update readme

This commit is contained in:
zy
2023-11-28 02:52:45 -05:00
parent 07aec699c9
commit 809f581cef
3 changed files with 351 additions and 351 deletions

302
README.md
View File

@@ -1,76 +1,83 @@
## Variable Monitor
Monitor numerical variables (given address, length), and print system stack information when the set conditions are exceeded.
Number of simultaneous monitoring
- Monitoring with the same timing length will be grouped into one group, corresponding to one timer.
- A set of up to 32 variables, after which a new timer is allocated.
- The global maximum number of timers is 128.
- The above quantity limit is defined in the `watch_module.h` header macro.
Currently, monitoring is limited to the same application, and simultaneous calls from multiple applications are not currently supported.
- Multiple applications can work normally if only one program calls `cancel_all_watch();`.
## Usage
Example: helloworld.c
- Add `#include "watch.h"`
- Set each variable that needs to be monitored: name && address && length, set threshold, comparison method, timer interval (ns), etc.
- `start_watch(watch_arg);` Start monitoring
- Call `cancel_all_watch();` when you need to cancel monitoring
When the set conditions are exceeded, the system stack information is printed and viewed with `dmesg`, as shown in the following example:
- Within a timer, if multiple variables exceed the threshold, the stack information will not be output repeatedly;
- The timer restart time after printing the stack is 1s, and the next round of monitoring will start after 1s.
changelog
```log
[86245.364861] -------------------------------------
[86245.364864] -------------watch monitor-----------
[86245.364865] Threshold reached:
name: temp0, threshold: 150
[86245.364866] Timestamp (ns): 1699589000606300743
[86245.364867] Recent Load: 116.65, 126.83, 151.17
[86245.365669] task: name lcore-worker-4, pid 803327
[86245.365672] task: name lcore-worker-5, pid 803328
[86245.365673] task: name lcore-worker-6, pid 803329
[86245.365674] task: name lcore-worker-7, pid 803330
[86245.365676] task: name lcore-worker-8, pid 803331
[86245.365677] task: name lcore-worker-9, pid 803332
[86245.365679] task: name lcore-worker-10, pid 803333
[86245.365681] task: name lcore-worker-11, pid 803334
[86245.365682] task: name lcore-worker-68, pid 803335
[86245.365683] task: name lcore-worker-69, pid 803336
[86245.365684] task: name lcore-worker-70, pid 803337
[86245.365685] task: name lcore-worker-71, pid 803338
[86245.365686] task: name lcore-worker-72, pid 803339
[86245.365687] task: name lcore-worker-73, pid 803340
[86245.365688] task: name lcore-worker-74, pid 803341
[86245.365689] task: name lcore-worker-75, pid 803342
[86245.365694] task: name pkt:worker-0, pid 803638
[86245.365702] hrtimer_nanosleep+0x8d/0x120
[86245.365709] __x64_sys_nanosleep+0x96/0xd0
[86245.365711] do_syscall_64+0x37/0x80
[86245.365716] entry_SYSCALL_64_after_hwframe+0x44/0xae
[86245.365718] task: name pkt:worker-1, pid 803639
[86245.365721] hrtimer_nanosleep+0x8d/0x120
[86245.365724] __x64_sys_nanosleep+0x96/0xd0
[86245.365726] do_syscall_64+0x37/0x80
[86245.365728] entry_SYSCALL_64_after_hwframe+0x44/0xae
[86245.365730] task: name pkt:worker-2, pid 803640
[86245.365732] hrtimer_nanosleep+0x8d/0x120
[86245.365734] __x64_sys_nanosleep+0x96/0xd0
[86245.365737] do_syscall_64+0x37/0x80
[86245.365739] entry_SYSCALL_64_after_hwframe+0x44/0xae
[86245.365740] task: name pkt:worker-3, pid 803641
[86245.365743] hrtimer_nanosleep+0x8d/0x120
11.9 多个变量监控支持
11.10 按照 pid 区分不同内核结构, 支持每个进程单独申请取消自己的监控.
11.13 用户接口 cancel_all_watch -> cancel_watch, 每个进程互不干扰.
11.28 完全重构,更新文档.
```
### Parameter Description
## 说明
start_watch passes in the watch_arg structure. The meaning of each field is as follows
- name limit `MAX_NAME_LEN`(15) valid characters
监控 数值变量(给定 地址,长度), 达到设定条件打印系统内 Task 信息(用户态堆栈/内核态堆栈/调用链信息).
- 支持多进程, 单个进程退出时,取消该进程的所有监控.
- 相同定时间隔会分配到同一个定时器,一个定时器最多监控 32 个变量,全局最多 128 个定时器.
- 以上数量限制定义在 `source/module/monitor_timer.h`.
