github actions: Optimize kernel tree clone/fetch #750
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
kerneltoast
requested review from
PlaidCat,
bmastbergen and
shreeya-patel98
as code owners
There was a problem hiding this comment.
Pull request overview
This PR optimizes the GitHub Actions workflow for validating kernel commits by implementing shallow cloning and targeted fetching strategies to reduce the amount of git history that needs to be cloned, significantly speeding up the CI process.
Key Changes
- Replaces full repository checkout with shallow clones using
--depth=1for the base branch and calculated depth for PR branches - Adds a staleness check to verify PR branches are rebased on the latest base commit
- Implements smart upstream mainline fetching using
--shallow-excludebased on kernel version tags - Updates all Python script calls to use commit SHAs instead of branch names for consistency
💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.
kerneltoast
force-pushed
the
{sultan}_gha-optimize-clone
branch
from
1dc2739 to
5f30a99
Compare
kerneltoast
force-pushed
the
{sultan}_gha-optimize-clone
branch
from
5f30a99 to
eff55e0
Compare
There was a problem hiding this comment.
Pull request overview
Copilot reviewed 1 out of 1 changed files in this pull request and generated 3 comments.
💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.
kerneltoast
force-pushed
the
{sultan}_gha-optimize-clone
branch
from
eff55e0 to
e409580
Compare
Check that the PR branch is up to date with the latest base branch commit, and fail if it isn't.
Cloning the base branch takes a long time because a fetch-depth of 0 causes all history for all branches and tags to be cloned (!). In addition, the entire history of the PR branch is fetched. Only the tip of the base branch along with the new commits present in a PR need to be cloned; anything more than that is unneeded. Reduce the depth of the base branch clone to 1 commit and the PR branch fetch to the number of commits in the PR plus 1 (to get the tip of the base branch). The same philosophy is applied to fetching the mainline branch, which is substantially more complex. All that is needed _at most_ is the history between the kernel version tag and the tip of mainline, since the kernel version tag is the most recent common ancestor between us and mainline. History older than the kernel version tag is thus excluded via --shallow-exclude. And as an added bonus, skip checkout on the base branch clone since all of the python scripts inspecting the tree perform checkouts themselves. That way, no time is wasted on checking out the tree to a different SHA than the first checkout by one of the python scripts.
kerneltoast
force-pushed
the
{sultan}_gha-optimize-clone
branch
from
e409580 to
cf8e45a
Compare
PlaidCat
approved these changes
Dec 5, 2025
Collaborator
PlaidCat
left a comment
PlaidCat
left a comment
There was a problem hiding this comment.
We may want to look at some of these optimization for the build workflows, but we can create a jira project to do that so everyone can learn this ... fun with GHA's
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Speed up the cloning process by only cloning what is necessary.
Successful test run: https://github.com/ctrliq/kernel-src-tree/actions/runs/19975988193/job/57292178451?pr=749