Checklist/SemUndo

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Contents

Current Status

Tasks using System V IPC Semaphores may require that we apply their semaphore undo list after restart. Currently that list is not saved and hence any application that relies on semaphore undo may not die properly after restart -- potentially causing other tasks to operate incorrectly.

Issues, Solutions, Impacts

Summary

Issue Solution(s) Current Impact Solution Impact
Does not cause checkpoint to
fail if they aren't checkpointed
Yes None Tiny
Save semaphore adjustment array Yes None Clean, relatively small

Details

  1. Need to save semadj array
  2. Need to do it per-task
  3. Semadj array may be shared, so we need to use objrefs
    • Should be simpler than code adding objrefs for files
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