- `testcase/helloworld.c` 有测试到单进程 2049 个变量;
文件结构
```log
├── build // output
├── source // all source code
│ ├── buffer // 模块与用户空间通信的缓冲区
│ ├── module // 模块代码
│ ├── uapi // 用户空间接口
│ ├── ucli // 用户空间命令行工具
│ └── ucli_py // 用户空间命令行 python (仅测试用,待完成)
│ └── libunwind // python 解析堆栈信息移植库
├── testcase // 测试用例
└── tools // 测试工具
```
## 使用
设定对变量监控有两种函数: 宏定义 或 定义 watch_arg 结构体
- 都需要添加 `source/uapi` 下的头文件 `#include "monitor_user.h"`
需要取消监控时调用 `cancel_watch();` variant_monitor 会取消该进程所有监控.
- 当进程退出后,也会执行相同的操作,取消该进程所有监控.
- 因此调用 `cancel_watch();` 是个可选项,但依然建议调用以避免可能的内存泄漏.
获取 Task 信息是一项耗时操作,这里使用了 workqueue 处理,且一次处理后该定时器重启间隔默认为 5s.
- 此值可以在 `/proc/variable_monitor/dump_reset_sec` 查看和修改.
### 挂载驱动
项目根目录
```bash
# 编译加载模块
make && insmod source/variable_monitor.ko
# 卸载模块,清理编译文件
# rmmod source/variable_monitor.ko && make clean
# 仅在 `kernel 5.17.15-1.el8.x86_64` 测试,其他内核版本未测试.
```
### 宏定义
示例如 `testcase/helloworld.c`, 对常见数值类型宏定义 方便使用:
- 其他类型见 `source/uapi/monitor_user_sw.h`
```c
// 传入变量名 | 地址 | 阈值
START_WATCH_INT("temp", &temp, 150);
START_WATCH_INT_LESS("temp", &temp, 150);
```
默认情况下,使用宏定义 定时器的时间间隔为 10us; 此值可以在 `/proc/variable_monitor/def_interval_ns` 查看和修改.
### watch_arg 结构体
如果需要对定时间隔等有更多控制,请定义 watch_arg 结构体,start_watch 启动监控:
- 对每个需要监控的变量 设置: 名称 && 地址 && 长度, 设置阈值, 比较方式, 定时器间隔(ns) 等.
- `start_watch(watch_arg);` 启动监控
- 需要取消监控时调用 `cancel_watch();`
```c
// start_watch 传入的是 watch_arg 结构体.各个字段意义如下
// - name 限制 `MAX_NAME_LEN`(15) 个有效字符
typedef struct
{
pid_t task_id; // current process id
@@ -82,63 +89,156 @@ typedef struct
unsigned char greater_flag; // reverse flag (true: >, false: <)
unsigned long time_ns; // timer interval (ns)
} watch_arg;
```
An initialization example
```c
//一个初始化示例
watch_args = (watch_arg){
.task_id = getpid(),
.ptr = &temp,
.name = "temp",
.length_byte = sizeof(int),
.threshold = 150 + i,
.threshold = 150,
.unsigned_flag = 0,
.greater_flag = 1,
.time_ns = 2000 + (i / 33) * 5000
.time_ns = 2000 + 5000
};
start_watch(watch_args);
```
### 打印输出
定时器不断按照设定间隔轮询变量,当达到设定条件时,采集此时系统内符合要求的 Task 信息(用户态堆栈/内核态堆栈/调用链信息).
- `dmesg` 可以查看到具体的超出设定条件的变量信息;
- Task 信息被输出到缓存区,使用 ucli 工具查看.
`dmesg` 打印示例如下
```log
[42865.640988] -------------------------------------
[42865.640992] -----------variable monitor----------
[42865.640993] 超出阈值1701141698684973655
[42865.640994] : pid: 63936, name: temp0, ptr: 00000000bade6e61, threshold:110
[42865.648068] -------------------------------------
[42875.640703] -------------------------------------
[42875.640706] -----------variable monitor----------
[42875.640706] 超出阈值1701141708684881779
[42875.640708] : pid: 63936, name: temp0, ptr: 00000000bade6e61, threshold:110
[42875.640710] : pid: 63936, name: temp1, ptr: 00000000ee645b96, threshold:111
[42875.640711] : pid: 63936, name: temp2, ptr: 00000000f62b7afe, threshold:112
[42875.640711] : pid: 63936, name: temp3, ptr: 00000000d100fa3c, threshold:113
[42875.640712] : pid: 63936, name: temp4, ptr: 000000006d31cae1, threshold:114
[42875.640712] : pid: 63936, name: temp5, ptr: 00000000723c7a2a, threshold:115
[42875.640713] : pid: 63936, name: temp6, ptr: 0000000026ef6e83, threshold:116
[42875.640714] : pid: 63936, name: temp7, ptr: 00000000fc1e5d5e, threshold:117
[42875.640714] : pid: 63936, name: temp8, ptr: 0000000069b2666e, threshold:118
[42875.640715] : pid: 63936, name: temp9, ptr: 000000000176263d, threshold:119
[42875.648023] -------------------------------------
```
默认情况下 `ucli` 编译后在 build 文件夹下
`ucli > output`
- ucli 会将缓存区内容解析后输出到 `output` 文件中.
