contrib/{internal/httptrace, net/http}: fix memory leak and request closure #2138
+19
−7
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Outdated suggestions cannot be applied.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.
What does this PR do?
This pull request addresses one major and one minor performance issue.
The major issue is in contrib/net/http, where (*ServeMux).ServeHTTP adds
an element to it's spanOpts slice every time a request is served. This is
both a race, and it grows the slice unbounded resulting in a memory leak,
and a huge amount of CPU time spent copying the slice.
The second, smaller issues is in contrib/internal/httptrace's
HeaderTagsFromRequest. This function created a closure which captured the
request including all of its headers. This may keep the request alive
longer than necessary. Instead we build the list of required headers and
return a function closing over just that list.
Reviewer's Checklist