hubcio commented on code in PR #2944: URL: https://github.com/apache/iggy/pull/2944#discussion_r2964691909
########## core/buf/src/lib.rs: ########## @@ -0,0 +1,461 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +use std::mem::ManuallyDrop; +use std::ptr::NonNull; +use std::slice; +use std::sync::atomic::{AtomicUsize, Ordering, fence}; + +use aligned_vec::{AVec, ConstAlign}; + +#[derive(Debug)] +pub struct Owned<const ALIGN: usize = 4096> { + inner: AVec<u8, ConstAlign<ALIGN>>, +} + +impl<const ALIGN: usize> From<AVec<u8, ConstAlign<ALIGN>>> for Owned<ALIGN> { + fn from(vec: AVec<u8, ConstAlign<ALIGN>>) -> Self { + Self { inner: vec } + } +} + +impl<const ALIGN: usize> From<Owned<ALIGN>> for AVec<u8, ConstAlign<ALIGN>> { + fn from(value: Owned<ALIGN>) -> Self { + value.inner + } +} + +impl<const ALIGN: usize> Owned<ALIGN> { + pub fn as_slice(&self) -> &[u8] { + &self.inner + } + + pub fn as_mut_slice(&mut self) -> &mut [u8] { + &mut self.inner + } + + /// Split `Owned` buffer into two halves + /// + /// # Panics + /// Panics if `split_at > self.len()` or if `split_at` is not a multiple of `ALIGN` bytes. + pub fn split_at(self, split_at: usize) -> TwoHalves<ALIGN> { + assert!(split_at <= self.inner.len()); + + // Take ownership of the AVec's allocation. After this, we are responsible + // for deallocating via `AVec::from_raw_parts` or equivalent. + let (ptr, _, len, capacity) = self.inner.into_raw_parts(); + + // SAFETY: both pointers are constructed from the same `Inner` allocation, the split_at bounds are validated. + // The control block captures original `Inner` metadata to allow reconstructing the original frame for merging/dropping. + // The ptr provenance rules are maintained by the use of `NonNull` apis. + let base: NonNull<u8> = unsafe { NonNull::new_unchecked(ptr) }; + let tail = unsafe { NonNull::new_unchecked(ptr.add(split_at)) }; + let ctrlb = ControlBlock::new(base, len, capacity); Review Comment: every `Owned::split_at()` does `Box::new(ControlBlock{...})` - a heap allocation. at 1M ops/sec this is 1M mallocs/sec just for control blocks. consider embedding the control block in the aligned allocation or using a slab allocator. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
