jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/g1RemSet.cpp@b803b1b9e206 (annotated)

src/share/vm/gc_implementation/g1/g1RemSet.cpp@b803b1b9e206 (annotated)

src/share/vm/gc_implementation/g1/g1RemSet.cpp

Mon, 27 Apr 2009 16:52:18 -0700

author: iveresov
date: Mon, 27 Apr 2009 16:52:18 -0700
changeset 1182: b803b1b9e206
parent 1112: 96b229c54d1e
child 1186: 20c6f43950b5
permissions: -rw-r--r--

6819098: G1: reduce RSet scanning times
Summary: Added a feedback-driven exponential skipping for parallel RSet scanning.
Reviewed-by: tonyp, apetrusenko

 /*
  * Copyright 2001-2009 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  * CA 95054 USA or visit www.sun.com if you need additional information or
  * have any questions.
  *
  */
 #include "incls/_precompiled.incl"
 #include "incls/_g1RemSet.cpp.incl"
 #define CARD_REPEAT_HISTO 0
 #if CARD_REPEAT_HISTO
 static size_t ct_freq_sz;
 static jbyte* ct_freq = NULL;
 void init_ct_freq_table(size_t heap_sz_bytes) {
   if (ct_freq == NULL) {
     ct_freq_sz = heap_sz_bytes/CardTableModRefBS::card_size;
     ct_freq = new jbyte[ct_freq_sz];
     for (size_t j = 0; j < ct_freq_sz; j++) ct_freq[j] = 0;
   }
 }
 void ct_freq_note_card(size_t index) {
   assert(0 <= index && index < ct_freq_sz, "Bounds error.");
   if (ct_freq[index] < 100) { ct_freq[index]++; }
 }
 static IntHistogram card_repeat_count(10, 10);
 void ct_freq_update_histo_and_reset() {
   for (size_t j = 0; j < ct_freq_sz; j++) {
     card_repeat_count.add_entry(ct_freq[j]);
     ct_freq[j] = 0;
   }
 }
 #endif
 class IntoCSOopClosure: public OopsInHeapRegionClosure {
   OopsInHeapRegionClosure* _blk;
   G1CollectedHeap* _g1;
 public:
   IntoCSOopClosure(G1CollectedHeap* g1, OopsInHeapRegionClosure* blk) :
     _g1(g1), _blk(blk) {}
   void set_region(HeapRegion* from) {
     _blk->set_region(from);
   }
   virtual void do_oop(narrowOop* p) {
     guarantee(false, "NYI");
   }
   virtual void do_oop(oop* p) {
     oop obj = *p;
     if (_g1->obj_in_cs(obj)) _blk->do_oop(p);
   }
   bool apply_to_weak_ref_discovered_field() { return true; }
   bool idempotent() { return true; }
 };
 class IntoCSRegionClosure: public HeapRegionClosure {
   IntoCSOopClosure _blk;
   G1CollectedHeap* _g1;
 public:
   IntoCSRegionClosure(G1CollectedHeap* g1, OopsInHeapRegionClosure* blk) :
     _g1(g1), _blk(g1, blk) {}
   bool doHeapRegion(HeapRegion* r) {
     if (!r->in_collection_set()) {
       _blk.set_region(r);
       if (r->isHumongous()) {
         if (r->startsHumongous()) {
           oop obj = oop(r->bottom());
           obj->oop_iterate(&_blk);
         }
       } else {
         r->oop_before_save_marks_iterate(&_blk);
       }
     }
     return false;
   }
 };
 void
 StupidG1RemSet::oops_into_collection_set_do(OopsInHeapRegionClosure* oc,
                                             int worker_i) {
   IntoCSRegionClosure rc(_g1, oc);
   _g1->heap_region_iterate(&rc);
 }
 class UpdateRSOutOfRegionClosure: public HeapRegionClosure {
   G1CollectedHeap*    _g1h;
   ModRefBarrierSet*   _mr_bs;
   UpdateRSOopClosure  _cl;
   int _worker_i;
 public:
   UpdateRSOutOfRegionClosure(G1CollectedHeap* g1, int worker_i = 0) :
     _cl(g1->g1_rem_set()->as_HRInto_G1RemSet(), worker_i),
     _mr_bs(g1->mr_bs()),
     _worker_i(worker_i),
     _g1h(g1)
     {}
   bool doHeapRegion(HeapRegion* r) {
     if (!r->in_collection_set() && !r->continuesHumongous()) {
       _cl.set_from(r);
       r->set_next_filter_kind(HeapRegionDCTOC::OutOfRegionFilterKind);
       _mr_bs->mod_oop_in_space_iterate(r, &_cl, true, true);
     }
     return false;
   }
 };
 class VerifyRSCleanCardOopClosure: public OopClosure {
   G1CollectedHeap* _g1;
 public:
   VerifyRSCleanCardOopClosure(G1CollectedHeap* g1) : _g1(g1) {}
   virtual void do_oop(narrowOop* p) {
     guarantee(false, "NYI");
   }
   virtual void do_oop(oop* p) {
     oop obj = *p;
     HeapRegion* to = _g1->heap_region_containing(obj);
     guarantee(to == NULL || !to->in_collection_set(),
               "Missed a rem set member.");
   }
 };
 HRInto_G1RemSet::HRInto_G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs)
   : G1RemSet(g1), _ct_bs(ct_bs), _g1p(_g1->g1_policy()),
     _cg1r(g1->concurrent_g1_refine()),
     _par_traversal_in_progress(false), _new_refs(NULL),
     _cards_scanned(NULL), _total_cards_scanned(0)
 {
   _seq_task = new SubTasksDone(NumSeqTasks);
   guarantee(n_workers() > 0, "There should be some workers");
   _new_refs = NEW_C_HEAP_ARRAY(GrowableArray<oop*>*, n_workers());
   for (uint i = 0; i < n_workers(); i++) {
