Revert "CP tokio_epoll_uring for read path"

This reverts commit 1556234d9a.
2026-01-15 09:22:55 +00:00 · 2023-10-10 09:55:35 +00:00
parent d91539b888
commit dbb8377983
5 changed files with 46 additions and 128 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2066,26 +2066,6 @@ dependencies = [
 "windows-sys 0.48.0",
 ]

-[[package]]
-name = "io-uring"
-version = "0.5.13"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dd1e1a01cfb924fd8c5c43b6827965db394f5a3a16c599ce03452266e1cf984c"
-dependencies = [
- "bitflags",
- "libc",
-]
-
-[[package]]
-name = "io-uring"
-version = "0.6.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "141a0f4546a50b2ed637c7a6df0d7dff45c9f41523254996764461c8ae0d9424"
-dependencies = [
- "bitflags",
- "libc",
-]
-
 [[package]]
 name = "ipnet"
 version = "2.7.2"
@@ -2185,9 +2165,9 @@ checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"

 [[package]]
 name = "libc"
-version = "0.2.147"
+version = "0.2.144"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b4668fb0ea861c1df094127ac5f1da3409a82116a4ba74fca2e58ef927159bb3"
+checksum = "2b00cc1c228a6782d0f076e7b232802e0c5689d41bb5df366f2a6b6621cfdfe1"

 [[package]]
 name = "libloading"
@@ -2767,7 +2747,6 @@ dependencies = [
 "tenant_size_model",
 "thiserror",
 "tokio",
- "tokio-epoll-uring",
 "tokio-io-timeout",
 "tokio-postgres",
 "tokio-tar",
@@ -3888,12 +3867,6 @@ dependencies = [
 "windows-sys 0.42.0",
 ]

-[[package]]
-name = "scoped-tls"
-version = "1.0.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e1cf6437eb19a8f4a6cc0f7dca544973b0b78843adbfeb3683d1a94a0024a294"
-
 [[package]]
 name = "scopeguard"
 version = "1.1.0"
@@ -4478,18 +4451,18 @@ dependencies = [

 [[package]]
 name = "thiserror"
-version = "1.0.47"
+version = "1.0.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "97a802ec30afc17eee47b2855fc72e0c4cd62be9b4efe6591edde0ec5bd68d8f"
+checksum = "978c9a314bd8dc99be594bc3c175faaa9794be04a5a5e153caba6915336cebac"
 dependencies = [
 "thiserror-impl",
 ]

 [[package]]
 name = "thiserror-impl"
-version = "1.0.47"
+version = "1.0.40"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6bb623b56e39ab7dcd4b1b98bb6c8f8d907ed255b18de254088016b27a8ee19b"
+checksum = "f9456a42c5b0d803c8cd86e73dd7cc9edd429499f37a3550d286d5e86720569f"
 dependencies = [
 "proc-macro2",
 "quote",
@@ -4574,39 +4547,22 @@ dependencies = [

 [[package]]
 name = "tokio"
-version = "1.32.0"
+version = "1.28.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "17ed6077ed6cd6c74735e21f37eb16dc3935f96878b1fe961074089cc80893f9"
+checksum = "0aa32867d44e6f2ce3385e89dceb990188b8bb0fb25b0cf576647a6f98ac5105"
 dependencies = [
- "backtrace",
+ "autocfg",
 "bytes",
 "libc",
 "mio",
 "num_cpus",
- "parking_lot 0.12.1",
 "pin-project-lite",
 "signal-hook-registry",
- "socket2 0.5.3",
+ "socket2 0.4.9",
 "tokio-macros",
 "windows-sys 0.48.0",
 ]

-[[package]]
-name = "tokio-epoll-uring"
-version = "0.1.0"
-dependencies = [
- "futures",
- "io-uring 0.6.1",
- "libc",
- "once_cell",
- "scopeguard",
- "thiserror",
- "tokio",
- "tokio-uring",
- "tokio-util",
- "tracing",
-]
-
 [[package]]
 name = "tokio-io-timeout"
 version = "1.2.0"
@@ -4723,20 +4679,6 @@ dependencies = [
 "tungstenite",
 ]

