# HG changeset patch # Parent dc85548673e78358fc7a3dcbe2f51cad5a91201f Change MarkAndSweep garbage collector to allow changing instances during redefinition. diff -r dc85548673e7 src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp --- a/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp Tue Mar 31 18:13:48 2015 -0700 +++ b/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp Wed Apr 01 11:22:01 2015 -0700 @@ -163,6 +163,12 @@ } } +HeapWord* CompactibleFreeListSpace::forward_compact_top(size_t size, + CompactPoint* cp, HeapWord* compact_top) { + ShouldNotReachHere(); + return NULL; +} + // Like CompactibleSpace forward() but always calls cross_threshold() to // update the block offset table. Removed initialize_threshold call because // CFLS does not use a block offset array for contiguous spaces. @@ -2097,7 +2103,7 @@ // Support for compaction void CompactibleFreeListSpace::prepare_for_compaction(CompactPoint* cp) { - SCAN_AND_FORWARD(cp,end,block_is_obj,block_size); + SCAN_AND_FORWARD(cp,end,block_is_obj,block_size,false); // prepare_for_compaction() uses the space between live objects // so that later phase can skip dead space quickly. So verification // of the free lists doesn't work after. @@ -2118,7 +2124,7 @@ } void CompactibleFreeListSpace::compact() { - SCAN_AND_COMPACT(obj_size); + SCAN_AND_COMPACT(obj_size, false); } // fragmentation_metric = 1 - [sum of (fbs**2) / (sum of fbs)**2] diff -r dc85548673e7 src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp --- a/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp Tue Mar 31 18:13:48 2015 -0700 +++ b/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp Wed Apr 01 11:22:01 2015 -0700 @@ -150,6 +150,7 @@ // Support for compacting cms HeapWord* cross_threshold(HeapWord* start, HeapWord* end); + HeapWord* forward_compact_top(size_t size, CompactPoint* cp, HeapWord* compact_top); HeapWord* forward(oop q, size_t size, CompactPoint* cp, HeapWord* compact_top); // Initialization helpers. diff -r dc85548673e7 src/share/vm/gc_implementation/g1/heapRegion.cpp --- a/src/share/vm/gc_implementation/g1/heapRegion.cpp Tue Mar 31 18:13:48 2015 -0700 +++ b/src/share/vm/gc_implementation/g1/heapRegion.cpp Wed Apr 01 11:22:01 2015 -0700 @@ -1063,7 +1063,7 @@ #define block_is_always_obj(q) true void G1OffsetTableContigSpace::prepare_for_compaction(CompactPoint* cp) { - SCAN_AND_FORWARD(cp, top, block_is_always_obj, block_size); + SCAN_AND_FORWARD(cp, top, block_is_always_obj, block_size, false); } #undef block_is_always_obj diff -r dc85548673e7 src/share/vm/gc_implementation/shared/markSweep.cpp --- a/src/share/vm/gc_implementation/shared/markSweep.cpp Tue Mar 31 18:13:48 2015 -0700 +++ b/src/share/vm/gc_implementation/shared/markSweep.cpp Wed Apr 01 11:22:01 2015 -0700 @@ -48,6 +48,8 @@ STWGCTimer* MarkSweep::_gc_timer = NULL; SerialOldTracer* MarkSweep::_gc_tracer = NULL; +GrowableArray* MarkSweep::_rescued_oops = NULL; + MarkSweep::FollowRootClosure MarkSweep::follow_root_closure; void MarkSweep::FollowRootClosure::do_oop(oop* p) { follow_root(p); } @@ -165,3 +167,100 @@ } #endif + +// (DCEVM) Copy the rescued objects to their destination address after compaction. +void MarkSweep::copy_rescued_objects_back() { + + if (_rescued_oops != NULL) { + + for (int i=0; i<_rescued_oops->length(); i++) { + HeapWord* rescued_ptr = _rescued_oops->at(i); + oop rescued_obj = (oop) rescued_ptr; + + int size = rescued_obj->size(); + oop new_obj = rescued_obj->forwardee(); + + assert(rescued_obj->klass()->new_version() != NULL, "just checking"); + + if (rescued_obj->klass()->new_version()->update_information() != NULL) { + MarkSweep::update_fields(rescued_obj, new_obj); + } else { + rescued_obj->set_klass(rescued_obj->klass()->new_version()); + Copy::aligned_disjoint_words((HeapWord*)rescued_obj, (HeapWord*)new_obj, size); + } + + FREE_RESOURCE_ARRAY(HeapWord, rescued_ptr, size); + + new_obj->init_mark(); + assert(new_obj->is_oop(), "must be a valid oop"); + } + _rescued_oops->clear(); + _rescued_oops = NULL; + } +} + +// (DCEVM) Update instances of a class whose fields changed. +void MarkSweep::update_fields(oop q, oop new_location) { + + assert(q->klass()->new_version() != NULL, "class of old object must have new version"); + + Klass* old_klass_oop = q->klass(); + Klass* new_klass_oop = q->klass()->new_version(); + + InstanceKlass *old_klass = InstanceKlass::cast(old_klass_oop); + InstanceKlass *new_klass = InstanceKlass::cast(new_klass_oop); + + int size = q->size_given_klass(old_klass); + int new_size = q->size_given_klass(new_klass); + + HeapWord* tmp = NULL; + oop tmp_obj = q; + + // Save object somewhere, there is an overlap in fields + if (new_klass_oop->is_copying_backwards()) { + if (((HeapWord *)q >= (HeapWord *)new_location && (HeapWord *)q < (HeapWord *)new_location + new_size) || + ((HeapWord *)new_location >= (HeapWord *)q && (HeapWord *)new_location < (HeapWord *)q + size)) { + tmp = NEW_RESOURCE_ARRAY(HeapWord, size); + q = (oop) tmp; + Copy::aligned_disjoint_words((HeapWord*)q, (HeapWord*)tmp_obj, size); + } + } + + q->set_klass(new_klass_oop); + int *cur = new_klass_oop->update_information(); + assert(cur != NULL, "just checking"); + MarkSweep::update_fields(new_location, q, cur); + + if (tmp != NULL) { + FREE_RESOURCE_ARRAY(HeapWord, tmp, size); + } +} + +void MarkSweep::update_fields(oop new_location, oop tmp_obj, int *cur) { + assert(cur != NULL, "just checking"); + char* to = (char*)(HeapWord*)new_location; + while (*cur != 0) { + int size = *cur; + if (size > 0) { + cur++; + int offset = *cur; + HeapWord* from = (HeapWord*)(((char *)(HeapWord*)tmp_obj) + offset); + if (size == HeapWordSize) { + *((HeapWord*)to) = *from; + } else if (size == HeapWordSize * 2) { + *((HeapWord*)to) = *from; + *(((HeapWord*)to) + 1) = *(from + 1); + } else { + Copy::conjoint_jbytes(from, to, size); + } + to += size; + cur++; + } else { + assert(size < 0, ""); + int skip = -*cur; + Copy::fill_to_bytes(to, skip, 0); + to += skip; + cur++; + } + } +} diff -r dc85548673e7 src/share/vm/gc_implementation/shared/markSweep.hpp --- a/src/share/vm/gc_implementation/shared/markSweep.hpp Tue Mar 31 18:13:48 2015 -0700 +++ b/src/share/vm/gc_implementation/shared/markSweep.hpp Wed Apr 01 11:22:01 2015 -0700 @@ -96,8 +96,12 @@ friend class AdjustPointerClosure; friend class KeepAliveClosure; friend class VM_MarkSweep; + friend class GenMarkSweep; friend void marksweep_init(); +public: + static GrowableArray* _rescued_oops; + // // Vars // @@ -157,6 +161,9 @@ static inline void push_objarray(oop obj, size_t index); + static void copy_rescued_objects_back(); + static void update_fields(oop q, oop new_location); + static void update_fields(oop new_location, oop tmp_obj, int *cur); static void follow_stack(); // Empty marking stack. static void follow_klass(Klass* klass); diff -r dc85548673e7 src/share/vm/memory/genMarkSweep.cpp --- a/src/share/vm/memory/genMarkSweep.cpp Tue Mar 31 18:13:48 2015 -0700 +++ b/src/share/vm/memory/genMarkSweep.cpp Wed Apr 01 11:22:01 2015 -0700 @@ -327,11 +327,16 @@ // in the same order in phase2, phase3 and phase4. We don't quite do that // here (perm_gen first rather than last), so we tell the validate code // to use a higher index (saved from phase2) when verifying perm_gen. + assert(_rescued_oops == NULL, "must be empty before processing"); GenCollectedHeap* gch = GenCollectedHeap::heap(); GCTraceTime tm("phase 4", PrintGC && Verbose, true, _gc_timer, _gc_tracer->gc_id()); trace("4"); + MarkSweep::copy_rescued_objects_back(); + GenCompactClosure blk; gch->generation_iterate(&blk, true); + + MarkSweep::copy_rescued_objects_back(); } diff -r dc85548673e7 src/share/vm/memory/space.cpp --- a/src/share/vm/memory/space.cpp Tue Mar 31 18:13:48 2015 -0700 +++ b/src/share/vm/memory/space.cpp Wed Apr 01 11:22:01 2015 -0700 @@ -377,9 +377,8 @@ _compaction_top = bottom(); } -HeapWord* CompactibleSpace::forward(oop q, size_t size, - CompactPoint* cp, HeapWord* compact_top) { - // q is alive +// (DCEVM) Calculates the compact_top that will be used for placing the next object with the giving size on the heap. +HeapWord* CompactibleSpace::forward_compact_top(size_t size, CompactPoint* cp, HeapWord* compact_top) { // First check if we should switch compaction space assert(this == cp->space, "'this' should be current compaction space."); size_t compaction_max_size = pointer_delta(end(), compact_top); @@ -399,8 +398,15 @@ compaction_max_size = pointer_delta(cp->space->end(), compact_top); } + return compact_top; +} + +HeapWord* CompactibleSpace::forward(oop q, size_t size, + CompactPoint* cp, HeapWord* compact_top) { + compact_top = forward_compact_top(size, cp, compact_top); + // store the forwarding pointer into the mark word - if ((HeapWord*)q != compact_top) { + if ((HeapWord*)q != compact_top || (size_t)q->size() != size) { q->forward_to(oop(compact_top)); assert(q->is_gc_marked(), "encoding the pointer should preserve the mark"); } else { @@ -421,6 +427,58 @@ return compact_top; } +// Compute the forward sizes and leave out objects whose position could +// possibly overlap other objects. +HeapWord* CompactibleSpace::forward_with_rescue(HeapWord* q, size_t size, + CompactPoint* cp, HeapWord* compact_top) { + size_t forward_size = size; + + // (DCEVM) There is a new version of the class of q => different size + if (oop(q)->klass()->new_version() != NULL && oop(q)->klass()->new_version()->update_information() != NULL) { + + size_t new_size = oop(q)->size_given_klass(oop(q)->klass()->new_version()); + assert(size != new_size, "instances without changed size have to be updated prior to GC run"); + forward_size = new_size; + } + + compact_top = forward_compact_top(forward_size, cp, compact_top); + + if (must_rescue(oop(q), oop(compact_top))) { + if (MarkSweep::_rescued_oops == NULL) { + MarkSweep::_rescued_oops = new GrowableArray(128); + } + MarkSweep::_rescued_oops->append(q); + return compact_top; + } + + return forward(oop(q), forward_size, cp, compact_top); +} + +// Compute the forwarding addresses for the objects that need to be rescued. +HeapWord* CompactibleSpace::forward_rescued(CompactPoint* cp, HeapWord* compact_top) { + // TODO: empty the _rescued_oops after ALL spaces are compacted! + if (MarkSweep::_rescued_oops != NULL) { + for (int i=0; ilength(); i++) { + HeapWord* q = MarkSweep::_rescued_oops->at(i); + + /* size_t size = oop(q)->size(); changing this for cms for perm gen */ + size_t size = block_size(q); + + // (DCEVM) There is a new version of the class of q => different size + if (oop(q)->klass()->new_version() != NULL) { + size_t new_size = oop(q)->size_given_klass(oop(q)->klass()->new_version()); + assert(size != new_size, "instances without changed size have to be updated prior to GC run"); + size = new_size; + } + + compact_top = cp->space->forward(oop(q), size, cp, compact_top); + assert(compact_top <= end(), "must not write over end of space!"); + } + MarkSweep::_rescued_oops->clear(); + MarkSweep::_rescued_oops = NULL; + } + return compact_top; +} bool