     _new_refs[i] = new (ResourceObj::C_HEAP) GrowableArray<oop*>(8192,true);
   }
 }
 HRInto_G1RemSet::~HRInto_G1RemSet() {
   delete _seq_task;
   for (uint i = 0; i < n_workers(); i++) {
     delete _new_refs[i];
   }
   FREE_C_HEAP_ARRAY(GrowableArray<oop*>*, _new_refs);
 }
 void CountNonCleanMemRegionClosure::do_MemRegion(MemRegion mr) {
   if (_g1->is_in_g1_reserved(mr.start())) {
     _n += (int) ((mr.byte_size() / CardTableModRefBS::card_size));
     if (_start_first == NULL) _start_first = mr.start();
   }
 }
 class ScanRSClosure : public HeapRegionClosure {
   size_t _cards_done, _cards;
   G1CollectedHeap* _g1h;
   OopsInHeapRegionClosure* _oc;
   G1BlockOffsetSharedArray* _bot_shared;
   CardTableModRefBS *_ct_bs;
   int _worker_i;
   bool _try_claimed;
   size_t _min_skip_distance, _max_skip_distance;
 public:
   ScanRSClosure(OopsInHeapRegionClosure* oc, int worker_i) :
     _oc(oc),
     _cards(0),
     _cards_done(0),
     _worker_i(worker_i),
     _try_claimed(false)
   {
     _g1h = G1CollectedHeap::heap();
     _bot_shared = _g1h->bot_shared();
     _ct_bs = (CardTableModRefBS*) (_g1h->barrier_set());
     _min_skip_distance = 16;
     _max_skip_distance = 2 * _g1h->n_par_threads() * _min_skip_distance;
   }
   void set_try_claimed() { _try_claimed = true; }
   void scanCard(size_t index, HeapRegion *r) {
     _cards_done++;
     DirtyCardToOopClosure* cl =
       r->new_dcto_closure(_oc,
                          CardTableModRefBS::Precise,
                          HeapRegionDCTOC::IntoCSFilterKind);
     // Set the "from" region in the closure.
     _oc->set_region(r);
     HeapWord* card_start = _bot_shared->address_for_index(index);
     HeapWord* card_end = card_start + G1BlockOffsetSharedArray::N_words;
     Space *sp = SharedHeap::heap()->space_containing(card_start);
     MemRegion sm_region;
     if (ParallelGCThreads > 0) {
       // first find the used area
       sm_region = sp->used_region_at_save_marks();
     } else {
       // The closure is not idempotent.  We shouldn't look at objects
       // allocated during the GC.
       sm_region = sp->used_region_at_save_marks();
     }
     MemRegion mr = sm_region.intersection(MemRegion(card_start,card_end));
     if (!mr.is_empty()) {
       cl->do_MemRegion(mr);
     }
   }
   void printCard(HeapRegion* card_region, size_t card_index,
                  HeapWord* card_start) {
     gclog_or_tty->print_cr("T %d Region [" PTR_FORMAT ", " PTR_FORMAT ") "
                            "RS names card %p: "
                            "[" PTR_FORMAT ", " PTR_FORMAT ")",
                            _worker_i,
                            card_region->bottom(), card_region->end(),
                            card_index,
                            card_start, card_start + G1BlockOffsetSharedArray::N_words);
   }
   bool doHeapRegion(HeapRegion* r) {
     assert(r->in_collection_set(), "should only be called on elements of CS.");
     HeapRegionRemSet* hrrs = r->rem_set();
     if (hrrs->iter_is_complete()) return false; // All done.
     if (!_try_claimed && !hrrs->claim_iter()) return false;
     // If we didn't return above, then
     //   _try_claimed || r->claim_iter()
     // is true: either we're supposed to work on claimed-but-not-complete
     // regions, or we successfully claimed the region.
     HeapRegionRemSetIterator* iter = _g1h->rem_set_iterator(_worker_i);
     hrrs->init_iterator(iter);
     size_t card_index;
     size_t skip_distance = 0, current_card = 0, jump_to_card = 0;
     while (iter->has_next(card_index)) {
       if (current_card < jump_to_card) {
         ++current_card;
         continue;
       }
       HeapWord* card_start = _g1h->bot_shared()->address_for_index(card_index);
 #if 0
       gclog_or_tty->print("Rem set iteration yielded card [" PTR_FORMAT ", " PTR_FORMAT ").\n",
                           card_start, card_start + CardTableModRefBS::card_size_in_words);
 #endif
       HeapRegion* card_region = _g1h->heap_region_containing(card_start);
       assert(card_region != NULL, "Yielding cards not in the heap?");
       _cards++;
        // If the card is dirty, then we will scan it during updateRS.
       if (!card_region->in_collection_set() && !_ct_bs->is_card_dirty(card_index)) {
           if (!_ct_bs->is_card_claimed(card_index) && _ct_bs->claim_card(card_index)) {
             scanCard(card_index, card_region);
           } else if (_try_claimed) {
             if (jump_to_card == 0 || jump_to_card != current_card) {
               // We did some useful work in the previous iteration.
