Issue #20652 has been updated by byroot (Jean Boussier). Right, so it's not as simple as marking the ISeq as not needing the backref because it doesn't use `getspecial`. I think we could only realistically do it in MRI if we accepted that `$~` and such wouldn't be accessible from `eval`. Could be worth asking at the developer meeting, but I'd be surprised if it was accepted. ---------------------------------------- Misc #20652: Memory allocation for gsub has increased from Ruby 2.7 to 3.3 https://bugs.ruby-lang.org/issues/20652#change-109290 * Author: orisano (Nao Yonashiro) * Status: Open * Assignee: jeremyevans0 (Jeremy Evans) ---------------------------------------- I recently upgraded from ruby 2.7.7 to 3.3.1 and noticed that the GC load increased. When I used the allocation profiler to investigate, I found that memory allocation from gsub had increased. The problem was code like this: ```ruby s = "foo " s.gsub(/ (\s+)/) { " #{' ' * Regexp.last_match(1).length}" } ``` When I compared the results of heap-profiler between 2.7.7 and 3.3.1, I found that MatchData was increasing. https://gist.github.com/orisano/98792dee260106e9b6fcb45bbabeb1e6 https://github.com/ruby/ruby/commit/abc0304cb28cb9dcc3476993bc487884c139fd11 I discovered that the cause is this commit, which stopped reusing backref to avoid race conditions. Is there a way to reuse backref while still avoiding race conditions? -- https://bugs.ruby-lang.org/