From 8cace3f05003c6cb4d38c36890055f03151c2ad4 Mon Sep 17 00:00:00 2001 From: Richard Qin Date: Fri, 16 Oct 2026 02:39:56 +0800 Subject: Remove old code Signed-off-by: Richard Qin --- docs/dev/dev_memory.md | 37 ------------------------------------- 1 file changed, 37 deletions(-) delete mode 100644 docs/dev/dev_memory.md (limited to 'docs/dev/dev_memory.md') diff --git a/docs/dev/dev_memory.md b/docs/dev/dev_memory.md deleted file mode 100644 index f05e336..0000000 --- a/docs/dev/dev_memory.md +++ /dev/null @@ -1,37 +0,0 @@ -# Dev log -## **1. Process Management:** -The core architecture has been upgraded from a simple single queue to a Per-CPU scheduler, supporting multi-core concurrency. - -* Process lifecycle: A complete process state machine has been implemented, including UNUSED, RUNNABLE, RUNNING, SLEEPING, and ZOMBIE states. - -* Core operations: - * fork(): process cloning, supporting COW (copy-on-write) isolation of memory space between parent and child processes. - * exit(): process termination and resource cleanup. - * wait(): parent process waits for child process to exit. - * sleep()/wakeup(): channel-based sleep and wakeup mechanism. - -* Scheduling algorithm: - * O(1) priority scheduling has been implemented (supporting 4 priority queues). - - * Per-CPU RunQueue: each CPU has its own independent run queue. - - * Supports Work Stealing: idle CPUs can fetch tasks from other CPUs’ queues. - -## **2. Memory Management:** -A complete virtual and physical memory management system has been implemented. - -* Physical Memory (PMM): Implements the Buddy System, supporting memory allocation and deallocation in $2^n$ pages. - -* Virtual Memory (VM): Based on RISC-V Sv39 paging mode. Provides secure data copying from user space to kernel space (copyin). - -* COW (Copy-On-Write): During fork, only page table entries are copied and pages are set to read-only; writes trigger page faults for physical copy, greatly improving process creation efficiency. - -* Kernel heap: Implements a Slab Allocator, providing efficient allocation of small objects (such as struct Proc). - -## **3. Synchronization:** - -* Spinlock: Used to protect very short critical sections (e.g., scheduler lock, PMM lock), supports disabling interrupts to prevent deadlocks. - -* Mutex (sleeping lock): Used for long critical sections (e.g., file I/O), allowing sleep while holding the lock. - -* Lock Handoff: Implements a complex lock handoff mechanism in the scheduler to ensure atomicity of context switches. \ No newline at end of file -- cgit v1.2.3