jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/heapRegion.cpp@2c6ef90f030a (annotated)

src/share/vm/gc_implementation/g1/heapRegion.cpp@2c6ef90f030a (annotated)

src/share/vm/gc_implementation/g1/heapRegion.cpp

Mon, 07 Jul 2014 10:12:40 +0200

author: stefank
date: Mon, 07 Jul 2014 10:12:40 +0200
changeset 6992: 2c6ef90f030a
parent 6990: 1526a938e670
child 7009: 3f2894c5052e
permissions: -rw-r--r--

8049421: G1 Class Unloading after completing a concurrent mark cycle
Reviewed-by: tschatzl, ehelin, brutisso, coleenp, roland, iveresov
Contributed-by: stefan.karlsson@oracle.com, mikael.gerdin@oracle.com

 /*
  * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #include "precompiled.hpp"
 #include "code/nmethod.hpp"
 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
 #include "gc_implementation/g1/heapRegion.inline.hpp"
 #include "gc_implementation/g1/heapRegionRemSet.hpp"
 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
 #include "gc_implementation/shared/liveRange.hpp"
 #include "memory/genOopClosures.inline.hpp"
 #include "memory/iterator.hpp"
 #include "memory/space.inline.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/orderAccess.inline.hpp"
 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
 int    HeapRegion::LogOfHRGrainBytes = 0;
 int    HeapRegion::LogOfHRGrainWords = 0;
 size_t HeapRegion::GrainBytes        = 0;
 size_t HeapRegion::GrainWords        = 0;
 size_t HeapRegion::CardsPerRegion    = 0;
 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
                                  HeapRegion* hr, ExtendedOopClosure* cl,
                                  CardTableModRefBS::PrecisionStyle precision,
                                  FilterKind fk) :
   DirtyCardToOopClosure(hr, cl, precision, NULL),
   _hr(hr), _fk(fk), _g1(g1) { }
 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
                                                    OopClosure* oc) :
   _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
 template<class ClosureType>
 HeapWord* walk_mem_region_loop(ClosureType* cl, G1CollectedHeap* g1h,
                                HeapRegion* hr,
                                HeapWord* cur, HeapWord* top) {
   oop cur_oop = oop(cur);
   size_t oop_size = hr->block_size(cur);
   HeapWord* next_obj = cur + oop_size;
   while (next_obj < top) {
     // Keep filtering the remembered set.
     if (!g1h->is_obj_dead(cur_oop, hr)) {
       // Bottom lies entirely below top, so we can call the
       // non-memRegion version of oop_iterate below.
       cur_oop->oop_iterate(cl);
     }
     cur = next_obj;
     cur_oop = oop(cur);
     oop_size = hr->block_size(cur);
     next_obj = cur + oop_size;
   }
   return cur;
 }
 void HeapRegionDCTOC::walk_mem_region(MemRegion mr,
                                       HeapWord* bottom,
                                       HeapWord* top) {
   G1CollectedHeap* g1h = _g1;
   size_t oop_size;
   ExtendedOopClosure* cl2 = NULL;
   FilterIntoCSClosure intoCSFilt(this, g1h, _cl);
   FilterOutOfRegionClosure outOfRegionFilt(_hr, _cl);
   switch (_fk) {
   case NoFilterKind:          cl2 = _cl; break;
   case IntoCSFilterKind:      cl2 = &intoCSFilt; break;
   case OutOfRegionFilterKind: cl2 = &outOfRegionFilt; break;
   default:                    ShouldNotReachHere();
   }
   // Start filtering what we add to the remembered set. If the object is
   // not considered dead, either because it is marked (in the mark bitmap)
   // or it was allocated after marking finished, then we add it. Otherwise
   // we can safely ignore the object.
   if (!g1h->is_obj_dead(oop(bottom), _hr)) {
     oop_size = oop(bottom)->oop_iterate(cl2, mr);
   } else {
     oop_size = _hr->block_size(bottom);
   }
   bottom += oop_size;
   if (bottom < top) {
     // We replicate the loop below for several kinds of possible filters.
     switch (_fk) {
     case NoFilterKind:
       bottom = walk_mem_region_loop(_cl, g1h, _hr, bottom, top);
       break;
     case IntoCSFilterKind: {
       FilterIntoCSClosure filt(this, g1h, _cl);
       bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
       break;
     }
     case OutOfRegionFilterKind: {
       FilterOutOfRegionClosure filt(_hr, _cl);
       bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
       break;
     }
     default:
       ShouldNotReachHere();
     }
     // Last object. Need to do dead-obj filtering here too.
     if (!g1h->is_obj_dead(oop(bottom), _hr)) {
       oop(bottom)->oop_iterate(cl2, mr);
     }
   }
 }
 // Minimum region size; we won't go lower than that.
