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/*
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* Copyright 2001-2007 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*
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*/
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#include "incls/_precompiled.incl"
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#include "incls/_heapRegionSeq.cpp.incl"
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// Local to this file.
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static int orderRegions(HeapRegion** hr1p, HeapRegion** hr2p) {
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if ((*hr1p)->end() <= (*hr2p)->bottom()) return -1;
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else if ((*hr2p)->end() <= (*hr1p)->bottom()) return 1;
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else if (*hr1p == *hr2p) return 0;
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else {
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assert(false, "We should never compare distinct overlapping regions.");
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}
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return 0;
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}
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HeapRegionSeq::HeapRegionSeq() :
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_alloc_search_start(0),
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// The line below is the worst bit of C++ hackery I've ever written
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// (Detlefs, 11/23). You should think of it as equivalent to
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// "_regions(100, true)": initialize the growable array and inform it
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// that it should allocate its elem array(s) on the C heap. The first
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// argument, however, is actually a comma expression (new-expr, 100).
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// The purpose of the new_expr is to inform the growable array that it
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// is *already* allocated on the C heap: it uses the placement syntax to
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// keep it from actually doing any allocation.
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_regions((ResourceObj::operator new (sizeof(GrowableArray<HeapRegion*>),
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(void*)&_regions,
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ResourceObj::C_HEAP),
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100),
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true),
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_next_rr_candidate(0),
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_seq_bottom(NULL)
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{}
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// Private methods.
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HeapWord*
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HeapRegionSeq::alloc_obj_from_region_index(int ind, size_t word_size) {
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assert(G1CollectedHeap::isHumongous(word_size),
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"Allocation size should be humongous");
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int cur = ind;
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int first = cur;
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size_t sumSizes = 0;
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while (cur < _regions.length() && sumSizes < word_size) {
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// Loop invariant:
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// For all i in [first, cur):
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// _regions.at(i)->is_empty()
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// && _regions.at(i) is contiguous with its predecessor, if any
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// && sumSizes is the sum of the sizes of the regions in the interval
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// [first, cur)
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HeapRegion* curhr = _regions.at(cur);
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if (curhr->is_empty()
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&& !curhr->is_reserved()
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&& (first == cur
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|| (_regions.at(cur-1)->end() ==
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curhr->bottom()))) {
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sumSizes += curhr->capacity() / HeapWordSize;
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} else {
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first = cur + 1;
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sumSizes = 0;
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}
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cur++;
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}
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if (sumSizes >= word_size) {
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_alloc_search_start = cur;
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// Mark the allocated regions as allocated.
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bool zf = G1CollectedHeap::heap()->allocs_are_zero_filled();
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HeapRegion* first_hr = _regions.at(first);
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for (int i = first; i < cur; i++) {
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HeapRegion* hr = _regions.at(i);
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if (zf)
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hr->ensure_zero_filled();
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{
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MutexLockerEx x(ZF_mon, Mutex::_no_safepoint_check_flag);
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hr->set_zero_fill_allocated();
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}
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size_t sz = hr->capacity() / HeapWordSize;
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HeapWord* tmp = hr->allocate(sz);
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assert(tmp != NULL, "Humongous allocation failure");
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MemRegion mr = MemRegion(tmp, sz);
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SharedHeap::fill_region_with_object(mr);
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hr->declare_filled_region_to_BOT(mr);
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if (i == first) {
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first_hr->set_startsHumongous();
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} else {
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assert(i > first, "sanity");
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hr->set_continuesHumongous(first_hr);
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}
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}
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HeapWord* first_hr_bot = first_hr->bottom();
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HeapWord* obj_end = first_hr_bot + word_size;
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first_hr->set_top(obj_end);
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return first_hr_bot;
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} else {
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// If we started from the beginning, we want to know why we can't alloc.
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return NULL;
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}
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}
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void HeapRegionSeq::print_empty_runs(bool reserved_are_empty) {
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int empty_run = 0;
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int n_empty = 0;
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bool at_least_one_reserved = false;
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int empty_run_start;
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for (int i = 0; i < _regions.length(); i++) {
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HeapRegion* r = _regions.at(i);
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if (r->continuesHumongous()) continue;
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if (r->is_empty() && (reserved_are_empty || !r->is_reserved())) {
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assert(!r->isHumongous(), "H regions should not be empty.");
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if (empty_run == 0) empty_run_start = i;
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empty_run++;
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n_empty++;
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if (r->is_reserved()) {
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at_least_one_reserved = true;
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}
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} else {
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if (empty_run > 0) {
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gclog_or_tty->print(" %d:%d", empty_run_start, empty_run);
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if (reserved_are_empty && at_least_one_reserved)
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gclog_or_tty->print("(R)");
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empty_run = 0;
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at_least_one_reserved = false;
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}
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}
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}
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if (empty_run > 0) {
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gclog_or_tty->print(" %d:%d", empty_run_start, empty_run);
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if (reserved_are_empty && at_least_one_reserved) gclog_or_tty->print("(R)");
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}
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gclog_or_tty->print_cr(" [tot = %d]", n_empty);
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}
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int HeapRegionSeq::find(HeapRegion* hr) {
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// FIXME: optimized for adjacent regions of fixed size.
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int ind = hr->hrs_index();
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if (ind != -1) {
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assert(_regions.at(ind) == hr, "Mismatch");
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}
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return ind;
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}
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// Public methods.
