changeset 34282:92f8f8941296

8139922: Get rid of dead code in ConcurrentMark Summary: ConcurrentMark contains lots of unused code which has been removed. Reviewed-by: jmasa, tschatzl
author jprovino
date Tue, 24 Nov 2015 15:13:02 -0500
parents 1b277b5ee6e3
children 77d7d188b204
files hotspot/src/share/vm/gc/g1/concurrentMark.cpp hotspot/src/share/vm/gc/g1/concurrentMark.hpp hotspot/src/share/vm/gc/g1/concurrentMark.inline.hpp
diffstat 3 files changed, 1 insertions(+), 207 deletions(-) [+]
line wrap: on
line diff
--- a/hotspot/src/share/vm/gc/g1/concurrentMark.cpp	Tue Nov 24 11:49:44 2015 +0000
+++ b/hotspot/src/share/vm/gc/g1/concurrentMark.cpp	Tue Nov 24 15:13:02 2015 -0500
@@ -74,9 +74,7 @@
   addr = (HeapWord*)align_size_up((intptr_t)addr,
                                   HeapWordSize << _shifter);
   size_t addrOffset = heapWordToOffset(addr);
-  if (limit == NULL) {
-    limit = _bmStartWord + _bmWordSize;
-  }
+  assert(limit != NULL, "limit must not be NULL");
   size_t limitOffset = heapWordToOffset(limit);
   size_t nextOffset = _bm.get_next_one_offset(addrOffset, limitOffset);
   HeapWord* nextAddr = offsetToHeapWord(nextOffset);
@@ -86,26 +84,6 @@
   return nextAddr;
 }
 
-HeapWord* CMBitMapRO::getNextUnmarkedWordAddress(const HeapWord* addr,
-                                                 const HeapWord* limit) const {
-  size_t addrOffset = heapWordToOffset(addr);
-  if (limit == NULL) {
-    limit = _bmStartWord + _bmWordSize;
-  }
-  size_t limitOffset = heapWordToOffset(limit);
-  size_t nextOffset = _bm.get_next_zero_offset(addrOffset, limitOffset);
-  HeapWord* nextAddr = offsetToHeapWord(nextOffset);
-  assert(nextAddr >= addr, "get_next_one postcondition");
-  assert(nextAddr == limit || !isMarked(nextAddr),
-         "get_next_one postcondition");
-  return nextAddr;
-}
-
-int CMBitMapRO::heapWordDiffToOffsetDiff(size_t diff) const {
-  assert((diff & ((1 << _shifter) - 1)) == 0, "argument check");
-  return (int) (diff >> _shifter);
-}
-
 #ifndef PRODUCT
 bool CMBitMapRO::covers(MemRegion heap_rs) const {
   // assert(_bm.map() == _virtual_space.low(), "map inconsistency");
@@ -211,17 +189,6 @@
   return;
 }
 
-void CMBitMap::markRange(MemRegion mr) {
-  mr.intersection(MemRegion(_bmStartWord, _bmWordSize));
-  assert(!mr.is_empty(), "unexpected empty region");
-  assert((offsetToHeapWord(heapWordToOffset(mr.end())) ==
-          ((HeapWord *) mr.end())),
-         "markRange memory region end is not card aligned");
-  // convert address range into offset range
-  _bm.at_put_range(heapWordToOffset(mr.start()),
-                   heapWordToOffset(mr.end()), true);
-}
-
 void CMBitMap::clearRange(MemRegion mr) {
   mr.intersection(MemRegion(_bmStartWord, _bmWordSize));
   assert(!mr.is_empty(), "unexpected empty region");
@@ -230,20 +197,6 @@
                    heapWordToOffset(mr.end()), false);
 }
 