- **此操作会清空缓存区**
`ucli` 工具输出示例如下(详情见 output_example)
- userstack 是 testcase 下的堆栈信息测试程序.
```log
##CGROUP:[/] 51666 [510] 采样命中[D]
进程信息: [/ / userstack] PID 51666 / 51666
##C++ pid 51666
用户态堆栈SP7ffcd5822298, BP:2, IP:7f071c720838
#~ 0x7f071c720838 __GI___nanosleep ([symbol])
#~ 0x7f071c72076e __sleep ([symbol])
#~ 0x400a08 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a75 main ([symbol])
#~ 0x7f071c661d85 __libc_start_main ([symbol])
#~ 0x40081e _start ([symbol])
内核态堆栈:
#@ 0xffffffff811730dd hrtimer_nanosleep ([kernel.kallsyms])
#@ 0xffffffff811733a6 __x64_sys_nanosleep ([kernel.kallsyms])
#@ 0xffffffff819fa117 do_syscall_64 ([kernel.kallsyms])
#@ 0xffffffff81c0007c entry_SYSCALL_64_after_hwframe ([kernel.kallsyms])
#@ 0xffffffff819fa117 do_syscall_64 ([kernel.kallsyms])
#@ 0xffffffff81c0007c entry_SYSCALL_64_after_hwframe ([kernel.kallsyms])
#@ 0xffffffff819fa117 do_syscall_64 ([kernel.kallsyms])
#@ 0xffffffff81c0007c entry_SYSCALL_64_after_hwframe ([kernel.kallsyms])
#* 0xffffffffffffff userstack (UNKNOWN)
进程链信息:
#^ 0xffffffffffffff ./build/userstack (UNKNOWN)
#^ 0xffffffffffffff /bin/bash --init-file /root/.vscode-server-insiders/cli/servers/Insiders-ca9da6c177fc4cf7429e1d0c1c52f710d6d953c6/server/out/vs/workbench/contrib/terminal/browser/media/shellIntegration-bash.sh (UNKNOWN)
#^ 0xffffffffffffff /root/.vscode-server-insiders/cli/servers/Insiders-ca9da6c177fc4cf7429e1d0c1c52f710d6d953c6/server/node /root/.vscode-server-insiders/cli/servers/Insiders-ca9da6c177fc4cf7429e1d0c1c52f710d6d953c6/server/out/bootstrap-fork --type=ptyHost --logsPath /root/ (UNKNOWN)
#^ 0xffffffffffffff /root/.vscode-server-insiders/cli/servers/Insiders-ca9da6c177fc4cf7429e1d0c1c52f710d6d953c6/server/node /root/.vscode-server-insiders/cli/servers/Insiders-ca9da6c177fc4cf7429e1d0c1c52f710d6d953c6/server/out/server-main.js --connection-token=remotessh --a (UNKNOWN)
#^ 0xffffffffffffff sh /root/.vscode-server-insiders/cli/servers/Insiders-ca9da6c177fc4cf7429e1d0c1c52f710d6d953c6/server/bin/code-server-insiders --connection-token=remotessh --accept-server-license-terms --start-server --enable-remote-auto-shutdown --socket-path=/tmp/code (UNKNOWN)
#^ 0xffffffffffffff /root/.vscode-server-insiders/code-insiders-ca9da6c177fc4cf7429e1d0c1c52f710d6d953c6 command-shell --cli-data-dir /root/.vscode-server-insiders/cli --on-port --require-token b5a047063eb7 (UNKNOWN)
#^ 0xffffffffffffff /usr/lib/systemd/systemd --switched-root --system --deserialize 17 (UNKNOWN)
##
```
## demo
In the main project directory:
usercase 文件夹下
- `helloworld.c`: 测试大量变量监控
- `userstack.c`: 测试用户态堆栈输出
- `hptest.c`: 测试 hugePage 挂载
```bash
make && insmod watch_module.ko
./watch
```
## 其他
You can see the printed stack information in dmesg
程序分为两部分: 字符设备 和 用户空间接口, 两者通过 ioctl 通信.
```bash
# Unload module and clean compile files
rmmod watch_module.ko && make clean
```
用户空间地址访问
- 用户程序传入的变量 虚拟地址, 使用 `get_user_pages_remote` 获取地址所在内存页, `kmap` 将其映射到内核.
