author | ysr |
Mon, 17 May 2010 00:47:28 -0700 | |
changeset 5541 | 19c39d42a747 |
parent 5434 | a2e785749780 |
child 5547 | f4b087cbb361 |
permissions | -rw-r--r-- |
5434 | 1 |
/* |
5541
19c39d42a747
6948539: CMS+UseCompressedOops: placement of cms_free bit interferes with promoted object link
ysr
parents:
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diff
changeset
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* Copyright 2010 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/_promotionInfo.cpp.incl" |
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///////////////////////////////////////////////////////////////////////// |
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//// PromotionInfo |
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///////////////////////////////////////////////////////////////////////// |
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////////////////////////////////////////////////////////////////////////////// |
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// We go over the list of promoted objects, removing each from the list, |
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// and applying the closure (this may, in turn, add more elements to |
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// the tail of the promoted list, and these newly added objects will |
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// also be processed) until the list is empty. |
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// To aid verification and debugging, in the non-product builds |
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// we actually forward _promoHead each time we process a promoted oop. |
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// Note that this is not necessary in general (i.e. when we don't need to |
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// call PromotionInfo::verify()) because oop_iterate can only add to the |
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// end of _promoTail, and never needs to look at _promoHead. |
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#define PROMOTED_OOPS_ITERATE_DEFN(OopClosureType, nv_suffix) \ |
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\ |
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void PromotionInfo::promoted_oops_iterate##nv_suffix(OopClosureType* cl) { \ |
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NOT_PRODUCT(verify()); \ |
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PromotedObject *curObj, *nextObj; \ |
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for (curObj = _promoHead; curObj != NULL; curObj = nextObj) { \ |
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if ((nextObj = curObj->next()) == NULL) { \ |
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/* protect ourselves against additions due to closure application \ |
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below by resetting the list. */ \ |
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assert(_promoTail == curObj, "Should have been the tail"); \ |
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_promoHead = _promoTail = NULL; \ |
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} \ |
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if (curObj->hasDisplacedMark()) { \ |
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/* restore displaced header */ \ |
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oop(curObj)->set_mark(nextDisplacedHeader()); \ |
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} else { \ |
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/* restore prototypical header */ \ |
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oop(curObj)->init_mark(); \ |
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} \ |
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/* The "promoted_mark" should now not be set */ \ |
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assert(!curObj->hasPromotedMark(), \ |
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"Should have been cleared by restoring displaced mark-word"); \ |
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NOT_PRODUCT(_promoHead = nextObj); \ |
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if (cl != NULL) oop(curObj)->oop_iterate(cl); \ |
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if (nextObj == NULL) { /* start at head of list reset above */ \ |
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nextObj = _promoHead; \ |
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} \ |
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} \ |
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assert(noPromotions(), "post-condition violation"); \ |
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assert(_promoHead == NULL && _promoTail == NULL, "emptied promoted list");\ |
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assert(_spoolHead == _spoolTail, "emptied spooling buffers"); \ |
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assert(_firstIndex == _nextIndex, "empty buffer"); \ |
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} |
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// This should have been ALL_SINCE_...() just like the others, |
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// but, because the body of the method above is somehwat longer, |
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// the MSVC compiler cannot cope; as a workaround, we split the |
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// macro into its 3 constituent parts below (see original macro |
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// definition in specializedOopClosures.hpp). |
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SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES_YOUNG(PROMOTED_OOPS_ITERATE_DEFN) |
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PROMOTED_OOPS_ITERATE_DEFN(OopsInGenClosure,_v) |
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// Return the next displaced header, incrementing the pointer and |
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// recycling spool area as necessary. |
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markOop PromotionInfo::nextDisplacedHeader() { |
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assert(_spoolHead != NULL, "promotionInfo inconsistency"); |
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assert(_spoolHead != _spoolTail || _firstIndex < _nextIndex, |
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"Empty spool space: no displaced header can be fetched"); |
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assert(_spoolHead->bufferSize > _firstIndex, "Off by one error at head?"); |
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markOop hdr = _spoolHead->displacedHdr[_firstIndex]; |
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// Spool forward |
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if (++_firstIndex == _spoolHead->bufferSize) { // last location in this block |
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// forward to next block, recycling this block into spare spool buffer |
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SpoolBlock* tmp = _spoolHead->nextSpoolBlock; |
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assert(_spoolHead != _spoolTail, "Spooling storage mix-up"); |
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_spoolHead->nextSpoolBlock = _spareSpool; |
