags associated with
them, the current implementation simply drops any passed flags on the floor.
These flags, however, might be meaningful, and we should attempt to
honor them in the cases we're not doing tail dispatch. (And when we are
doing tail dispatch, we can verify that the requested flags are not
asking for peculiar things.)
Differential Revision: https://phabricator.services.mozilla.com/D51702
GetCurrentPhysicalThread and GetCurrentVirtualThread are, in practice,
identical, as the TLS override that GetCurrentVirtualThread depends on
is never actually set. This simply removes that and renames some things/
deletes some comments.
Differential Revision: https://phabricator.services.mozilla.com/D41247
Summary:
With this change TaskQueue no longer requires an explicit call to BeginShutdown(). The taskqueue will automatically shutdown once it's now longer referenced.
Depends on D1620
Tags: #secure-revision
Bug #: 1409664
Differential Revision: https://phabricator.services.mozilla.com/D1621
This was done automatically replacing:
s/mozilla::Move/std::move/
s/ Move(/ std::move(/
s/(Move(/(std::move(/
Removing the 'using mozilla::Move;' lines.
And then with a few manual fixups, see the bug for the split series..
MozReview-Commit-ID: Jxze3adipUh
Karl Tomlinson