- 192.168.40.204 环境下,HugeTLB Pages 测试挂载正常.
- 内存页地址 + 偏移量存入定时器对应的 `kernel_watch_arg` 中, hrTimer 轮询时访问 `kernel_watch_arg` 得到真实值.
Only tested on kernel 5.17.15-1.el8.x86_64.
定时器分组
- hrTimer 数据结构定义在全局数组 `kernel_wtimer_list`.分配定时器时,会检查遍历 `kernel_wtimer_list` 比较定时器间隔,
- 相同定时间隔的 watch 分配到同一组,对应同一个 hrTimer.
- 若一个定时器监控变量数量超过 `TIMER_MAX_WATCH_NUM` (32),则会创建一个新的 hrTimer.
- hrTimer 的总数量(`kernel_wtimer_list` 数组长度)限制是 `MAX_TIMER_NUM`(128).
## Other
内存页 mount/unmount
- `get_user_pages_remote`/ `kmap` 会增加对应的计数,需要对等的 `put_page`/`kunmap`.
- 一个模块内全局链表 `watch_local_memory_list` 存储每一个成功挂载的变量对应的 page 和 kt,执行字符设备的 close 操作时,遍历并卸载.
The program is divided into two parts: character device and user space interface, both of which communicate through ioctl.
variable monitor 添加/删除
- kernel_watch_arg 数据结构中有 pid 的成员变量,但添加变量监控时,不按照进程区分.
- 删除时遍历全部监控变量,比较 pid.
- 删除造成的缺位,将最后的变量移动到空位, sentinel--; hrTimer 同理.
User space address access
- The variable virtual address passed in by the user program, use `get_user_pages_remote` to obtain the memory page where the address is located, and `kmap` maps it to the kernel.
- In the 192.168.40.204 environment, the HugeTLB Pages test mounts normally.
- The memory page address + offset is stored in the `kernel_watch_arg` corresponding to the timer, and hrTimer accesses `kernel_watch_arg` when polling to get the real value.
timer grouping
- The hrTimer data structure is defined in the global array `kernel_wtimer_list`. When allocating a timer, it will check the traversal `kernel_wtimer_list` to compare the timer interval.
- Watches with the same timing interval are assigned to the same group and correspond to the same hrTimer.
- If the number of variables monitored by a timer exceeds `TIMER_MAX_WATCH_NUM` (32), a new hrTimer will be created.
- The total number of hrTimers (`kernel_wtimer_list` array length) limit is `MAX_TIMER_NUM`(128).
Memory page mount/unmount
- `get_user_pages_remote`/ `kmap` will increase the corresponding count and requires the equivalent `put_page`/`kunmap`.
- A global linked list in the module `watch_local_memory_list` stores the page and kt corresponding to each successfully mounted variable. When performing the close operation of the character device, it is traversed and unloaded.
Stack output conditions: The conditions are referenced from [diagnose-tools::load.c](https://github.com/alibaba/diagnose-tools/blob/e285bc4626a7d207eabd4a69cb276e1a3b1b7c76/SOURCE/module/kernel/load.c#L209)
- `TASK` must satisfy TASK_RUNNING and `__task_contributes_to_load`.
- `__task_contributes_to_load` corresponds to the kernel macro `task_contributes_to_loa`.
堆栈输出条件: 条件参考自 [diagnose-tools::load.c](https://github.com/alibaba/diagnose-tools/blob/e285bc4626a7d207eabd4a69cb276e1a3b1b7c76/SOURCE/module/kernel/load.c#L209)
- `TASK` 要满足 TASK_RUNNING 和 `__task_contributes_to_load``TASK_IDLE`(可能有阻塞进程).
- `__task_contributes_to_load` 对应内核宏 `task_contributes_to_loa`.
```c
// https://www.spinics.net/lists/kernel/msg3582022.html

150
README_en.md Normal file
View File

@@ -0,0 +1,150 @@
## Variable Monitor
Monitor numerical variables (given address, length), and print system stack information when the set conditions are exceeded.
Number of simultaneous monitoring
- Monitoring with the same timing length will be grouped into one group, corresponding to one timer.
- A set of up to 32 variables, after which a new timer is allocated.
- The global maximum number of timers is 128.
- The above quantity limit is defined in the `watch_module.h` header macro.
Currently, monitoring is limited to the same application, and simultaneous calls from multiple applications are not currently supported.
- Multiple applications can work normally if only one program calls `cancel_all_watch();`.
## Usage
Example: helloworld.c
- Add `#include "watch.h"`
- Set each variable that needs to be monitored: name && address && length, set threshold, comparison method, timer interval (ns), etc.
