author | kvn |
Thu, 27 May 2010 18:01:56 -0700 | |
changeset 5694 | 1e0532a6abff |
parent 2131 | 98f9cef66a34 |
child 5547 | f4b087cbb361 |
permissions | -rw-r--r-- |
1 | 1 |
/* |
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* Copyright 2001-2008 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/_cardTableExtension.cpp.incl" |
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// Checks an individual oop for missing precise marks. Mark |
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// may be either dirty or newgen. |
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class CheckForUnmarkedOops : public OopClosure { |
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private: |
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PSYoungGen* _young_gen; |
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CardTableExtension* _card_table; |
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HeapWord* _unmarked_addr; |
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jbyte* _unmarked_card; |
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protected: |
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template <class T> void do_oop_work(T* p) { |
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oop obj = oopDesc::load_decode_heap_oop_not_null(p); |
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if (_young_gen->is_in_reserved(obj) && |
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!_card_table->addr_is_marked_imprecise(p)) { |
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// Don't overwrite the first missing card mark |
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if (_unmarked_addr == NULL) { |
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_unmarked_addr = (HeapWord*)p; |
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_unmarked_card = _card_table->byte_for(p); |
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} |
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} |
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} |
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public: |
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CheckForUnmarkedOops(PSYoungGen* young_gen, CardTableExtension* card_table) : |
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_young_gen(young_gen), _card_table(card_table), _unmarked_addr(NULL) { } |
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virtual void do_oop(oop* p) { CheckForUnmarkedOops::do_oop_work(p); } |
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virtual void do_oop(narrowOop* p) { CheckForUnmarkedOops::do_oop_work(p); } |
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bool has_unmarked_oop() { |
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return _unmarked_addr != NULL; |
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} |
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}; |
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// Checks all objects for the existance of some type of mark, |
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// precise or imprecise, dirty or newgen. |
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class CheckForUnmarkedObjects : public ObjectClosure { |
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private: |
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PSYoungGen* _young_gen; |
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CardTableExtension* _card_table; |
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public: |
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CheckForUnmarkedObjects() { |
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ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
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assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
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_young_gen = heap->young_gen(); |
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_card_table = (CardTableExtension*)heap->barrier_set(); |
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// No point in asserting barrier set type here. Need to make CardTableExtension |
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// a unique barrier set type. |
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} |
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// Card marks are not precise. The current system can leave us with |
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// a mismash of precise marks and beginning of object marks. This means |
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// we test for missing precise marks first. If any are found, we don't |
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// fail unless the object head is also unmarked. |
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virtual void do_object(oop obj) { |
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CheckForUnmarkedOops object_check(_young_gen, _card_table); |
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obj->oop_iterate(&object_check); |
87 |
if (object_check.has_unmarked_oop()) { |
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assert(_card_table->addr_is_marked_imprecise(obj), "Found unmarked young_gen object"); |
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} |
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} |
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}; |
