| /* |
| * Copyright (c) 2010, 2014, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp" |
| #include "gc_implementation/concurrentMarkSweep/promotionInfo.hpp" |
| #include "oops/markOop.inline.hpp" |
| #include "oops/oop.inline.hpp" |
| |
| PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC |
| |
| ///////////////////////////////////////////////////////////////////////// |
| //// PromotionInfo |
| ///////////////////////////////////////////////////////////////////////// |
| |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| // We go over the list of promoted objects, removing each from the list, |
| // and applying the closure (this may, in turn, add more elements to |
| // the tail of the promoted list, and these newly added objects will |
| // also be processed) until the list is empty. |
| // To aid verification and debugging, in the non-product builds |
| // we actually forward _promoHead each time we process a promoted oop. |
| // Note that this is not necessary in general (i.e. when we don't need to |
| // call PromotionInfo::verify()) because oop_iterate can only add to the |
| // end of _promoTail, and never needs to look at _promoHead. |
| |
| #define PROMOTED_OOPS_ITERATE_DEFN(OopClosureType, nv_suffix) \ |
| \ |
| void PromotionInfo::promoted_oops_iterate##nv_suffix(OopClosureType* cl) { \ |
| NOT_PRODUCT(verify()); \ |
| PromotedObject *curObj, *nextObj; \ |
| for (curObj = _promoHead; curObj != NULL; curObj = nextObj) { \ |
| if ((nextObj = curObj->next()) == NULL) { \ |
| /* protect ourselves against additions due to closure application \ |
| below by resetting the list. */ \ |
| assert(_promoTail == curObj, "Should have been the tail"); \ |
| _promoHead = _promoTail = NULL; \ |
| } \ |
| if (curObj->hasDisplacedMark()) { \ |
| /* restore displaced header */ \ |
| oop(curObj)->set_mark(nextDisplacedHeader()); \ |
| } else { \ |
| /* restore prototypical header */ \ |
| oop(curObj)->init_mark(); \ |
| } \ |
| /* The "promoted_mark" should now not be set */ \ |
| assert(!curObj->hasPromotedMark(), \ |
| "Should have been cleared by restoring displaced mark-word"); \ |
| NOT_PRODUCT(_promoHead = nextObj); \ |
| if (cl != NULL) oop(curObj)->oop_iterate(cl); \ |
| if (nextObj == NULL) { /* start at head of list reset above */ \ |
| nextObj = _promoHead; \ |
| } \ |
| } \ |
| assert(noPromotions(), "post-condition violation"); \ |
| assert(_promoHead == NULL && _promoTail == NULL, "emptied promoted list");\ |
| assert(_spoolHead == _spoolTail, "emptied spooling buffers"); \ |
| assert(_firstIndex == _nextIndex, "empty buffer"); \ |
| } |
| |
| // This should have been ALL_SINCE_...() just like the others, |
| // but, because the body of the method above is somehwat longer, |
| // the MSVC compiler cannot cope; as a workaround, we split the |
| // macro into its 3 constituent parts below (see original macro |
| // definition in specializedOopClosures.hpp). |
| SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES_YOUNG(PROMOTED_OOPS_ITERATE_DEFN) |
| PROMOTED_OOPS_ITERATE_DEFN(OopsInGenClosure,_v) |
| |
| |
| // Return the next displaced header, incrementing the pointer and |
| // recycling spool area as necessary. |
| markOop PromotionInfo::nextDisplacedHeader() { |
| assert(_spoolHead != NULL, "promotionInfo inconsistency"); |
| assert(_spoolHead != _spoolTail || _firstIndex < _nextIndex, |
| "Empty spool space: no displaced header can be fetched"); |
| assert(_spoolHead->bufferSize > _firstIndex, "Off by one error at head?"); |