- `start_watch(watch_arg);` Start monitoring
- Call `cancel_all_watch();` when you need to cancel monitoring
When the set conditions are exceeded, the system stack information is printed and viewed with `dmesg`, as shown in the following example:
- Within a timer, if multiple variables exceed the threshold, the stack information will not be output repeatedly;
- The timer restart time after printing the stack is 1s, and the next round of monitoring will start after 1s.
```log
[86245.364861] -------------------------------------
[86245.364864] -------------watch monitor-----------
[86245.364865] Threshold reached:
name: temp0, threshold: 150
[86245.364866] Timestamp (ns): 1699589000606300743
[86245.364867] Recent Load: 116.65, 126.83, 151.17
[86245.365669] task: name lcore-worker-4, pid 803327
[86245.365672] task: name lcore-worker-5, pid 803328
[86245.365673] task: name lcore-worker-6, pid 803329
[86245.365674] task: name lcore-worker-7, pid 803330
[86245.365676] task: name lcore-worker-8, pid 803331
[86245.365677] task: name lcore-worker-9, pid 803332
[86245.365679] task: name lcore-worker-10, pid 803333
[86245.365681] task: name lcore-worker-11, pid 803334
[86245.365682] task: name lcore-worker-68, pid 803335
[86245.365683] task: name lcore-worker-69, pid 803336
[86245.365684] task: name lcore-worker-70, pid 803337
[86245.365685] task: name lcore-worker-71, pid 803338
[86245.365686] task: name lcore-worker-72, pid 803339
[86245.365687] task: name lcore-worker-73, pid 803340
[86245.365688] task: name lcore-worker-74, pid 803341
[86245.365689] task: name lcore-worker-75, pid 803342
[86245.365694] task: name pkt:worker-0, pid 803638
[86245.365702] hrtimer_nanosleep+0x8d/0x120
[86245.365709] __x64_sys_nanosleep+0x96/0xd0
[86245.365711] do_syscall_64+0x37/0x80
[86245.365716] entry_SYSCALL_64_after_hwframe+0x44/0xae
[86245.365718] task: name pkt:worker-1, pid 803639
[86245.365721] hrtimer_nanosleep+0x8d/0x120
[86245.365724] __x64_sys_nanosleep+0x96/0xd0
[86245.365726] do_syscall_64+0x37/0x80
[86245.365728] entry_SYSCALL_64_after_hwframe+0x44/0xae
[86245.365730] task: name pkt:worker-2, pid 803640
[86245.365732] hrtimer_nanosleep+0x8d/0x120
[86245.365734] __x64_sys_nanosleep+0x96/0xd0
[86245.365737] do_syscall_64+0x37/0x80
[86245.365739] entry_SYSCALL_64_after_hwframe+0x44/0xae
[86245.365740] task: name pkt:worker-3, pid 803641
[86245.365743] hrtimer_nanosleep+0x8d/0x120
```
### Parameter Description
start_watch passes in the watch_arg structure. The meaning of each field is as follows
- name limit `MAX_NAME_LEN`(15) valid characters
```c
typedef struct
{
pid_t task_id; // current process id
char name[MAX_NAME_LEN + 1]; // name (15+1)
void *ptr; // virtual address
int length_byte; // byte
long long threshold; // threshold value
unsigned char unsigned_flag; // unsigned flag (true: unsigned, false: signed)
unsigned char greater_flag; // reverse flag (true: >, false: <)
unsigned long time_ns; // timer interval (ns)
} watch_arg;
```
An initialization example
```c
watch_args = (watch_arg){
.task_id = getpid(),
.ptr = &temp,
.name = "temp",
.length_byte = sizeof(int),
.threshold = 150 + i,
.unsigned_flag = 0,
.greater_flag = 1,
.time_ns = 2000 + (i / 33) * 5000
};
```
## demo
In the main project directory:
```bash
make && insmod watch_module.ko
./watch
```
You can see the printed stack information in dmesg
```bash
# Unload module and clean compile files
rmmod watch_module.ko && make clean
```
Only tested on kernel 5.17.15-1.el8.x86_64.
## Other
The program is divided into two parts: character device and user space interface, both of which communicate through ioctl.
User space address access
- The variable virtual address passed in by the user program, use `get_user_pages_remote` to obtain the memory page where the address is located, and `kmap` maps it to the kernel.
- In the 192.168.40.204 environment, the HugeTLB Pages test mounts normally.
- The memory page address + offset is stored in the `kernel_watch_arg` corresponding to the timer, and hrTimer accesses `kernel_watch_arg` when polling to get the real value.
timer grouping
- The hrTimer data structure is defined in the global array `kernel_wtimer_list`. When allocating a timer, it will check the traversal `kernel_wtimer_list` to compare the timer interval.