-MemRegion CMBitMap::getAndClearMarkedRegion(HeapWord* addr,
-                                            HeapWord* end_addr) {
-  HeapWord* start = getNextMarkedWordAddress(addr);
-  start = MIN2(start, end_addr);
-  HeapWord* end   = getNextUnmarkedWordAddress(start);
-  end = MIN2(end, end_addr);
-  assert(start <= end, "Consistency check");
-  MemRegion mr(start, end);
-  if (!mr.is_empty()) {
-    clearRange(mr);
-  }
-  return mr;
-}
-
 CMMarkStack::CMMarkStack(ConcurrentMark* cm) :
   _base(NULL), _cm(cm)
 {}
@@ -466,8 +419,6 @@
   _max_parallel_marking_threads(0),
   _sleep_factor(0.0),
   _marking_task_overhead(1.0),
-  _cleanup_sleep_factor(0.0),
-  _cleanup_task_overhead(1.0),
   _cleanup_list("Cleanup List"),
   _region_bm((BitMap::idx_t)(g1h->max_regions()), false /* in_resource_area*/),
   _card_bm((g1h->reserved_region().byte_size() + CardTableModRefBS::card_size - 1) >>
@@ -568,22 +519,6 @@
   _parallel_marking_threads = ConcGCThreads;
   _max_parallel_marking_threads = _parallel_marking_threads;
 
-  if (parallel_marking_threads() > 1) {
-    _cleanup_task_overhead = 1.0;
-  } else {
-    _cleanup_task_overhead = marking_task_overhead();
-  }
-  _cleanup_sleep_factor =
-                   (1.0 - cleanup_task_overhead()) / cleanup_task_overhead();
-
-#if 0
-  gclog_or_tty->print_cr("Marking Threads          %d", parallel_marking_threads());
-  gclog_or_tty->print_cr("CM Marking Task Overhead %1.4lf", marking_task_overhead());
-  gclog_or_tty->print_cr("CM Sleep Factor          %1.4lf", sleep_factor());
-  gclog_or_tty->print_cr("CL Marking Task Overhead %1.4lf", cleanup_task_overhead());
-  gclog_or_tty->print_cr("CL Sleep Factor          %1.4lf", cleanup_sleep_factor());
-#endif
-
   _parallel_workers = new WorkGang("G1 Marker",
        _max_parallel_marking_threads, false, true);
   if (_parallel_workers == NULL) {
@@ -840,14 +775,6 @@
 void ConcurrentMark::checkpointRootsInitialPost() {
   G1CollectedHeap*   g1h = G1CollectedHeap::heap();
 
-  // If we force an overflow during remark, the remark operation will
-  // actually abort and we'll restart concurrent marking. If we always
-  // force an overflow during remark we'll never actually complete the
-  // marking phase. So, we initialize this here, at the start of the
-  // cycle, so that at the remaining overflow number will decrease at
-  // every remark and we'll eventually not need to cause one.
-  force_overflow_stw()->init();
-
   // Start Concurrent Marking weak-reference discovery.
   ReferenceProcessor* rp = g1h->ref_processor_cm();
   // enable ("weak") refs discovery
@@ -920,7 +847,6 @@
       // we exit this method to abort the pause and restart concurrent
       // marking.
       reset_marking_state(true /* clear_overflow */);
-      force_overflow()->update();
 
       if (G1Log::fine()) {
         gclog_or_tty->gclog_stamp();
@@ -940,32 +866,6 @@
   // at this point everything should be re-initialized and ready to go
 }
 
-#ifndef PRODUCT
-void ForceOverflowSettings::init() {
-  _num_remaining = G1ConcMarkForceOverflow;
-  _force = false;
-  update();
-}
-
-void ForceOverflowSettings::update() {
-  if (_num_remaining > 0) {
-    _num_remaining -= 1;
-    _force = true;
-  } else {
-    _force = false;
-  }
-}
-
-bool ForceOverflowSettings::should_force() {
-  if (_force) {
-    _force = false;
-    return true;
-  } else {
-    return false;
-  }
-}
-#endif // !PRODUCT
-
 class CMConcurrentMarkingTask: public AbstractGangTask {
 private:
   ConcurrentMark*       _cm;
@@ -1131,7 +1031,6 @@
   // stop-the-world GC happens even as we mark in this generation.
 