 // We might want to decrease this in the future, to deal with small
 // heaps a bit more efficiently.
 #define MIN_REGION_SIZE  (      1024 * 1024 )
 // Maximum region size; we don't go higher than that. There's a good
 // reason for having an upper bound. We don't want regions to get too
 // large, otherwise cleanup's effectiveness would decrease as there
 // will be fewer opportunities to find totally empty regions after
 // marking.
 #define MAX_REGION_SIZE  ( 32 * 1024 * 1024 )
 // The automatic region size calculation will try to have around this
 // many regions in the heap (based on the min heap size).
 #define TARGET_REGION_NUMBER          2048
 size_t HeapRegion::max_region_size() {
   return (size_t)MAX_REGION_SIZE;
 }
 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
   uintx region_size = G1HeapRegionSize;
   if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
     size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
     region_size = MAX2(average_heap_size / TARGET_REGION_NUMBER,
                        (uintx) MIN_REGION_SIZE);
   }
   int region_size_log = log2_long((jlong) region_size);
   // Recalculate the region size to make sure it's a power of
   // 2. This means that region_size is the largest power of 2 that's
   // <= what we've calculated so far.
   region_size = ((uintx)1 << region_size_log);
   // Now make sure that we don't go over or under our limits.
   if (region_size < MIN_REGION_SIZE) {
     region_size = MIN_REGION_SIZE;
   } else if (region_size > MAX_REGION_SIZE) {
     region_size = MAX_REGION_SIZE;
   }
   // And recalculate the log.
   region_size_log = log2_long((jlong) region_size);
   // Now, set up the globals.
   guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
   LogOfHRGrainBytes = region_size_log;
   guarantee(LogOfHRGrainWords == 0, "we should only set it once");
   LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
   guarantee(GrainBytes == 0, "we should only set it once");
   // The cast to int is safe, given that we've bounded region_size by
   // MIN_REGION_SIZE and MAX_REGION_SIZE.
   GrainBytes = (size_t)region_size;
   guarantee(GrainWords == 0, "we should only set it once");
   GrainWords = GrainBytes >> LogHeapWordSize;
   guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
   guarantee(CardsPerRegion == 0, "we should only set it once");
   CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
 }
 void HeapRegion::reset_after_compaction() {
   G1OffsetTableContigSpace::reset_after_compaction();
   // After a compaction the mark bitmap is invalid, so we must
   // treat all objects as being inside the unmarked area.
   zero_marked_bytes();
   init_top_at_mark_start();
 }
 void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
   assert(_humongous_type == NotHumongous,
          "we should have already filtered out humongous regions");
   assert(_humongous_start_region == NULL,
          "we should have already filtered out humongous regions");
   assert(_end == _orig_end,
          "we should have already filtered out humongous regions");
   _in_collection_set = false;
   set_young_index_in_cset(-1);
   uninstall_surv_rate_group();
   set_young_type(NotYoung);
   reset_pre_dummy_top();
   if (!par) {
     // If this is parallel, this will be done later.
     HeapRegionRemSet* hrrs = rem_set();
     if (locked) {
       hrrs->clear_locked();
     } else {
       hrrs->clear();
     }
     _claimed = InitialClaimValue;
   }
   zero_marked_bytes();
   _offsets.resize(HeapRegion::GrainWords);
   init_top_at_mark_start();
   if (clear_space) clear(SpaceDecorator::Mangle);
 }
 void HeapRegion::par_clear() {
   assert(used() == 0, "the region should have been already cleared");
   assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
   HeapRegionRemSet* hrrs = rem_set();
   hrrs->clear();
   CardTableModRefBS* ct_bs =
                    (CardTableModRefBS*)G1CollectedHeap::heap()->barrier_set();
   ct_bs->clear(MemRegion(bottom(), end()));
 }
 void HeapRegion::calc_gc_efficiency() {
   // GC efficiency is the ratio of how much space would be
   // reclaimed over how long we predict it would take to reclaim it.