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// Checks for precise marking of oops as newgen. |
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class CheckForPreciseMarks : public OopClosure { |
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private: |
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PSYoungGen* _young_gen; |
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CardTableExtension* _card_table; |
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protected: |
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template <class T> void do_oop_work(T* p) { |
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oop obj = oopDesc::load_decode_heap_oop_not_null(p); |
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if (_young_gen->is_in_reserved(obj)) { |
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assert(_card_table->addr_is_marked_precise(p), "Found unmarked precise oop"); |
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_card_table->set_card_newgen(p); |
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} |
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} |
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public: |
109 |
CheckForPreciseMarks( PSYoungGen* young_gen, CardTableExtension* card_table ) : |
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_young_gen(young_gen), _card_table(card_table) { } |
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virtual void do_oop(oop* p) { CheckForPreciseMarks::do_oop_work(p); } |
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virtual void do_oop(narrowOop* p) { CheckForPreciseMarks::do_oop_work(p); } |
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}; |
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116 |
// We get passed the space_top value to prevent us from traversing into |
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// the old_gen promotion labs, which cannot be safely parsed. |
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void CardTableExtension::scavenge_contents(ObjectStartArray* start_array, |
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MutableSpace* sp, |
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HeapWord* space_top, |
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PSPromotionManager* pm) |
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{ |
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assert(start_array != NULL && sp != NULL && pm != NULL, "Sanity"); |
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assert(start_array->covered_region().contains(sp->used_region()), |
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"ObjectStartArray does not cover space"); |
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bool depth_first = pm->depth_first(); |
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if (sp->not_empty()) { |
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oop* sp_top = (oop*)space_top; |
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oop* prev_top = NULL; |
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jbyte* current_card = byte_for(sp->bottom()); |
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jbyte* end_card = byte_for(sp_top - 1); // sp_top is exclusive |
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// scan card marking array |
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while (current_card <= end_card) { |
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jbyte value = *current_card; |
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// skip clean cards |
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if (card_is_clean(value)) { |
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current_card++; |
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} else { |
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// we found a non-clean card |
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jbyte* first_nonclean_card = current_card++; |
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oop* bottom = (oop*)addr_for(first_nonclean_card); |
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// find object starting on card |
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oop* bottom_obj = (oop*)start_array->object_start((HeapWord*)bottom); |
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// bottom_obj = (oop*)start_array->object_start((HeapWord*)bottom); |
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assert(bottom_obj <= bottom, "just checking"); |
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// make sure we don't scan oops we already looked at |
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if (bottom < prev_top) bottom = prev_top; |
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// figure out when to stop scanning |
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jbyte* first_clean_card; |
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oop* top; |
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bool restart_scanning; |
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do { |
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restart_scanning = false; |
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// find a clean card |
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while (current_card <= end_card) { |
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value = *current_card; |