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_spareSpool = _spoolHead; |
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_spoolHead = tmp; |
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_firstIndex = 1; |
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NOT_PRODUCT( |
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if (_spoolHead == NULL) { // all buffers fully consumed |
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assert(_spoolTail == NULL && _nextIndex == 1, |
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"spool buffers processing inconsistency"); |
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} |
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) |
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} |
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return hdr; |
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} |
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void PromotionInfo::track(PromotedObject* trackOop) { |
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track(trackOop, oop(trackOop)->klass()); |
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} |
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void PromotionInfo::track(PromotedObject* trackOop, klassOop klassOfOop) { |
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// make a copy of header as it may need to be spooled |
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markOop mark = oop(trackOop)->mark(); |
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trackOop->clearNext(); |
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if (mark->must_be_preserved_for_cms_scavenge(klassOfOop)) { |
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// save non-prototypical header, and mark oop |
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saveDisplacedHeader(mark); |
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trackOop->setDisplacedMark(); |
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} else { |
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// we'd like to assert something like the following: |
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// assert(mark == markOopDesc::prototype(), "consistency check"); |
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// ... but the above won't work because the age bits have not (yet) been |
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// cleared. The remainder of the check would be identical to the |
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// condition checked in must_be_preserved() above, so we don't really |
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// have anything useful to check here! |
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} |
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if (_promoTail != NULL) { |
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assert(_promoHead != NULL, "List consistency"); |
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_promoTail->setNext(trackOop); |
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_promoTail = trackOop; |
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} else { |
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assert(_promoHead == NULL, "List consistency"); |
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_promoHead = _promoTail = trackOop; |
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} |
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// Mask as newly promoted, so we can skip over such objects |
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// when scanning dirty cards |
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assert(!trackOop->hasPromotedMark(), "Should not have been marked"); |
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trackOop->setPromotedMark(); |
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} |
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// Save the given displaced header, incrementing the pointer and |
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// obtaining more spool area as necessary. |
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void PromotionInfo::saveDisplacedHeader(markOop hdr) { |
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assert(_spoolHead != NULL && _spoolTail != NULL, |
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"promotionInfo inconsistency"); |
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assert(_spoolTail->bufferSize > _nextIndex, "Off by one error at tail?"); |
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_spoolTail->displacedHdr[_nextIndex] = hdr; |
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// Spool forward |
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if (++_nextIndex == _spoolTail->bufferSize) { // last location in this block |
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// get a new spooling block |
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assert(_spoolTail->nextSpoolBlock == NULL, "tail should terminate spool list"); |
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_splice_point = _spoolTail; // save for splicing |
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_spoolTail->nextSpoolBlock = getSpoolBlock(); // might fail |
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_spoolTail = _spoolTail->nextSpoolBlock; // might become NULL ... |
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// ... but will attempt filling before next promotion attempt |
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_nextIndex = 1; |
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} |
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} |
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// Ensure that spooling space exists. Return false if spooling space |
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// could not be obtained. |
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bool PromotionInfo::ensure_spooling_space_work() { |
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assert(!has_spooling_space(), "Only call when there is no spooling space"); |
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// Try and obtain more spooling space |
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SpoolBlock* newSpool = getSpoolBlock(); |
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assert(newSpool == NULL || |
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(newSpool->bufferSize != 0 && newSpool->nextSpoolBlock == NULL), |
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"getSpoolBlock() sanity check"); |
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if (newSpool == NULL) { |
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return false; |
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} |
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_nextIndex = 1; |
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if (_spoolTail == NULL) { |
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_spoolTail = newSpool; |
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if (_spoolHead == NULL) { |
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_spoolHead = newSpool; |
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_firstIndex = 1; |
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} else { |
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assert(_splice_point != NULL && _splice_point->nextSpoolBlock == NULL, |
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"Splice point invariant"); |
