rt: add infrastructure code for io_uring

Author: mox692

.github/workflows/ci.yml

@@ -350,6 +350,40 @@ jobs:
           # the unstable cfg to RustDoc
           RUSTDOCFLAGS: --cfg tokio_unstable --cfg tokio_taskdump
 
+  test-unstable-uring:
+    name: test tokio full --cfg tokio_unstable_uring
+    needs: basics
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        include:
+          - os: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Rust ${{ env.rust_stable }}
+        uses: dtolnay/rust-toolchain@stable
+        with:
+            toolchain: ${{ env.rust_stable }}
+
+      - name: Install cargo-nextest
+        uses: taiki-e/install-action@v2
+        with:
+          tool: cargo-nextest
+
+      - uses: Swatinem/rust-cache@v2
+      # Run `tokio` with "unstable" and "taskdump" cfg flags.
+      - name: test tokio full --cfg tokio_unstable_uring
+        run: |
+          set -euxo pipefail
+          cargo nextest run --all-features
+          cargo test --doc --all-features
+        working-directory: tokio
+        env:
+          RUSTFLAGS: --cfg tokio_unstable_uring -Dwarnings
+          # in order to run doctests for unstable features, we must also pass
+          # the unstable cfg to RustDoc
+          RUSTDOCFLAGS: --cfg tokio_unstable_uring
+
   check-unstable-mt-counters:
     name: check tokio full --internal-mt-counters
     needs: basics
@@ -664,7 +698,7 @@ jobs:
           cargo test --doc -Zbuild-std --target target-specs/i686-unknown-linux-gnu.json -p tokio --all-features
         env:
           RUST_TEST_THREADS: 1
-          RUSTFLAGS: --cfg tokio_unstable --cfg tokio_taskdump -Dwarnings --cfg tokio_no_tuning_tests
+          RUSTFLAGS: --cfg tokio_unstable --cfg tokio_taskdump --cfg=io_uring_skip_arch_check -Dwarnings --cfg tokio_no_tuning_tests
 
   no-atomic-u64-check:
     name: Check tokio --feature-powerset --depth 2 on i686-unknown-linux-gnu without AtomicU64
@@ -702,7 +736,7 @@ jobs:
           # Try with unstable feature flags
           - { name: "--unstable", rustflags: "--cfg tokio_unstable -Dwarnings" }
           # Try with unstable and taskdump feature flags
-          - { name: "--unstable --taskdump", rustflags: "--cfg tokio_unstable -Dwarnings --cfg tokio_taskdump" }
+          - { name: "--unstable --taskdump", rustflags: "--cfg tokio_unstable -Dwarnings --cfg tokio_taskdump --cfg tokio_unstable_uring" }
     steps:
       - uses: actions/checkout@v4
       - name: Install Rust ${{ env.rust_nightly }}
@@ -765,7 +799,7 @@ jobs:
           cargo hack check --all-features --ignore-private
       - name: "check --all-features --unstable -Z minimal-versions"
         env:
-          RUSTFLAGS: --cfg tokio_unstable --cfg tokio_taskdump -Dwarnings
+          RUSTFLAGS: --cfg tokio_unstable --cfg tokio_taskdump --cfg tokio_unstable_uring -Dwarnings
         run: |
           # Remove dev-dependencies from Cargo.toml to prevent the next `cargo update`
           # from determining minimal versions based on dev-dependencies.
@@ -817,8 +851,8 @@ jobs:
         run:
           - os: windows-latest
           - os: ubuntu-latest
-            RUSTFLAGS: --cfg tokio_taskdump
-            RUSTDOCFLAGS: --cfg tokio_taskdump
+            RUSTFLAGS: --cfg tokio_taskdump --cfg tokio_unstable_uring
+            RUSTDOCFLAGS: --cfg tokio_taskdump --cfg tokio_unstable_uring
 
