add policy

Author: vickiegpt

include/cxlcontroller.h

@@ -74,7 +74,21 @@ class PagingPolicy : public Policy {
 class CachingPolicy : public Policy {
 public:
     CachingPolicy();
-    // paging related
+
+    // 判断是否应该缓存数据
+    virtual bool should_cache(uint64_t addr, uint64_t timestamp) {
+        return true; // 默认行为，可以被子类覆盖
+    }
+
+    // 判断是否应该进行后向失效
+    virtual bool should_invalidate(uint64_t addr, uint64_t timestamp) {
+        return false; // 默认行为，可以被子类覆盖
+    }
+
+    // 获取需要失效的地址列表
+    virtual std::vector<uint64_t> get_invalidation_list(CXLController* controller) {
+        return {}; // 默认行为，可以被子类覆盖
+    }
 };
 
 struct LRUCacheEntry {
@@ -216,6 +230,9 @@ class CXLController : public CXLSwitch {
 
     // 添加缓存更新方法
     void update_cache(uint64_t addr, uint64_t value, uint64_t timestamp) { lru_cache.put(addr, value, timestamp); }
+    void perform_back_invalidation();
+    void invalidate_in_expanders(uint64_t addr);
+    void invalidate_in_switch(CXLSwitch* switch_, uint64_t addr);
 };
 
 template <> struct std::formatter<CXLController> {

include/cxlcounter.h

@@ -28,6 +28,8 @@ const char hitOldName[] = "hit_old";
 const char localName[] = "local";
 const char remoteName[] = "remote";
 const char hitmName[] = "hitm";
+const char backinvName[] = "backinv";
+
 
 // 基础计数器模板类
 template<const char* Name>
@@ -78,10 +80,8 @@ struct std::formatter<AtomicCounter<Name>> {
     }
 
     template <typename FormatContext>
-    constexpr auto format(const AtomicCounter<Name>& counter, FormatContext& ctx) const
-        -> decltype(ctx.out())
-    {
-        // 直接使用format_to避免嵌套std::format调用
+    auto format(const AtomicCounter<Name>& counter, FormatContext& ctx) const -> decltype(ctx.out()) {
+        // 简化formatter实现，避免嵌套std::format调用
         return format_to(ctx.out(), "{}", counter.get());
     }
 };
@@ -193,6 +193,7 @@ class CXLCounter {
     AtomicCounter<localName> local;
     AtomicCounter<remoteName> remote;
     AtomicCounter<hitmName> hitm;
+    AtomicCounter<backinvName> backinv;
 
     constexpr CXLCounter() noexcept = default;
 
@@ -210,6 +211,7 @@ class CXLCounter {
     constexpr void inc_local() noexcept { local.increment(); }
     constexpr void inc_remote() noexcept { remote.increment(); }
     constexpr void inc_hitm() noexcept { hitm.increment(); }
+    constexpr void inc_backinv() noexcept { backinv.increment(); }
 
     // 便捷方法:计算本地命中率
     constexpr double local_hit_ratio() const noexcept {