Merge

hotspot/src/share/vm/gc_implementation/g1/concurrentMark.cpp

@@ -819,7 +819,7 @@ void ConcurrentMark::set_concurrency_and_phase(uint active_tasks, bool concurren
     // false before we start remark. At this point we should also be
     // in a STW phase.
     assert(!concurrent_marking_in_progress(), "invariant");
-    assert(_finger == _heap_end,
+    assert(out_of_regions(),
            err_msg("only way to get here: _finger: "PTR_FORMAT", _heap_end: "PTR_FORMAT,
                    p2i(_finger), p2i(_heap_end)));
     update_g1_committed(true);
@@ -978,7 +978,9 @@ void ConcurrentMark::enter_first_sync_barrier(uint worker_id) {
   if (concurrent()) {
     SuspendibleThreadSet::leave();
   }
-  _first_overflow_barrier_sync.enter();
+
+  bool barrier_aborted = !_first_overflow_barrier_sync.enter();
+
   if (concurrent()) {
     SuspendibleThreadSet::join();
   }
@@ -986,8 +988,18 @@ void ConcurrentMark::enter_first_sync_barrier(uint worker_id) {
   // more work
 
   if (verbose_low()) {
+    if (barrier_aborted) {
+      gclog_or_tty->print_cr("[%u] aborted first barrier", worker_id);
+    } else {
       gclog_or_tty->print_cr("[%u] leaving first barrier", worker_id);
     }
+  }
+
+  if (barrier_aborted) {
+    // If the barrier aborted we ignore the overflow condition and
+    // just abort the whole marking phase as quickly as possible.
+    return;
+  }
 
   // If we're executing the concurrent phase of marking, reset the marking
   // state; otherwise the marking state is reset after reference processing,
@@ -1026,16 +1038,22 @@ void ConcurrentMark::enter_second_sync_barrier(uint worker_id) {
   if (concurrent()) {
     SuspendibleThreadSet::leave();
   }
-  _second_overflow_barrier_sync.enter();
+
+  bool barrier_aborted = !_second_overflow_barrier_sync.enter();
+
   if (concurrent()) {
     SuspendibleThreadSet::join();
   }
   // at this point everything should be re-initialized and ready to go
 
   if (verbose_low()) {
+    if (barrier_aborted) {
+      gclog_or_tty->print_cr("[%u] aborted second barrier", worker_id);
+    } else {
       gclog_or_tty->print_cr("[%u] leaving second barrier", worker_id);
     }
   }
+}
 
 #ifndef PRODUCT
 void ForceOverflowSettings::init() {
@@ -3240,6 +3258,8 @@ void ConcurrentMark::abort() {
   for (uint i = 0; i < _max_worker_id; ++i) {
     _tasks[i]->clear_region_fields();
   }
+  _first_overflow_barrier_sync.abort();
+  _second_overflow_barrier_sync.abort();
   _has_aborted = true;
 
   SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set();

hotspot/src/share/vm/gc_implementation/g1/concurrentMark.hpp

@@ -542,8 +542,12 @@ protected:
   // frequently.
   HeapRegion* claim_region(uint worker_id);
 
-  // It determines whether we've run out of regions to scan
+  // It determines whether we've run out of regions to scan. Note that
-  bool        out_of_regions() { return _finger == _heap_end; }
+  // the finger can point past the heap end in case the heap was expanded
+  // to satisfy an allocation without doing a GC. This is fine, because all
+  // objects in those regions will be considered live anyway because of
+  // SATB guarantees (i.e. their TAMS will be equal to bottom).
+  bool        out_of_regions() { return _finger >= _heap_end; }
 
   // Returns the task with the given id
   CMTask* task(int id) {

hotspot/src/share/vm/gc_implementation/g1/sparsePRT.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
+ * 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
@@ -194,23 +194,16 @@ bool RSHashTable::add_card(RegionIdx_t region_ind, CardIdx_t card_index) {
 }
 
 bool RSHashTable::get_cards(RegionIdx_t region_ind, CardIdx_t* cards) {
-  int ind = (int) (region_ind & capacity_mask());
+  SparsePRTEntry* entry = get_entry(region_ind);
-  int cur_ind = _buckets[ind];
+  if (entry == NULL) {
-  SparsePRTEntry* cur;
+    return false;
-  while (cur_ind != NullEntry &&
-         (cur = entry(cur_ind))->r_ind() != region_ind) {
-    cur_ind = cur->next_index();
   }
-
-  if (cur_ind == NullEntry) return false;
   // Otherwise...
-  assert(cur->r_ind() == region_ind, "Postcondition of loop + test above.");
+  entry->copy_cards(cards);
-  assert(cur->num_valid_cards() > 0, "Inv");
-  cur->copy_cards(cards);
   return true;
 }
 
