D3963: merge: mark file gets as CPU heavy

[yuja (Yuya Nishihara)]

yuja added a comment.


  > +    cpuheavy = repo.ui.configbool('experimental', 'worker.wdir-get-cpu-heavy')
  > 
  >   prog = worker.worker(repo.ui, cost, batchget, (repo, mctx, wctx),
  > 
  > - actions[ACTION_GET]) +                         actions[ACTION_GET], +                         cpuheavy=cpuheavy)
  
  My two cents. It's better to add a flag to enable threading (e.g. `threadsafe`)
  instead of `cpuheavy`, and make it off by default.
  
  This is somewhat related to the issue5933. In short, merge functions aren't
  thread safe if keywords extension is involved. I suspect the "fix" extension
  would be also unsafe since it calls `repo[rev]`.
  
  https://bz.mercurial-scm.org/show_bug.cgi?id=5933

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D3963

To: indygreg, #hg-reviewers
Cc: yuja, wlis, mercurial-devel