Commit graph

13 commits

Author SHA1 Message Date
Chirantan Ekbote
f1ce859903 cros_async: Refactor executors
There are a lot of changes in this one but these are the high-level
points:

* Both executors now support non-fd futures and it's now possible to
  start a poll operation on one thread and then await the result inside
  a UringExecutor on another thread.  The reverse doesn't work yet but
  will once we make UringContext sync.
* A few layers of indirection have been removed so hopefully both the
  implementation and the interface are simpler.
* The thread local magic is gone in favor of directly calling methods on
  an executor.  Executor handles can be cheaply cloned to make this
  easier.
* Heap allocations are limited to the spawn and spawn_local methods so
  it's possible to completely avoid heap allocations if callers only use
  the run_until method.
* The IoSource, Executor, FutureList traits are gone.

BUG=none
TEST=unit tests

Cq-Depend: chromium:2629068
Change-Id: I86053007929c36da66f3b2499cdefce0b5e9a180
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2571401
Commit-Queue: Chirantan Ekbote <chirantan@chromium.org>
Tested-by: Chirantan Ekbote <chirantan@chromium.org>
Reviewed-by: Noah Gold <nkgold@google.com>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
2021-01-25 08:52:27 +00:00
Keiichi Watanabe
0d46a14212 Cargo.lock: Uprev cfg-if and paste crates
Use the latest version of cfg-if and paste, which gdbstub crate will require.

BUG=chromium:1141812
TEST=cargo build

Cq-Depend: chromium:2507270
Change-Id: I9187cfc9a880f62b2aa1fcf5e5d47a720e5fbe60
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2499241
Tested-by: Keiichi Watanabe <keiichiw@chromium.org>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>
Commit-Queue: Keiichi Watanabe <keiichiw@chromium.org>
2020-11-11 08:08:49 +00:00
Noah Gold
b3fca20e24 Refactor cros_async interface to avoid RawFd.
Instead of creating IoSourceExt from AsRawFd implementers, we've
switched to creating from a marker trait `IntoAsync`. This lets us use
other types like RawDescriptor easily with this crate.  By using the
marker, we also provide some type safety by requiring consumers of
IoSourceExt to declare that their type is expected to work with async
operations. This way we can provide stronger guarantees that an async
IO trait object will behave in a reasonable way.

This CL also purges the cros_async -> base and io_uring -> base
references, and provides the base types needed to add new async
primitives to base.

BUG=none
TEST=builds

Change-Id: I0b0ce6ca7938b22ae8e8fb4e604439f0292678f2
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2504481
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Noah Gold <nkgold@google.com>
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
2020-11-10 11:40:50 +00:00
Noah Gold
5767987e5f Replace PollOrRing w/ async trait IoSourceExt.
This CL makes the following fundamental changes to cros_async:
1. Removes PollOrRing and replaces it with IoSourceExt, and the
   subtraits ReadAsync & WriteAsync. The blanket implementation of
   IoSourceExt has been dropped, and replaced with source specific
   implementations of the trait. Those implementations are where
   the code from PollOrRing has been moved.
2. Pinning for IoSource has been dropped from UringSource & the uring
   futures. This appears to be safe because the IoSource doesn't contain
   any self refs, or perform any operations beyond forwarding to the
   RegisteredSource. (The FD is duped before being passed to
   RingWakerState by RegisteredSource, so there doesn't seem to be any
   data which would require pinning.)
3. U64Source was replaced by EventAsync.

It also switches all Error enums to use thiserror, which reduces
boilerplate.

BUG=None
TEST=cargo test -p cros_async

Cq-Depend: chromium:2421742
Change-Id: Ie1dd958da2e1f8dec1ae1fd8c0b4e754223d330d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2416996
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Noah Gold <nkgold@google.com>
2020-10-16 02:15:40 +00:00
Chirantan Ekbote
8ea889fccf cros_async: Refactor executors
This CL includes several smaller changes to how executors work:

  * Replace BTreeMap with Slab, which should give us some small
    performance benefits by giving O(1) lookups and reducing memory
    allocations when adding new I/O operations. It also gives some
    improvements to readability as we no longer have to carry around
    "next_*" variables. Slab has no dependencies and we're already
    pulling it in via the futures crate.
  * WakerToken no longer implements Clone.
  * Merge pending_ops and completed_ops in URingExecutor into a single
    `ops` Slab and introduce an OpStatus enum that indicates whether an
    operation is pending or completed.  This also fixes a resource leak
    where an operation that was canceled before completion would end up
    staying in completed_ops ~forever. Add a test for this leak.
  * Add a generation number to RingWakerState and include it in all
    RegisteredSources. Since a RegisteredSource can outlive the
    RingWakerState that created it, the generation number ensures that
    it will only affect the RingWakerState that created it. Add a test
    for this.
  * Poison RegisteredSource so that it doesn't implement Send or Sync.
    Since it's associated with a thread-local executor, sending it
    across thread boundaries is not ok.