   _restart_for_overflow = false;
-  force_overflow_conc()->init();
 
   // _g1h has _n_par_threads
   _parallel_marking_threads = calc_parallel_marking_threads();
@@ -2440,10 +2339,6 @@
   ((CMBitMap*)_prevMarkBitMap)->clearRange(mr);
 }
 
-void ConcurrentMark::clearRangeNextBitmap(MemRegion mr) {
-  _nextMarkBitMap->clearRange(mr);
-}
-
 HeapRegion*
 ConcurrentMark::claim_region(uint worker_id) {
   // "checkpoint" the finger
@@ -3535,15 +3430,6 @@
     }
   }
 
-  // If we are about to wrap up and go into termination, check if we
-  // should raise the overflow flag.
-  if (do_termination && !has_aborted()) {
-    if (_cm->force_overflow()->should_force()) {
-      _cm->set_has_overflown();
-      regular_clock_call();
-    }
-  }
-
   // We still haven't aborted. Now, let's try to get into the
   // termination protocol.
   if (do_termination && !has_aborted()) {
--- a/hotspot/src/share/vm/gc/g1/concurrentMark.hpp	Tue Nov 24 11:49:44 2015 +0000
+++ b/hotspot/src/share/vm/gc/g1/concurrentMark.hpp	Tue Nov 24 15:13:02 2015 -0500
@@ -65,11 +65,8 @@
   // constructor
   CMBitMapRO(int shifter);
 
-  enum { do_yield = true };
-
   // inquiries
   HeapWord* startWord()   const { return _bmStartWord; }
-  size_t    sizeInWords() const { return _bmWordSize;  }
   // the following is one past the last word in space
   HeapWord* endWord()     const { return _bmStartWord + _bmWordSize; }
 
@@ -83,18 +80,12 @@
 
   // iteration
   inline bool iterate(BitMapClosure* cl, MemRegion mr);
-  inline bool iterate(BitMapClosure* cl);
 
   // Return the address corresponding to the next marked bit at or after
   // "addr", and before "limit", if "limit" is non-NULL.  If there is no
   // such bit, returns "limit" if that is non-NULL, or else "endWord()".
   HeapWord* getNextMarkedWordAddress(const HeapWord* addr,
                                      const HeapWord* limit = NULL) const;
-  // Return the address corresponding to the next unmarked bit at or after
-  // "addr", and before "limit", if "limit" is non-NULL.  If there is no
-  // such bit, returns "limit" if that is non-NULL, or else "endWord()".
-  HeapWord* getNextUnmarkedWordAddress(const HeapWord* addr,
-                                       const HeapWord* limit = NULL) const;
 
   // conversion utilities
   HeapWord* offsetToHeapWord(size_t offset) const {
@@ -103,7 +94,6 @@
   size_t heapWordToOffset(const HeapWord* addr) const {
     return pointer_delta(addr, _bmStartWord) >> _shifter;
   }
-  int heapWordDiffToOffsetDiff(size_t diff) const;
 
   // The argument addr should be the start address of a valid object
   HeapWord* nextObject(HeapWord* addr) {
@@ -153,20 +143,9 @@
   inline void mark(HeapWord* addr);
   inline void clear(HeapWord* addr);
   inline bool parMark(HeapWord* addr);
-  inline bool parClear(HeapWord* addr);
 
-  void markRange(MemRegion mr);
   void clearRange(MemRegion mr);
 
-  // Starting at the bit corresponding to "addr" (inclusive), find the next
-  // "1" bit, if any.  This bit starts some run of consecutive "1"'s; find
-  // the end of this run (stopping at "end_addr").  Return the MemRegion
-  // covering from the start of the region corresponding to the first bit
-  // of the run to the end of the region corresponding to the last bit of
-  // the run.  If there is no "1" bit at or after "addr", return an empty
-  // MemRegion.
-  MemRegion getAndClearMarkedRegion(HeapWord* addr, HeapWord* end_addr);
-
   // Clear the whole mark bitmap.
   void clearAll();
 };
@@ -231,19 +210,6 @@
   template<typename Fn> void iterate(Fn fn);
 };
 
-class ForceOverflowSettings VALUE_OBJ_CLASS_SPEC {
-private:
-#ifndef PRODUCT
-  uintx _num_remaining;
-  bool _force;
-#endif // !defined(PRODUCT)
-
-public:
-  void init() PRODUCT_RETURN;
-  void update() PRODUCT_RETURN;
-  bool should_force() PRODUCT_RETURN_( return false; );
-};
-
 class YoungList;
 
 // Root Regions are regions that are not empty at the beginning of a
@@ -326,10 +292,6 @@
   double                _marking_task_overhead; // Marking target overhead for
                                                 // a single task
 
-  // Same as the two above, but for the cleanup task
-  double                _cleanup_sleep_factor;
-  double                _cleanup_task_overhead;
-
   FreeRegionList        _cleanup_list;
 
