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  "contentMarkdown": "# Android PSS 内存的含义与分析方法\n\n> [!note] 通用化说明\n> 原笔记中的项目截图已移入私有工作资料。本文不使用固定“合格线”，因为内存预算必须结合设备、系统版本、进程模型和业务场景确定。\n\n## PSS 是什么\n\nPSS（Proportional Set Size，按比例分摊集）用于估算一个进程应承担的物理内存：私有页全部计入，共享页按共享进程数近似分摊。它比简单相加 RSS 更适合比较进程的总体内存压力，但仍是一次采样结果，不等于进程独占内存，也不能单独证明发生泄漏。\n\nAndroid 的内存报告常见分类包括：\n\n- **Java/Kotlin Heap**：ART 管理的对象。\n- **Native Heap**：原生分配器管理的内存。\n- **Code**：可执行文件、共享库、DEX/OAT 等映射。\n- **Stack**：线程栈。\n- **Graphics**：图形缓冲和驱动相关分配；不同系统版本的归类可能变化。\n- **Private Other / System / Unknown**：无法归入上述类别或由系统按其他口径统计的内存。\n\nPrivate Dirty、Private Clean、Shared Dirty、Shared Clean 描述页面的共享性与是否被修改；它们不是“好/坏”的标签，需要结合映射来源和变化趋势解释。\n\n## 采样\n\n```bash\nadb shell dumpsys meminfo <package-name>\nadb shell dumpsys meminfo --local <package-name>\n```\n\n必要时结合以下信息：\n\n- Unity Profiler 或 Memory Profiler 中的托管堆、原生对象与纹理等分类；\n- Perfetto、Android Studio Memory Profiler 或 heapprofd；\n- `/proc/<pid>/smaps` 或系统提供的等价明细；\n- 场景、设备、系统版本、构建配置和采样时间。\n\n## 可复现的分析流程\n\n1. **定义场景**：冷启动、登录、进入关卡、反复切换、退回大厅等。\n2. **控制变量**：固定设备、构建、画质、资源包和操作脚本。\n3. **建立基线**：在相同时间点采样多次，记录中位数和波动范围。\n4. **观察趋势**：完成一轮操作并回到稳定状态，判断 PSS 与各分类是否持续抬升。\n5. **交叉验证**：用对象快照、分配调用栈或映射明细定位增长来源。\n6. **验证释放**：触发资源卸载、场景切换或 GC 后复测；注意分配器保留内存不等于仍有可达对象。\n\n## 避免常见误判\n\n- 一次 PSS 变大不等于泄漏，缓存、资源预热和分配器扩容都可能造成增长。\n- Java/Native/Graphics 的分类不能直接映射为 Unity 的 Managed/Native 分类。\n- 系统回收压力、后台进程和驱动会影响结果，跨设备绝对值不可直接横比。\n- “回不到启动值”不是充分证据；应寻找多轮操作后单调增长且无法解释的保留对象或映射。\n\n## 参考资料\n\n- [Android Developers：内存管理概览](https://developer.android.com/topic/performance/memory-overview)\n- [Android Developers：游戏性能工具](https://developer.android.com/games/tools)\n"
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