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// Extra check that _splice_point is connected to list |
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#ifdef ASSERT |
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{ |
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SpoolBlock* blk = _spoolHead; |
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for (; blk->nextSpoolBlock != NULL; |
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blk = blk->nextSpoolBlock); |
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assert(blk != NULL && blk == _splice_point, |
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"Splice point incorrect"); |
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} |
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#endif // ASSERT |
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_splice_point->nextSpoolBlock = newSpool; |
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} |
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} else { |
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assert(_spoolHead != NULL, "spool list consistency"); |
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_spoolTail->nextSpoolBlock = newSpool; |
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_spoolTail = newSpool; |
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} |
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return true; |
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} |
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// Get a free spool buffer from the free pool, getting a new block |
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// from the heap if necessary. |
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SpoolBlock* PromotionInfo::getSpoolBlock() { |
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SpoolBlock* res; |
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if ((res = _spareSpool) != NULL) { |
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_spareSpool = _spareSpool->nextSpoolBlock; |
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res->nextSpoolBlock = NULL; |
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} else { // spare spool exhausted, get some from heap |
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res = (SpoolBlock*)(space()->allocateScratch(refillSize())); |
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if (res != NULL) { |
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res->init(); |
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} |
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} |
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assert(res == NULL || res->nextSpoolBlock == NULL, "postcondition"); |
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return res; |
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} |
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void PromotionInfo::startTrackingPromotions() { |
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assert(_spoolHead == _spoolTail && _firstIndex == _nextIndex, |
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"spooling inconsistency?"); |
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_firstIndex = _nextIndex = 1; |
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_tracking = true; |
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} |
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#define CMSPrintPromoBlockInfo 1 |
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void PromotionInfo::stopTrackingPromotions(uint worker_id) { |
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assert(_spoolHead == _spoolTail && _firstIndex == _nextIndex, |
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"spooling inconsistency?"); |
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_firstIndex = _nextIndex = 1; |
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_tracking = false; |
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if (CMSPrintPromoBlockInfo > 1) { |
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print_statistics(worker_id); |
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} |
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} |
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void PromotionInfo::print_statistics(uint worker_id) const { |
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assert(_spoolHead == _spoolTail && _firstIndex == _nextIndex, |
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"Else will undercount"); |
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assert(CMSPrintPromoBlockInfo > 0, "Else unnecessary call"); |
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// Count the number of blocks and slots in the free pool |
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size_t slots = 0; |
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size_t blocks = 0; |
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for (SpoolBlock* cur_spool = _spareSpool; |
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cur_spool != NULL; |
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cur_spool = cur_spool->nextSpoolBlock) { |
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// the first entry is just a self-pointer; indices 1 through |
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// bufferSize - 1 are occupied (thus, bufferSize - 1 slots). |
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guarantee((void*)cur_spool->displacedHdr == (void*)&cur_spool->displacedHdr, |
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"first entry of displacedHdr should be self-referential"); |
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slots += cur_spool->bufferSize - 1; |
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blocks++; |
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} |
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if (_spoolHead != NULL) { |
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slots += _spoolHead->bufferSize - 1; |
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blocks++; |
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} |
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gclog_or_tty->print_cr(" [worker %d] promo_blocks = %d, promo_slots = %d ", |
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worker_id, blocks, slots); |
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} |
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// When _spoolTail is not NULL, then the slot <_spoolTail, _nextIndex> |
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// points to the next slot available for filling. |
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// The set of slots holding displaced headers are then all those in the |
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// right-open interval denoted by: |
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// |
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// [ <_spoolHead, _firstIndex>, <_spoolTail, _nextIndex> ) |
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// |
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// When _spoolTail is NULL, then the set of slots with displaced headers |
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// is all those starting at the slot <_spoolHead, _firstIndex> and |
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// going up to the last slot of last block in the linked list. |
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// In this lartter case, _splice_point points to the tail block of |
