src/hotspot/share/gc/z/zBitMap.inline.hpp
author pliden
Tue, 12 Jun 2018 17:40:28 +0200
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8204210: Implementation: JEP 333: ZGC: A Scalable Low-Latency Garbage Collector (Experimental) Reviewed-by: pliden, stefank, eosterlund, ehelin, sjohanss, rbackman, coleenp, ihse, jgeorge, lmesnik, rkennke Contributed-by: per.liden@oracle.com, stefan.karlsson@oracle.com, erik.osterlund@oracle.com, mikael.gerdin@oracle.com, kim.barrett@oracle.com, nils.eliasson@oracle.com, rickard.backman@oracle.com, rwestrel@redhat.com, coleen.phillimore@oracle.com, robbin.ehn@oracle.com, gerard.ziemski@oracle.com, hugh.wilkinson@intel.com, sandhya.viswanathan@intel.com, bill.npo.wheeler@intel.com, vinay.k.awasthi@intel.com, yasuenag@gmail.com
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/*
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 * Copyright (c) 2016, 2017, Oracle and/or its affiliates. All rights reserved.
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
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 * This code is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License version 2 only, as
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 * published by the Free Software Foundation.
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 *
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * accompanied this code).
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 *
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 * You should have received a copy of the GNU General Public License version
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 *
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * or visit www.oracle.com if you need additional information or have any
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 * questions.
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 */
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#ifndef SHARE_GC_Z_ZBITMAP_INLINE_HPP
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#define SHARE_GC_Z_ZBITMAP_INLINE_HPP
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#include "gc/z/zBitMap.hpp"
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#include "runtime/atomic.hpp"
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#include "utilities/bitMap.inline.hpp"
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#include "utilities/debug.hpp"
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inline ZBitMap::ZBitMap(idx_t size_in_bits) :
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    CHeapBitMap(size_in_bits, mtGC, false /* clear */) {}
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inline BitMap::bm_word_t ZBitMap::bit_mask_pair(idx_t bit) {
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  assert(bit_in_word(bit) < BitsPerWord - 1, "Invalid bit index");
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  return (bm_word_t)3 << bit_in_word(bit);
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}
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inline bool ZBitMap::par_set_bit_pair_finalizable(idx_t bit, bool& inc_live) {
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  inc_live = par_set_bit(bit);
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  return inc_live;
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}
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inline bool ZBitMap::par_set_bit_pair_strong(idx_t bit, bool& inc_live) {
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  verify_index(bit);
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  volatile bm_word_t* const addr = word_addr(bit);
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  const bm_word_t pair_mask = bit_mask_pair(bit);
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  bm_word_t old_val = *addr;
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  do {
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    const bm_word_t new_val = old_val | pair_mask;
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    if (new_val == old_val) {
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      inc_live = false;
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      return false;     // Someone else beat us to it.
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    }
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    const bm_word_t cur_val = Atomic::cmpxchg(new_val, addr, old_val);
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    if (cur_val == old_val) {
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      const bm_word_t marked_mask = bit_mask(bit);
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      inc_live = !(old_val & marked_mask);
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      return true;      // Success.
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    }
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    old_val = cur_val;  // The value changed, try again.
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  } while (true);
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}
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inline bool ZBitMap::par_set_bit_pair(idx_t bit, bool finalizable, bool& inc_live) {
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  if (finalizable) {
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    return par_set_bit_pair_finalizable(bit, inc_live);
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  } else {
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    return par_set_bit_pair_strong(bit, inc_live);
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  }
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}
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#endif // SHARE_GC_Z_ZBITMAP_INLINE_HPP