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Breaks the one process = one server = one session = one context equation
that the whole stack's correctness used to rest on. Design and per-slice
shape: docs/Disaggregated/design/11-state-ownership.md.
S1 wire: bind_context ring record (opcode 84) announces the current
context at the make-current edge; CreateContext/DestroyContext join the
SurfaceOp control frames; control revision 5 -> 6; the server keeps a
per-session token table and refuses unknown tokens by name.
S2 server: SessionRuntime per session with thread-scoped resolution
(singletons become fallbacks), per-thread gPipeInputs, per-session latch
domains, per-thread segment resolvers; the in-process unix supervisor
serves up to MOBILEGL_IPC_INPROC_MAX_SESSIONS (16) concurrent sessions;
surface mode is declared per session and the display lease refuses a
second on-screen session by name.
S3 frontend: ShareGroupState owns the shared object stores and name
generators (buffer/texture/renderbuffer/sampler/program), GLContext keeps
per-context bindings/errors/container objects; pGLContext becomes
thread-local with a process default context preserving the single-context
world verbatim; eglCreateContext builds a real GLContext and joins the
sharing context's group.
S4 backend: native EGL tuples keyed by (session, context token);
InitDisplayAndContext's unconditional teardown is gone - creating a
second context or surface no longer destroys the first; eglCreateContext
sharing is wired to the native driver; bind_context is the native switch
point.
S5 applier: MGPipeApplierState splits into MGPipeObjectRecords (per
share group) and MGPipeWorkingState (per context), resolved through a
{session, token} registry with a thread-local cached fast path.
Tests: MultiSessionTest (incl. two sessions x two contexts interleaved
with real clear/readback witnesses), ApplierOwnershipTest (with a
null-resolver negative control), ContextStateOwnershipTest,
ServerLoopEglTest native-context liveness; 99/99 of the acceptance set
green on the host build.
Known debts (documented in the design doc): twin registries still keyed
by handle alone, no per-record ContextSlot, process-global backend
generations, MakeCurrent dedup per current binding.
37 lines
3.9 KiB
Markdown
37 lines
3.9 KiB
Markdown
# 设计与架构（索引）
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> 这一页只有设计要点和章节去向；每一部分的完整设计在 [`design/`](design/)。章节编号 §1–§17、附 A / B 沿用至今，代码注释里写的 `ARCHITECTURE.md §N` 按下表找到对应文件。wire 契约原文在 `MobileGL/MG_Remote/CONTRACT-*.md`，与设计文字冲突时以更新的契约为准。
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## 一句话
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后端本来就维护着一台贴着 GLES / Vulkan 的状态机，缺的只是"我被告知了什么"。MGPipe 让前端在每条做事的命令之前，把状态变化以**记录**的形式推给后端；后端只认这些记录、不读前端内存，所以两者之间可以隔一个线程、一个进程或一根网线。
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## 设计要点
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1. **一份调用目录生成一切**：`PipeCalls.def` 一行一个调用，线上编号就是行序、只追加；两张函数指针表、编解码、校验器都由它生成。
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2. **对象用句柄 `{slot, gen}` 寻址**：由前端分配，后端从不回传，所以创建对象不需要往返。
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3. **状态在命令之前一次性推送**，不是每个 GL setter 都推；整块数据过线、按内容去重，没变就不发。
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4. **同一份后端实现，三种拓扑**：单线程直调 / 同进程两线程 / 两个进程（可跨机）。
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5. **反向消息是具名回调**（错误、GPU 写回、窗口尺寸……），走一条与命令同样有序的事件通道。
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6. **着色器以 SPIR-V + 反射信息过线**：编译在前端，转译与按状态特化在后端。
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7. **传输分两层**：控制面（握手、EGL 控制）与数据面（命令、批量数据），各自可选本机共享内存或字节流 / TCP，可以混搭；上层代码不区分链路种类。
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8. **client 发完就走（run-ahead）**：只有需要答案的命令才等；靠 present 配额限速。
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9. **出错不崩**：server 崩溃或断线时 client 进入"设备丢失"状态；外来连接要令牌，畸形输入被拒绝而不是让 server 退出。
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10. **可证明的迁移**：每个门都必须能变红；单进程构建的二进制在整个拆分过程中逐字节不变（G1）。
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## 章节去向
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| § | 内容 | 文件 |
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|---|---|---|
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| 1–2 | 边界：两张表、三种拓扑；对象模型：句柄、两种代数、CSO | [`design/01-boundary-and-objects.md`](design/01-boundary-and-objects.md) |
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| 3–4 | 调用目录、生成器 G1–G8、能力位；记录与 payload 格式 | [`design/02-catalogue-and-records.md`](design/02-catalogue-and-records.md) |
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| 5–7 | 前端 tracker（何时推、推什么、怎么去重）；纹理上传；着色器 | [`design/03-frontend.md`](design/03-frontend.md) |
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| 8 | 反向通道：七个回调、有序性、错误与 ack、纹理重铸（server 本地，无拉取）、XFB | [`design/04-reverse-channel.md`](design/04-reverse-channel.md) |
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| 9–10 | 后端改造（`PipeInputs`、memo 重键、A/B 臂）；server 侧 applier | [`design/05-backend-and-server.md`](design/05-backend-and-server.md) |
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| 11 | 传输：共享段、环、门铃、控制面、背压、等待规则、事件、两根轴 | [`design/06-transport.md`](design/06-transport.md) |
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| 12–13 | persistent map 与大缓冲采纳；回读、往返清单、五部分验证门 | [`design/07-memory-readback-verification.md`](design/07-memory-readback-verification.md) |
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| 14–15 | 帧节奏与线程；进程、握手、EGL、Android（含上屏 server）、崩溃处理 | [`design/08-runtime-and-platform.md`](design/08-runtime-and-platform.md) |
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| 16、附 A、附 B | 源码目录与构建选项；全部开关；边界计数器 | [`design/09-build-switches-counters.md`](design/09-build-switches-counters.md) |
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| 17 | 各阶段落地时的形状与仍生效的规则（链到 `notes/`） | [`design/10-phase-shapes.md`](design/10-phase-shapes.md) |
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| — | 状态归属：多 session / 多 context / share group（anland 统一 server 前置） | [`design/11-state-ownership.md`](design/11-state-ownership.md) |
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