6977804: G1: remove the zero-filling thread
Summary: This changeset removes the zero-filling thread from G1 and collapses the two free region lists we had before (the "free" and "unclean" lists) into one. The new free list uses the new heap region sets / lists abstractions that we'll ultimately use it to keep track of all regions in the heap. A heap region set was also introduced for the humongous regions. Finally, this change increases the concurrency between the thread that completes freeing regions (after a cleanup pause) and the rest of the system (before we'd have to wait for said thread to complete before allocating a new region). The changest also includes a lot of refactoring and code simplification.
Reviewed-by: jcoomes, johnc
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#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSETS_HPP
#define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSETS_HPP
#include "gc_implementation/g1/heapRegionSet.inline.hpp"
//////////////////// FreeRegionList ////////////////////
class FreeRegionList : public HeapRegionLinkedList {
protected:
virtual const char* verify_region_extra(HeapRegion* hr);
virtual bool regions_humongous() { return false; }
virtual bool regions_empty() { return true; }
public:
FreeRegionList(const char* name) : HeapRegionLinkedList(name) { }
};
//////////////////// MasterFreeRegionList ////////////////////
class MasterFreeRegionList : public FreeRegionList {
protected:
virtual bool check_mt_safety();
public:
MasterFreeRegionList(const char* name) : FreeRegionList(name) { }
};
//////////////////// SecondaryFreeRegionList ////////////////////
class SecondaryFreeRegionList : public FreeRegionList {
protected:
virtual bool check_mt_safety();
public:
SecondaryFreeRegionList(const char* name) : FreeRegionList(name) { }
};
//////////////////// HumongousRegionSet ////////////////////
class HumongousRegionSet : public HeapRegionSet {
protected:
virtual const char* verify_region_extra(HeapRegion* hr);
virtual bool regions_humongous() { return true; }
virtual bool regions_empty() { return false; }
public:
HumongousRegionSet(const char* name) : HeapRegionSet(name) { }
};
//////////////////// MasterHumongousRegionSet ////////////////////
class MasterHumongousRegionSet : public HumongousRegionSet {
protected:
virtual bool check_mt_safety();
public:
MasterHumongousRegionSet(const char* name) : HumongousRegionSet(name) { }
};
#endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSETS_HPP