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   G1CollectorPolicy* g1p = g1h->g1_policy();
   // Retrieve a prediction of the elapsed time for this region for
   // a mixed gc because the region will only be evacuated during a
   // mixed gc.
   double region_elapsed_time_ms =
     g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
   _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
 }
 void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) {
   assert(!isHumongous(), "sanity / pre-condition");
   assert(end() == _orig_end,
          "Should be normal before the humongous object allocation");
   assert(top() == bottom(), "should be empty");
   assert(bottom() <= new_top && new_top <= new_end, "pre-condition");
   _humongous_type = StartsHumongous;
   _humongous_start_region = this;
   set_end(new_end);
   _offsets.set_for_starts_humongous(new_top);
 }
 void HeapRegion::set_continuesHumongous(HeapRegion* first_hr) {
   assert(!isHumongous(), "sanity / pre-condition");
   assert(end() == _orig_end,
          "Should be normal before the humongous object allocation");
   assert(top() == bottom(), "should be empty");
   assert(first_hr->startsHumongous(), "pre-condition");
   _humongous_type = ContinuesHumongous;
   _humongous_start_region = first_hr;
 }
 void HeapRegion::set_notHumongous() {
   assert(isHumongous(), "pre-condition");
   if (startsHumongous()) {
     assert(top() <= end(), "pre-condition");
     set_end(_orig_end);
     if (top() > end()) {
       // at least one "continues humongous" region after it
       set_top(end());
     }
   } else {
     // continues humongous
     assert(end() == _orig_end, "sanity");
   }
   assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
   _humongous_type = NotHumongous;
   _humongous_start_region = NULL;
 }
 bool HeapRegion::claimHeapRegion(jint claimValue) {
   jint current = _claimed;
   if (current != claimValue) {
     jint res = Atomic::cmpxchg(claimValue, &_claimed, current);
     if (res == current) {
       return true;
     }
   }
   return false;
 }
 HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) {
   HeapWord* low = addr;
   HeapWord* high = end();
   while (low < high) {
     size_t diff = pointer_delta(high, low);
     // Must add one below to bias toward the high amount.  Otherwise, if
   // "high" were at the desired value, and "low" were one less, we
     // would not converge on "high".  This is not symmetric, because
     // we set "high" to a block start, which might be the right one,
     // which we don't do for "low".
     HeapWord* middle = low + (diff+1)/2;
     if (middle == high) return high;
     HeapWord* mid_bs = block_start_careful(middle);
     if (mid_bs < addr) {
       low = middle;
     } else {
       high = mid_bs;
     }
   }
   assert(low == high && low >= addr, "Didn't work.");
   return low;
 }
 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
 #endif // _MSC_VER
 HeapRegion::HeapRegion(uint hrs_index,
                        G1BlockOffsetSharedArray* sharedOffsetArray,
                        MemRegion mr) :
     G1OffsetTableContigSpace(sharedOffsetArray, mr),
     _hrs_index(hrs_index),
     _humongous_type(NotHumongous), _humongous_start_region(NULL),
     _in_collection_set(false),
     _next_in_special_set(NULL), _orig_end(NULL),
     _claimed(InitialClaimValue), _evacuation_failed(false),
     _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
     _young_type(NotYoung), _next_young_region(NULL),
     _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL), _pending_removal(false),
 #ifdef ASSERT
     _containing_set(NULL),
 #endif // ASSERT
      _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
     _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
     _predicted_bytes_to_copy(0)
 {
   _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
   _orig_end = mr.end();
   // Note that initialize() will set the start of the unmarked area of the
   // region.
   hr_clear(false /*par*/, false /*clear_space*/);
   set_top(bottom());
   record_top_and_timestamp();
   assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
 }
 CompactibleSpace* HeapRegion::next_compaction_space() const {
   // We're not using an iterator given that it will wrap around when
   // it reaches the last region and this is not what we want here.
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   uint index = hrs_index() + 1;
   while (index < g1h->n_regions()) {
     HeapRegion* hr = g1h->region_at(index);
     if (!hr->isHumongous()) {
       return hr;
     }
     index += 1;
   }
   return NULL;
 }
 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
                                                     bool during_conc_mark) {
   // We always recreate the prev marking info and we'll explicitly
   // mark all objects we find to be self-forwarded on the prev
   // bitmap. So all objects need to be below PTAMS.
   _prev_marked_bytes = 0;
   if (during_initial_mark) {
     // During initial-mark, we'll also explicitly mark all objects
     // we find to be self-forwarded on the next bitmap. So all
     // objects need to be below NTAMS.
     _next_top_at_mark_start = top();
     _next_marked_bytes = 0;
   } else if (during_conc_mark) {
     // During concurrent mark, all objects in the CSet (including
     // the ones we find to be self-forwarded) are implicitly live.
     // So all objects need to be above NTAMS.