CompactibleSpace::insert_deadspace(size_t& allowed_deadspace_words, HeapWord* q, size_t deadlength) { @@ -442,12 +500,17 @@ #define adjust_obj_size(s) s void CompactibleSpace::prepare_for_compaction(CompactPoint* cp) { - SCAN_AND_FORWARD(cp, end, block_is_obj, block_size); + SCAN_AND_FORWARD(cp, end, block_is_obj, block_size, false); } // Faster object search. void ContiguousSpace::prepare_for_compaction(CompactPoint* cp) { - SCAN_AND_FORWARD(cp, top, block_is_always_obj, obj_size); + if (!Universe::is_redefining_gc_run()) { + SCAN_AND_FORWARD(cp, top, block_is_always_obj, obj_size, false); + } else { + // Redefinition run + SCAN_AND_FORWARD(cp, top, block_is_always_obj, obj_size, true); + } } void Space::adjust_pointers() { @@ -485,6 +548,111 @@ assert(q == t, "just checking"); } + +#ifdef ASSERT + +int CompactibleSpace::space_index(oop obj) { + GenCollectedHeap* heap = GenCollectedHeap::heap(); + + //if (heap->is_in_permanent(obj)) { + // return -1; + //} + + int index = 0; + for (int i = heap->n_gens() - 1; i >= 0; i--) { + Generation* gen = heap->get_gen(i); + CompactibleSpace* space = gen->first_compaction_space(); + while (space != NULL) { + if (space->is_in_reserved(obj)) { + return index; + } + space = space->next_compaction_space(); + index++; + } + } + + tty->print_cr("could not compute space_index for %08xh", (HeapWord*)obj); + index = 0; + for (int i = heap->n_gens() - 1; i >= 0; i--) { + Generation* gen = heap->get_gen(i); + tty->print_cr(" generation %s: %08xh - %08xh", gen->name(), gen->reserved().start(), gen->reserved().end()); + + CompactibleSpace* space = gen->first_compaction_space(); + while (space != NULL) { + tty->print_cr(" %2d space %08xh - %08xh", index, space->bottom(), space->end()); + space = space->next_compaction_space(); + index++; + } + } + + ShouldNotReachHere(); + return 0; +} +#endif + +bool CompactibleSpace::must_rescue(oop old_obj, oop new_obj) { + // Only redefined objects can have the need to be rescued. + if (oop(old_obj)->klass()->new_version() == NULL) return false; + + //if (old_obj->is_perm()) { + // // This object is in perm gen: Always rescue to satisfy invariant obj->klass() <= obj. + // return true; + //} + + int new_size = old_obj->size_given_klass(oop(old_obj)->klass()->new_version()); + int original_size = old_obj->size(); + + Generation* tenured_gen = GenCollectedHeap::heap()->get_gen(1); + bool old_in_tenured = tenured_gen->is_in_reserved(old_obj); + bool new_in_tenured = tenured_gen->is_in_reserved(new_obj); + if (old_in_tenured == new_in_tenured) { + // Rescue if object may overlap with a higher memory address. + bool overlap = ((HeapWord*)old_obj + original_size < (HeapWord*)new_obj + new_size); + if (old_in_tenured) { + // Old and new address are in same space, so just compare the address. + // Must rescue if object moves towards the top of the space. + assert(space_index(old_obj) == space_index(new_obj), "old_obj and new_obj must be in same space"); + } else { + // In the new generation, eden is located before the from space, so a + // simple pointer comparison is sufficient. + assert(GenCollectedHeap::heap()->get_gen(0)->is_in_reserved(old_obj), "old_obj must be in DefNewGeneration"); + assert(GenCollectedHeap::heap()->get_gen(0)->is_in_reserved(new_obj), "new_obj must be in DefNewGeneration"); + assert(overlap == (space_index(old_obj) < space_index(new_obj)), "slow and fast computation must yield same result"); + } + return overlap; + + } else { + assert(space_index(old_obj) != space_index(new_obj), "old_obj and new_obj must be in different spaces"); + if (tenured_gen->is_in_reserved(new_obj)) { + // Must never rescue when moving from the new into the old