     steps:
       - uses: actions/checkout@v4

Cargo.toml

@@ -29,4 +29,5 @@ unexpected_cfgs = { level = "warn", check-cfg = [
   'cfg(tokio_no_tuning_tests)',
   'cfg(tokio_taskdump)',
   'cfg(tokio_unstable)',
+  'cfg(tokio_unstable_uring)',
 ] }

spellcheck.dic

@@ -1,4 +1,4 @@
-302
+306
 &
 +
 <
@@ -70,6 +70,9 @@ connectionless
 coroutines
 cpu
 cpus
+cqe
+CQE
+cqe's
 customizable
 Customizable
 datagram
@@ -287,6 +290,7 @@ unsets
 Unsets
 unsynchronized
 untrusted
+uring
 usecases
 Valgrind
 Varghese

tokio/Cargo.toml

@@ -103,6 +103,12 @@ socket2 = { version = "0.5.5", optional = true, features = ["all"] }
 [target.'cfg(tokio_unstable)'.dependencies]
 tracing = { version = "0.1.29", default-features = false, features = ["std"], optional = true } # Not in full
 
+[target.'cfg(all(tokio_unstable_uring, target_os = "linux"))'.dependencies]
+io-uring = { version = "0.7.6", default-features = false }
+libc = { version = "0.2.168" }
+mio = { version = "1.0.1", default-features = false, features = ["os-poll", "os-ext"] }
+slab = "0.4.9"
+
 # Currently unstable. The API exposed by these features may be broken at any time.
 # Requires `--cfg tokio_unstable` to enable.
 [target.'cfg(tokio_taskdump)'.dependencies]

tokio/src/io/mod.rs

@@ -214,11 +214,11 @@ pub use self::read_buf::ReadBuf;
 #[doc(no_inline)]
 pub use std::io::{Error, ErrorKind, Result, SeekFrom};
 
-cfg_io_driver_impl! {
+cfg_io_driver_impl_or_uring! {
     pub(crate) mod interest;
     pub(crate) mod ready;
 
-    cfg_net! {
+    cfg_net_or_uring! {
         pub use interest::Interest;
         pub use ready::Ready;
     }

tokio/src/io/poll_evented.rs

@@ -9,7 +9,7 @@ use std::ops::Deref;
 use std::panic::{RefUnwindSafe, UnwindSafe};
 use std::task::ready;
 
-cfg_io_driver! {
+cfg_io_driver_or_uring! {
     /// Associates an I/O resource that implements the [`std::io::Read`] and/or
     /// [`std::io::Write`] traits with the reactor that drives it.
     ///

tokio/src/macros/cfg.rs

@@ -131,6 +131,36 @@ macro_rules! cfg_io_driver {
     }
 }
 
+macro_rules! cfg_io_driver_or_uring {
+    ($($item:item)*) => {
+        $(
+            #[cfg(any(
+                feature = "net",
+                all(unix, feature = "process"),
+                all(unix, feature = "signal"),
+                all(
+                    tokio_unstable_uring,
+                    feature = "rt",
+                    feature = "fs",
+                    target_os = "linux",
+                )
+            ))]
+            #[cfg_attr(docsrs, doc(cfg(any(
+                feature = "net",
+                all(unix, feature = "process"),
+                all(unix, feature = "signal"),
+                all(
+                    tokio_unstable_uring,
+                    feature = "rt",
+                    feature = "fs",
+                    target_os = "linux",
+                )
+            ))))]
+            $item
+        )*
+    }
+}
+
 macro_rules! cfg_io_driver_impl {
     ( $( $item:item )* ) => {
         $(
@@ -157,6 +187,44 @@ macro_rules! cfg_not_io_driver {
     }
 }
 
