author | pliden |
Mon, 18 Mar 2019 11:50:39 +0100 | |
changeset 54162 | f344a0c6e19e |
parent 52799 | src/hotspot/share/gc/z/zForwardingTable.cpp@cd19c580ba9c |
child 54163 | 790679f86a51 |
permissions | -rw-r--r-- |
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/* |
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* Copyright (c) 2015, 2019, 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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|
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#include "precompiled.hpp" |
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#include "gc/z/zForwarding.inline.hpp" |
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#include "gc/z/zUtils.inline.hpp" |
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#include "memory/allocation.hpp" |
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#include "utilities/debug.hpp" |
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ZForwarding::ZForwarding(uintptr_t start, size_t object_alignment_shift, uint32_t nentries) : |
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_start(start), |
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_object_alignment_shift(object_alignment_shift), |
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_nentries(nentries), |
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_refcount(1), |
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_pinned(false) {} |
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ZForwarding* ZForwarding::create(uintptr_t start, size_t object_alignment_shift, uint32_t live_objects) { |
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assert(live_objects > 0, "Invalid value"); |
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// Allocate table for linear probing. The size of the table must be |
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// a power of two to allow for quick and inexpensive indexing/masking. |
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// The table is sized to have a load factor of 50%, i.e. sized to have |
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// double the number of entries actually inserted. |
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const uint32_t nentries = ZUtils::round_up_power_of_2(live_objects * 2); |
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const size_t size = sizeof(ZForwarding) + (sizeof(ZForwardingEntry) * nentries); |
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uint8_t* const addr = NEW_C_HEAP_ARRAY(uint8_t, size, mtGC); |
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ZForwardingEntry* const entries = ::new (addr + sizeof(ZForwarding)) ZForwardingEntry[nentries]; |
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ZForwarding* const forwarding = ::new (addr) ZForwarding(start, object_alignment_shift, nentries); |
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return forwarding; |
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} |
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void ZForwarding::destroy(ZForwarding* forwarding) { |
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FREE_C_HEAP_ARRAY(uint8_t, forwarding); |
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} |
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void ZForwarding::verify(uint32_t object_max_count, uint32_t live_objects) const { |
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uint32_t count = 0; |
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for (ZForwardingCursor i = 0; i < _nentries; i++) { |
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const ZForwardingEntry entry = at(&i); |
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if (entry.is_empty()) { |
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// Skip empty entries |
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continue; |
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} |
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// Check from index |
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guarantee(entry.from_index() < object_max_count, "Invalid from index"); |
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// Check for duplicates |
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for (ZForwardingCursor j = i + 1; j < _nentries; j++) { |
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const ZForwardingEntry other = at(&j); |
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guarantee(entry.from_index() != other.from_index(), "Duplicate from"); |
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guarantee(entry.to_offset() != other.to_offset(), "Duplicate to"); |
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} |
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count++; |
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} |
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// Check number of non-null entries |
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guarantee(live_objects == count, "Count mismatch"); |
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} |