Fix races related to OS scheduling and spurious wakeup #759
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If a worker spuriously wakes up while the coordinator closes all buckets, it may read inconsistent states.
qinsoon
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Added methods to initiate and execute coordinator work packets. This will unify the handling of all coordinator work.
qinsoon
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wenyuzhao
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wenyuzhao
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Mar 20, 2023
This PR fixes two race conditions. 1. If a GC worker spuriously wakes up after the `Finish` coordinator message is sent, the coordinator may deactivate work packets while the GC worker is trying to schedule sentinels or open new buckets. 2. If `Plan::schedule_collection` runs too slowly due to OS scheduling, workers may open subsequent work buckets while `Plan::schedule_collection` still has pending packets to be added in prior buckets. Fixes: mmtk#758
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This PR fixes two race conditions.
If a GC worker spuriously wakes up after the
Finishcoordinator message is sent, the coordinator may deactivate work packets while the GC worker is trying to schedule sentinels or open new buckets.If
Plan::schedule_collectionruns too slowly due to OS scheduling, workers may open subsequent work buckets whilePlan::schedule_collectionstill has pending packets to be added in prior buckets.Fixes: #758