               // Decrease the distance.
               skip_distance = MAX2(skip_distance >> 1, _min_skip_distance);
             } else {
               // Previous iteration resulted in a claim failure.
               // Increase the distance.
               skip_distance = MIN2(skip_distance << 1, _max_skip_distance);
             }
             jump_to_card = current_card + skip_distance;
           }
       }
       ++current_card;
     }
     if (!_try_claimed) {
       hrrs->set_iter_complete();
     }
     return false;
   }
   // Set all cards back to clean.
   void cleanup() {_g1h->cleanUpCardTable();}
   size_t cards_done() { return _cards_done;}
   size_t cards_looked_up() { return _cards;}
 };
 // We want the parallel threads to start their scanning at
 // different collection set regions to avoid contention.
 // If we have:
 //          n collection set regions
 //          p threads
 // Then thread t will start at region t * floor (n/p)
 HeapRegion* HRInto_G1RemSet::calculateStartRegion(int worker_i) {
   HeapRegion* result = _g1p->collection_set();
   if (ParallelGCThreads > 0) {
     size_t cs_size = _g1p->collection_set_size();
     int n_workers = _g1->workers()->total_workers();
     size_t cs_spans = cs_size / n_workers;
     size_t ind      = cs_spans * worker_i;
     for (size_t i = 0; i < ind; i++)
       result = result->next_in_collection_set();
   }
   return result;
 }
 void HRInto_G1RemSet::scanRS(OopsInHeapRegionClosure* oc, int worker_i) {
   double rs_time_start = os::elapsedTime();
   HeapRegion *startRegion = calculateStartRegion(worker_i);
   BufferingOopsInHeapRegionClosure boc(oc);
   ScanRSClosure scanRScl(&boc, worker_i);
   _g1->collection_set_iterate_from(startRegion, &scanRScl);
   scanRScl.set_try_claimed();
   _g1->collection_set_iterate_from(startRegion, &scanRScl);
   boc.done();
   double closure_app_time_sec = boc.closure_app_seconds();
   double scan_rs_time_sec = (os::elapsedTime() - rs_time_start) -
     closure_app_time_sec;
   double closure_app_time_ms = closure_app_time_sec * 1000.0;
   assert( _cards_scanned != NULL, "invariant" );
   _cards_scanned[worker_i] = scanRScl.cards_done();
   _g1p->record_scan_rs_start_time(worker_i, rs_time_start * 1000.0);
   _g1p->record_scan_rs_time(worker_i, scan_rs_time_sec * 1000.0);
   double scan_new_refs_time_ms = _g1p->get_scan_new_refs_time(worker_i);
   if (scan_new_refs_time_ms > 0.0) {
     closure_app_time_ms += scan_new_refs_time_ms;
   }
   _g1p->record_obj_copy_time(worker_i, closure_app_time_ms);
 }
 void HRInto_G1RemSet::updateRS(int worker_i) {
   ConcurrentG1Refine* cg1r = _g1->concurrent_g1_refine();
   double start = os::elapsedTime();
   _g1p->record_update_rs_start_time(worker_i, start * 1000.0);
   if (G1RSBarrierUseQueue && !cg1r->do_traversal()) {
     // Apply the appropriate closure to all remaining log entries.
     _g1->iterate_dirty_card_closure(false, worker_i);
     // Now there should be no dirty cards.
     if (G1RSLogCheckCardTable) {
       CountNonCleanMemRegionClosure cl(_g1);
       _ct_bs->mod_card_iterate(&cl);
       // XXX This isn't true any more: keeping cards of young regions
       // marked dirty broke it.  Need some reasonable fix.
       guarantee(cl.n() == 0, "Card table should be clean.");
     }
   } else {
     UpdateRSOutOfRegionClosure update_rs(_g1, worker_i);
     _g1->heap_region_iterate(&update_rs);
     // We did a traversal; no further one is necessary.
     if (G1RSBarrierUseQueue) {
       assert(cg1r->do_traversal(), "Or we shouldn't have gotten here.");
       cg1r->set_pya_cancel();
     }
     if (_cg1r->use_cache()) {
       _cg1r->clear_and_record_card_counts();
       _cg1r->clear_hot_cache();
     }
   }
   _g1p->record_update_rs_time(worker_i, (os::elapsedTime() - start) * 1000.0);
 }
 #ifndef PRODUCT
 class PrintRSClosure : public HeapRegionClosure {
   int _count;
 public:
   PrintRSClosure() : _count(0) {}
   bool doHeapRegion(HeapRegion* r) {
     HeapRegionRemSet* hrrs = r->rem_set();
     _count += (int) hrrs->occupied();
     if (hrrs->occupied() == 0) {
       gclog_or_tty->print("Heap Region [" PTR_FORMAT ", " PTR_FORMAT ") "
                           "has no remset entries\n",
                           r->bottom(), r->end());
     } else {
       gclog_or_tty->print("Printing rem set for heap region [" PTR_FORMAT ", " PTR_FORMAT ")\n",
                           r->bottom(), r->end());
       r->print();
       hrrs->print();
       gclog_or_tty->print("\nDone printing rem set\n");
     }
     return false;
   }
   int occupied() {return _count;}
 };
 #endif
 class CountRSSizeClosure: public HeapRegionClosure {
   size_t _n;
   size_t _tot;
   size_t _max;
   HeapRegion* _max_r;
   enum {
     N = 20,
     MIN = 6
   };
   int _histo[N];
 public:
   CountRSSizeClosure() : _n(0), _tot(0), _max(0), _max_r(NULL) {
     for (int i = 0; i < N; i++) _histo[i] = 0;
   }
   bool doHeapRegion(HeapRegion* r) {
     if (!r->continuesHumongous()) {
       size_t occ = r->rem_set()->occupied();
       _n++;
       _tot += occ;
       if (occ > _max) {
         _max = occ;
         _max_r = r;
       }
       // Fit it into a histo bin.