   // Concurrent marking support structures
@@ -404,9 +366,6 @@
 
   WorkGang* _parallel_workers;
 
-  ForceOverflowSettings _force_overflow_conc;
-  ForceOverflowSettings _force_overflow_stw;
-
   void weakRefsWorkParallelPart(BoolObjectClosure* is_alive, bool purged_classes);
   void weakRefsWork(bool clear_all_soft_refs);
 
@@ -443,8 +402,6 @@
   uint max_parallel_marking_threads() const { return _max_parallel_marking_threads;}
   double sleep_factor()                     { return _sleep_factor; }
   double marking_task_overhead()            { return _marking_task_overhead;}
-  double cleanup_sleep_factor()             { return _cleanup_sleep_factor; }
-  double cleanup_task_overhead()            { return _cleanup_task_overhead;}
 
   HeapWord*               finger()          { return _finger;   }
   bool                    concurrent()      { return _concurrent; }
@@ -502,22 +459,6 @@
   void enter_first_sync_barrier(uint worker_id);
   void enter_second_sync_barrier(uint worker_id);
 
-  ForceOverflowSettings* force_overflow_conc() {
-    return &_force_overflow_conc;
-  }
-
-  ForceOverflowSettings* force_overflow_stw() {
-    return &_force_overflow_stw;
-  }
-
-  ForceOverflowSettings* force_overflow() {
-    if (concurrent()) {
-      return force_overflow_conc();
-    } else {
-      return force_overflow_stw();
-    }
-  }
-
   // Live Data Counting data structures...
   // These data structures are initialized at the start of
   // marking. They are written to while marking is active.
@@ -625,28 +566,6 @@
                        uint worker_id,
                        HeapRegion* hr = NULL);
 
-  // It iterates over the heap and for each object it comes across it
-  // will dump the contents of its reference fields, as well as
-  // liveness information for the object and its referents. The dump
-  // will be written to a file with the following name:
-  // G1PrintReachableBaseFile + "." + str.
-  // vo decides whether the prev (vo == UsePrevMarking), the next
-  // (vo == UseNextMarking) marking information, or the mark word
-  // (vo == UseMarkWord) will be used to determine the liveness of
-  // each object / referent.
-  // If all is true, all objects in the heap will be dumped, otherwise
-  // only the live ones. In the dump the following symbols / breviations
-  // are used:
-  //   M : an explicitly live object (its bitmap bit is set)
-  //   > : an implicitly live object (over tams)
-  //   O : an object outside the G1 heap (typically: in the perm gen)
-  //   NOT : a reference field whose referent is not live
-  //   AND MARKED : indicates that an object is both explicitly and
-  //   implicitly live (it should be one or the other, not both)
-  void print_reachable(const char* str,
-                       VerifyOption vo,
-                       bool all) PRODUCT_RETURN;
-
   // Clear the next marking bitmap (will be called concurrently).
   void clearNextBitmap();
 
@@ -686,7 +605,6 @@
   // next bitmaps.  NB: the previous bitmap is usually
   // read-only, so use this carefully!
   void clearRangePrevBitmap(MemRegion mr);
-  void clearRangeNextBitmap(MemRegion mr);
 
   // Notify data structures that a GC has started.
   void note_start_of_gc() {
--- a/hotspot/src/share/vm/gc/g1/concurrentMark.inline.hpp	Tue Nov 24 11:49:44 2015 +0000
+++ b/hotspot/src/share/vm/gc/g1/concurrentMark.inline.hpp	Tue Nov 24 15:13:02 2015 -0500
@@ -185,11 +185,6 @@
   return true;
 }
 
-inline bool CMBitMapRO::iterate(BitMapClosure* cl) {
-  MemRegion mr(startWord(), sizeInWords());
-  return iterate(cl, mr);
-}
-
 #define check_mark(addr)                                                       \
   assert(_bmStartWord <= (addr) && (addr) < (_bmStartWord + _bmWordSize),      \
          "outside underlying space?");                                         \
@@ -213,11 +208,6 @@
   return _bm.par_set_bit(heapWordToOffset(addr));
 }
 
-inline bool CMBitMap::parClear(HeapWord* addr) {
-  check_mark(addr);
-  return _bm.par_clear_bit(heapWordToOffset(addr));
-}
-
 #undef check_mark
 
 template<typename Fn>