ThreadCache.cpp

//
// Created by ASUS on 2026/3/21.
//
#include "ThreadCache.h"
#include"CentralCache.h"
thread_local ThreadCache* pTLSThreadCache = nullptr;
void *ThreadCache::allocate(size_t size) {
    assert(size<MAX_BYTE);
    size_t pad_size=SizeClass::Roundup(size);
    size_t index=SizeClass::index(pad_size);
    if (freelist_[index].empty()) {
        return FetchFromCentralCache(index,pad_size);
    }
    void* ptr=freelist_[index].pop();
    if (ptr==nullptr) {
        return nullptr;
    }
    else {
        return ptr;
    }
}
void ThreadCache::deallocate(void *ptr, size_t size) {
    assert(size < MAX_BYTE && ptr != nullptr);

    size_t pad_size = SizeClass::Roundup(size);
    size_t index = SizeClass::index(pad_size);

    Freelist& list = freelist_[index];
    list.push(ptr);

    // freelist 过长时，回收一批对象给 CentralCache
    if (list.Size() >= list.MaxSize()) {
        ListTooLong(list, pad_size);
    }
}

void* ThreadCache::FetchFromCentralCache(size_t index, size_t alignSize) {
#ifdef _WIN32
    size_t batchNum = std::min(freelist_[index].MaxSize(), SizeClass::NumMoveSize(alignSize));
#else
    size_t batchNum = std::min(freelist_[index].MaxSize(), SizeClass::NumMoveSize(alignSize));
#endif

    if (batchNum == freelist_[index].MaxSize()) {
        freelist_[index].MaxSize()++;
    }

    void* start = nullptr;
    void* end = nullptr;
    size_t actualNum = CentralCache::GetInstance()->FetchRangeObj(start, end, alignSize, batchNum);
    assert(actualNum >= 1);

    if (actualNum == 1) {
        assert(start == end);
        return start;
    } else {
        // 把第一个返回给用户，剩下的挂到 freelist
        void* next = *reinterpret_cast<void**>(start);
        freelist_[index].PushRange(next, end, actualNum - 1);

        // 断开返回对象和后面链表的关系，避免误串
        *reinterpret_cast<void**>(start) = nullptr;

        return start;
    }
}

void ThreadCache::ListTooLong(Freelist &list, size_t size) {
    void* start=nullptr;
    void* end=nullptr;
    list.PopRange(start,end,list.MaxSize());
    CentralCache::GetInstance()->ReleaseListToSpans(start,size);
}