       int s = 1 << MIN;
       int i = 0;
       while (occ > (size_t) s && i < (N-1)) {
         s = s << 1;
         i++;
       }
       _histo[i]++;
     }
     return false;
   }
   size_t n() { return _n; }
   size_t tot() { return _tot; }
   size_t mx() { return _max; }
   HeapRegion* mxr() { return _max_r; }
   void print_histo() {
     int mx = N;
     while (mx >= 0) {
       if (_histo[mx-1] > 0) break;
       mx--;
     }
     gclog_or_tty->print_cr("Number of regions with given RS sizes:");
     gclog_or_tty->print_cr("           <= %8d   %8d", 1 << MIN, _histo[0]);
     for (int i = 1; i < mx-1; i++) {
       gclog_or_tty->print_cr("  %8d  - %8d   %8d",
                     (1 << (MIN + i - 1)) + 1,
 << (MIN + i),
                     _histo[i]);
     }
     gclog_or_tty->print_cr("            > %8d   %8d", (1 << (MIN+mx-2))+1, _histo[mx-1]);
   }
 };
 void
 HRInto_G1RemSet::scanNewRefsRS(OopsInHeapRegionClosure* oc,
                                              int worker_i) {
   double scan_new_refs_start_sec = os::elapsedTime();
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   CardTableModRefBS* ct_bs = (CardTableModRefBS*) (g1h->barrier_set());
   for (int i = 0; i < _new_refs[worker_i]->length(); i++) {
     oop* p = _new_refs[worker_i]->at(i);
     oop obj = *p;
     // *p was in the collection set when p was pushed on "_new_refs", but
     // another thread may have processed this location from an RS, so it
     // might not point into the CS any longer.  If so, it's obviously been
     // processed, and we don't need to do anything further.
     if (g1h->obj_in_cs(obj)) {
       HeapRegion* r = g1h->heap_region_containing(p);
       DEBUG_ONLY(HeapRegion* to = g1h->heap_region_containing(obj));
       oc->set_region(r);
       // If "p" has already been processed concurrently, this is
       // idempotent.
       oc->do_oop(p);
     }
   }
   _g1p->record_scan_new_refs_time(worker_i,
                                   (os::elapsedTime() - scan_new_refs_start_sec)
                                   * 1000.0);
 }
 void HRInto_G1RemSet::set_par_traversal(bool b) {
   _par_traversal_in_progress = b;
   HeapRegionRemSet::set_par_traversal(b);
 }
 void HRInto_G1RemSet::cleanupHRRS() {
   HeapRegionRemSet::cleanup();
 }
 void
 HRInto_G1RemSet::oops_into_collection_set_do(OopsInHeapRegionClosure* oc,
                                              int worker_i) {
 #if CARD_REPEAT_HISTO
   ct_freq_update_histo_and_reset();
 #endif
   if (worker_i == 0) {
     _cg1r->clear_and_record_card_counts();
   }
   // Make this into a command-line flag...
   if (G1RSCountHisto && (ParallelGCThreads == 0 || worker_i == 0)) {
     CountRSSizeClosure count_cl;
     _g1->heap_region_iterate(&count_cl);
     gclog_or_tty->print_cr("Avg of %d RS counts is %f, max is %d, "
                   "max region is " PTR_FORMAT,
                   count_cl.n(), (float)count_cl.tot()/(float)count_cl.n(),
                   count_cl.mx(), count_cl.mxr());
     count_cl.print_histo();
   }
   if (ParallelGCThreads > 0) {
     // The two flags below were introduced temporarily to serialize
     // the updating and scanning of remembered sets. There are some
     // race conditions when these two operations are done in parallel
     // and they are causing failures. When we resolve said race
     // conditions, we'll revert back to parallel remembered set
     // updating and scanning. See CRs 6677707 and 6677708.