     _next_top_at_mark_start = bottom();
     _next_marked_bytes = 0;
   }
 }
 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
                                                   bool during_conc_mark,
                                                   size_t marked_bytes) {
   assert(0 <= marked_bytes && marked_bytes <= used(),
          err_msg("marked: "SIZE_FORMAT" used: "SIZE_FORMAT,
                  marked_bytes, used()));
   _prev_top_at_mark_start = top();
   _prev_marked_bytes = marked_bytes;
 }
 HeapWord*
 HeapRegion::object_iterate_mem_careful(MemRegion mr,
                                                  ObjectClosure* cl) {
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   // We used to use "block_start_careful" here.  But we're actually happy
   // to update the BOT while we do this...
   HeapWord* cur = block_start(mr.start());
   mr = mr.intersection(used_region());
   if (mr.is_empty()) return NULL;
   // Otherwise, find the obj that extends onto mr.start().
   assert(cur <= mr.start()
          && (oop(cur)->klass_or_null() == NULL ||
              cur + oop(cur)->size() > mr.start()),
          "postcondition of block_start");
   oop obj;
   while (cur < mr.end()) {
     obj = oop(cur);
     if (obj->klass_or_null() == NULL) {
       // Ran into an unparseable point.
       return cur;
     } else if (!g1h->is_obj_dead(obj)) {
       cl->do_object(obj);
     }
     if (cl->abort()) return cur;
     // The check above must occur before the operation below, since an
     // abort might invalidate the "size" operation.
     cur += block_size(cur);
   }
   return NULL;
 }
 HeapWord*
 HeapRegion::
 oops_on_card_seq_iterate_careful(MemRegion mr,
                                  FilterOutOfRegionClosure* cl,
                                  bool filter_young,
                                  jbyte* card_ptr) {
   // Currently, we should only have to clean the card if filter_young
   // is true and vice versa.
   if (filter_young) {
     assert(card_ptr != NULL, "pre-condition");
   } else {
     assert(card_ptr == NULL, "pre-condition");
   }
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   // If we're within a stop-world GC, then we might look at a card in a
   // GC alloc region that extends onto a GC LAB, which may not be
   // parseable.  Stop such at the "saved_mark" of the region.
   if (g1h->is_gc_active()) {
     mr = mr.intersection(used_region_at_save_marks());
   } else {
     mr = mr.intersection(used_region());
   }
   if (mr.is_empty()) return NULL;
   // Otherwise, find the obj that extends onto mr.start().
   // The intersection of the incoming mr (for the card) and the
   // allocated part of the region is non-empty. This implies that
   // we have actually allocated into this region. The code in
   // G1CollectedHeap.cpp that allocates a new region sets the
   // is_young tag on the region before allocating. Thus we
   // safely know if this region is young.
   if (is_young() && filter_young) {
     return NULL;
   }
   assert(!is_young(), "check value of filter_young");
   // We can only clean the card here, after we make the decision that
   // the card is not young. And we only clean the card if we have been
   // asked to (i.e., card_ptr != NULL).
   if (card_ptr != NULL) {
     *card_ptr = CardTableModRefBS::clean_card_val();
     // We must complete this write before we do any of the reads below.
     OrderAccess::storeload();
   }
   // Cache the boundaries of the memory region in some const locals
   HeapWord* const start = mr.start();
   HeapWord* const end = mr.end();
   // We used to use "block_start_careful" here.  But we're actually happy
   // to update the BOT while we do this...
   HeapWord* cur = block_start(start);
   assert(cur <= start, "Postcondition");
   oop obj;
   HeapWord* next = cur;
   while (next <= start) {
     cur = next;
     obj = oop(cur);
     if (obj->klass_or_null() == NULL) {
       // Ran into an unparseable point.
       return cur;
     }
     // Otherwise...
     next = cur + block_size(cur);
   }
   // If we finish the above loop...We have a parseable object that
   // begins on or before the start of the memory region, and ends
   // inside or spans the entire region.
   assert(obj == oop(cur), "sanity");
   assert(cur <= start, "Loop postcondition");
   assert(obj->klass_or_null() != NULL, "Loop postcondition");
   assert((cur + block_size(cur)) > start, "Loop postcondition");
   if (!g1h->is_obj_dead(obj)) {
     obj->oop_iterate(cl, mr);
   }
   while (cur < end) {
     obj = oop(cur);
     if (obj->klass_or_null() == NULL) {
       // Ran into an unparseable point.
       return cur;
     };
     // Otherwise:
     next = cur + block_size(cur);
     if (!g1h->is_obj_dead(obj)) {
       if (next < end || !obj->is_objArray()) {
         // This object either does not span the MemRegion
         // boundary, or if it does it's not an array.
         // Apply closure to whole object.
         obj->oop_iterate(cl);
       } else {
         // This obj is an array that spans the boundary.