- Watches with the same timing interval are assigned to the same group and correspond to the same hrTimer.
- If the number of variables monitored by a timer exceeds `TIMER_MAX_WATCH_NUM` (32), a new hrTimer will be created.
- The total number of hrTimers (`kernel_wtimer_list` array length) limit is `MAX_TIMER_NUM`(128).
Memory page mount/unmount
- `get_user_pages_remote`/ `kmap` will increase the corresponding count and requires the equivalent `put_page`/`kunmap`.
- A global linked list in the module `watch_local_memory_list` stores the page and kt corresponding to each successfully mounted variable. When performing the close operation of the character device, it is traversed and unloaded.
Stack output conditions: The conditions are referenced from [diagnose-tools::load.c](https://github.com/alibaba/diagnose-tools/blob/e285bc4626a7d207eabd4a69cb276e1a3b1b7c76/SOURCE/module/kernel/load.c#L209)
- `TASK` must satisfy TASK_RUNNING and `__task_contributes_to_load`.
- `__task_contributes_to_load` corresponds to the kernel macro `task_contributes_to_loa`.
```c
// https://www.spinics.net/lists/kernel/msg3582022.html
// remove from 5.8.rc3,but it still work
// whether the task contributes to the load
#define __task_contributes_to_load(task) \
((READ_ONCE(task->__state) & TASK_UNINTERRUPTIBLE) != 0 && (task->flags & PF_FROZEN) == 0 && \
(READ_ONCE(task->__state) & TASK_NOLOAD) == 0)
```

View File

@@ -1,250 +0,0 @@
## Variable Monitor
changelog
```log
11.9 多个变量监控支持
11.10 按照 pid 区分不同内核结构, 支持每个进程单独申请取消自己的监控.
11.13 用户接口 cancel_all_watch -> cancel_watch, 每个进程互不干扰.
11.28 完全重构,更新文档.
```
## 说明
监控 数值变量(给定 地址,长度), 达到设定条件打印系统内 Task 信息(用户态堆栈/内核态堆栈/调用链信息).
- 支持多进程, 单个进程退出时,取消该进程的所有监控.
- 相同定时间隔会分配到同一个定时器,一个定时器最多监控 32 个变量,全局最多 128 个定时器.
- 以上数量限制定义在 `source/module/monitor_timer.h`.
- `testcase/helloworld.c` 有测试到单进程 2049 个变量;
文件结构
```log
├── build // output
├── source // all source code
│ ├── buffer // 模块与用户空间通信的缓冲区
│ ├── module // 模块代码
│ ├── uapi // 用户空间接口
│ ├── ucli // 用户空间命令行工具
│ └── ucli_py // 用户空间命令行 python (仅测试用,待完成)
│ └── libunwind // python 解析堆栈信息移植库
├── testcase // 测试用例
└── tools // 测试工具
```
## 使用
设定对变量监控有两种函数: 宏定义 或 定义 watch_arg 结构体
- 都需要添加 `source/uapi` 下的头文件 `#include "monitor_user.h"`
需要取消监控时调用 `cancel_watch();` variant_monitor 会取消该进程所有监控.
- 当进程退出后,也会执行相同的操作,取消该进程所有监控.
- 因此调用 `cancel_watch();` 是个可选项,但依然建议调用以避免可能的内存泄漏.
获取 Task 信息是一项耗时操作,这里使用了 workqueue 处理,且一次处理后该定时器重启间隔默认为 5s.
- 此值可以在 `/proc/variable_monitor/dump_reset_sec` 查看和修改.
### 挂载驱动
项目根目录
```bash
# 编译加载模块
make && insmod source/variable_monitor.ko
# 卸载模块,清理编译文件
# rmmod source/variable_monitor.ko && make clean
# 仅在 `kernel 5.17.15-1.el8.x86_64` 测试,其他内核版本未测试.
```
### 宏定义
示例如 `testcase/helloworld.c`, 对常见数值类型宏定义 方便使用:
- 其他类型见 `source/uapi/monitor_user_sw.h`
```c
// 传入变量名 | 地址 | 阈值
START_WATCH_INT("temp", &temp, 150);
START_WATCH_INT_LESS("temp", &temp, 150);
```
默认情况下,使用宏定义 定时器的时间间隔为 10us; 此值可以在 `/proc/variable_monitor/def_interval_ns` 查看和修改.
### watch_arg 结构体
如果需要对定时间隔等有更多控制,请定义 watch_arg 结构体,start_watch 启动监控:
- 对每个需要监控的变量 设置: 名称 && 地址 && 长度, 设置阈值, 比较方式, 定时器间隔(ns) 等.