     if (G1EnableParallelRSetUpdating || (worker_i == 0)) {
       updateRS(worker_i);
       scanNewRefsRS(oc, worker_i);
     } else {
       _g1p->record_update_rs_start_time(worker_i, os::elapsedTime());
       _g1p->record_update_rs_processed_buffers(worker_i, 0.0);
       _g1p->record_update_rs_time(worker_i, 0.0);
       _g1p->record_scan_new_refs_time(worker_i, 0.0);
     }
     if (G1EnableParallelRSetScanning || (worker_i == 0)) {
       scanRS(oc, worker_i);
     } else {
       _g1p->record_scan_rs_start_time(worker_i, os::elapsedTime());
       _g1p->record_scan_rs_time(worker_i, 0.0);
     }
   } else {
     assert(worker_i == 0, "invariant");
     updateRS(0);
     scanNewRefsRS(oc, 0);
     scanRS(oc, 0);
   }
 }
 void HRInto_G1RemSet::
 prepare_for_oops_into_collection_set_do() {
 #if G1_REM_SET_LOGGING
   PrintRSClosure cl;
   _g1->collection_set_iterate(&cl);
 #endif
   cleanupHRRS();
   ConcurrentG1Refine* cg1r = _g1->concurrent_g1_refine();
   _g1->set_refine_cte_cl_concurrency(false);
   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
   dcqs.concatenate_logs();
   assert(!_par_traversal_in_progress, "Invariant between iterations.");
   if (ParallelGCThreads > 0) {
     set_par_traversal(true);
     _seq_task->set_par_threads((int)n_workers());
     if (cg1r->do_traversal()) {
       updateRS(0);
       // Have to do this again after updaters
       cleanupHRRS();
     }
   }
   guarantee( _cards_scanned == NULL, "invariant" );
   _cards_scanned = NEW_C_HEAP_ARRAY(size_t, n_workers());
   for (uint i = 0; i < n_workers(); ++i) {
     _cards_scanned[i] = 0;
   }
   _total_cards_scanned = 0;
 }
 class cleanUpIteratorsClosure : public HeapRegionClosure {
   bool doHeapRegion(HeapRegion *r) {
     HeapRegionRemSet* hrrs = r->rem_set();
     hrrs->init_for_par_iteration();
     return false;
   }
 };
 class UpdateRSetOopsIntoCSImmediate : public OopClosure {
   G1CollectedHeap* _g1;
 public:
   UpdateRSetOopsIntoCSImmediate(G1CollectedHeap* g1) : _g1(g1) { }
   virtual void do_oop(narrowOop* p) {
     guarantee(false, "NYI");
   }
   virtual void do_oop(oop* p) {
     HeapRegion* to = _g1->heap_region_containing(*p);
     if (to->in_collection_set()) {
       to->rem_set()->add_reference(p, 0);
     }
   }
 };
 class UpdateRSetOopsIntoCSDeferred : public OopClosure {
   G1CollectedHeap* _g1;
   CardTableModRefBS* _ct_bs;
   DirtyCardQueue* _dcq;
 public:
   UpdateRSetOopsIntoCSDeferred(G1CollectedHeap* g1, DirtyCardQueue* dcq) :
     _g1(g1), _ct_bs((CardTableModRefBS*)_g1->barrier_set()), _dcq(dcq) { }
   virtual void do_oop(narrowOop* p) {
     guarantee(false, "NYI");
   }
   virtual void do_oop(oop* p) {
     oop obj = *p;
     if (_g1->obj_in_cs(obj)) {
       size_t card_index = _ct_bs->index_for(p);
       if (_ct_bs->mark_card_deferred(card_index)) {
         _dcq->enqueue((jbyte*)_ct_bs->byte_for_index(card_index));
       }
     }
   }
 };
 void HRInto_G1RemSet::new_refs_iterate(OopClosure* cl) {
   for (size_t i = 0; i < n_workers(); i++) {
     for (int j = 0; j < _new_refs[i]->length(); j++) {
       oop* p = _new_refs[i]->at(j);
       cl->do_oop(p);
     }
   }
 }
 void HRInto_G1RemSet::cleanup_after_oops_into_collection_set_do() {
   guarantee( _cards_scanned != NULL, "invariant" );
   _total_cards_scanned = 0;
   for (uint i = 0; i < n_workers(); ++i)
     _total_cards_scanned += _cards_scanned[i];
   FREE_C_HEAP_ARRAY(size_t, _cards_scanned);
   _cards_scanned = NULL;
   // Cleanup after copy
 #if G1_REM_SET_LOGGING
   PrintRSClosure cl;
   _g1->heap_region_iterate(&cl);
 #endif
   _g1->set_refine_cte_cl_concurrency(true);
   cleanUpIteratorsClosure iterClosure;
   _g1->collection_set_iterate(&iterClosure);
   // Set all cards back to clean.
   _g1->cleanUpCardTable();
   if (ParallelGCThreads > 0) {
     ConcurrentG1Refine* cg1r = _g1->concurrent_g1_refine();
     if (cg1r->do_traversal()) {
       cg1r->cg1rThread()->set_do_traversal(false);
     }
     set_par_traversal(false);
   }
   if (_g1->evacuation_failed()) {
     // Restore remembered sets for the regions pointing into
     // the collection set.