         // Stop at the boundary.
         obj->oop_iterate(cl, mr);
       }
     }
     cur = next;
   }
   return NULL;
 }
 // Code roots support
 void HeapRegion::add_strong_code_root(nmethod* nm) {
   HeapRegionRemSet* hrrs = rem_set();
   hrrs->add_strong_code_root(nm);
 }
 void HeapRegion::remove_strong_code_root(nmethod* nm) {
   HeapRegionRemSet* hrrs = rem_set();
   hrrs->remove_strong_code_root(nm);
 }
 void HeapRegion::migrate_strong_code_roots() {
   assert(in_collection_set(), "only collection set regions");
   assert(!isHumongous(),
           err_msg("humongous region "HR_FORMAT" should not have been added to collection set",
                   HR_FORMAT_PARAMS(this)));
   HeapRegionRemSet* hrrs = rem_set();
   hrrs->migrate_strong_code_roots();
 }
 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
   HeapRegionRemSet* hrrs = rem_set();
   hrrs->strong_code_roots_do(blk);
 }
 class VerifyStrongCodeRootOopClosure: public OopClosure {
   const HeapRegion* _hr;
   nmethod* _nm;
   bool _failures;
   bool _has_oops_in_region;
   template <class T> void do_oop_work(T* p) {
     T heap_oop = oopDesc::load_heap_oop(p);
     if (!oopDesc::is_null(heap_oop)) {
       oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
       // Note: not all the oops embedded in the nmethod are in the
       // current region. We only look at those which are.
       if (_hr->is_in(obj)) {
         // Object is in the region. Check that its less than top
         if (_hr->top() <= (HeapWord*)obj) {
           // Object is above top
           gclog_or_tty->print_cr("Object "PTR_FORMAT" in region "
                                  "["PTR_FORMAT", "PTR_FORMAT") is above "
                                  "top "PTR_FORMAT,
                                  (void *)obj, _hr->bottom(), _hr->end(), _hr->top());
           _failures = true;
           return;
         }
         // Nmethod has at least one oop in the current region
         _has_oops_in_region = true;
       }
     }
   }
 public:
   VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
     _hr(hr), _failures(false), _has_oops_in_region(false) {}
   void do_oop(narrowOop* p) { do_oop_work(p); }
   void do_oop(oop* p)       { do_oop_work(p); }
   bool failures()           { return _failures; }
   bool has_oops_in_region() { return _has_oops_in_region; }
 };
 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
   const HeapRegion* _hr;
   bool _failures;
 public:
   VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
     _hr(hr), _failures(false) {}
   void do_code_blob(CodeBlob* cb) {
     nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
     if (nm != NULL) {
       // Verify that the nemthod is live
       if (!nm->is_alive()) {
         gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has dead nmethod "
                                PTR_FORMAT" in its strong code roots",
                                _hr->bottom(), _hr->end(), nm);
         _failures = true;
       } else {
         VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
         nm->oops_do(&oop_cl);
         if (!oop_cl.has_oops_in_region()) {
           gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has nmethod "
                                  PTR_FORMAT" in its strong code roots "
                                  "with no pointers into region",
                                  _hr->bottom(), _hr->end(), nm);
           _failures = true;
         } else if (oop_cl.failures()) {
           gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has other "
                                  "failures for nmethod "PTR_FORMAT,
                                  _hr->bottom(), _hr->end(), nm);
           _failures = true;
         }
       }
     }
   }
   bool failures()       { return _failures; }
 };
 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
   if (!G1VerifyHeapRegionCodeRoots) {
     // We're not verifying code roots.
     return;
   }
   if (vo == VerifyOption_G1UseMarkWord) {
     // Marking verification during a full GC is performed after class
     // unloading, code cache unloading, etc so the strong code roots
     // attached to each heap region are in an inconsistent state. They won't
     // be consistent until the strong code roots are rebuilt after the
     // actual GC. Skip verifying the strong code roots in this particular
     // time.