generation. + assert(GenCollectedHeap::heap()->get_gen(0)->is_in_reserved(old_obj), "old_obj must be in DefNewGeneration"); + assert(space_index(old_obj) > space_index(new_obj), "must be"); + return false; + + } else /* if (tenured_gen->is_in_reserved(old_obj)) */ { + // Must always rescue when moving from the old into the new generation. + assert(GenCollectedHeap::heap()->get_gen(0)->is_in_reserved(new_obj), "new_obj must be in DefNewGeneration"); + assert(space_index(old_obj) < space_index(new_obj), "must be"); + return true; + } + } +} + +HeapWord* CompactibleSpace::rescue(HeapWord* old_obj) { + assert(must_rescue(oop(old_obj), oop(old_obj)->forwardee()), "do not call otherwise"); + + int size = oop(old_obj)->size(); + HeapWord* rescued_obj = NEW_RESOURCE_ARRAY(HeapWord, size); + Copy::aligned_disjoint_words(old_obj, rescued_obj, size); + + if (MarkSweep::_rescued_oops == NULL) { + MarkSweep::_rescued_oops = new GrowableArray(128); + } + + MarkSweep::_rescued_oops->append(rescued_obj); + return rescued_obj; +} + void CompactibleSpace::adjust_pointers() { // Check first is there is any work to do. if (used() == 0) { @@ -495,7 +663,12 @@ } void CompactibleSpace::compact() { - SCAN_AND_COMPACT(obj_size); + if(!Universe::is_redefining_gc_run()) { + SCAN_AND_COMPACT(obj_size, false); + } else { + // Redefinition run + SCAN_AND_COMPACT(obj_size, true) + } } void Space::print_short() const { print_short_on(tty); } diff -r dc85548673e7 src/share/vm/memory/space.hpp --- a/src/share/vm/memory/space.hpp Tue Mar 31 18:13:48 2015 -0700 +++ b/src/share/vm/memory/space.hpp Wed Apr 01 11:22:01 2015 -0700 @@ -392,6 +392,9 @@ // indicates when the next such action should be taken. virtual void prepare_for_compaction(CompactPoint* cp); // MarkSweep support phase3 + DEBUG_ONLY(int space_index(oop obj)); + bool must_rescue(oop old_obj, oop new_obj); + HeapWord* rescue(HeapWord* old_obj); virtual void adjust_pointers(); // MarkSweep support phase4 virtual void compact(); @@ -421,6 +424,15 @@ // accordingly". virtual HeapWord* forward(oop q, size_t size, CompactPoint* cp, HeapWord* compact_top); + // (DCEVM) same as forwad, but can rescue objects. Invoked only during + // redefinition runs + HeapWord* forward_with_rescue(HeapWord* q, size_t size, CompactPoint* cp, + HeapWord* compact_top); + + HeapWord* forward_rescued(CompactPoint* cp, HeapWord* compact_top); + + // (tw) Compute new compact top without actually forwarding the object. + virtual HeapWord* forward_compact_top(size_t size, CompactPoint* cp, HeapWord* compact_top); // Return a size with adjusments as required of the space. virtual size_t adjust_object_size_v(size_t size) const { return size; } diff -r dc85548673e7 src/share/vm/memory/space.inline.hpp --- a/src/share/vm/memory/space.inline.hpp Tue Mar 31 18:13:48 2015 -0700 +++ b/src/share/vm/memory/space.inline.hpp Wed Apr 01 11:22:01 2015 -0700 @@ -35,7 +35,7 @@ return block_start_const(p); } -#define SCAN_AND_FORWARD(cp,scan_limit,block_is_obj,block_size) { \ +#define SCAN_AND_FORWARD(cp,scan_limit,block_is_obj,block_size,redefinition_run) { \ /* Compute the new addresses for the live objects and store it in the mark \ * Used by universe::mark_sweep_phase2() \ */ \ @@ -93,7 +93,17 @@ /* prefetch beyond q */ \ Prefetch::write(q, interval); \ size_t size = block_size(q); \ + if (redefinition_run) { \ + compact_top = cp->space->forward_with_rescue(q, size, \ + cp, compact_top); \ + if (q < first_dead && oop(q)->is_gc_marked()) { \ + /* Was moved (otherwise, forward would reset mark), \ + set first_dead to here */ \ + first_dead = q; \ + } \ + } else { \ compact_top = cp->space->forward(oop(q), size, cp, compact_top); \ + } \ q += size; \ end_of_live = q; \ } else { \ @@ -142,6 +152,8 @@ } \ } \ \ + if (redefinition_run) { compact_top = forward_rescued(cp, compact_top); } \ + \ assert(q == t, "just checking"); \ if (liveRange != NULL) { \ liveRange->set_end(q); \ @@ -188,13 +200,8 @@ q += size; \ } \ \ - if (_first_dead == t) { \ - q = t; \ - } else { \ - /* $$$ This is funky. Using this to read the previously written \ - * LiveRange. See also use below. */ \ - q = (HeapWord*)oop(_first_dead)->mark()->decode_pointer(); \ - } \ + /* (DCEVM) first_dead can be live object if we move/rescue resized objects */ \ + q = _first_dead; \ } \ \ const intx interval = PrefetchScanIntervalInBytes; \ @@ -222,7 +229,7 @@ assert(q == t, "just checking"); \ } -#define SCAN_AND_COMPACT(obj_size) { \ +#define SCAN_AND_COMPACT(obj_size, redefinition_run) { \ /* Copy all live objects to their new location \ * Used by MarkSweep::mark_sweep_phase4() */ \ \ @@ -247,13 +254,9 @@ } \ ) /* debug_only */ \ \ - if (_first_dead == t) { \ - q = t; \ - } else { \ - /* $$$ Funky */ \ - q = (HeapWord*) oop(_first_dead)->mark()->decode_pointer(); \ + /* (DCEVM) first_dead can be live object if we move/rescue resized objects */ \ + q = _first_dead; \ } \ - } \ \ const intx scan_interval = PrefetchScanIntervalInBytes; \ const intx copy_interval = PrefetchCopyIntervalInBytes; \ @@ -271,11 +274,34 @@ size_t size = obj_size(q); \ HeapWord* compaction_top = (HeapWord*)oop(q)->forwardee(); \ \ + if (redefinition_run && must_rescue(oop(q), oop(q)->forwardee())) { \ + rescue(q); \ + debug_only(Copy::fill_to_words(q, size, 0)); \ + q += size; \ + continue; \ + } \ + \ /* prefetch beyond compaction_top */ \ Prefetch::write(compaction_top, copy_interval); \ \ /* copy object and reinit its mark */ \ - assert(q != compaction_top, "everything in this pass should be moving"); \ + assert(q != compaction_top || oop(q)->klass()->new_version() != NULL, \ + "everything in this pass should be moving"); \ + if (redefinition_run && oop(q)->klass()->new_version() != NULL) { \ + Klass* new_version = oop(q)->klass()->new_version(); \ + if (new_version->update_information() == NULL) { \ + Copy::aligned_conjoint_words(q, compaction_top, size); \ + oop(compaction_top)->set_klass(new_version); \ + } else { \ + MarkSweep::update_fields(oop(q), oop(compaction_top)); \ + } \ + oop(compaction_top)->init_mark(); \ + assert(oop(compaction_top)->klass() != NULL, "should have a class"); \ + \ + debug_only(prev_q = q); \ + q += size; \ + continue; \ + } \ Copy::aligned_conjoint_words(q, compaction_top, size); \ oop(compaction_top)->init_mark(); \ assert(oop(compaction_top)->klass() != NULL, "should have a class"); \ diff -r dc85548673e7 src/share/vm/memory/universe.cpp --- a/src/share/vm/memory/universe.cpp Tue Mar 31 18:13:48 2015 -0700 +++ b/src/share/vm/memory/universe.cpp Wed Apr 01 11:22:01 2015 -0700 @@ -84,6 +84,8 @@ PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC +bool Universe::_is_redefining_gc_run = false; + // Known objects Klass* Universe::_boolArrayKlassObj = NULL; Klass* Universe::_byteArrayKlassObj = NULL; diff -r dc85548673e7 src/share/vm/memory/universe.hpp --- a/src/share/vm/memory/universe.hpp Tue Mar 31 18:13:48 2015 -0700 +++ b/src/share/vm/memory/universe.hpp Wed Apr 01 11:22:01 2015 -0700 @@ -251,7 +251,13 @@ static void compute_verify_oop_data(); + static bool _is_redefining_gc_run; + public: + + static bool is_redefining_gc_run() { return _is_redefining_gc_run; } + static void set_redefining_gc_run(bool b) { _is_redefining_gc_run = b; } + // Known classes in the VM static Klass* boolArrayKlassObj() { return _boolArrayKlassObj; } static Klass* byteArrayKlassObj() { return _byteArrayKlassObj; }