     if (G1DeferredRSUpdate) {
       DirtyCardQueue dcq(&_g1->dirty_card_queue_set());
       UpdateRSetOopsIntoCSDeferred deferred_update(_g1, &dcq);
       new_refs_iterate(&deferred_update);
     } else {
       UpdateRSetOopsIntoCSImmediate immediate_update(_g1);
       new_refs_iterate(&immediate_update);
     }
   }
   for (uint i = 0; i < n_workers(); i++) {
     _new_refs[i]->clear();
   }
   assert(!_par_traversal_in_progress, "Invariant between iterations.");
 }
 class UpdateRSObjectClosure: public ObjectClosure {
   UpdateRSOopClosure* _update_rs_oop_cl;
 public:
   UpdateRSObjectClosure(UpdateRSOopClosure* update_rs_oop_cl) :
     _update_rs_oop_cl(update_rs_oop_cl) {}
   void do_object(oop obj) {
     obj->oop_iterate(_update_rs_oop_cl);
   }
 };
 class ScrubRSClosure: public HeapRegionClosure {
   G1CollectedHeap* _g1h;
   BitMap* _region_bm;
   BitMap* _card_bm;
   CardTableModRefBS* _ctbs;
 public:
   ScrubRSClosure(BitMap* region_bm, BitMap* card_bm) :
     _g1h(G1CollectedHeap::heap()),
     _region_bm(region_bm), _card_bm(card_bm),
     _ctbs(NULL)
   {
     ModRefBarrierSet* bs = _g1h->mr_bs();
     guarantee(bs->is_a(BarrierSet::CardTableModRef), "Precondition");
     _ctbs = (CardTableModRefBS*)bs;
   }
   bool doHeapRegion(HeapRegion* r) {
     if (!r->continuesHumongous()) {
       r->rem_set()->scrub(_ctbs, _region_bm, _card_bm);
     }
     return false;
   }
 };
 void HRInto_G1RemSet::scrub(BitMap* region_bm, BitMap* card_bm) {
   ScrubRSClosure scrub_cl(region_bm, card_bm);
   _g1->heap_region_iterate(&scrub_cl);
 }
 void HRInto_G1RemSet::scrub_par(BitMap* region_bm, BitMap* card_bm,
                                 int worker_num, int claim_val) {
   ScrubRSClosure scrub_cl(region_bm, card_bm);
   _g1->heap_region_par_iterate_chunked(&scrub_cl, worker_num, claim_val);
 }
 class ConcRefineRegionClosure: public HeapRegionClosure {
   G1CollectedHeap* _g1h;
   CardTableModRefBS* _ctbs;
   ConcurrentGCThread* _cgc_thrd;
   ConcurrentG1Refine* _cg1r;
   unsigned _cards_processed;
   UpdateRSOopClosure _update_rs_oop_cl;
 public:
   ConcRefineRegionClosure(CardTableModRefBS* ctbs,
                           ConcurrentG1Refine* cg1r,
                           HRInto_G1RemSet* g1rs) :
     _ctbs(ctbs), _cg1r(cg1r), _cgc_thrd(cg1r->cg1rThread()),
     _update_rs_oop_cl(g1rs), _cards_processed(0),
     _g1h(G1CollectedHeap::heap())
   {}
   bool doHeapRegion(HeapRegion* r) {
     if (!r->in_collection_set() &&
         !r->continuesHumongous() &&
         !r->is_young()) {
       _update_rs_oop_cl.set_from(r);
       UpdateRSObjectClosure update_rs_obj_cl(&_update_rs_oop_cl);
       // For each run of dirty card in the region:
       //   1) Clear the cards.
       //   2) Process the range corresponding to the run, adding any
       //      necessary RS entries.
       // 1 must precede 2, so that a concurrent modification redirties the
       // card.  If a processing attempt does not succeed, because it runs
       // into an unparseable region, we will do binary search to find the
       // beginning of the next parseable region.
       HeapWord* startAddr = r->bottom();
       HeapWord* endAddr = r->used_region().end();
       HeapWord* lastAddr;
       HeapWord* nextAddr;
       for (nextAddr = lastAddr = startAddr;
            nextAddr < endAddr;
            nextAddr = lastAddr) {
         MemRegion dirtyRegion;
         // Get and clear dirty region from card table
         MemRegion next_mr(nextAddr, endAddr);
         dirtyRegion =
           _ctbs->dirty_card_range_after_reset(
                            next_mr,
                            true, CardTableModRefBS::clean_card_val());
         assert(dirtyRegion.start() >= nextAddr,
                "returned region inconsistent?");
         if (!dirtyRegion.is_empty()) {
           HeapWord* stop_point =
             r->object_iterate_mem_careful(dirtyRegion,
                                           &update_rs_obj_cl);
           if (stop_point == NULL) {
             lastAddr = dirtyRegion.end();
             _cards_processed +=
               (int) (dirtyRegion.word_size() / CardTableModRefBS::card_size_in_words);
           } else {
             // We're going to skip one or more cards that we can't parse.
             HeapWord* next_parseable_card =
               r->next_block_start_careful(stop_point);
             // Round this up to a card boundary.
             next_parseable_card =
               _ctbs->addr_for(_ctbs->byte_after_const(next_parseable_card));
             // Now we invalidate the intervening cards so we'll see them
             // again.
             MemRegion remaining_dirty =
               MemRegion(stop_point, dirtyRegion.end());
             MemRegion skipped =
               MemRegion(stop_point, next_parseable_card);
             _ctbs->invalidate(skipped.intersection(remaining_dirty));
             // Now start up again where we can parse.
             lastAddr = next_parseable_card;
             // Count how many we did completely.
             _cards_processed +=
               (stop_point - dirtyRegion.start()) /
               CardTableModRefBS::card_size_in_words;
           }
           // Allow interruption at regular intervals.
