GC poll from the last parked GC worker - #1550
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qinsoon
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Aug 17, 2026
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| let plan = self.plan(); | ||
| if self.policy.is_gc_required(false, None, plan) { |
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We could additionally pass an argument to the plan to indicate that this is a poll from GC threads.
qinsoon
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August 17, 2026 23:14
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I suggest we merge this PR after the LXR PR, in case this may cause any issue for LXR. |
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This PR allows the last parked GC worker to poll for a GC. When a concurrent GC has done its concurrent work, we can directly poll for a pause, instead of waiting for a failed allocation. Closes #1523.
This is not just an optimization. It is also needed for correctness. #1457 added a
gc_disableAPI, which asks the binding to block if a concurrent GC is happening and MMTk cannot disable GC right now. If the only mutator thread callsgc_disableand gets blocked, no allocation would be made. Thus no one would poll for a pause when the concurrent marking is done. The mutator is blocked to wait for the concurrent GC to finish, but the concurent GC cannot finish as no one would poll for the final mark pause.