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// this linked list of blocks holding displaced headers. |
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void PromotionInfo::verify() const { |
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// Verify the following: |
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// 1. the number of displaced headers matches the number of promoted |
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// objects that have displaced headers |
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// 2. each promoted object lies in this space |
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debug_only( |
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PromotedObject* junk = NULL; |
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assert(junk->next_addr() == (void*)(oop(junk)->mark_addr()), |
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"Offset of PromotedObject::_next is expected to align with " |
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" the OopDesc::_mark within OopDesc"); |
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) |
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// FIXME: guarantee???? |
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guarantee(_spoolHead == NULL || _spoolTail != NULL || |
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_splice_point != NULL, "list consistency"); |
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guarantee(_promoHead == NULL || _promoTail != NULL, "list consistency"); |
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// count the number of objects with displaced headers |
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size_t numObjsWithDisplacedHdrs = 0; |
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for (PromotedObject* curObj = _promoHead; curObj != NULL; curObj = curObj->next()) { |
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guarantee(space()->is_in_reserved((HeapWord*)curObj), "Containment"); |
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// the last promoted object may fail the mark() != NULL test of is_oop(). |
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guarantee(curObj->next() == NULL || oop(curObj)->is_oop(), "must be an oop"); |
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if (curObj->hasDisplacedMark()) { |
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numObjsWithDisplacedHdrs++; |
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} |
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} |
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// Count the number of displaced headers |
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size_t numDisplacedHdrs = 0; |
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for (SpoolBlock* curSpool = _spoolHead; |
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curSpool != _spoolTail && curSpool != NULL; |
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curSpool = curSpool->nextSpoolBlock) { |
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// the first entry is just a self-pointer; indices 1 through |
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// bufferSize - 1 are occupied (thus, bufferSize - 1 slots). |
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guarantee((void*)curSpool->displacedHdr == (void*)&curSpool->displacedHdr, |
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"first entry of displacedHdr should be self-referential"); |
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numDisplacedHdrs += curSpool->bufferSize - 1; |
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} |
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guarantee((_spoolHead == _spoolTail) == (numDisplacedHdrs == 0), |
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"internal consistency"); |
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guarantee(_spoolTail != NULL || _nextIndex == 1, |
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"Inconsistency between _spoolTail and _nextIndex"); |
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// We overcounted (_firstIndex-1) worth of slots in block |
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// _spoolHead and we undercounted (_nextIndex-1) worth of |
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// slots in block _spoolTail. We make an appropriate |
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// adjustment by subtracting the first and adding the |
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// second: - (_firstIndex - 1) + (_nextIndex - 1) |
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numDisplacedHdrs += (_nextIndex - _firstIndex); |
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guarantee(numDisplacedHdrs == numObjsWithDisplacedHdrs, "Displaced hdr count"); |
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} |
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void PromotionInfo::print_on(outputStream* st) const { |
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SpoolBlock* curSpool = NULL; |
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size_t i = 0; |
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st->print_cr("start & end indices: [" SIZE_FORMAT ", " SIZE_FORMAT ")", |
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_firstIndex, _nextIndex); |
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for (curSpool = _spoolHead; curSpool != _spoolTail && curSpool != NULL; |
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curSpool = curSpool->nextSpoolBlock) { |
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curSpool->print_on(st); |
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st->print_cr(" active "); |
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i++; |
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340 |
} |
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for (curSpool = _spoolTail; curSpool != NULL; |
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curSpool = curSpool->nextSpoolBlock) { |
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curSpool->print_on(st); |
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st->print_cr(" inactive "); |
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i++; |
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} |
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347 |
for (curSpool = _spareSpool; curSpool != NULL; |
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curSpool = curSpool->nextSpoolBlock) { |
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349 |
curSpool->print_on(st); |
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350 |
st->print_cr(" free "); |
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i++; |
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352 |
} |
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st->print_cr(SIZE_FORMAT " header spooling blocks", i); |
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354 |
} |
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356 |
void SpoolBlock::print_on(outputStream* st) const { |
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st->print("[" PTR_FORMAT "," PTR_FORMAT "), " SIZE_FORMAT " HeapWords -> " PTR_FORMAT, |
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this, (HeapWord*)displacedHdr + bufferSize, |
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bufferSize, nextSpoolBlock); |
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} |