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if (card_is_clean(value)) break; |
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current_card++; |
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} |
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// check if we reached the end, if so we are done |
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if (current_card >= end_card) { |
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first_clean_card = end_card + 1; |
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current_card++; |
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top = sp_top; |
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} else { |
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// we have a clean card, find object starting on that card |
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first_clean_card = current_card++; |
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top = (oop*)addr_for(first_clean_card); |
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oop* top_obj = (oop*)start_array->object_start((HeapWord*)top); |
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// top_obj = (oop*)start_array->object_start((HeapWord*)top); |
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assert(top_obj <= top, "just checking"); |
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if (oop(top_obj)->is_objArray() || oop(top_obj)->is_typeArray()) { |
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// an arrayOop is starting on the clean card - since we do exact store |
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// checks for objArrays we are done |
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} else { |
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// otherwise, it is possible that the object starting on the clean card |
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// spans the entire card, and that the store happened on a later card. |
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// figure out where the object ends |
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top = top_obj + oop(top_obj)->size(); |
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jbyte* top_card = CardTableModRefBS::byte_for(top - 1); // top is exclusive |
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if (top_card > first_clean_card) { |
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// object ends a different card |
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current_card = top_card + 1; |
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if (card_is_clean(*top_card)) { |
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// the ending card is clean, we are done |
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first_clean_card = top_card; |
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} else { |
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// the ending card is not clean, continue scanning at start of do-while |
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restart_scanning = true; |
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} |
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} else { |
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// object ends on the clean card, we are done. |
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assert(first_clean_card == top_card, "just checking"); |
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} |
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} |
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} |
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} while (restart_scanning); |
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// we know which cards to scan, now clear them |
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while (first_nonclean_card < first_clean_card) { |
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*first_nonclean_card++ = clean_card; |
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} |
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// scan oops in objects |
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// hoisted the if (depth_first) check out of the loop |
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if (depth_first){ |
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do { |
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oop(bottom_obj)->push_contents(pm); |
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bottom_obj += oop(bottom_obj)->size(); |
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assert(bottom_obj <= sp_top, "just checking"); |
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} while (bottom_obj < top); |
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pm->drain_stacks_cond_depth(); |
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} else { |
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do { |
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oop(bottom_obj)->copy_contents(pm); |
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bottom_obj += oop(bottom_obj)->size(); |
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assert(bottom_obj <= sp_top, "just checking"); |
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} while (bottom_obj < top); |
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} |
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// remember top oop* scanned |