BUG=none
TEST=unit tests

Change-Id: I43dcfbb8166002995ec8773522c22fab8fb2da9e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2374885
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Commit-Queue: Chirantan Ekbote <chirantan@chromium.org>
2020-09-12 09:39:26 +00:00
Dylan Reid
d086568932 cros_async: Fix reference to mem being dropped early
The Rc to BackingMemory that is passed in to memory operations was being
dropped before it is safe, The kernel can still access it until the op
is completed, so keep the reference in the pending_ops map.

Add tests so that this safety guarantees made by the executor are
exercise in unit tests.

Thanks to nkgold for finding the issue via code inspection.

BUG=none
TEST=cargo test dont_drop_backing_mem, cargo run with uring block and
run fio tests.

Change-Id: I8e4efedbbafefcbd57d7d7c340dc91a9b159b38c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2345377
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Dylan Reid <dgreid@chromium.org>
2020-08-13 00:04:56 +00:00
Michael Hoyle
6b19695c81 Add "base" crate and transition crosvm usages to it from sys_util
For now, this crate simply re-exports all of sys_util, but it will
be updated to provide new interfaces when needed. This is the
first step to making crosvm not directly depend on sys_util, so
that we can make the interface changes we need without fear of
negatively affecting (i.e. completely breaking) other usages
within chromeos.

BUG=b:162363783
TEST=./build_test

Change-Id: I7d0aa3d8a1f66af1c7fee8fd649723ef17027150
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2325168
Tested-by: Michael Hoyle <mikehoyle@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Michael Hoyle <mikehoyle@google.com>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>
2020-08-06 18:19:44 +00:00
Dylan Reid
82d7b9f094 vm_memory: Implement cros_async::BackingMemory for GuestMemory
Implementing `BackingMemory` signals that `GuestMemory` regions can be
used in uring transactions where the lifetime in which the kernel can
modify the memory is not well defined.

Change-Id: I3541fff4c5dac226062a94483672f570e7adeb18
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2275725
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
Commit-Queue: Dylan Reid <dgreid@chromium.org>
Tested-by: Dylan Reid <dgreid@chromium.org>
2020-07-28 21:36:21 +00:00
Dylan Reid
ec058d6c46 vm_memory: A crate to hold vm-specific memory objects
Move GuestAddress and GuestMemory to a new crate for VM memory. This
will make separating sys_util and crosvm independent making it easier
to use sys_util functions outside of crosvm.

Change-Id: I12e14948ea85754dfa6267b3a3fb32b77ef6796e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2311251
Auto-Submit: Dylan Reid <dgreid@chromium.org>
Commit-Queue: Dylan Reid <dgreid@chromium.org>
Tested-by: Dylan Reid <dgreid@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>
2020-07-24 21:42:34 +00:00
Dylan Reid
eef1c93fdc uring/async: Add fsync and fallocate
These will be needed by by block.
Note that support for uring fallocate was added in 5.6. The users will
have to handle falling back to synchronous calls if fallocate returns
EINVAL.

BUG=901139
TEST=added fallocate unit tests

Change-Id: I51d635adcf0bb4dd55c5bfe50719f2fde2b88e49
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2274996
Reviewed-by: Dylan Reid <dgreid@chromium.org>
Tested-by: Dylan Reid <dgreid@chromium.org>
Commit-Queue: Dylan Reid <dgreid@chromium.org>
2020-07-17 06:13:17 +00:00
Chirantan Ekbote
906b43c5c9 cros_async: Make raw waker Send + Sync
std::task::Waker unconditionally implements Send + Sync so the raw waker
that we provide also must implement those traits.  Switch to using an
Arc<AtomicBool>.

This also fixes an inconsistency where the waker was defined to be an
Rc<Cell<bool>> but all the vtable functions were treating as an
Rc<AtomicBool>.

To reduce the vtable boilerplate use the ArcWake trait from the futures
crate.

BUG=none
TEST=unit tests

Change-Id: I3870e4d7f6ce0de9f6ac3313a2f4474ae29018b2
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2287079
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
Tested-by: Chirantan Ekbote <chirantan@chromium.org>
Commit-Queue: Chirantan Ekbote <chirantan@chromium.org>
2020-07-15 09:28:23 +00:00
Dylan Reid
0edf83a0b5 cros_async: add uring_executor
Add an executor, similar to `fd_executor`, except driven by io_uring
instead of `PollContext`. This will allow for queueing actions instead
of waiting for 'ready' from poll. This reduces the number of syscalls
and increases the parallelism possible when doing IO.

Change-Id: Ie2e69cb09ee3ab1086ef31d5ebd0169843a8228d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2227083
Commit-Queue: Dylan Reid <dgreid@chromium.org>
Tested-by: Dylan Reid <dgreid@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
2020-06-17 19:17:21 +00:00
Dylan Reid
2cc138341d Add a cros_async crate.
This crate will house code using the new async/await features to be used
by other parts of crosvm.

Start the crate with a Future executor that runs tasks in a single
thread and allows futures that block on system file descriptors.

Change-Id: If77778ac056210dabbfc6e6e1e63df1c1b904a7f
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/1955045
Reviewed-by: Dylan Reid <dgreid@chromium.org>
Tested-by: Dylan Reid <dgreid@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Dylan Reid <dgreid@chromium.org>
2020-02-10 23:46:11 +00:00