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void HeapRegionSeq::insert(HeapRegion* hr) {
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if (_regions.length() == 0
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|| _regions.top()->end() <= hr->bottom()) {
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hr->set_hrs_index(_regions.length());
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_regions.append(hr);
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} else {
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_regions.append(hr);
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_regions.sort(orderRegions);
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for (int i = 0; i < _regions.length(); i++) {
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_regions.at(i)->set_hrs_index(i);
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}
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}
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char* bot = (char*)_regions.at(0)->bottom();
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if (_seq_bottom == NULL || bot < _seq_bottom) _seq_bottom = bot;
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}
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size_t HeapRegionSeq::length() {
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return _regions.length();
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}
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size_t HeapRegionSeq::free_suffix() {
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size_t res = 0;
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int first = _regions.length() - 1;
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int cur = first;
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while (cur >= 0 &&
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(_regions.at(cur)->is_empty()
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&& !_regions.at(cur)->is_reserved()
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&& (first == cur
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|| (_regions.at(cur+1)->bottom() ==
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_regions.at(cur)->end())))) {
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res++;
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cur--;
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}
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return res;
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}
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HeapWord* HeapRegionSeq::obj_allocate(size_t word_size) {
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int cur = _alloc_search_start;
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// Make sure "cur" is a valid index.
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assert(cur >= 0, "Invariant.");
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HeapWord* res = alloc_obj_from_region_index(cur, word_size);
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if (res == NULL)
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res = alloc_obj_from_region_index(0, word_size);
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return res;
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}
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void HeapRegionSeq::iterate(HeapRegionClosure* blk) {
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iterate_from((HeapRegion*)NULL, blk);
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}
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// The first argument r is the heap region at which iteration begins.
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// This operation runs fastest when r is NULL, or the heap region for
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// which a HeapRegionClosure most recently returned true, or the
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// heap region immediately to its right in the sequence. In all
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// other cases a linear search is required to find the index of r.
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void HeapRegionSeq::iterate_from(HeapRegion* r, HeapRegionClosure* blk) {
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// :::: FIXME ::::
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// Static cache value is bad, especially when we start doing parallel
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// remembered set update. For now just don't cache anything (the
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// code in the def'd out blocks).
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#if 0
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static int cached_j = 0;
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#endif
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int len = _regions.length();
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int j = 0;
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// Find the index of r.
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if (r != NULL) {
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#if 0
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assert(cached_j >= 0, "Invariant.");
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if ((cached_j < len) && (r == _regions.at(cached_j))) {
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j = cached_j;
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} else if ((cached_j + 1 < len) && (r == _regions.at(cached_j + 1))) {
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j = cached_j + 1;
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} else {
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j = find(r);
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#endif
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if (j < 0) {
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j = 0;
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}
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#if 0
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}
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#endif
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}
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int i;
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for (i = j; i < len; i += 1) {
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int res = blk->doHeapRegion(_regions.at(i));
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if (res) {
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#if 0
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cached_j = i;
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#endif
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blk->incomplete();
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return;
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}
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}
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for (i = 0; i < j; i += 1) {
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int res = blk->doHeapRegion(_regions.at(i));
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if (res) {
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#if 0
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cached_j = i;
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#endif
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blk->incomplete();
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return;
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}
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}
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}
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void HeapRegionSeq::iterate_from(int idx, HeapRegionClosure* blk) {
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int len = _regions.length();
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int i;
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for (i = idx; i < len; i++) {
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if (blk->doHeapRegion(_regions.at(i))) {
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blk->incomplete();
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return;
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}
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}
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for (i = 0; i < idx; i++) {
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if (blk->doHeapRegion(_regions.at(i))) {
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blk->incomplete();
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return;
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}
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}
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}
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MemRegion HeapRegionSeq::shrink_by(size_t shrink_bytes,
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size_t& num_regions_deleted) {
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assert(shrink_bytes % os::vm_page_size() == 0, "unaligned");
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assert(shrink_bytes % HeapRegion::GrainBytes == 0, "unaligned");
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if (_regions.length() == 0) {
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num_regions_deleted = 0;
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return MemRegion();
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}
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int j = _regions.length() - 1;
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HeapWord* end = _regions.at(j)->end();
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HeapWord* last_start = end;
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while (j >= 0 && shrink_bytes > 0) {
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HeapRegion* cur = _regions.at(j);
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// We have to leave humongous regions where they are,
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// and work around them.
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if (cur->isHumongous()) {
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return MemRegion(last_start, end);
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}
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cur->reset_zero_fill();
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assert(cur == _regions.top(), "Should be top");
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if (!cur->is_empty()) break;
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shrink_bytes -= cur->capacity();
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num_regions_deleted++;
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_regions.pop();
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last_start = cur->bottom();
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// We need to delete these somehow, but can't currently do so here: if
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// we do, the ZF thread may still access the deleted region. We'll
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// leave this here as a reminder that we have to do something about
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// this.
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// delete cur;
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j--;
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}
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return MemRegion(last_start, end);
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}
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class PrintHeapRegionClosure : public HeapRegionClosure {
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public:
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bool doHeapRegion(HeapRegion* r) {
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gclog_or_tty->print(PTR_FORMAT ":", r);
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r->print();
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return false;
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}
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};
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void HeapRegionSeq::print() {
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PrintHeapRegionClosure cl;
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iterate(&cl);
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}
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