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prev_top = top; |
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} |
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} |
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} |
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} |
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225 |
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void CardTableExtension::scavenge_contents_parallel(ObjectStartArray* start_array, |
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MutableSpace* sp, |
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HeapWord* space_top, |
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PSPromotionManager* pm, |
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uint stripe_number) { |
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int ssize = 128; // Naked constant! Work unit = 64k. |
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int dirty_card_count = 0; |
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bool depth_first = pm->depth_first(); |
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oop* sp_top = (oop*)space_top; |
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jbyte* start_card = byte_for(sp->bottom()); |
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jbyte* end_card = byte_for(sp_top - 1) + 1; |
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oop* last_scanned = NULL; // Prevent scanning objects more than once |
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for (jbyte* slice = start_card; slice < end_card; slice += ssize*ParallelGCThreads) { |
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240 |
jbyte* worker_start_card = slice + stripe_number * ssize; |
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if (worker_start_card >= end_card) |
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return; // We're done. |
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243 |
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244 |
jbyte* worker_end_card = worker_start_card + ssize; |
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if (worker_end_card > end_card) |
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worker_end_card = end_card; |
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// We do not want to scan objects more than once. In order to accomplish |
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// this, we assert that any object with an object head inside our 'slice' |
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// belongs to us. We may need to extend the range of scanned cards if the |
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// last object continues into the next 'slice'. |
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252 |
// |
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253 |
// Note! ending cards are exclusive! |
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254 |
HeapWord* slice_start = addr_for(worker_start_card); |
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255 |
HeapWord* slice_end = MIN2((HeapWord*) sp_top, addr_for(worker_end_card)); |
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256 |
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257 |
// If there are not objects starting within the chunk, skip it. |
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258 |
if (!start_array->object_starts_in_range(slice_start, slice_end)) { |
|
259 |
continue; |
|
260 |
} |
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2131 | 261 |
// Update our beginning addr |
1 | 262 |
HeapWord* first_object = start_array->object_start(slice_start); |
263 |
debug_only(oop* first_object_within_slice = (oop*) first_object;) |
|
264 |
if (first_object < slice_start) { |
|
265 |
last_scanned = (oop*)(first_object + oop(first_object)->size()); |
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266 |
debug_only(first_object_within_slice = last_scanned;) |
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267 |
worker_start_card = byte_for(last_scanned); |
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268 |
} |
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269 |
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270 |
// Update the ending addr |
|
271 |
if (slice_end < (HeapWord*)sp_top) { |
|
272 |
// The subtraction is important! An object may start precisely at slice_end. |
|
273 |
HeapWord* last_object = start_array->object_start(slice_end - 1); |
|
274 |
slice_end = last_object + oop(last_object)->size(); |
|
275 |
// worker_end_card is exclusive, so bump it one past the end of last_object's |
|
276 |
// covered span. |
|
277 |
worker_end_card = byte_for(slice_end) + 1; |
|
278 |
||
279 |
if (worker_end_card > end_card) |
|
280 |
worker_end_card = end_card; |
|
281 |
} |
|
282 |
||
283 |
assert(slice_end <= (HeapWord*)sp_top, "Last object in slice crosses space boundary"); |
|
284 |
assert(is_valid_card_address(worker_start_card), "Invalid worker start card"); |
|
285 |
assert(is_valid_card_address(worker_end_card), "Invalid worker end card"); |
|
286 |
// Note that worker_start_card >= worker_end_card is legal, and happens when |
|
287 |
// an object spans an entire slice. |
|
288 |
assert(worker_start_card <= end_card, "worker start card beyond end card"); |
|
289 |
assert(worker_end_card <= end_card, "worker end card beyond end card"); |