     assert(VerifyDuringGC, "only way to get here");
     return;
   }
   HeapRegionRemSet* hrrs = rem_set();
   size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
   // if this region is empty then there should be no entries
   // on its strong code root list
   if (is_empty()) {
     if (strong_code_roots_length > 0) {
       gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is empty "
                              "but has "SIZE_FORMAT" code root entries",
                              bottom(), end(), strong_code_roots_length);
       *failures = true;
     }
     return;
   }
   if (continuesHumongous()) {
     if (strong_code_roots_length > 0) {
       gclog_or_tty->print_cr("region "HR_FORMAT" is a continuation of a humongous "
                              "region but has "SIZE_FORMAT" code root entries",
                              HR_FORMAT_PARAMS(this), strong_code_roots_length);
       *failures = true;
     }
     return;
   }
   VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
   strong_code_roots_do(&cb_cl);
   if (cb_cl.failures()) {
     *failures = true;
   }
 }
 void HeapRegion::print() const { print_on(gclog_or_tty); }
 void HeapRegion::print_on(outputStream* st) const {
   if (isHumongous()) {
     if (startsHumongous())
       st->print(" HS");
     else
       st->print(" HC");
   } else {
     st->print("   ");
   }
   if (in_collection_set())
     st->print(" CS");
   else
     st->print("   ");
   if (is_young())
     st->print(is_survivor() ? " SU" : " Y ");
   else
     st->print("   ");
   if (is_empty())
     st->print(" F");
   else
     st->print("  ");
   st->print(" TS %5d", _gc_time_stamp);
   st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT,
             prev_top_at_mark_start(), next_top_at_mark_start());
   G1OffsetTableContigSpace::print_on(st);
 }
 class VerifyLiveClosure: public OopClosure {
 private:
   G1CollectedHeap* _g1h;
   CardTableModRefBS* _bs;
   oop _containing_obj;
   bool _failures;
   int _n_failures;
   VerifyOption _vo;
 public:
   // _vo == UsePrevMarking -> use "prev" marking information,
   // _vo == UseNextMarking -> use "next" marking information,
   // _vo == UseMarkWord    -> use mark word from object header.
   VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) :
     _g1h(g1h), _bs(NULL), _containing_obj(NULL),
     _failures(false), _n_failures(0), _vo(vo)
   {
     BarrierSet* bs = _g1h->barrier_set();
     if (bs->is_a(BarrierSet::CardTableModRef))
       _bs = (CardTableModRefBS*)bs;
   }
   void set_containing_obj(oop obj) {
     _containing_obj = obj;
   }
   bool failures() { return _failures; }
   int n_failures() { return _n_failures; }
   virtual void do_oop(narrowOop* p) { do_oop_work(p); }
   virtual void do_oop(      oop* p) { do_oop_work(p); }
   void print_object(outputStream* out, oop obj) {
 #ifdef PRODUCT
     Klass* k = obj->klass();
     const char* class_name = InstanceKlass::cast(k)->external_name();
     out->print_cr("class name %s", class_name);
 #else // PRODUCT
     obj->print_on(out);
 #endif // PRODUCT
   }
   template <class T>
   void do_oop_work(T* p) {
     assert(_containing_obj != NULL, "Precondition");
     assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
            "Precondition");
     T heap_oop = oopDesc::load_heap_oop(p);
     if (!oopDesc::is_null(heap_oop)) {
       oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
       bool failed = false;
       if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
         MutexLockerEx x(ParGCRareEvent_lock,
                         Mutex::_no_safepoint_check_flag);
         if (!_failures) {
           gclog_or_tty->cr();
           gclog_or_tty->print_cr("----------");
         }
         if (!_g1h->is_in_closed_subset(obj)) {
           HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
           gclog_or_tty->print_cr("Field "PTR_FORMAT
                                  " of live obj "PTR_FORMAT" in region "
                                  "["PTR_FORMAT", "PTR_FORMAT")",
                                  p, (void*) _containing_obj,
                                  from->bottom(), from->end());
           print_object(gclog_or_tty, _containing_obj);
           gclog_or_tty->print_cr("points to obj "PTR_FORMAT" not in the heap",
                                  (void*) obj);
         } else {
           HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
           HeapRegion* to   = _g1h->heap_region_containing((HeapWord*)obj);
           gclog_or_tty->print_cr("Field "PTR_FORMAT
                                  " of live obj "PTR_FORMAT" in region "
                                  "["PTR_FORMAT", "PTR_FORMAT")",
                                  p, (void*) _containing_obj,
                                  from->bottom(), from->end());
           print_object(gclog_or_tty, _containing_obj);
           gclog_or_tty->print_cr("points to dead obj "PTR_FORMAT" in region "
                                  "["PTR_FORMAT", "PTR_FORMAT")",
                                  (void*) obj, to->bottom(), to->end());
           print_object(gclog_or_tty, obj);
         }
         gclog_or_tty->print_cr("----------");
         gclog_or_tty->flush();
         _failures = true;
         failed = true;
         _n_failures++;
       }
       if (!_g1h->full_collection() || G1VerifyRSetsDuringFullGC) {
         HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
         HeapRegion* to   = _g1h->heap_region_containing(obj);
         if (from != NULL && to != NULL &&
             from != to &&
             !to->isHumongous()) {
           jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
           jbyte cv_field = *_bs->byte_for_const(p);
           const jbyte dirty = CardTableModRefBS::dirty_card_val();
           bool is_bad = !(from->is_young()
                           || to->rem_set()->contains_reference(p)
                           || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
                               (_containing_obj->is_objArray() ?