| markOop hdr = _spoolHead->displacedHdr[_firstIndex]; |
| // Spool forward |
| if (++_firstIndex == _spoolHead->bufferSize) { // last location in this block |
| // forward to next block, recycling this block into spare spool buffer |
| SpoolBlock* tmp = _spoolHead->nextSpoolBlock; |
| assert(_spoolHead != _spoolTail, "Spooling storage mix-up"); |
| _spoolHead->nextSpoolBlock = _spareSpool; |
| _spareSpool = _spoolHead; |
| _spoolHead = tmp; |
| _firstIndex = 1; |
| NOT_PRODUCT( |
| if (_spoolHead == NULL) { // all buffers fully consumed |
| assert(_spoolTail == NULL && _nextIndex == 1, |
| "spool buffers processing inconsistency"); |
| } |
| ) |
| } |
| return hdr; |
| } |
| |
| void PromotionInfo::track(PromotedObject* trackOop) { |
| track(trackOop, oop(trackOop)->klass()); |
| } |
| |
| void PromotionInfo::track(PromotedObject* trackOop, Klass* klassOfOop) { |
| // make a copy of header as it may need to be spooled |
| markOop mark = oop(trackOop)->mark(); |
| trackOop->clear_next(); |
| if (mark->must_be_preserved_for_cms_scavenge(klassOfOop)) { |
| // save non-prototypical header, and mark oop |
| saveDisplacedHeader(mark); |
| trackOop->setDisplacedMark(); |
| } else { |
| // we'd like to assert something like the following: |
| // assert(mark == markOopDesc::prototype(), "consistency check"); |
| // ... but the above won't work because the age bits have not (yet) been |
| // cleared. The remainder of the check would be identical to the |
| // condition checked in must_be_preserved() above, so we don't really |
| // have anything useful to check here! |
| } |
| if (_promoTail != NULL) { |
| assert(_promoHead != NULL, "List consistency"); |
| _promoTail->setNext(trackOop); |
| _promoTail = trackOop; |
| } else { |
| assert(_promoHead == NULL, "List consistency"); |
| _promoHead = _promoTail = trackOop; |
| } |
| // Mask as newly promoted, so we can skip over such objects |
| // when scanning dirty cards |
| assert(!trackOop->hasPromotedMark(), "Should not have been marked"); |
| trackOop->setPromotedMark(); |
| } |
| |
| // Save the given displaced header, incrementing the pointer and |
| // obtaining more spool area as necessary. |
| void PromotionInfo::saveDisplacedHeader(markOop hdr) { |
| assert(_spoolHead != NULL && _spoolTail != NULL, |
| "promotionInfo inconsistency"); |
| assert(_spoolTail->bufferSize > _nextIndex, "Off by one error at tail?"); |
| _spoolTail->displacedHdr[_nextIndex] = hdr; |
| // Spool forward |
| if (++_nextIndex == _spoolTail->bufferSize) { // last location in this block |
| // get a new spooling block |
| assert(_spoolTail->nextSpoolBlock == NULL, "tail should terminate spool list"); |
| _splice_point = _spoolTail; // save for splicing |
| _spoolTail->nextSpoolBlock = getSpoolBlock(); // might fail |
| _spoolTail = _spoolTail->nextSpoolBlock; // might become NULL ... |
| // ... but will attempt filling before next promotion attempt |
| _nextIndex = 1; |
| } |
| } |
| |
| // Ensure that spooling space exists. Return false if spooling space |
| // could not be obtained. |
| bool PromotionInfo::ensure_spooling_space_work() { |
| assert(!has_spooling_space(), "Only call when there is no spooling space"); |
| // Try and obtain more spooling space |
| SpoolBlock* newSpool = getSpoolBlock(); |
| assert(newSpool == NULL || |
| (newSpool->bufferSize != 0 && newSpool->nextSpoolBlock == NULL), |
| "getSpoolBlock() sanity check"); |
| if (newSpool == NULL) { |
| return false; |
| } |
