The I/O driver uses a slab to store per-resource state. Doing this
provides two benefits. First, allocating state is streamlined. Second,
resources may be safely indexed using a `usize` type. The `usize` is
used passed to the OS's selector when registering for receiving events.
The original slab implementation used a `Vec` backed by `RwLock`. This
primarily caused contention when reading state. This implementation also
only **grew** the slab capacity but never shrank. In #1625, the slab was
rewritten to use a lock-free strategy. The lock contention was removed
but this implementation was still grow-only.
This change adds the ability to release memory. Similar to the previous
implementation, it structures the slab to use a vector of pages. This
enables growing the slab without having to move any previous entries. It
also adds the ability to release pages. This is done by introducing a
lock when allocating/releasing slab entries. This does not impact
benchmarks, primarily due to the existing implementation not being
"done" and also having a lock around allocating and releasing.
A `Slab::compact()` function is added. Pages are iterated. When a page
is found with no slots in use, the page is freed. The `compact()`
function is called occasionally by the I/O driver.
Fixes#2505
JoinHandle of threads created by the pool are now tracked and properly joined at
shutdown. If the thread does not return within the timeout, then it's not joined and
left to the OS for cleanup.
Also, break a cycle between wakers held by the timer and the runtime.
Fixes#2641, #2535
Previously, we would fail to reset the coop budget in this case, making
it so that `coop::poll_proceed` would perpetually yield `Poll::Pending`
in nested executers even when run in `block_in_place`.
This is also a further improvement on #2645.
The new implementation changes the behavior such that set_len is called
after poll_read. The motivation of this change is that it makes it much
more obvious that a rouge panic won't give the caller access to a vector
containing exposed uninitialized memory. The new implementation also
makes sure to not zero memory twice.
Additionally, it makes the various implementations more consistent with
each other regarding the naming of variables, and whether we store how many
bytes we have read, or how many were in the container originally.
Fixes: #2544
* Add Unit Test demonstrating the issue
This test demonstrates a panic that occurs when the user inserts an
item with an instant in the past, and then tries to reset the timeout
using the returned key
* Guard reset_at against removals of expired items
Trying to remove an already expired Timer Wheel entry (called by
DelayQueue.reset()) causes panics in some cases as described in (#2573)
This prevents this panic by removing the item from the expired queue and
not the wheel in these cases
Fixes: #2473
The documentation build failed with errors such as
error: `[read]` public documentation for `take` links to a private item
--> tokio/src/io/util/async_read_ext.rs:1078:9
|
1078 | / /// Creates an adaptor which reads at most `limit` bytes from it.
1079 | | ///
1080 | | /// This function returns a new instance of `AsyncRead` which will read
1081 | | /// at most `limit` bytes, after which it will always return EOF
... |
1103 | | /// }
1104 | | /// ```
| |_______________^
|
note: the lint level is defined here
--> tokio/src/lib.rs:13:9
|
13 | #![deny(intra_doc_link_resolution_failure)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: the link appears in this line:
bytes read and future calls to [`read()`][read] may succeed.
`duplex` returns a pair of connected `DuplexStream`s.
`DuplexStream` is a bidirectional type that can be used to simulate IO,
but over an in-process piece of memory.
Dropping a runtime normally involves waiting for any outstanding blocking tasks
to complete. When this drop happens in an asynchronous context, we previously
would issue a cryptic panic due to trying to block in an asynchronous context.
This change improves the panic message, and adds a `shutdown_blocking()` function
which can be used to shutdown a runtime without blocking at all, as an out for
cases where this really is necessary.
Co-authored-by: Bryan Donlan <bdonlan@amazon.com>
Co-authored-by: Alice Ryhl <alice@ryhl.io>
For some yet unknown reason using the default on a wrapped `Bufreader<TcpStream>`
causes the hyper server to sometimes fail to send the entire body in the
response.
This fixes that problem for us and ensures that hyper has a chance to
use vectored IO (making it a good change regardless of the mentioned
bug)
