Due to the confusion around "dirty", Verifier skipped cset regions. Fixing that, and implementing the walk over humongous regions too: http://cr.openjdk.java.net/~shade/shenandoah/verifier-cset-humongous/webrev.01/ Roman, this might be useful for your current partial GC work. Testing: hotspot_gc_shenandoah Thanks, -Aleksey