-[[package]]
-name = "tokio-uring"
-version = "0.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0d5e02bb137e030b3a547c65a3bd2f1836d66a97369fdcc69034002b10e155ef"
-dependencies = [
- "io-uring 0.5.13",
- "libc",
- "scoped-tls",
- "slab",
- "socket2 0.4.9",
- "tokio",
-]
-
 [[package]]
 name = "tokio-util"
 version = "0.7.8"
--- a/pageserver/Cargo.toml
+++ b/pageserver/Cargo.toml
@@ -83,7 +83,6 @@ enum-map.workspace = true
 enumset.workspace = true
 strum.workspace = true
 strum_macros.workspace = true
-tokio-epoll-uring = { path = "/home/admin/tokio-epoll-uring/tokio-epoll-uring" }

 [dev-dependencies]
 criterion.workspace = true
--- a/pageserver/src/tenant/block_io.rs
+++ b/pageserver/src/tenant/block_io.rs
@@ -5,7 +5,7 @@
 use super::ephemeral_file::EphemeralFile;
 use super::storage_layer::delta_layer::{Adapter, DeltaLayerInner};
 use crate::context::RequestContext;
-use crate::page_cache::{self, PageReadGuard, ReadBufResult, PAGE_SZ, PageWriteGuard};
+use crate::page_cache::{self, PageReadGuard, ReadBufResult, PAGE_SZ};
 use crate::virtual_file::VirtualFile;
 use bytes::Bytes;
 use std::ops::{Deref, DerefMut};
@@ -169,7 +169,7 @@ impl FileBlockReader {
    }

    /// Read a page from the underlying file into given buffer.
-    async fn fill_buffer(&self, buf: PageWriteGuard<'static>, blkno: u32) -> Result<PageWriteGuard<'static>, std::io::Error> {
+    async fn fill_buffer(&self, buf: &mut [u8], blkno: u32) -> Result<(), std::io::Error> {
        assert!(buf.len() == PAGE_SZ);
        self.file
            .read_exact_at(buf, blkno as u64 * PAGE_SZ as u64)
@@ -198,7 +198,7 @@ impl FileBlockReader {
            ReadBufResult::Found(guard) => Ok(guard.into()),
            ReadBufResult::NotFound(mut write_guard) => {
                // Read the page from disk into the buffer
-                let write_guard = self.fill_buffer(write_guard, blknum).await?;
+                self.fill_buffer(write_guard.deref_mut(), blknum).await?;
                Ok(write_guard.mark_valid().into())
            }
        }
--- a/pageserver/src/tenant/ephemeral_file.rs
+++ b/pageserver/src/tenant/ephemeral_file.rs
@@ -89,8 +89,10 @@ impl EphemeralFile {
                    return Ok(BlockLease::PageReadGuard(guard))
                }
                page_cache::ReadBufResult::NotFound(mut write_guard) => {
-                    let write_guard = self.file
-                        .read_exact_at(write_guard, blknum as u64 * PAGE_SZ as u64)
+                    let buf: &mut [u8] = write_guard.deref_mut();
+                    debug_assert_eq!(buf.len(), PAGE_SZ);
+                    self.file
+                        .read_exact_at(&mut buf[..], blknum as u64 * PAGE_SZ as u64)
                        .await?;
                    let read_guard = write_guard.mark_valid();
                    return Ok(BlockLease::PageReadGuard(read_guard));
--- a/pageserver/src/virtual_file.rs
+++ b/pageserver/src/virtual_file.rs
@@ -11,13 +11,11 @@
 //! src/backend/storage/file/fd.c
 //!
 use crate::metrics::{StorageIoOperation, STORAGE_IO_SIZE, STORAGE_IO_TIME_METRIC};
-use crate::page_cache::PageWriteGuard;
 use crate::tenant::TENANTS_SEGMENT_NAME;
 use camino::{Utf8Path, Utf8PathBuf};
 use once_cell::sync::OnceCell;
 use std::fs::{self, File, OpenOptions};
 use std::io::{Error, ErrorKind, Seek, SeekFrom};
-use std::os::fd::{AsRawFd, FromRawFd, IntoRawFd, OwnedFd};
 use std::os::unix::fs::FileExt;
 use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
 use tokio::sync::{RwLock, RwLockReadGuard, RwLockWriteGuard};
@@ -372,7 +370,7 @@ impl VirtualFile {
    ///
    /// We are doing it via a macro as Rust doesn't support async closures that
    /// take on parameters with lifetimes.
-    async fn lock_file(&self) -> Result<FileGuard<'static>, Error> {
+    async fn lock_file(&self) -> Result<FileGuard<'_>, Error> {
        let open_files = get_open_files();