- `start_watch(watch_arg);` 启动监控
- 需要取消监控时调用 `cancel_watch();`
```c
// start_watch 传入的是 watch_arg 结构体.各个字段意义如下
// - name 限制 `MAX_NAME_LEN`(15) 个有效字符
typedef struct
{
pid_t task_id; // current process id
char name[MAX_NAME_LEN + 1]; // name (15+1)
void *ptr; // virtual address
int length_byte; // byte
long long threshold; // threshold value
unsigned char unsigned_flag; // unsigned flag (true: unsigned, false: signed)
unsigned char greater_flag; // reverse flag (true: >, false: <)
unsigned long time_ns; // timer interval (ns)
} watch_arg;
//一个初始化示例
watch_args = (watch_arg){
.task_id = getpid(),
.ptr = &temp,
.name = "temp",
.length_byte = sizeof(int),
.threshold = 150,
.unsigned_flag = 0,
.greater_flag = 1,
.time_ns = 2000 + 5000
};
start_watch(watch_args);
```
### 打印输出
定时器不断按照设定间隔轮询变量,当达到设定条件时,采集此时系统内符合要求的 Task 信息(用户态堆栈/内核态堆栈/调用链信息).
- `dmesg` 可以查看到具体的超出设定条件的变量信息;
- Task 信息被输出到缓存区,使用 ucli 工具查看.
`dmesg` 打印示例如下
```log
[42865.640988] -------------------------------------
[42865.640992] -----------variable monitor----------
[42865.640993] 超出阈值1701141698684973655
[42865.640994] : pid: 63936, name: temp0, ptr: 00000000bade6e61, threshold:110
[42865.648068] -------------------------------------
[42875.640703] -------------------------------------
[42875.640706] -----------variable monitor----------
[42875.640706] 超出阈值1701141708684881779
[42875.640708] : pid: 63936, name: temp0, ptr: 00000000bade6e61, threshold:110
[42875.640710] : pid: 63936, name: temp1, ptr: 00000000ee645b96, threshold:111
[42875.640711] : pid: 63936, name: temp2, ptr: 00000000f62b7afe, threshold:112
[42875.640711] : pid: 63936, name: temp3, ptr: 00000000d100fa3c, threshold:113
[42875.640712] : pid: 63936, name: temp4, ptr: 000000006d31cae1, threshold:114
[42875.640712] : pid: 63936, name: temp5, ptr: 00000000723c7a2a, threshold:115
[42875.640713] : pid: 63936, name: temp6, ptr: 0000000026ef6e83, threshold:116
[42875.640714] : pid: 63936, name: temp7, ptr: 00000000fc1e5d5e, threshold:117
[42875.640714] : pid: 63936, name: temp8, ptr: 0000000069b2666e, threshold:118
[42875.640715] : pid: 63936, name: temp9, ptr: 000000000176263d, threshold:119
[42875.648023] -------------------------------------
```
默认情况下 `ucli` 编译后在 build 文件夹下
`ucli > output`
- ucli 会将缓存区内容解析后输出到 `output` 文件中.
- **此操作会清空缓存区**
`ucli` 工具输出示例如下(详情见 output_example)
- userstack 是 testcase 下的堆栈信息测试程序.
```log
##CGROUP:[/] 51666 [510] 采样命中[D]
进程信息: [/ / userstack] PID 51666 / 51666
##C++ pid 51666
用户态堆栈SP7ffcd5822298, BP:2, IP:7f071c720838
#~ 0x7f071c720838 __GI___nanosleep ([symbol])
#~ 0x7f071c72076e __sleep ([symbol])
#~ 0x400a08 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a64 customFunction3 ([symbol])
#~ 0x400a42 customFunction2 ([symbol])
#~ 0x400a21 customFunction1 ([symbol])
#~ 0x400a75 main ([symbol])
#~ 0x7f071c661d85 __libc_start_main ([symbol])
#~ 0x40081e _start ([symbol])
内核态堆栈:
#@ 0xffffffff811730dd hrtimer_nanosleep ([kernel.kallsyms])
#@ 0xffffffff811733a6 __x64_sys_nanosleep ([kernel.kallsyms])
#@ 0xffffffff819fa117 do_syscall_64 ([kernel.kallsyms])
#@ 0xffffffff81c0007c entry_SYSCALL_64_after_hwframe ([kernel.kallsyms])
#@ 0xffffffff819fa117 do_syscall_64 ([kernel.kallsyms])
#@ 0xffffffff81c0007c entry_SYSCALL_64_after_hwframe ([kernel.kallsyms])