                                   cv_field == dirty
                                : cv_obj == dirty || cv_field == dirty));
           if (is_bad) {
             MutexLockerEx x(ParGCRareEvent_lock,
                             Mutex::_no_safepoint_check_flag);
             if (!_failures) {
               gclog_or_tty->cr();
               gclog_or_tty->print_cr("----------");
             }
             gclog_or_tty->print_cr("Missing rem set entry:");
             gclog_or_tty->print_cr("Field "PTR_FORMAT" "
                                    "of obj "PTR_FORMAT", "
                                    "in region "HR_FORMAT,
                                    p, (void*) _containing_obj,
                                    HR_FORMAT_PARAMS(from));
             _containing_obj->print_on(gclog_or_tty);
             gclog_or_tty->print_cr("points to obj "PTR_FORMAT" "
                                    "in region "HR_FORMAT,
                                    (void*) obj,
                                    HR_FORMAT_PARAMS(to));
             obj->print_on(gclog_or_tty);
             gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
                           cv_obj, cv_field);
             gclog_or_tty->print_cr("----------");
             gclog_or_tty->flush();
             _failures = true;
             if (!failed) _n_failures++;
           }
         }
       }
     }
   }
 };
 // This really ought to be commoned up into OffsetTableContigSpace somehow.
 // We would need a mechanism to make that code skip dead objects.
 void HeapRegion::verify(VerifyOption vo,
                         bool* failures) const {
   G1CollectedHeap* g1 = G1CollectedHeap::heap();
   *failures = false;
   HeapWord* p = bottom();
   HeapWord* prev_p = NULL;
   VerifyLiveClosure vl_cl(g1, vo);
   bool is_humongous = isHumongous();
   bool do_bot_verify = !is_young();
   size_t object_num = 0;
   while (p < top()) {
     oop obj = oop(p);
     size_t obj_size = block_size(p);
     object_num += 1;
     if (is_humongous != g1->isHumongous(obj_size) &&
         !g1->is_obj_dead(obj, this)) { // Dead objects may have bigger block_size since they span several objects.
       gclog_or_tty->print_cr("obj "PTR_FORMAT" is of %shumongous size ("
                              SIZE_FORMAT" words) in a %shumongous region",
                              p, g1->isHumongous(obj_size) ? "" : "non-",
                              obj_size, is_humongous ? "" : "non-");
        *failures = true;
        return;
     }
     // If it returns false, verify_for_object() will output the
     // appropriate messasge.
     if (do_bot_verify &&
         !g1->is_obj_dead(obj, this) &&
         !_offsets.verify_for_object(p, obj_size)) {
       *failures = true;
       return;
     }
     if (!g1->is_obj_dead_cond(obj, this, vo)) {
       if (obj->is_oop()) {
         Klass* klass = obj->klass();
         bool is_metaspace_object = Metaspace::contains(klass) ||
                                    (vo == VerifyOption_G1UsePrevMarking &&
                                    ClassLoaderDataGraph::unload_list_contains(klass));
         if (!is_metaspace_object) {
           gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
                                  "not metadata", klass, (void *)obj);
           *failures = true;
           return;
         } else if (!klass->is_klass()) {
           gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
                                  "not a klass", klass, (void *)obj);
           *failures = true;
           return;
         } else {
           vl_cl.set_containing_obj(obj);
           obj->oop_iterate_no_header(&vl_cl);
           if (vl_cl.failures()) {
             *failures = true;
           }
           if (G1MaxVerifyFailures >= 0 &&
               vl_cl.n_failures() >= G1MaxVerifyFailures) {
             return;
           }
         }
       } else {
         gclog_or_tty->print_cr(PTR_FORMAT" no an oop", (void *)obj);
         *failures = true;
         return;
       }
     }
     prev_p = p;
     p += obj_size;
   }
   if (p != top()) {
     gclog_or_tty->print_cr("end of last object "PTR_FORMAT" "
                            "does not match top "PTR_FORMAT, p, top());
     *failures = true;
     return;
   }
   HeapWord* the_end = end();
   assert(p == top(), "it should still hold");
   // Do some extra BOT consistency checking for addresses in the
   // range [top, end). BOT look-ups in this range should yield
   // top. No point in doing that if top == end (there's nothing there).