|
290 |
||
291 |
jbyte* current_card = worker_start_card; |
|
292 |
while (current_card < worker_end_card) { |
|
293 |
// Find an unclean card. |
|
294 |
while (current_card < worker_end_card && card_is_clean(*current_card)) { |
|
295 |
current_card++; |
|
296 |
} |
|
297 |
jbyte* first_unclean_card = current_card; |
|
298 |
||
299 |
// Find the end of a run of contiguous unclean cards |
|
300 |
while (current_card < worker_end_card && !card_is_clean(*current_card)) { |
|
301 |
while (current_card < worker_end_card && !card_is_clean(*current_card)) { |
|
302 |
current_card++; |
|
303 |
} |
|
304 |
||
305 |
if (current_card < worker_end_card) { |
|
306 |
// Some objects may be large enough to span several cards. If such |
|
307 |
// an object has more than one dirty card, separated by a clean card, |
|
308 |
// we will attempt to scan it twice. The test against "last_scanned" |
|
309 |
// prevents the redundant object scan, but it does not prevent newly |
|
310 |
// marked cards from being cleaned. |
|
311 |
HeapWord* last_object_in_dirty_region = start_array->object_start(addr_for(current_card)-1); |
|
312 |
size_t size_of_last_object = oop(last_object_in_dirty_region)->size(); |
|
313 |
HeapWord* end_of_last_object = last_object_in_dirty_region + size_of_last_object; |
|
314 |
jbyte* ending_card_of_last_object = byte_for(end_of_last_object); |
|
315 |
assert(ending_card_of_last_object <= worker_end_card, "ending_card_of_last_object is greater than worker_end_card"); |
|
316 |
if (ending_card_of_last_object > current_card) { |
|
317 |
// This means the object spans the next complete card. |
|
318 |
// We need to bump the current_card to ending_card_of_last_object |
|
319 |
current_card = ending_card_of_last_object; |
|
320 |
} |
|
321 |
} |
|
322 |
} |
|
323 |
jbyte* following_clean_card = current_card; |
|
324 |
||
325 |
if (first_unclean_card < worker_end_card) { |
|
326 |
oop* p = (oop*) start_array->object_start(addr_for(first_unclean_card)); |
|
327 |
assert((HeapWord*)p <= addr_for(first_unclean_card), "checking"); |
|
328 |
// "p" should always be >= "last_scanned" because newly GC dirtied |
|
329 |
// cards are no longer scanned again (see comment at end |
|
330 |
// of loop on the increment of "current_card"). Test that |
|
331 |
// hypothesis before removing this code. |
|
332 |
// If this code is removed, deal with the first time through |
|
333 |
// the loop when the last_scanned is the object starting in |
|
334 |
// the previous slice. |
|
335 |
assert((p >= last_scanned) || |
|
336 |
(last_scanned == first_object_within_slice), |
|
337 |
"Should no longer be possible"); |
|
338 |
if (p < last_scanned) { |
|
339 |
// Avoid scanning more than once; this can happen because |
|
340 |
// newgen cards set by GC may a different set than the |
|
341 |
// originally dirty set |
|
342 |
p = last_scanned; |
|
343 |
} |
|
344 |
oop* to = (oop*)addr_for(following_clean_card); |
|
345 |
||
346 |
// Test slice_end first! |
|
347 |
if ((HeapWord*)to > slice_end) { |
|
348 |
to = (oop*)slice_end; |
|
349 |
} else if (to > sp_top) { |
|
350 |
to = sp_top; |
|
351 |
} |
|
352 |
||
353 |
// we know which cards to scan, now clear them |
|
354 |
if (first_unclean_card <= worker_start_card+1) |
|
355 |
first_unclean_card = worker_start_card+1; |
|
356 |
if (following_clean_card >= worker_end_card-1) |
|
357 |
following_clean_card = worker_end_card-1; |
|
358 |
||
359 |
while (first_unclean_card < following_clean_card) { |
|
360 |
*first_unclean_card++ = clean_card; |
|
361 |
} |
|
362 |
||
363 |
const int interval = PrefetchScanIntervalInBytes; |
|
364 |
// scan all objects in the range |
|
365 |
if (interval != 0) { |
|
366 |
// hoisted the if (depth_first) check out of the loop |
|
367 |
if (depth_first) { |
|
368 |
while (p < to) { |
|
369 |
Prefetch::write(p, interval); |
|
370 |
oop m = oop(p); |
|
371 |
assert(m->is_oop_or_null(), "check for header"); |
|
372 |
m->push_contents(pm); |
|
373 |
p += m->size(); |
|
374 |
} |
|
375 |
pm->drain_stacks_cond_depth(); |
|
376 |
} else { |
|
377 |
while (p < to) { |
|
378 |
Prefetch::write(p, interval); |
|
379 |
oop m = oop(p); |
|
380 |
assert(m->is_oop_or_null(), "check for header"); |
|
381 |
m->copy_contents(pm); |
|
382 |
p += m->size(); |
|
383 |
} |
|
384 |
} |
|
385 |
} else { |
|
386 |
// hoisted the if (depth_first) check out of the loop |
|
387 |
if (depth_first) { |
|
388 |
while (p < to) { |
|
389 |
oop m = oop(p); |
|
390 |
assert(m->is_oop_or_null(), "check for header"); |
|
391 |
m->push_contents(pm); |
|
392 |
p += m->size(); |
|
393 |
} |
|
394 |
pm->drain_stacks_cond_depth(); |
|
395 |
} else { |
|
396 |
while (p < to) { |
|
397 |
oop m = oop(p); |
|
398 |
assert(m->is_oop_or_null(), "check for header"); |
|
399 |
m->copy_contents(pm); |
|
400 |
p += m->size(); |
|
401 |
} |
|
402 |
} |
|
403 |
} |
|
404 |
last_scanned = p; |
|
405 |
} |
|
406 |
// "current_card" is still the "following_clean_card" or |
|
407 |
// the current_card is >= the worker_end_card so the |
|
408 |
// loop will not execute again. |
|
409 |
assert((current_card == following_clean_card) || |
|
410 |
(current_card >= worker_end_card), |
|
411 |
"current_card should only be incremented if it still equals " |
|
412 |
"following_clean_card"); |
|
413 |
// Increment current_card so that it is not processed again. |
|
414 |
// It may now be dirty because a old-to-young pointer was |