           // (Might need to make them more regular, if we get big
           // dirty regions.)
           if (_cgc_thrd != NULL) {
             if (_cgc_thrd->should_yield()) {
               _cgc_thrd->yield();
               switch (_cg1r->get_pya()) {
               case PYA_continue:
                 // This may have changed: re-read.
                 endAddr = r->used_region().end();
                 continue;
               case PYA_restart: case PYA_cancel:
                 return true;
               }
             }
           }
         } else {
           break;
         }
       }
     }
     // A good yield opportunity.
     if (_cgc_thrd != NULL) {
       if (_cgc_thrd->should_yield()) {
         _cgc_thrd->yield();
         switch (_cg1r->get_pya()) {
         case PYA_restart: case PYA_cancel:
           return true;
         default:
           break;
         }
       }
     }
     return false;
   }
   unsigned cards_processed() { return _cards_processed; }
 };
 void HRInto_G1RemSet::concurrentRefinementPass(ConcurrentG1Refine* cg1r) {
   ConcRefineRegionClosure cr_cl(ct_bs(), cg1r, this);
   _g1->heap_region_iterate(&cr_cl);
   _conc_refine_traversals++;
   _conc_refine_cards += cr_cl.cards_processed();
 }
 static IntHistogram out_of_histo(50, 50);
 void HRInto_G1RemSet::concurrentRefineOneCard(jbyte* card_ptr, int worker_i) {
   // If the card is no longer dirty, nothing to do.
   if (*card_ptr != CardTableModRefBS::dirty_card_val()) return;
   // Construct the region representing the card.
   HeapWord* start = _ct_bs->addr_for(card_ptr);
   // And find the region containing it.
   HeapRegion* r = _g1->heap_region_containing(start);
   if (r == NULL) {
     guarantee(_g1->is_in_permanent(start), "Or else where?");
     return;  // Not in the G1 heap (might be in perm, for example.)
   }
   // Why do we have to check here whether a card is on a young region,
   // given that we dirty young regions and, as a result, the
   // post-barrier is supposed to filter them out and never to enqueue
   // them? When we allocate a new region as the "allocation region" we
   // actually dirty its cards after we release the lock, since card
   // dirtying while holding the lock was a performance bottleneck. So,
   // as a result, it is possible for other threads to actually
   // allocate objects in the region (after the acquire the lock)
   // before all the cards on the region are dirtied. This is unlikely,
   // and it doesn't happen often, but it can happen. So, the extra
   // check below filters out those cards.
   if (r->is_young()) {
     return;
   }
   // While we are processing RSet buffers during the collection, we
   // actually don't want to scan any cards on the collection set,
   // since we don't want to update remebered sets with entries that
   // point into the collection set, given that live objects from the
   // collection set are about to move and such entries will be stale
   // very soon. This change also deals with a reliability issue which
   // involves scanning a card in the collection set and coming across
   // an array that was being chunked and looking malformed. Note,
   // however, that if evacuation fails, we have to scan any objects
   // that were not moved and create any missing entries.
   if (r->in_collection_set()) {
     return;
   }
   // Should we defer it?
   if (_cg1r->use_cache()) {
     card_ptr = _cg1r->cache_insert(card_ptr);
     // If it was not an eviction, nothing to do.
     if (card_ptr == NULL) return;
     // OK, we have to reset the card start, region, etc.
     start = _ct_bs->addr_for(card_ptr);
     r = _g1->heap_region_containing(start);
     if (r == NULL) {
       guarantee(_g1->is_in_permanent(start), "Or else where?");
       return;  // Not in the G1 heap (might be in perm, for example.)
     }
     guarantee(!r->is_young(), "It was evicted in the current minor cycle.");
   }
   HeapWord* end   = _ct_bs->addr_for(card_ptr + 1);
   MemRegion dirtyRegion(start, end);
 #if CARD_REPEAT_HISTO
   init_ct_freq_table(_g1->g1_reserved_obj_bytes());
   ct_freq_note_card(_ct_bs->index_for(start));
 #endif
   UpdateRSOopClosure update_rs_oop_cl(this, worker_i);
   update_rs_oop_cl.set_from(r);
   FilterOutOfRegionClosure filter_then_update_rs_oop_cl(r, &update_rs_oop_cl);
   // Undirty the card.
   *card_ptr = CardTableModRefBS::clean_card_val();
   // We must complete this write before we do any of the reads below.
   OrderAccess::storeload();
   // And process it, being careful of unallocated portions of TLAB's.
   HeapWord* stop_point =
     r->oops_on_card_seq_iterate_careful(dirtyRegion,
                                         &filter_then_update_rs_oop_cl);
   // If stop_point is non-null, then we encountered an unallocated region
   // (perhaps the unfilled portion of a TLAB.)  For now, we'll dirty the
   // card and re-enqueue: if we put off the card until a GC pause, then the
   // unallocated portion will be filled in.  Alternatively, we might try
   // the full complexity of the technique used in "regular" precleaning.
   if (stop_point != NULL) {
     // The card might have gotten re-dirtied and re-enqueued while we
     // worked.  (In fact, it's pretty likely.)
