Since a waker can trigger arbitrary code, such as with a custom waker,
and even more so now that it can emit a tracing event that could do
respond, we must be careful about the internal state when that code is
triggered. The clone method of a waker is one of those instances.
This changes the internals of `Notify` so that the waker is cloned
*before* locking the waiter list. While this does mean that in some
contended cases, we'll have made an optimistic clone, it makes `Notify`
more robust and correct.
Note that the included test case is built from an instance that did
happen naturally in another project, see
https://github.com/tokio-rs/console/issues/133.
This change enables `tokio-console` to parse the location information
for a spawned task into a structured object rather than simply displaying
this info as a field on the task.
Signed-off-by: Zahari Dichev <zaharidichev@gmail.com>
This branch instruments the `Sleep` resource to allow the tokio-console
to consume data about resources usage. The corresponding console branch
is here: https://github.com/tokio-rs/console/pull/77
Signed-off-by: Zahari Dichev <zaharidichev@gmail.com>
## Motivation
PR #4055 added a new `WakeList` type, to manage a potentially
uninitialized array when waking batches of wakers. This has the
advantage of not initializing a bunch of empty `Option`s when only a
small number of tasks are being woken, potentially improving performance
in these cases.
Currently, `WakeList` is used only in the IO driver. However,
`tokio::sync` contains some code that's almost identical to the code in
the IO driver that was replaced with `WakeList`, so we can apply the
same optimizations there.
## Solution
This branch changes `tokio::sync::Notify` and
`tokio::sync::batch_semaphore::Semaphore` to use `WakeList` when waking
batches of wakers. This was a pretty straightforward drop-in
replacement.
Signed-off-by: Eliza Weisman <eliza@buoyant.io>
