feat(starry-perf): add O_NONBLOCK support for perf event fd#1403
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CN-TangLin wants to merge 5 commits into
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feat(starry-perf): add O_NONBLOCK support for perf event fd#1403CN-TangLin wants to merge 5 commits into
CN-TangLin wants to merge 5 commits into
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Replace raw config values 0/1 in kprobe/uprobe dispatch with named constants PROBE_CONFIG_ENTRY / PROBE_CONFIG_RETURN, matching the Linux PERF_TYPE_PROBE ABI. Also refactor the kprobe config match from a nested if/else chain into flat const-pattern match arms.
为 BpfPerfEventWrapper 实现 try_read_record 方法，使 perf event fd 支持 read(2) 系统调用读取 ringbuf 中的 eBPF 输出记录。 主要变更： - bpf.rs: 添加 mmap_kvirt 字段保存 ringbuf 内核虚拟地址，实现 try_read_record 从 perf_event_mmap_page 读取 data_head/data_tail， 处理环缓冲区 wrapping，读取 perf_event_header 确定记录尺寸， 推进 data_tail；添加 wrapping_add/copy_ring 辅助函数 - mod.rs: 实现 FileLike::read，通过 downcast 获取 BpfPerfEventWrapper 并调用 try_read_record，使用 PAGE_SIZE_4K 作为栈缓冲区尺寸常量
将 PerfEvent::read 从轮询式非阻塞读重构为基于 block_on(poll_io(...)) 的阻塞读模式，匹配 Linux read(perf_fd) 语义。当 ringbuf 无数据时 返回 WouldBlock 让 poll_io 等待，数据到达后由已有的 BpfPerfEventWrapper poll 基础设施（poll_ready/poll_notify/IrqNotify） 唤醒任务继续读取。 重构要点： - 使用 block_on(poll_io(...)) 替代简单轮询，复用已有的 Pollable 实现 - read 闭包在返回 WouldBlock 前释放 SpinNoPreempt 锁 - 通过 PerfEvent::poll → BpfPerfEventWrapper::poll 获取可读性状态 - 通过 PerfEvent::register → BpfPerfEventWrapper::register 注册 waker
消除 perf 模块中的两处硬编码： - BPF_JIT_MEM_PAGES = 4：x86_64 JIT 可执行内存页数 - KRETPROBE_MAX_ACTIVE = 10：kretprobe 最大并发实例数 使用命名常量替代字面量，提高代码可读性和可维护性。
为 PerfEvent 添加 nonblocking 标志支持： - PerfEvent 新增 AtomicBool 字段存储 O_NONBLOCK 状态 - 实现 FileLike::nonblocking() / set_nonblocking() - read(2) 在 nonblocking 模式下，ringbuf 为空时立即返回 EAGAIN 而非阻塞等待（通过 poll_io 的 non_blocking 参数传递）
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Merged into #1414 — consolidated perf event fd read/poll/nonblock support. |
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审阅总结
PR 已关闭 — 作者已将本 PR 合并入 #1414（整合 perf event fd 的 read/poll/nonblock 支持）。以下为代码质量审阅。
变更概要
本 PR 为 PerfEvent 添加 O_NONBLOCK 支持，同时实现 read(2) 读取 perf ringbuf 记录：
- bpf.rs：新增
try_read_record()从 perf ringbuf 读取记录（含wrapping_add/copy_ring处理环形缓冲区环绕），新增mmap_kvirt字段保存内核虚拟地址，BPF_JIT_MEM_PAGES常量替代硬编码 - kprobe.rs：
PROBE_CONFIG_ENTRY/PROBE_CONFIG_RETURN/KRETPROBE_MAX_ACTIVE命名常量替代魔法数，重构为 const-pattern match - mod.rs：
AtomicBool实现nonblocking()/set_nonblocking()（匹配 eventfd/signalfd 模式），FileLike::read使用block_on(poll_io(...))支持阻塞/非阻塞读 - uprobe.rs：使用 kprobe.rs 共享常量
代码质量
- ✅
cargo fmt --check通过 - ✅
cargo clippy --all-features -D warnings通过 - ✅
nonblocking实现与 eventfd/signalfd/timerfd 等现有模式完全一致 - ✅
try_read_record的 SAFETY 注解详尽，ring buffer 环绕逻辑正确 - ✅
copy_ring/wrapping_add辅助函数实现正确 - ✅ read 闭包中正确释放 spin lock 后再返回 WouldBlock，避免死锁
- ✅ 无 crates.io patch 引入
注意事项
⚠️ 缺少 test-suit 回归测试：O_NONBLOCK + perf event fd read 是新增行为，但没有对应的 test-suit 用例覆盖。建议在 #1414 中补充最小化 perf event read/nonblocking 回归测试- ℹ️ CI check runs 全部 skipped（PR 关闭过快，CI 未运行），#1414 应验证 CI
- ℹ️ 当前仅 BPF perf event（
BpfPerfEventWrapper）支持 read，其他类型（kprobe/tracepoint）返回 Unsupported，符合 Linux perf_event 惯例
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问题
PerfEvent 不支持 O_NONBLOCK 文件标志。PerfEvent::read 总是阻塞等待数据，无法在非阻塞模式下立即返回 EAGAIN。
变更
nonblocking: AtomicBool字段FileLike::nonblocking()和FileLike::set_nonblocking()poll_io的non_blocking参数在 O_NONBLOCK 时立即返回 EAGAIN逻辑
遵循 StarryOS 其他文件类型（signalfd/eventfd/pipe）的模式：使用 AtomicBool 存储标志，通过 poll_io 的 non_blocking 参数控制行为。