|
415 |
// found on it an updated. If it is now dirty, it cannot be |
|
416 |
// be safely cleaned in the next iteration. |
|
417 |
current_card++; |
|
418 |
} |
|
419 |
} |
|
420 |
} |
|
421 |
||
422 |
// This should be called before a scavenge. |
|
423 |
void CardTableExtension::verify_all_young_refs_imprecise() { |
|
424 |
CheckForUnmarkedObjects check; |
|
425 |
||
426 |
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
|
427 |
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
|
428 |
||
429 |
PSOldGen* old_gen = heap->old_gen(); |
|
430 |
PSPermGen* perm_gen = heap->perm_gen(); |
|
431 |
||
432 |
old_gen->object_iterate(&check); |
|
433 |
perm_gen->object_iterate(&check); |
|
434 |
} |
|
435 |
||
436 |
// This should be called immediately after a scavenge, before mutators resume. |
|
437 |
void CardTableExtension::verify_all_young_refs_precise() { |
|
438 |
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
|
439 |
assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
|
440 |
||
441 |
PSOldGen* old_gen = heap->old_gen(); |
|
442 |
PSPermGen* perm_gen = heap->perm_gen(); |
|
443 |
||
444 |
CheckForPreciseMarks check(heap->young_gen(), (CardTableExtension*)heap->barrier_set()); |
|
445 |
||
446 |
old_gen->oop_iterate(&check); |
|
447 |
perm_gen->oop_iterate(&check); |
|
448 |
||
449 |
verify_all_young_refs_precise_helper(old_gen->object_space()->used_region()); |
|
450 |
verify_all_young_refs_precise_helper(perm_gen->object_space()->used_region()); |
|
451 |
} |
|
452 |
||
453 |
void CardTableExtension::verify_all_young_refs_precise_helper(MemRegion mr) { |
|
454 |
CardTableExtension* card_table = (CardTableExtension*)Universe::heap()->barrier_set(); |
|
455 |
// FIX ME ASSERT HERE |
|
456 |
||
457 |
jbyte* bot = card_table->byte_for(mr.start()); |
|
458 |
jbyte* top = card_table->byte_for(mr.end()); |
|
459 |
while(bot <= top) { |
|
460 |
assert(*bot == clean_card || *bot == verify_card, "Found unwanted or unknown card mark"); |
|
461 |
if (*bot == verify_card) |
|
462 |
*bot = youngergen_card; |
|
463 |
bot++; |
|
464 |
} |
|
465 |
} |
|
466 |
||
467 |
bool CardTableExtension::addr_is_marked_imprecise(void *addr) { |
|
468 |
jbyte* p = byte_for(addr); |
|
469 |
jbyte val = *p; |
|
470 |
||
471 |
if (card_is_dirty(val)) |
|
472 |
return true; |
|
473 |
||
474 |
if (card_is_newgen(val)) |
|
475 |
return true; |
|
476 |
||
477 |
if (card_is_clean(val)) |
|
478 |
return false; |
|
479 |
||
480 |
assert(false, "Found unhandled card mark type"); |
|
481 |
||
482 |
return false; |
|
483 |
} |
|
484 |
||
485 |
// Also includes verify_card |
|
486 |
bool CardTableExtension::addr_is_marked_precise(void *addr) { |
|
487 |
jbyte* p = byte_for(addr); |
|
488 |
jbyte val = *p; |
|
489 |
||
490 |
if (card_is_newgen(val)) |
|
491 |
return true; |
|
492 |
||
493 |
if (card_is_verify(val)) |
|
494 |
return true; |
|
495 |
||
496 |
if (card_is_clean(val)) |
|
497 |
return false; |
|
498 |
||
499 |
if (card_is_dirty(val)) |
|
500 |
return false; |
|
501 |
||
502 |
assert(false, "Found unhandled card mark type"); |
|
503 |
||
504 |
return false; |
|
505 |
} |
|
506 |
||
507 |
// Assumes that only the base or the end changes. This allows indentification |
|
508 |
// of the region that is being resized. The |
|
509 |
// CardTableModRefBS::resize_covered_region() is used for the normal case |
|
510 |
// where the covered regions are growing or shrinking at the high end. |
|
511 |
// The method resize_covered_region_by_end() is analogous to |
|
512 |
// CardTableModRefBS::resize_covered_region() but |
|
513 |
// for regions that grow or shrink at the low end. |
|
514 |
void CardTableExtension::resize_covered_region(MemRegion new_region) { |
|
515 |
||
516 |
for (int i = 0; i < _cur_covered_regions; i++) { |
|
517 |
if (_covered[i].start() == new_region.start()) { |
|
518 |
// Found a covered region with the same start as the |
|
519 |
// new region. The region is growing or shrinking |
|
520 |
// from the start of the region. |
|
521 |
resize_covered_region_by_start(new_region); |
|
522 |
return; |
|
523 |
} |
|
524 |
if (_covered[i].start() > new_region.start()) { |
|
525 |
break; |
|
526 |
} |
|
527 |
} |
|
528 |
||
529 |
int changed_region = -1; |
|
530 |
for (int j = 0; j < _cur_covered_regions; j++) { |
|
531 |
if (_covered[j].end() == new_region.end()) { |
|
532 |
changed_region = j; |
|
533 |
// This is a case where the covered region is growing or shrinking |
|
534 |
// at the start of the region. |
|
535 |
assert(changed_region != -1, "Don't expect to add a covered region"); |
|
536 |
assert(_covered[changed_region].byte_size() != new_region.byte_size(), |
|
537 |
"The sizes should be different here"); |
|
538 |
resize_covered_region_by_end(changed_region, new_region); |
|
539 |
return; |
|
540 |
} |
|
541 |
} |
|
542 |
// This should only be a new covered region (where no existing |
|
543 |
// covered region matches at the start or the end). |
|
544 |
assert(_cur_covered_regions < _max_covered_regions, |
|
545 |
"An existing region should have been found"); |
|
546 |
resize_covered_region_by_start(new_region); |
|
547 |
} |
|
548 |
||
549 |
void CardTableExtension::resize_covered_region_by_start(MemRegion new_region) { |
|
550 |
CardTableModRefBS::resize_covered_region(new_region); |
|
551 |
debug_only(verify_guard();) |
|
552 |
} |
|
553 |
||
554 |
void CardTableExtension::resize_covered_region_by_end(int changed_region, |
