Revert "新的内存管理模块 (#301)" (#302)

This reverts commit d8ad0a5e77.

kernel/src/mm/allocator/slab.rs

@@ -1,123 +0,0 @@
-//! 当前slab分配器暂时不使用，等待后续完善后合并主线
-#![allow(dead_code)]
-
-use core::alloc::Layout;
-
-// 定义Slab，用来存放空闲块
-pub struct Slab {
-    block_size: usize,
-    free_block_list: FreeBlockList,
-}
-
-impl Slab {
-    /// @brief: 初始化一个slab
-    /// @param {usize} start_addr
-    /// @param {usize} slab_size
-    /// @param {usize} block_size
-    pub unsafe fn new(start_addr: usize, slab_size: usize, block_size: usize) -> Slab {
-        let blocks_num = slab_size / block_size;
-        return Slab {
-            block_size: block_size,
-            free_block_list: FreeBlockList::new(start_addr, block_size, blocks_num),
-        };
-    }
-
-    /// @brief: 获取slab中可用的block数
-    pub fn used_blocks(&self) -> usize {
-        return self.free_block_list.len();
-    }
-
-    /// @brief: 扩大free_block_list
-    /// @param {*} mut
-    /// @param {usize} start_addr
-    /// @param {usize} slab_size
-    pub fn grow(&mut self, start_addr: usize, slab_size: usize) {
-        let num_of_blocks = slab_size / self.block_size;
-        let mut block_list =
-            unsafe { FreeBlockList::new(start_addr, self.block_size, num_of_blocks) };
-        // 将新链表接到原链表的后面
-        while let Some(block) = block_list.pop() {
-            self.free_block_list.push(block);
-        }
-    }
-    /// @brief: 从slab中分配一个block
-    /// @return 分配的内存地址
-    pub fn allocate(&mut self, _layout: Layout) -> Option<*mut u8> {
-        match self.free_block_list.pop() {
-            Some(block) => return Some(block.addr() as *mut u8),
-            None => return None,
-        }
-    }
-    /// @brief: 将block归还给slab
-    pub fn free(&mut self, ptr: *mut u8) {
-        let ptr = ptr as *mut FreeBlock;
-        unsafe {
-            self.free_block_list.push(&mut *ptr);
-        }
-    }
-}
-/// slab中的空闲块
-struct FreeBlockList {
-    len: usize,
-    head: Option<&'static mut FreeBlock>,
-}
-
-impl FreeBlockList {
-    unsafe fn new(start_addr: usize, block_size: usize, num_of_blocks: usize) -> FreeBlockList {
-        let mut new_list = FreeBlockList::new_empty();
-        for i in (0..num_of_blocks).rev() {
-            // 从后往前分配，避免内存碎片
-            let new_block = (start_addr + i * block_size) as *mut FreeBlock;
-            new_list.push(&mut *new_block);
-        }
-        return new_list;
-    }
-
-    fn new_empty() -> FreeBlockList {
-        return FreeBlockList { len: 0, head: None };
-    }
-
-    fn len(&self) -> usize {
-        return self.len;
-    }
-
-    /// @brief: 将空闲块从链表中弹出
-    fn pop(&mut self) -> Option<&'static mut FreeBlock> {
-        // 从链表中弹出一个空闲块
-        let block = self.head.take().map(|node| {
-            self.head = node.next.take();
-            self.len -= 1;
-            node
-        });
-        return block;
-    }
-
-    /// @brief: 将空闲块压入链表
-    fn push(&mut self, free_block: &'static mut FreeBlock) {
-        free_block.next = self.head.take();
-        self.len += 1;
-        self.head = Some(free_block);
-    }
-
-    fn is_empty(&self) -> bool {
-        return self.head.is_none();
-    }
-}
-
-impl Drop for FreeBlockList {
-    fn drop(&mut self) {
-        while let Some(_) = self.pop() {}
-    }
-}
-
-struct FreeBlock {
-    next: Option<&'static mut FreeBlock>,
-}
-
-impl FreeBlock {
-    /// @brief: 获取FreeBlock的地址
-    /// @return {*}
-    fn addr(&self) -> usize {
-        return self as *const _ as usize;
-    }
-}