src/share/vm/gc_implementation/g1/g1CodeCacheRemSet.cpp

*** 28,54 ****
  #include "gc_implementation/g1/g1CodeCacheRemSet.hpp"
  #include "memory/iterator.hpp"
  
  PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
  
! G1CodeRootChunk::G1CodeRootChunk() : _top(NULL), _next(NULL), _prev(NULL) {
    _top = bottom();
  }
  
  void G1CodeRootChunk::reset() {
    _next = _prev = NULL;
    _top = bottom();
  }
  
  void G1CodeRootChunk::nmethods_do(CodeBlobClosure* cl) {
!   nmethod** cur = bottom();
    while (cur != _top) {
!     cl->do_code_blob(*cur);
      cur++;
    }
  }
  
  G1CodeRootChunkManager::G1CodeRootChunkManager() : _free_list(), _num_chunks_handed_out(0) {
    _free_list.initialize();
    _free_list.set_size(G1CodeRootChunk::word_size());
  }
  
--- 28,83 ----
  #include "gc_implementation/g1/g1CodeCacheRemSet.hpp"
  #include "memory/iterator.hpp"
  
  PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
  
! G1CodeRootChunk::G1CodeRootChunk() : _top(NULL), _next(NULL), _prev(NULL), _free(NULL) {
    _top = bottom();
  }
  
  void G1CodeRootChunk::reset() {
    _next = _prev = NULL;
+   _free = NULL;
    _top = bottom();
  }
  
  void G1CodeRootChunk::nmethods_do(CodeBlobClosure* cl) {
!   NmethodOrLink* cur = bottom();
    while (cur != _top) {
!     if (is_nmethod(cur)) {
!       cl->do_code_blob(cur->_nmethod);
!     }
      cur++;
    }
  }
  
+ bool G1CodeRootChunk::remove_lock_free(nmethod* method) {
+   NmethodOrLink* cur = bottom();
+ 
+   for (NmethodOrLink* cur = bottom(); cur != _top; cur++) {
+     if (cur->_nmethod == method) {
+       bool result = Atomic::cmpxchg_ptr(NULL, &cur->_nmethod, method) == method;
+ 
+       if (!result) {
+         // Someone else cleared out this entry.
+         return false;
+       }
+ 
+       // The method was cleared. Time to link it into the free list.
+       NmethodOrLink* prev_free;
+       do {
+         prev_free = (NmethodOrLink*)_free;
+         cur->_link = prev_free;
+       } while (Atomic::cmpxchg_ptr(cur, &_free, prev_free) != prev_free);
+ 
+       return true;
+     }
+   }
+ 
+   return false;
+ }
+ 
  G1CodeRootChunkManager::G1CodeRootChunkManager() : _free_list(), _num_chunks_handed_out(0) {
    _free_list.initialize();
    _free_list.set_size(G1CodeRootChunk::word_size());
  }
  
*** 138,175 ****
    clear();
  }
  
  void G1CodeRootSet::add(nmethod* method) {
    if (!contains(method)) {
!     // Try to add the nmethod. If there is not enough space, get a new chunk.
!     if (_list.head() == NULL || _list.head()->is_full()) {
!       G1CodeRootChunk* cur = new_chunk();
        _list.return_chunk_at_head(cur);
      }
!     bool result = _list.head()->add(method);
      guarantee(result, err_msg("Not able to add nmethod "PTR_FORMAT" to newly allocated chunk.", method));
      _length++;
    }
  }
  
! void G1CodeRootSet::remove(nmethod* method) {
    G1CodeRootChunk* found = find(method);
    if (found != NULL) {
!     bool result = found->remove(method);
!     guarantee(result, err_msg("could not find nmethod "PTR_FORMAT" during removal although we previously found it", method));
!     // eventually free completely emptied chunk
!     if (found->is_empty()) {
!       _list.remove_chunk(found);
!       free(found);
      }
-     _length--;
    }
    assert(!contains(method), err_msg(PTR_FORMAT" still contains nmethod "PTR_FORMAT, this, method));
  }
  
  nmethod* G1CodeRootSet::pop() {
!   do {
      G1CodeRootChunk* cur = _list.head();
      if (cur == NULL) {
        assert(_length == 0, "when there are no chunks, there should be no elements");
        return NULL;
      }
--- 167,213 ----
    clear();
  }
  
  void G1CodeRootSet::add(nmethod* method) {
    if (!contains(method)) {
!     // Find the first chunk thatisn't full.
!     G1CodeRootChunk* cur = _list.head();
!     while (cur != NULL) {
!       if (!cur->is_full()) {
!         break;
!       }
!       cur = cur->next();
!     }
! 
!     // All chunks are full, get a new chunk.
!     if (cur == NULL) {
!       cur = new_chunk();
        _list.return_chunk_at_head(cur);
      }
! 
!     // Add the nmethod.
!     bool result = cur->add(method);
! 
      guarantee(result, err_msg("Not able to add nmethod "PTR_FORMAT" to newly allocated chunk.", method));
+ 
      _length++;
    }
  }
  
! void G1CodeRootSet::remove_lock_free(nmethod* method) {
    G1CodeRootChunk* found = find(method);
    if (found != NULL) {
!     bool result = found->remove_lock_free(method);
!     if (result) {
!       Atomic::dec_ptr((volatile intptr_t*)&_length);
      }
    }
    assert(!contains(method), err_msg(PTR_FORMAT" still contains nmethod "PTR_FORMAT, this, method));
  }
  
  nmethod* G1CodeRootSet::pop() {
!   while (true) {
      G1CodeRootChunk* cur = _list.head();
      if (cur == NULL) {
        assert(_length == 0, "when there are no chunks, there should be no elements");
        return NULL;
      }
*** 178,188 ****
        _length--;
        return result;
      } else {
        free(_list.get_chunk_at_head());
      }
!   } while (true);
  }
  
  G1CodeRootChunk* G1CodeRootSet::find(nmethod* method) {
    G1CodeRootChunk* cur = _list.head();
    while (cur != NULL) {
--- 216,226 ----
        _length--;
        return result;
      } else {
        free(_list.get_chunk_at_head());
      }
!   }
  }
  
  G1CodeRootChunk* G1CodeRootSet::find(nmethod* method) {
    G1CodeRootChunk* cur = _list.head();
    while (cur != NULL) {