-SparsePRTEntry* RSHashTable::get_entry(RegionIdx_t region_ind) {
+SparsePRTEntry* RSHashTable::get_entry(RegionIdx_t region_ind) const {
   int ind = (int) (region_ind & capacity_mask());
   int cur_ind = _buckets[ind];
   SparsePRTEntry* cur;
@@ -246,28 +239,9 @@ bool RSHashTable::delete_entry(RegionIdx_t region_ind) {
   return true;
 }
 
-SparsePRTEntry*
-RSHashTable::entry_for_region_ind(RegionIdx_t region_ind) const {
-  assert(occupied_entries() < capacity(), "Precondition");
-  int ind = (int) (region_ind & capacity_mask());
-  int cur_ind = _buckets[ind];
-  SparsePRTEntry* cur;
-  while (cur_ind != NullEntry &&
-         (cur = entry(cur_ind))->r_ind() != region_ind) {
-    cur_ind = cur->next_index();
-  }
-
-  if (cur_ind != NullEntry) {
-    assert(cur->r_ind() == region_ind, "Loop postcondition + test");
-    return cur;
-  } else {
-    return NULL;
-  }
-}
-
 SparsePRTEntry*
 RSHashTable::entry_for_region_ind_create(RegionIdx_t region_ind) {
-  SparsePRTEntry* res = entry_for_region_ind(region_ind);
+  SparsePRTEntry* res = get_entry(region_ind);
   if (res == NULL) {
     int new_ind = alloc_entry();
     assert(0 <= new_ind && (size_t)new_ind < capacity(), "There should be room.");
@@ -365,7 +339,7 @@ bool RSHashTableIter::has_next(size_t& card_index) {
 }
 
 bool RSHashTable::contains_card(RegionIdx_t region_index, CardIdx_t card_index) const {
-  SparsePRTEntry* e = entry_for_region_ind(region_index);
+  SparsePRTEntry* e = get_entry(region_index);
   return (e != NULL && e->contains_card(card_index));
 }
 

hotspot/src/share/vm/gc_implementation/g1/sparsePRT.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
+ * 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
@@ -119,12 +119,6 @@ class RSHashTable : public CHeapObj<mtGC> {
   int  _free_region;
   int  _free_list;
 
-  // Requires that the caller hold a lock preventing parallel modifying
-  // operations, and that the the table be less than completely full.  If
-  // an entry for "region_ind" is already in the table, finds it and
-  // returns its address; otherwise returns "NULL."
-  SparsePRTEntry* entry_for_region_ind(RegionIdx_t region_ind) const;
-
   // Requires that the caller hold a lock preventing parallel modifying
   // operations, and that the the table be less than completely full.  If
   // an entry for "region_ind" is already in the table, finds it and
@@ -158,7 +152,7 @@ public:
 
   void add_entry(SparsePRTEntry* e);
 
-  SparsePRTEntry* get_entry(RegionIdx_t region_id);
+  SparsePRTEntry* get_entry(RegionIdx_t region_id) const;
 
   void clear();
 

hotspot/src/share/vm/memory/metaspace.cpp

@@ -1433,10 +1433,9 @@ size_t MetaspaceGC::allowed_expansion() {
   }
 
   size_t capacity_until_gc = capacity_until_GC();
-
+  assert(capacity_until_gc >= committed_bytes,
-  if (capacity_until_gc <= committed_bytes) {
+         err_msg("capacity_until_gc: " SIZE_FORMAT " < committed_bytes: " SIZE_FORMAT,
-    return 0;
+                 capacity_until_gc, committed_bytes));
-  }
 
   size_t left_until_GC = capacity_until_gc - committed_bytes;
   size_t left_to_commit = MIN2(left_until_GC, left_until_max);
@@ -1449,7 +1448,15 @@ void MetaspaceGC::compute_new_size() {
   uint current_shrink_factor = _shrink_factor;
   _shrink_factor = 0;
 