#@ 0xffffffff819fa117 do_syscall_64 ([kernel.kallsyms])
#@ 0xffffffff81c0007c entry_SYSCALL_64_after_hwframe ([kernel.kallsyms])
#* 0xffffffffffffff userstack (UNKNOWN)
进程链信息:
#^ 0xffffffffffffff ./build/userstack (UNKNOWN)
#^ 0xffffffffffffff /bin/bash --init-file /root/.vscode-server-insiders/cli/servers/Insiders-ca9da6c177fc4cf7429e1d0c1c52f710d6d953c6/server/out/vs/workbench/contrib/terminal/browser/media/shellIntegration-bash.sh (UNKNOWN)
#^ 0xffffffffffffff /root/.vscode-server-insiders/cli/servers/Insiders-ca9da6c177fc4cf7429e1d0c1c52f710d6d953c6/server/node /root/.vscode-server-insiders/cli/servers/Insiders-ca9da6c177fc4cf7429e1d0c1c52f710d6d953c6/server/out/bootstrap-fork --type=ptyHost --logsPath /root/ (UNKNOWN)
#^ 0xffffffffffffff /root/.vscode-server-insiders/cli/servers/Insiders-ca9da6c177fc4cf7429e1d0c1c52f710d6d953c6/server/node /root/.vscode-server-insiders/cli/servers/Insiders-ca9da6c177fc4cf7429e1d0c1c52f710d6d953c6/server/out/server-main.js --connection-token=remotessh --a (UNKNOWN)
#^ 0xffffffffffffff sh /root/.vscode-server-insiders/cli/servers/Insiders-ca9da6c177fc4cf7429e1d0c1c52f710d6d953c6/server/bin/code-server-insiders --connection-token=remotessh --accept-server-license-terms --start-server --enable-remote-auto-shutdown --socket-path=/tmp/code (UNKNOWN)
#^ 0xffffffffffffff /root/.vscode-server-insiders/code-insiders-ca9da6c177fc4cf7429e1d0c1c52f710d6d953c6 command-shell --cli-data-dir /root/.vscode-server-insiders/cli --on-port --require-token b5a047063eb7 (UNKNOWN)
#^ 0xffffffffffffff /usr/lib/systemd/systemd --switched-root --system --deserialize 17 (UNKNOWN)
##
```
## demo
usercase 文件夹下
- `helloworld.c`: 测试大量变量监控
- `userstack.c`: 测试用户态堆栈输出
- `hptest.c`: 测试 hugePage 挂载
## 其他
程序分为两部分: 字符设备 和 用户空间接口, 两者通过 ioctl 通信.
用户空间地址访问
- 用户程序传入的变量 虚拟地址, 使用 `get_user_pages_remote` 获取地址所在内存页, `kmap` 将其映射到内核.
- 192.168.40.204 环境下,HugeTLB Pages 测试挂载正常.
- 内存页地址 + 偏移量存入定时器对应的 `kernel_watch_arg` 中, hrTimer 轮询时访问 `kernel_watch_arg` 得到真实值.
定时器分组
- hrTimer 数据结构定义在全局数组 `kernel_wtimer_list`.分配定时器时,会检查遍历 `kernel_wtimer_list` 比较定时器间隔,
- 相同定时间隔的 watch 分配到同一组,对应同一个 hrTimer.
- 若一个定时器监控变量数量超过 `TIMER_MAX_WATCH_NUM` (32),则会创建一个新的 hrTimer.
- hrTimer 的总数量(`kernel_wtimer_list` 数组长度)限制是 `MAX_TIMER_NUM`(128).
内存页 mount/unmount
- `get_user_pages_remote`/ `kmap` 会增加对应的计数,需要对等的 `put_page`/`kunmap`.
- 一个模块内全局链表 `watch_local_memory_list` 存储每一个成功挂载的变量对应的 page 和 kt,执行字符设备的 close 操作时,遍历并卸载.
variable monitor 添加/删除
- kernel_watch_arg 数据结构中有 pid 的成员变量,但添加变量监控时,不按照进程区分.
- 删除时遍历全部监控变量,比较 pid.
- 删除造成的缺位,将最后的变量移动到空位, sentinel--; hrTimer 同理.
堆栈输出条件: 条件参考自 [diagnose-tools::load.c](https://github.com/alibaba/diagnose-tools/blob/e285bc4626a7d207eabd4a69cb276e1a3b1b7c76/SOURCE/module/kernel/load.c#L209)
- `TASK` 要满足 TASK_RUNNING 和 `__task_contributes_to_load``TASK_IDLE`(可能有阻塞进程).
- `__task_contributes_to_load` 对应内核宏 `task_contributes_to_loa`.
```c
// https://www.spinics.net/lists/kernel/msg3582022.html
// remove from 5.8.rc3,but it still work
// whether the task contributes to the load
#define __task_contributes_to_load(task) \
((READ_ONCE(task->__state) & TASK_UNINTERRUPTIBLE) != 0 && (task->flags & PF_FROZEN) == 0 && \
(READ_ONCE(task->__state) & TASK_NOLOAD) == 0)
```