        let mut handle_guard = {
@@ -462,59 +460,24 @@ impl VirtualFile {
    }

    // Copied from https://doc.rust-lang.org/1.72.0/src/std/os/unix/fs.rs.html#117-135
-    pub async fn read_exact_at(
-        &self,
-        mut write_guard: PageWriteGuard<'static>,
-        mut offset: u64,
-    ) -> Result<PageWriteGuard<'static>, Error> {
-        let file_guard: FileGuard<'static> = self.lock_file().await?;
-
-        let system = tokio_epoll_uring::thread_local_system().await;
-        struct PageWriteGuardBuf {
-            buf: PageWriteGuard<'static>,
-            init_up_to: usize,
-        }
-        unsafe impl tokio_epoll_uring::IoBuf for PageWriteGuardBuf {
-            fn stable_ptr(&self) -> *const u8 {
-                self.buf.as_ptr()
-            }
-            fn bytes_init(&self) -> usize {
-                self.init_up_to
-            }
-            fn bytes_total(&self) -> usize {
-                self.buf.len()
+    pub async fn read_exact_at(&self, mut buf: &mut [u8], mut offset: u64) -> Result<(), Error> {
+        while !buf.is_empty() {
+            match self.read_at(buf, offset).await {
+                Ok(0) => {
+                    return Err(Error::new(
+                        std::io::ErrorKind::UnexpectedEof,
+                        "failed to fill whole buffer",
+                    ))
+                }
+                Ok(n) => {
+                    buf = &mut buf[n..];
+                    offset += n as u64;
+                }
+                Err(ref e) if e.kind() == std::io::ErrorKind::Interrupted => {}
+                Err(e) => return Err(e),
            }
        }
-        unsafe impl tokio_epoll_uring::IoBufMut for PageWriteGuardBuf {
-            fn stable_mut_ptr(&mut self) -> *mut u8 {
-                self.buf.as_mut_ptr()
-            }
-
-            unsafe fn set_init(&mut self, pos: usize) {
-                assert!(pos <= self.buf.len());
-                self.init_up_to = pos;
-            }
-        }
-        let buf = PageWriteGuardBuf {
-            buf: write_guard,
-            init_up_to: 0,
-        };
-        let owned_fd = unsafe { OwnedFd::from_raw_fd(file_guard.as_ref().as_raw_fd()) };
-        let guard = scopeguard::guard(file_guard, |_| {
-            panic!("must not drop future while operation is ongoing (todo: pass file_guard to tokio_epoll_uring to aovid this)")
-        });
-        let ((owned_fd, buf), res) = system.read(owned_fd, offset, buf).await;
-        let _ = OwnedFd::into_raw_fd(owned_fd);
-        let _ = scopeguard::ScopeGuard::into_inner(guard);
-        let PageWriteGuardBuf {
-            buf: write_guard,
-            init_up_to,
-        } = buf;
-        if let Ok(num_read) = res {
-            assert!(init_up_to == num_read); // TODO need to deal with short reads here
-        }
-        res.map(|_| write_guard)
-            .map_err(|e| Error::new(ErrorKind::Other, e))
+        Ok(())
    }

    // Copied from https://doc.rust-lang.org/1.72.0/src/std/os/unix/fs.rs.html#219-235
@@ -564,6 +527,18 @@ impl VirtualFile {
        Ok(n)
    }

+    pub async fn read_at(&self, buf: &mut [u8], offset: u64) -> Result<usize, Error> {
+        let result = with_file!(self, StorageIoOperation::Read, |file| file
+            .as_ref()
+            .read_at(buf, offset));
+        if let Ok(size) = result {
+            STORAGE_IO_SIZE
+                .with_label_values(&["read", &self.tenant_id, &self.timeline_id])
+                .add(size as i64);
+        }
+        result
+    }
+
    async fn write_at(&self, buf: &[u8], offset: u64) -> Result<usize, Error> {
        let result = with_file!(self, StorageIoOperation::Write, |file| file
            .as_ref()