|
555 |
MemRegion new_region) { |
|
556 |
assert(SafepointSynchronize::is_at_safepoint(), |
|
557 |
"Only expect an expansion at the low end at a GC"); |
|
558 |
debug_only(verify_guard();) |
|
559 |
#ifdef ASSERT |
|
560 |
for (int k = 0; k < _cur_covered_regions; k++) { |
|
561 |
if (_covered[k].end() == new_region.end()) { |
|
562 |
assert(changed_region == k, "Changed region is incorrect"); |
|
563 |
break; |
|
564 |
} |
|
565 |
} |
|
566 |
#endif |
|
567 |
||
568 |
// Commit new or uncommit old pages, if necessary. |
|
569 |
resize_commit_uncommit(changed_region, new_region); |
|
570 |
||
571 |
// Update card table entries |
|
572 |
resize_update_card_table_entries(changed_region, new_region); |
|
573 |
||
574 |
// Set the new start of the committed region |
|
575 |
resize_update_committed_table(changed_region, new_region); |
|
576 |
||
577 |
// Update the covered region |
|
578 |
resize_update_covered_table(changed_region, new_region); |
|
579 |
||
580 |
if (TraceCardTableModRefBS) { |
|
581 |
int ind = changed_region; |
|
582 |
gclog_or_tty->print_cr("CardTableModRefBS::resize_covered_region: "); |
|
583 |
gclog_or_tty->print_cr(" " |
|
584 |
" _covered[%d].start(): " INTPTR_FORMAT |
|
585 |
" _covered[%d].last(): " INTPTR_FORMAT, |
|
586 |
ind, _covered[ind].start(), |
|
587 |
ind, _covered[ind].last()); |
|
588 |
gclog_or_tty->print_cr(" " |
|
589 |
" _committed[%d].start(): " INTPTR_FORMAT |
|
590 |
" _committed[%d].last(): " INTPTR_FORMAT, |
|
591 |
ind, _committed[ind].start(), |
|
592 |
ind, _committed[ind].last()); |
|
593 |
gclog_or_tty->print_cr(" " |
|
594 |
" byte_for(start): " INTPTR_FORMAT |
|
595 |
" byte_for(last): " INTPTR_FORMAT, |
|
596 |
byte_for(_covered[ind].start()), |
|
597 |
byte_for(_covered[ind].last())); |
|
598 |
gclog_or_tty->print_cr(" " |
|
599 |
" addr_for(start): " INTPTR_FORMAT |
|
600 |
" addr_for(last): " INTPTR_FORMAT, |
|
601 |
addr_for((jbyte*) _committed[ind].start()), |
|
602 |
addr_for((jbyte*) _committed[ind].last())); |
|
603 |
} |
|
604 |
debug_only(verify_guard();) |
|
605 |
} |
|
606 |
||
607 |
void CardTableExtension::resize_commit_uncommit(int changed_region, |
|
608 |
MemRegion new_region) { |
|
609 |
// Commit new or uncommit old pages, if necessary. |
|
610 |
MemRegion cur_committed = _committed[changed_region]; |
|
611 |
assert(_covered[changed_region].end() == new_region.end(), |
|
612 |
"The ends of the regions are expected to match"); |
|
613 |
// Extend the start of this _committed region to |
|
614 |
// to cover the start of any previous _committed region. |
|
615 |
// This forms overlapping regions, but never interior regions. |
|
616 |
HeapWord* min_prev_start = lowest_prev_committed_start(changed_region); |
|
617 |
if (min_prev_start < cur_committed.start()) { |
|
618 |
// Only really need to set start of "cur_committed" to |
|
619 |
// the new start (min_prev_start) but assertion checking code |
|
620 |
// below use cur_committed.end() so make it correct. |
|
621 |
MemRegion new_committed = |
|
622 |
MemRegion(min_prev_start, cur_committed.end()); |
|
623 |
cur_committed = new_committed; |
|
624 |
} |
|
625 |
#ifdef ASSERT |
|
626 |
ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
|
627 |
assert(cur_committed.start() == |
|
628 |
(HeapWord*) align_size_up((uintptr_t) cur_committed.start(), |
|
629 |
os::vm_page_size()), |
|
630 |
"Starts should have proper alignment"); |
|
631 |
#endif |
|
632 |
||
633 |
jbyte* new_start = byte_for(new_region.start()); |
|
634 |
// Round down because this is for the start address |
|
635 |
HeapWord* new_start_aligned = |
|
636 |
(HeapWord*)align_size_down((uintptr_t)new_start, os::vm_page_size()); |
|
637 |
// The guard page is always committed and should not be committed over. |
|
638 |
// This method is used in cases where the generation is growing toward |
|
639 |
// lower addresses but the guard region is still at the end of the |
|
640 |
// card table. That still makes sense when looking for writes |
|
641 |
// off the end of the card table. |
|
642 |
if (new_start_aligned < cur_committed.start()) { |
|
643 |
// Expand the committed region |
|
644 |
// |
|
645 |
// Case A |
|
646 |
// |+ guard +| |
|
647 |
// |+ cur committed +++++++++| |
|
648 |
// |+ new committed +++++++++++++++++| |
|
649 |
// |
|
650 |
// Case B |
|
651 |
// |+ guard +| |
|
652 |
// |+ cur committed +| |
|
653 |
// |+ new committed +++++++| |
|
654 |
// |
|
655 |
// These are not expected because the calculation of the |
|
656 |
// cur committed region and the new committed region |
|
657 |
// share the same end for the covered region. |
|
658 |
// Case C |
|
659 |
// |+ guard +| |
|
660 |
// |+ cur committed +| |
|
661 |
// |+ new committed +++++++++++++++++| |
|
662 |
// Case D |
|
663 |
// |+ guard +| |
|
664 |
// |+ cur committed +++++++++++| |
|
665 |
// |+ new committed +++++++| |
|
666 |
||
667 |
HeapWord* new_end_for_commit = |
|
668 |
MIN2(cur_committed.end(), _guard_region.start()); |
|
971
f0b20be4165d
6672698: mangle_unused_area() should not remangle the entire heap at each collection.
jmasa
parents:
360
diff
changeset
|
669 |
if(new_start_aligned < new_end_for_commit) { |
f0b20be4165d
6672698: mangle_unused_area() should not remangle the entire heap at each collection.
jmasa
parents:
360
diff
changeset
|
670 |
MemRegion new_committed = |
f0b20be4165d
6672698: mangle_unused_area() should not remangle the entire heap at each collection.