   if (p < the_end) {
     // Look up top
     HeapWord* addr_1 = p;
     HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
     if (b_start_1 != p) {
       gclog_or_tty->print_cr("BOT look up for top: "PTR_FORMAT" "
                              " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
                              addr_1, b_start_1, p);
       *failures = true;
       return;
     }
     // Look up top + 1
     HeapWord* addr_2 = p + 1;
     if (addr_2 < the_end) {
       HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
       if (b_start_2 != p) {
         gclog_or_tty->print_cr("BOT look up for top + 1: "PTR_FORMAT" "
                                " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
                                addr_2, b_start_2, p);
         *failures = true;
         return;
       }
     }
     // Look up an address between top and end
     size_t diff = pointer_delta(the_end, p) / 2;
     HeapWord* addr_3 = p + diff;
     if (addr_3 < the_end) {
       HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
       if (b_start_3 != p) {
         gclog_or_tty->print_cr("BOT look up for top + diff: "PTR_FORMAT" "
                                " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
                                addr_3, b_start_3, p);
         *failures = true;
         return;
       }
     }
     // Loook up end - 1
     HeapWord* addr_4 = the_end - 1;
     HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
     if (b_start_4 != p) {
       gclog_or_tty->print_cr("BOT look up for end - 1: "PTR_FORMAT" "
                              " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
                              addr_4, b_start_4, p);
       *failures = true;
       return;
     }
   }
   if (is_humongous && object_num > 1) {
     gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous "
                            "but has "SIZE_FORMAT", objects",
                            bottom(), end(), object_num);
     *failures = true;
     return;
   }
   verify_strong_code_roots(vo, failures);
 }
 void HeapRegion::verify() const {
   bool dummy = false;
   verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
 }
 // G1OffsetTableContigSpace code; copied from space.cpp.  Hope this can go
 // away eventually.
 void G1OffsetTableContigSpace::clear(bool mangle_space) {
   set_top(bottom());
   set_saved_mark_word(bottom());
   CompactibleSpace::clear(mangle_space);
   _offsets.zero_bottom_entry();
   _offsets.initialize_threshold();
 }
 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
   Space::set_bottom(new_bottom);
   _offsets.set_bottom(new_bottom);
 }
 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
   Space::set_end(new_end);
   _offsets.resize(new_end - bottom());
 }
 void G1OffsetTableContigSpace::print() const {
   print_short();
   gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
                 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
                 bottom(), top(), _offsets.threshold(), end());
 }
 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
   return _offsets.initialize_threshold();
 }
 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
                                                     HeapWord* end) {
   _offsets.alloc_block(start, end);
   return _offsets.threshold();
 }
 HeapWord* G1OffsetTableContigSpace::saved_mark_word() const {
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   assert( _gc_time_stamp <= g1h->get_gc_time_stamp(), "invariant" );
   if (_gc_time_stamp < g1h->get_gc_time_stamp())
     return top();
   else
     return Space::saved_mark_word();
 }
 void G1OffsetTableContigSpace::record_top_and_timestamp() {
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
   if (_gc_time_stamp < curr_gc_time_stamp) {
     // The order of these is important, as another thread might be
     // about to start scanning this region. If it does so after
     // set_saved_mark and before _gc_time_stamp = ..., then the latter
     // will be false, and it will pick up top() as the high water mark
     // of region. If it does so after _gc_time_stamp = ..., then it
     // will pick up the right saved_mark_word() as the high water mark
     // of the region. Either way, the behaviour will be correct.
     Space::set_saved_mark_word(top());
     OrderAccess::storestore();
     _gc_time_stamp = curr_gc_time_stamp;
     // No need to do another barrier to flush the writes above. If
     // this is called in parallel with other threads trying to
     // allocate into the region, the caller should call this while
     // holding a lock and when the lock is released the writes will be
     // flushed.
   }
 }
 void G1OffsetTableContigSpace::safe_object_iterate(ObjectClosure* blk) {
   object_iterate(blk);
 }
 void G1OffsetTableContigSpace::object_iterate(ObjectClosure* blk) {
   HeapWord* p = bottom();
   while (p < top()) {
     if (block_is_obj(p)) {
       blk->do_object(oop(p));
     }
     p += block_size(p);
   }
 }
 #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);
 }
 #undef block_is_always_obj
 G1OffsetTableContigSpace::
 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
                          MemRegion mr) :
   _offsets(sharedOffsetArray, mr),
   _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
   _gc_time_stamp(0)
 {
   _offsets.set_space(this);
   // false ==> we'll do the clearing if there's clearing to be done.
   CompactibleSpace::initialize(mr, false, SpaceDecorator::Mangle);
   _top = bottom();
   _offsets.zero_bottom_entry();
   _offsets.initialize_threshold();
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/heapRegion.cpp@2c6ef90f030a (annotated)

src/share/vm/gc_implementation/g1/heapRegion.cpp