+macro_rules! cfg_io_driver_impl_or_uring {
+    ( $( $item:item )* ) => {
+        $(
+            #[cfg(any(
+                feature = "net",
+                all(unix, feature = "process"),
+                all(unix, feature = "signal"),
+                all(
+                    tokio_unstable_uring,
+                    feature = "rt",
+                    feature = "fs",
+                    target_os = "linux",
+                )
+            ))]
+            $item
+        )*
+    }
+}
+
+macro_rules! cfg_not_io_driver_impl_or_uring {
+    ( $( $item:item )* ) => {
+        $(
+            #[cfg(not(any(
+                feature = "net",
+                all(unix, feature = "process"),
+                all(unix, feature = "signal"),
+                all(
+                    tokio_unstable_uring,
+                    feature = "rt",
+                    feature = "fs",
+                    target_os = "linux",
+                )
+            )))]
+            $item
+        )*
+    }
+}
+
 macro_rules! cfg_io_readiness {
     ($($item:item)*) => {
         $(
@@ -279,6 +347,35 @@ macro_rules! cfg_net {
     }
 }
 
+macro_rules! cfg_net_or_uring {
+    ($($item:item)*) => {
+        $(
+            #[cfg(any(
+                feature = "net",
+                all(
+                    tokio_unstable_uring,
+                    feature = "rt",
+                    feature = "fs",
+                    target_os = "linux",
+                )
+            ))]
+            #[cfg_attr(
+                docsrs,
+                doc(cfg(any(
+                    feature = "net",
+                    all(
+                        tokio_unstable_uring,
+                        feature = "rt",
+                        feature = "fs",
+                        target_os = "linux",
+                    )
+                )))
+            )]
+            $item
+        )*
+    }
+}
+
 macro_rules! cfg_net_unix {
     ($($item:item)*) => {
         $(
@@ -616,3 +713,17 @@ macro_rules! cfg_metrics_variant {
         }
     }
 }
+
+macro_rules! cfg_tokio_unstable_uring {
+    ($($item:item)*) => {
+        $(
+            #[cfg(all(
+                tokio_unstable_uring,
+                feature = "rt",
+                feature = "fs",
+                target_os = "linux",
+            ))]
+            $item
+        )*
+    };
+}

tokio/src/runtime/driver.rs

@@ -84,7 +84,7 @@ impl Handle {
         self.io.unpark();
     }
 
-    cfg_io_driver! {
+    cfg_io_driver_or_uring! {
         #[track_caller]
         pub(crate) fn io(&self) -> &crate::runtime::io::Handle {
             self.io
@@ -121,7 +121,7 @@ impl Handle {
 
 // ===== io driver =====
 
-cfg_io_driver! {
+cfg_io_driver_impl_or_uring! {
     pub(crate) type IoDriver = crate::runtime::io::Driver;
 
     #[derive(Debug)]
@@ -196,7 +196,7 @@ cfg_io_driver! {
     }
 }
 
-cfg_not_io_driver! {
+cfg_not_io_driver_impl_or_uring! {
     pub(crate) type IoHandle = UnparkThread;
 
     #[derive(Debug)]
@@ -226,6 +226,13 @@ cfg_not_io_driver! {
             false
         }
     }
+    cfg_io_driver_or_uring! {
+        impl IoHandle {
+            pub(crate) fn as_ref(&self) -> Option<&crate::runtime::io::Handle> {
+                todo!()
+            }
+        }
+    }
 }
 
 // ===== signal driver =====
@@ -244,7 +251,7 @@ cfg_signal_internal_and_unix! {
 cfg_not_signal_internal! {
     pub(crate) type SignalHandle = ();
 
-    cfg_io_driver! {
+    cfg_io_driver_impl_or_uring! {
         type SignalDriver = IoDriver;
 
         fn create_signal_driver(io_driver: IoDriver, _io_handle: &crate::runtime::io::Handle) -> io::Result<(SignalDriver, SignalHandle)> {
@@ -264,7 +271,7 @@ cfg_process_driver! {
 }
 
 cfg_not_process_driver! {
-    cfg_io_driver! {
+    cfg_io_driver_impl_or_uring! {
         type ProcessDriver = SignalDriver;
 
         fn create_process_driver(signal_driver: SignalDriver) -> ProcessDriver {
@@ -347,3 +354,7 @@ cfg_not_time! {
         (io_stack, ())
     }
 }
+
+cfg_tokio_unstable_uring! {
+    pub(crate) mod op;
+}