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https://github.com/DragonOS-Community/DragonOS.git
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7c28051e8c
* chore: update toolchain version to 2024-11-05 * update dragon reach to e945c217b3 * update dog to 6f2c0c8f12 --------- Co-authored-by: longjin <longjin@DragonOS.org>
92 lines
3.0 KiB
Rust
92 lines
3.0 KiB
Rust
//! A slab allocator implementation for objects less than a page-size (4 KiB or 2MiB).
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//!
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//! # Overview
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//!
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//! The organization is as follows:
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//!
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//! * A `ZoneAllocator` manages many `SCAllocator` and can
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//! satisfy requests for different allocation sizes.
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//! * A `SCAllocator` allocates objects of exactly one size.
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//! It stores the objects and meta-data in one or multiple `AllocablePage` objects.
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//! * A trait `AllocablePage` that defines the page-type from which we allocate objects.
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//!
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//! Lastly, it provides two default `AllocablePage` implementations `ObjectPage` and `LargeObjectPage`:
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//! * A `ObjectPage` that is 4 KiB in size and contains allocated objects and associated meta-data.
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//! * A `LargeObjectPage` that is 2 MiB in size and contains allocated objects and associated meta-data.
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//!
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//!
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//! # Implementing GlobalAlloc
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//! See the [global alloc](https://github.com/gz/rust-slabmalloc/tree/master/examples/global_alloc.rs) example.
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#![allow(unused_features)]
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#![no_std]
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#![crate_name = "slabmalloc"]
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#![crate_type = "lib"]
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#![feature(maybe_uninit_as_bytes)]
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extern crate alloc;
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mod pages;
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mod sc;
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mod zone;
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pub use pages::*;
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pub use sc::*;
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pub use zone::*;
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use core::alloc::Layout;
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use core::fmt;
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use core::ptr::{self, NonNull};
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use log::trace;
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/// How many bytes in the page are used by allocator meta-data.
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const OBJECT_PAGE_METADATA_OVERHEAD: usize = 80;
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/// How many bytes a [`ObjectPage`] is.
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const OBJECT_PAGE_SIZE: usize = 4096;
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type VAddr = usize;
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/// Error that can be returned for `allocation` and `deallocation` requests.
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#[derive(Debug)]
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pub enum AllocationError {
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/// Can't satisfy the allocation request for Layout because the allocator
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/// does not have enough memory (you may be able to `refill` it).
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OutOfMemory,
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/// Allocator can't deal with the provided size of the Layout.
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InvalidLayout,
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}
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/// Allocator trait to be implemented by users of slabmalloc to provide memory to slabmalloc.
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///
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/// # Safety
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/// Needs to adhere to safety requirements of a rust allocator (see GlobalAlloc et. al.).
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pub unsafe trait Allocator<'a> {
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fn allocate(&mut self, layout: Layout) -> Result<NonNull<u8>, AllocationError>;
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/// # Safety
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/// The caller must ensure that the memory is valid and that the layout is correct.
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unsafe fn deallocate(
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&mut self,
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ptr: NonNull<u8>,
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layout: Layout,
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slab_callback: &'static dyn CallBack,
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) -> Result<(), AllocationError>;
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/// Refill the allocator with a [`ObjectPage`].
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///
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/// # Safety
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/// TBD (this API needs to change anyways, likely new page should be a raw pointer)
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unsafe fn refill(
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&mut self,
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layout: Layout,
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new_page: &'a mut ObjectPage<'a>,
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) -> Result<(), AllocationError>;
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}
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/// 将slab_page归还Buddy的回调函数
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pub trait CallBack: Send + Sync {
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/// # Safety
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/// The caller must ensure that the memory is valid and that the size is correct.
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unsafe fn free_slab_page(&self, _: *mut u8, _: usize) {}
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}
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