| _nextIndex = 1; |
| if (_spoolTail == NULL) { |
| _spoolTail = newSpool; |
| if (_spoolHead == NULL) { |
| _spoolHead = newSpool; |
| _firstIndex = 1; |
| } else { |
| assert(_splice_point != NULL && _splice_point->nextSpoolBlock == NULL, |
| "Splice point invariant"); |
| // Extra check that _splice_point is connected to list |
| #ifdef ASSERT |
| { |
| SpoolBlock* blk = _spoolHead; |
| for (; blk->nextSpoolBlock != NULL; |
| blk = blk->nextSpoolBlock); |
| assert(blk != NULL && blk == _splice_point, |
| "Splice point incorrect"); |
| } |
| #endif // ASSERT |
| _splice_point->nextSpoolBlock = newSpool; |
| } |
| } else { |
| assert(_spoolHead != NULL, "spool list consistency"); |
| _spoolTail->nextSpoolBlock = newSpool; |
| _spoolTail = newSpool; |
| } |
| return true; |
| } |
| |
| // Get a free spool buffer from the free pool, getting a new block |
| // from the heap if necessary. |
| SpoolBlock* PromotionInfo::getSpoolBlock() { |
| SpoolBlock* res; |
| if ((res = _spareSpool) != NULL) { |
| _spareSpool = _spareSpool->nextSpoolBlock; |
| res->nextSpoolBlock = NULL; |
| } else { // spare spool exhausted, get some from heap |
| res = (SpoolBlock*)(space()->allocateScratch(refillSize())); |
| if (res != NULL) { |
| res->init(); |
| } |
| } |
| assert(res == NULL || res->nextSpoolBlock == NULL, "postcondition"); |
| return res; |
| } |
| |
| void PromotionInfo::startTrackingPromotions() { |
| assert(_spoolHead == _spoolTail && _firstIndex == _nextIndex, |
| "spooling inconsistency?"); |
| _firstIndex = _nextIndex = 1; |
| _tracking = true; |
| } |
| |
| #define CMSPrintPromoBlockInfo 1 |
| |
| void PromotionInfo::stopTrackingPromotions(uint worker_id) { |
| assert(_spoolHead == _spoolTail && _firstIndex == _nextIndex, |
| "spooling inconsistency?"); |
| _firstIndex = _nextIndex = 1; |
| _tracking = false; |
| if (CMSPrintPromoBlockInfo > 1) { |
| print_statistics(worker_id); |
| } |
| } |
| |
| void PromotionInfo::print_statistics(uint worker_id) const { |
| assert(_spoolHead == _spoolTail && _firstIndex == _nextIndex, |
| "Else will undercount"); |
| assert(CMSPrintPromoBlockInfo > 0, "Else unnecessary call"); |
| // Count the number of blocks and slots in the free pool |
| size_t slots = 0; |
| size_t blocks = 0; |
| for (SpoolBlock* cur_spool = _spareSpool; |
| cur_spool != NULL; |
| cur_spool = cur_spool->nextSpoolBlock) { |
| // the first entry is just a self-pointer; indices 1 through |
| // bufferSize - 1 are occupied (thus, bufferSize - 1 slots). |
| assert((void*)cur_spool->displacedHdr == (void*)&cur_spool->displacedHdr, |
| "first entry of displacedHdr should be self-referential"); |
| slots += cur_spool->bufferSize - 1; |
| blocks++; |
| } |
| if (_spoolHead != NULL) { |
| slots += _spoolHead->bufferSize - 1; |
| blocks++; |
| } |
| gclog_or_tty->print_cr(" [worker %d] promo_blocks = %d, promo_slots = %d ", |
| worker_id, blocks, slots); |
| } |
| |
| // When _spoolTail is not NULL, then the slot <_spoolTail, _nextIndex> |
| // points to the next slot available for filling. |
| // The set of slots holding displaced headers are then all those in the |
| // right-open interval denoted by: |
| // |
| // [ <_spoolHead, _firstIndex>, <_spoolTail, _nextIndex> ) |
| // |
| // When _spoolTail is NULL, then the set of slots with displaced headers |
| // is all those starting at the slot <_spoolHead, _firstIndex> and |
| // going up to the last slot of last block in the linked list. |
| // In this lartter case, _splice_point points to the tail block of |