     if (*card_ptr != CardTableModRefBS::dirty_card_val()) {
       *card_ptr = CardTableModRefBS::dirty_card_val();
       MutexLockerEx x(Shared_DirtyCardQ_lock,
                       Mutex::_no_safepoint_check_flag);
       DirtyCardQueue* sdcq =
         JavaThread::dirty_card_queue_set().shared_dirty_card_queue();
       sdcq->enqueue(card_ptr);
     }
   } else {
     out_of_histo.add_entry(filter_then_update_rs_oop_cl.out_of_region());
     _conc_refine_cards++;
   }
 }
 class HRRSStatsIter: public HeapRegionClosure {
   size_t _occupied;
   size_t _total_mem_sz;
   size_t _max_mem_sz;
   HeapRegion* _max_mem_sz_region;
 public:
   HRRSStatsIter() :
     _occupied(0),
     _total_mem_sz(0),
     _max_mem_sz(0),
     _max_mem_sz_region(NULL)
   {}
   bool doHeapRegion(HeapRegion* r) {
     if (r->continuesHumongous()) return false;
     size_t mem_sz = r->rem_set()->mem_size();
     if (mem_sz > _max_mem_sz) {
       _max_mem_sz = mem_sz;
       _max_mem_sz_region = r;
     }
     _total_mem_sz += mem_sz;
     size_t occ = r->rem_set()->occupied();
     _occupied += occ;
     return false;
   }
   size_t total_mem_sz() { return _total_mem_sz; }
   size_t max_mem_sz() { return _max_mem_sz; }
   size_t occupied() { return _occupied; }
   HeapRegion* max_mem_sz_region() { return _max_mem_sz_region; }
 };
 void HRInto_G1RemSet::print_summary_info() {
   G1CollectedHeap* g1 = G1CollectedHeap::heap();
   ConcurrentG1RefineThread* cg1r_thrd =
     g1->concurrent_g1_refine()->cg1rThread();
 #if CARD_REPEAT_HISTO
   gclog_or_tty->print_cr("\nG1 card_repeat count histogram: ");
   gclog_or_tty->print_cr("  # of repeats --> # of cards with that number.");
   card_repeat_count.print_on(gclog_or_tty);
 #endif
   if (FILTEROUTOFREGIONCLOSURE_DOHISTOGRAMCOUNT) {
     gclog_or_tty->print_cr("\nG1 rem-set out-of-region histogram: ");
     gclog_or_tty->print_cr("  # of CS ptrs --> # of cards with that number.");
     out_of_histo.print_on(gclog_or_tty);
   }
   gclog_or_tty->print_cr("\n Concurrent RS processed %d cards in "
                 "%5.2fs.",
                 _conc_refine_cards, cg1r_thrd->vtime_accum());
   DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
   jint tot_processed_buffers =
     dcqs.processed_buffers_mut() + dcqs.processed_buffers_rs_thread();
   gclog_or_tty->print_cr("  Of %d completed buffers:", tot_processed_buffers);
   gclog_or_tty->print_cr("     %8d (%5.1f%%) by conc RS thread.",
                 dcqs.processed_buffers_rs_thread(),
 .0*(float)dcqs.processed_buffers_rs_thread()/
                 (float)tot_processed_buffers);
   gclog_or_tty->print_cr("     %8d (%5.1f%%) by mutator threads.",
                 dcqs.processed_buffers_mut(),
 .0*(float)dcqs.processed_buffers_mut()/
                 (float)tot_processed_buffers);
   gclog_or_tty->print_cr("   Did %d concurrent refinement traversals.",
                 _conc_refine_traversals);
   if (!G1RSBarrierUseQueue) {
     gclog_or_tty->print_cr("   Scanned %8.2f cards/traversal.",
                   _conc_refine_traversals > 0 ?
                   (float)_conc_refine_cards/(float)_conc_refine_traversals :
 );
   }
   gclog_or_tty->print_cr("");
   if (G1UseHRIntoRS) {
     HRRSStatsIter blk;
     g1->heap_region_iterate(&blk);
     gclog_or_tty->print_cr("  Total heap region rem set sizes = " SIZE_FORMAT "K."
                            "  Max = " SIZE_FORMAT "K.",
                            blk.total_mem_sz()/K, blk.max_mem_sz()/K);
     gclog_or_tty->print_cr("  Static structures = " SIZE_FORMAT "K,"
                            " free_lists = " SIZE_FORMAT "K.",
                            HeapRegionRemSet::static_mem_size()/K,
                            HeapRegionRemSet::fl_mem_size()/K);
     gclog_or_tty->print_cr("    %d occupied cards represented.",
                            blk.occupied());
     gclog_or_tty->print_cr("    Max sz region = [" PTR_FORMAT ", " PTR_FORMAT " )"
                            ", cap = " SIZE_FORMAT "K, occ = " SIZE_FORMAT "K.",
                            blk.max_mem_sz_region()->bottom(), blk.max_mem_sz_region()->end(),
                            (blk.max_mem_sz_region()->rem_set()->mem_size() + K - 1)/K,
                            (blk.max_mem_sz_region()->rem_set()->occupied() + K - 1)/K);
     gclog_or_tty->print_cr("    Did %d coarsenings.",
                   HeapRegionRemSet::n_coarsenings());
   }
 }
 void HRInto_G1RemSet::prepare_for_verify() {
   if (G1HRRSFlushLogBuffersOnVerify &&
       (VerifyBeforeGC || VerifyAfterGC)
       &&  !_g1->full_collection()) {
     cleanupHRRS();
     _g1->set_refine_cte_cl_concurrency(false);
     if (SafepointSynchronize::is_at_safepoint()) {
       DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();
       dcqs.concatenate_logs();
     }
     bool cg1r_use_cache = _cg1r->use_cache();
     _cg1r->set_use_cache(false);
     updateRS(0);
     _cg1r->set_use_cache(cg1r_use_cache);
     assert(JavaThread::dirty_card_queue_set().completed_buffers_num() == 0, "All should be consumed");
   }
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/g1RemSet.cpp@b803b1b9e206 (annotated)

src/share/vm/gc_implementation/g1/g1RemSet.cpp