jmasa
parents:
360
diff
changeset
|
671 |
MemRegion(new_start_aligned, new_end_for_commit); |
1 | 672 |
if (!os::commit_memory((char*)new_committed.start(), |
673 |
new_committed.byte_size())) { |
|
674 |
vm_exit_out_of_memory(new_committed.byte_size(), |
|
675 |
"card table expansion"); |
|
676 |
} |
|
677 |
} |
|
678 |
} else if (new_start_aligned > cur_committed.start()) { |
|
679 |
// Shrink the committed region |
|
680 |
MemRegion uncommit_region = committed_unique_to_self(changed_region, |
|
681 |
MemRegion(cur_committed.start(), new_start_aligned)); |
|
682 |
if (!uncommit_region.is_empty()) { |
|
683 |
if (!os::uncommit_memory((char*)uncommit_region.start(), |
|
684 |
uncommit_region.byte_size())) { |
|
685 |
vm_exit_out_of_memory(uncommit_region.byte_size(), |
|
686 |
"card table contraction"); |
|
687 |
} |
|
688 |
} |
|
689 |
} |
|
690 |
assert(_committed[changed_region].end() == cur_committed.end(), |
|
691 |
"end should not change"); |
|
692 |
} |
|
693 |
||
694 |
void CardTableExtension::resize_update_committed_table(int changed_region, |
|
695 |
MemRegion new_region) { |
|
696 |
||
697 |
jbyte* new_start = byte_for(new_region.start()); |
|
698 |
// Set the new start of the committed region |
|
699 |
HeapWord* new_start_aligned = |
|
700 |
(HeapWord*)align_size_down((uintptr_t)new_start, |
|
701 |
os::vm_page_size()); |
|
702 |
MemRegion new_committed = MemRegion(new_start_aligned, |
|
703 |
_committed[changed_region].end()); |
|
704 |
_committed[changed_region] = new_committed; |
|
705 |
_committed[changed_region].set_start(new_start_aligned); |
|
706 |
} |
|
707 |
||
708 |
void CardTableExtension::resize_update_card_table_entries(int changed_region, |
|
709 |
MemRegion new_region) { |
|
710 |
debug_only(verify_guard();) |
|
711 |
MemRegion original_covered = _covered[changed_region]; |
|
712 |
// Initialize the card entries. Only consider the |
|
713 |
// region covered by the card table (_whole_heap) |
|
714 |
jbyte* entry; |
|
715 |
if (new_region.start() < _whole_heap.start()) { |
|
716 |
entry = byte_for(_whole_heap.start()); |
|
717 |
} else { |
|
718 |
entry = byte_for(new_region.start()); |
|
719 |
} |
|
720 |
jbyte* end = byte_for(original_covered.start()); |
|
721 |
// If _whole_heap starts at the original covered regions start, |
|
722 |
// this loop will not execute. |
|
723 |
while (entry < end) { *entry++ = clean_card; } |
|
724 |
} |
|
725 |
||
726 |
void CardTableExtension::resize_update_covered_table(int changed_region, |
|
727 |
MemRegion new_region) { |
|
728 |
// Update the covered region |
|
729 |
_covered[changed_region].set_start(new_region.start()); |
|
730 |
_covered[changed_region].set_word_size(new_region.word_size()); |
|
731 |
||
732 |
// reorder regions. There should only be at most 1 out |
|
733 |
// of order. |
|
734 |
for (int i = _cur_covered_regions-1 ; i > 0; i--) { |
|
735 |
if (_covered[i].start() < _covered[i-1].start()) { |
|
736 |
MemRegion covered_mr = _covered[i-1]; |
|
737 |
_covered[i-1] = _covered[i]; |
|
738 |
_covered[i] = covered_mr; |
|
739 |
MemRegion committed_mr = _committed[i-1]; |
|
740 |
_committed[i-1] = _committed[i]; |
|
741 |
_committed[i] = committed_mr; |
|
742 |
break; |
|
743 |
} |
|
744 |
} |
|
745 |
#ifdef ASSERT |
|
746 |
for (int m = 0; m < _cur_covered_regions-1; m++) { |
|
747 |
assert(_covered[m].start() <= _covered[m+1].start(), |
|
748 |
"Covered regions out of order"); |
|
749 |
assert(_committed[m].start() <= _committed[m+1].start(), |
|
750 |
"Committed regions out of order"); |
|
751 |
} |
|
752 |
#endif |
|
753 |
} |
|
754 |
||
755 |
// Returns the start of any committed region that is lower than |
|
756 |
// the target committed region (index ind) and that intersects the |
|
757 |
// target region. If none, return start of target region. |
|
758 |
// |
|
759 |
// ------------- |
|
760 |
// | | |
|
761 |
// ------------- |
|
762 |
// ------------ |
|
763 |
// | target | |
|
764 |
// ------------ |
|
765 |
// ------------- |
|
766 |
// | | |
|
767 |
// ------------- |
|
768 |
// ^ returns this |
|
769 |
// |
|
770 |
// ------------- |
|
771 |
// | | |
|
772 |
// ------------- |
|
773 |
// ------------ |
|
774 |
// | target | |
|
775 |
// ------------ |
|
776 |
// ------------- |
|
777 |
// | | |
|
778 |
// ------------- |
|
779 |
// ^ returns this |
|
780 |
||
781 |
HeapWord* CardTableExtension::lowest_prev_committed_start(int ind) const { |
|
782 |
assert(_cur_covered_regions >= 0, "Expecting at least on region"); |
|
783 |
HeapWord* min_start = _committed[ind].start(); |
|
784 |
for (int j = 0; j < ind; j++) { |
|
785 |
HeapWord* this_start = _committed[j].start(); |
|
786 |
if ((this_start < min_start) && |
|
787 |
!(_committed[j].intersection(_committed[ind])).is_empty()) { |
|
788 |
min_start = this_start; |
|
789 |
} |
|
790 |
} |
|
791 |
return min_start; |
|
792 |
} |