| // this linked list of blocks holding displaced headers. |
| void PromotionInfo::verify() const { |
| // Verify the following: |
| // 1. the number of displaced headers matches the number of promoted |
| // objects that have displaced headers |
| // 2. each promoted object lies in this space |
| debug_only( |
| PromotedObject* junk = NULL; |
| assert(junk->next_addr() == (void*)(oop(junk)->mark_addr()), |
| "Offset of PromotedObject::_next is expected to align with " |
| " the OopDesc::_mark within OopDesc"); |
| ) |
| // FIXME: guarantee???? |
| guarantee(_spoolHead == NULL || _spoolTail != NULL || |
| _splice_point != NULL, "list consistency"); |
| guarantee(_promoHead == NULL || _promoTail != NULL, "list consistency"); |
| // count the number of objects with displaced headers |
| size_t numObjsWithDisplacedHdrs = 0; |
| for (PromotedObject* curObj = _promoHead; curObj != NULL; curObj = curObj->next()) { |
| guarantee(space()->is_in_reserved((HeapWord*)curObj), "Containment"); |
| // the last promoted object may fail the mark() != NULL test of is_oop(). |
| guarantee(curObj->next() == NULL || oop(curObj)->is_oop(), "must be an oop"); |
| if (curObj->hasDisplacedMark()) { |
| numObjsWithDisplacedHdrs++; |
| } |
| } |
| // Count the number of displaced headers |
| size_t numDisplacedHdrs = 0; |
| for (SpoolBlock* curSpool = _spoolHead; |
| curSpool != _spoolTail && curSpool != NULL; |
| curSpool = curSpool->nextSpoolBlock) { |
| // the first entry is just a self-pointer; indices 1 through |
| // bufferSize - 1 are occupied (thus, bufferSize - 1 slots). |
| guarantee((void*)curSpool->displacedHdr == (void*)&curSpool->displacedHdr, |
| "first entry of displacedHdr should be self-referential"); |
| numDisplacedHdrs += curSpool->bufferSize - 1; |
| } |
| guarantee((_spoolHead == _spoolTail) == (numDisplacedHdrs == 0), |
| "internal consistency"); |
| guarantee(_spoolTail != NULL || _nextIndex == 1, |
| "Inconsistency between _spoolTail and _nextIndex"); |
| // We overcounted (_firstIndex-1) worth of slots in block |
| // _spoolHead and we undercounted (_nextIndex-1) worth of |
| // slots in block _spoolTail. We make an appropriate |
| // adjustment by subtracting the first and adding the |
| // second: - (_firstIndex - 1) + (_nextIndex - 1) |
| numDisplacedHdrs += (_nextIndex - _firstIndex); |
| guarantee(numDisplacedHdrs == numObjsWithDisplacedHdrs, "Displaced hdr count"); |
| } |
| |
| void PromotionInfo::print_on(outputStream* st) const { |
| SpoolBlock* curSpool = NULL; |
| size_t i = 0; |
| st->print_cr(" start & end indices: [" SIZE_FORMAT ", " SIZE_FORMAT ")", |
| _firstIndex, _nextIndex); |
| for (curSpool = _spoolHead; curSpool != _spoolTail && curSpool != NULL; |
| curSpool = curSpool->nextSpoolBlock) { |
| curSpool->print_on(st); |
| st->print_cr(" active "); |
| i++; |
| } |
| for (curSpool = _spoolTail; curSpool != NULL; |
| curSpool = curSpool->nextSpoolBlock) { |
| curSpool->print_on(st); |
| st->print_cr(" inactive "); |
| i++; |
| } |
| for (curSpool = _spareSpool; curSpool != NULL; |
| curSpool = curSpool->nextSpoolBlock) { |
| curSpool->print_on(st); |
| st->print_cr(" free "); |
| i++; |
| } |
| st->print_cr(" " SIZE_FORMAT " header spooling blocks", i); |
| } |
| |
| void SpoolBlock::print_on(outputStream* st) const { |
| st->print("[" PTR_FORMAT "," PTR_FORMAT "), " SIZE_FORMAT " HeapWords -> " PTR_FORMAT, |
| this, (HeapWord*)displacedHdr + bufferSize, |
| bufferSize, nextSpoolBlock); |
| } |