-  const size_t used_after_gc = MetaspaceAux::capacity_bytes();
+  // Using committed_bytes() for used_after_gc is an overestimation, since the
+  // chunk free lists are included in committed_bytes() and the memory in an
+  // un-fragmented chunk free list is available for future allocations.
+  // However, if the chunk free lists becomes fragmented, then the memory may
+  // not be available for future allocations and the memory is therefore "in use".
+  // Including the chunk free lists in the definition of "in use" is therefore
+  // necessary. Not including the chunk free lists can cause capacity_until_GC to
+  // shrink below committed_bytes() and this has caused serious bugs in the past.
+  const size_t used_after_gc = MetaspaceAux::committed_bytes();
   const size_t capacity_until_GC = MetaspaceGC::capacity_until_GC();
 
   const double minimum_free_percentage = MinMetaspaceFreeRatio / 100.0;

hotspot/src/share/vm/utilities/workgroup.cpp

@@ -378,21 +378,22 @@ const char* AbstractGangTask::name() const {
 
 WorkGangBarrierSync::WorkGangBarrierSync()
   : _monitor(Mutex::safepoint, "work gang barrier sync", true),
-    _n_workers(0), _n_completed(0), _should_reset(false) {
+    _n_workers(0), _n_completed(0), _should_reset(false), _aborted(false) {
 }
 
 WorkGangBarrierSync::WorkGangBarrierSync(uint n_workers, const char* name)
   : _monitor(Mutex::safepoint, name, true),
-    _n_workers(n_workers), _n_completed(0), _should_reset(false) {
+    _n_workers(n_workers), _n_completed(0), _should_reset(false), _aborted(false) {
 }
 
 void WorkGangBarrierSync::set_n_workers(uint n_workers) {
   _n_workers    = n_workers;
   _n_completed  = 0;
   _should_reset = false;
+  _aborted      = false;
 }
 
-void WorkGangBarrierSync::enter() {
+bool WorkGangBarrierSync::enter() {
   MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag);
   if (should_reset()) {
     // The should_reset() was set and we are the first worker to enter
@@ -415,10 +416,17 @@ void WorkGangBarrierSync::enter() {
     set_should_reset(true);
     monitor()->notify_all();
   } else {
-    while (n_completed() != n_workers()) {
+    while (n_completed() != n_workers() && !aborted()) {
       monitor()->wait(/* no_safepoint_check */ true);
     }
   }
+  return !aborted();
+}
+
+void WorkGangBarrierSync::abort() {
+  MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag);
+  set_aborted();
+  monitor()->notify_all();
 }
 
 // SubTasksDone functions.

hotspot/src/share/vm/utilities/workgroup.hpp

@@ -362,15 +362,17 @@ protected:
   uint    _n_workers;
   uint    _n_completed;
   bool    _should_reset;
+  bool    _aborted;
 
   Monitor* monitor()        { return &_monitor; }
   uint     n_workers()      { return _n_workers; }
   uint     n_completed()    { return _n_completed; }
   bool     should_reset()   { return _should_reset; }
+  bool     aborted()        { return _aborted; }
 
   void     zero_completed() { _n_completed = 0; }
   void     inc_completed()  { _n_completed++; }
-
+  void     set_aborted()    { _aborted = true; }
   void     set_should_reset(bool v) { _should_reset = v; }
 
 public:
@@ -383,8 +385,14 @@ public:
 
   // Enter the barrier. A worker that enters the barrier will
   // not be allowed to leave until all other threads have
-  // also entered the barrier.
+  // also entered the barrier or the barrier is aborted.
-  void enter();
+  // Returns false if the barrier was aborted.
+  bool enter();
+
+  // Aborts the barrier and wakes up any threads waiting for
+  // the barrier to complete. The barrier will remain in the
+  // aborted state until the next call to set_n_workers().
+  void abort();
 };
 
 // A class to manage claiming of subtasks within a group of tasks.  The

hotspot/test/gc/g1/TestGCLogMessages.java

@@ -22,7 +22,7 @@
  */
 
 /*
- * @test TestPrintGCDetails
+ * @test TestGCLogMessages
  * @bug 8035406 8027295 8035398 8019342
  * @summary Ensure that the PrintGCDetails output for a minor GC with G1
  * includes the expected necessary messages.
@@ -90,12 +90,6 @@ public class TestGCLogMessages {
     output.shouldContain("[String Dedup Fixup");
     output.shouldContain("[Young Free CSet");
     output.shouldContain("[Non-Young Free CSet");
-
-    // also check evacuation failure messages once
-    output.shouldNotContain("[Evacuation Failure");
-    output.shouldNotContain("[Recalculate Used");
-    output.shouldNotContain("[Remove Self Forwards");
-    output.shouldNotContain("[Restore RemSet");
     output.shouldHaveExitValue(0);
   }