mirror of
https://github.com/checkpoint-restore/criu.git
synced 2026-07-21 01:06:58 +00:00
15bd860947
Add repository-specific guidance for GitHub Copilot in .github/copilot-instructions.md. This file includes information about: - Coding style (Linux Kernel Coding Style) - Architectural overview of the project - PIE code requirements (must be self-contained and depend on compel) - Descriptions of CRIU commands - ZDTM test suite details - Commit message formatting guidelines This is just initial skeleton designed to optimize GitHub Copilot reviews. Signed-off-by: Andrei Vagin <avagin@gmail.com>
95 lines
4.4 KiB
Markdown
95 lines
4.4 KiB
Markdown
# GitHub Copilot Instructions for CRIU
|
|
|
|
CRIU (Checkpoint/Restore In User-space) is a specialized tool for checkpointing
|
|
and restoring running processes on Linux.
|
|
|
|
## Coding Style & Conventions
|
|
All C code MUST follow the [Linux Kernel Coding Style](https://www.kernel.org/doc/html/latest/process/coding-style.html).
|
|
|
|
- **Indentation**: Use hard tabs. Set tab width to 8 characters.
|
|
- **Line Length**: Preferred limit is 80 characters. Max 120 if it
|
|
significantly improves readability.
|
|
- **Braces**:
|
|
- Functions: Opening brace on a new line.
|
|
- Blocks (`if`, `for`, `while`, `switch`): Opening brace on the same line as
|
|
the statement.
|
|
- **Spaces**: Use spaces around operators (`+`, `-`, `*`, `/`, `%`, `<`, `>`,
|
|
`=`, etc.).
|
|
- **Naming**: Use descriptive, snake_case names for functions and variables.
|
|
- **Comments**: Use C-style comments (`/* ... */`).
|
|
- Multi-line format:
|
|
```c
|
|
/*
|
|
* This is a multi-line
|
|
* comment.
|
|
*/
|
|
```
|
|
|
|
## Architecture Overview
|
|
- **criu/**: Contains the main logic for checkpoint and restore.
|
|
- **compel/**: Sub-project for "parasite" code injection and PIE blob
|
|
generation.
|
|
- **images/**: Protobuf descriptions for image files. Use these to understand
|
|
the state being saved.
|
|
- **restorer**: PIE code that handles the final stages of process restoration.
|
|
See `criu/include/restorer.h` for `CR_STATE_*` definitions.
|
|
- **crit**: Tooling for inspecting CRIU image files.
|
|
- **soccr**: Library for TCP socket checkpoint/restore.
|
|
- **pie/ directories**: Code in these directories (e.g., `criu/pie/`) should be
|
|
self-contained Position-Independent Executable (PIE) code. It MUST NOT
|
|
depend on any external libraries and can only depend on things implemented by
|
|
Compel.
|
|
|
|
### CRIU Commands
|
|
- **dump**: Saves a process tree and all its related resources into a
|
|
collection of image files.
|
|
- **restore**: Restores processes from image files to the same state they were
|
|
in before the dump.
|
|
- **check**: Checks whether the kernel supports the features needed by CRIU to
|
|
dump and restore a process tree.
|
|
- **pre-dump**: Performs the pre-dump procedure, creating a snapshot of memory
|
|
changes since the previous dump/pre-dump (incremental checkpointing).
|
|
- **service**: Launches CRIU in RPC daemon mode, listening for commands over a
|
|
socket.
|
|
- **dedup**: Starts pagemap data deduplication, minimizing image size by
|
|
obtaining references from parent images.
|
|
- **page-server**: Launches CRIU in page server mode to send memory pages over
|
|
the network during migration.
|
|
|
|
## Development & Testing
|
|
- **ZDTM (Zero-Downtime Migration)**: The primary test suite located in
|
|
`test/zdtm`.
|
|
- **Test Scope**: Each test case targets a specific kernel primitive type
|
|
(e.g., file descriptors, sockets, timers).
|
|
- **Test Purpose**: Verifies that the targeted kernel primitive is
|
|
Checkpointed/Restored (C/R-ed) correctly.
|
|
- **Test Executor**: `test/zdtm.py`.
|
|
- **Running a test**: `sudo ./test/zdtm.py run -t zdtm/static/env00`.
|
|
- **Test Structure**: Tests typically use `test_daemon()` to signal readiness
|
|
and `test_waitsig()` to wait for the C/R cycle to complete. After being
|
|
restored, the test checks that all its resources are still in a valid state.
|
|
|
|
## Commit Message Guidelines
|
|
Follow these principles when forming commits:
|
|
|
|
- **Separate each logical change into a separate patch**: Each commit must
|
|
represent a single logical change. Separate bug fixes from performance
|
|
improvements or API updates.
|
|
- **The commit subject has to start with the sub-system prefix**: Prefix the
|
|
subject with the affected component (e.g., `criu:`, `compel:`, `images:`,
|
|
`test:`, or specific file names like `criu-ns:`).
|
|
- **Imperative Mood**: Use the imperative mood in the subject (e.g., "make
|
|
xyzzy do frotz" instead of "changed xyzzy").
|
|
- **Detailed Body**: Explain the problem being solved (the "why") and the
|
|
technical details of the implementation (the "how").
|
|
- **Hard Wrap**: The commit message has to be hard wrapped at 72 characters.
|
|
- **Signed-off-by**: Every commit MUST be signed off (`git commit -s`). This
|
|
certifies the Developer's Certificate of Origin (DCO).
|
|
- **Fixes Tag**:
|
|
- For bugs: `Fixes: <12-char-commit-id> ("summary")`. The `<commit-id>` has
|
|
to be the first 12 characters of the commit SHA-1 ID.
|
|
- For GitHub issues: `Fixes: #<issue-number>`
|
|
- **Atomicity**: Ensure CRIU builds and tests pass after *every* commit in a
|
|
series to maintain bisectability.
|
|
- **No Fixups**: Squash "fixup!" or "work in progress" commits before final
|
|
submission.
|