--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegionManager.hpp Tue Aug 26 09:36:53 2014 +0200
@@ -0,0 +1,239 @@
+/*
+ * Copyright (c) 2001, 2013, 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.
+ *
+ */
+
+#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONMANAGER_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONMANAGER_HPP
+
+#include "gc_implementation/g1/g1BiasedArray.hpp"
+#include "gc_implementation/g1/g1RegionToSpaceMapper.hpp"
+#include "gc_implementation/g1/heapRegionSet.hpp"
+
+class HeapRegion;
+class HeapRegionClosure;
+class FreeRegionList;
+
+class G1HeapRegionTable : public G1BiasedMappedArray<HeapRegion*> {
+ protected:
+ virtual HeapRegion* default_value() const { return NULL; }
+};
+
+// This class keeps track of the actual heap memory, auxiliary data
+// and its metadata (i.e., HeapRegion instances) and the list of free regions.
+//
+// This allows maximum flexibility for deciding what to commit or uncommit given
+// a request from outside.
+//
+// HeapRegions are kept in the _regions array in address order. A region's
+// index in the array corresponds to its index in the heap (i.e., 0 is the
+// region at the bottom of the heap, 1 is the one after it, etc.). Two
+// regions that are consecutive in the array should also be adjacent in the
+// address space (i.e., region(i).end() == region(i+1).bottom().
+//
+// We create a HeapRegion when we commit the region's address space
+// for the first time. When we uncommit the address space of a
+// region we retain the HeapRegion to be able to re-use it in the
+// future (in case we recommit it).
+//
+// We keep track of three lengths:
+//
+// * _num_committed (returned by length()) is the number of currently
+// committed regions. These may not be contiguous.
+// * _allocated_heapregions_length (not exposed outside this class) is the
+// number of regions+1 for which we have HeapRegions.
+// * max_length() returns the maximum number of regions the heap can have.
+//
+
+class HeapRegionManager: public CHeapObj<mtGC> {
+ friend class VMStructs;
+
+ G1HeapRegionTable _regions;
+
+ G1RegionToSpaceMapper* _heap_mapper;
+ G1RegionToSpaceMapper* _prev_bitmap_mapper;
+ G1RegionToSpaceMapper* _next_bitmap_mapper;
+ G1RegionToSpaceMapper* _bot_mapper;
+ G1RegionToSpaceMapper* _cardtable_mapper;
+ G1RegionToSpaceMapper* _card_counts_mapper;
+
+ FreeRegionList _free_list;
+
+ // Each bit in this bitmap indicates that the corresponding region is available
+ // for allocation.
+ BitMap _available_map;
+
+ // The number of regions committed in the heap.
+ uint _num_committed;
+
+ // Internal only. The highest heap region +1 we allocated a HeapRegion instance for.
+ uint _allocated_heapregions_length;
+
+ HeapWord* heap_bottom() const { return _regions.bottom_address_mapped(); }
+ HeapWord* heap_end() const {return _regions.end_address_mapped(); }
+
+ void make_regions_available(uint index, uint num_regions = 1);
+
+ // Pass down commit calls to the VirtualSpace.
+ void commit_regions(uint index, size_t num_regions = 1);
+ void uncommit_regions(uint index, size_t num_regions = 1);
+
+ // Notify other data structures about change in the heap layout.
+ void update_committed_space(HeapWord* old_end, HeapWord* new_end);
+ // Calculate the starting region for each worker during parallel iteration so
+ // that they do not all start from the same region.
+ uint start_region_for_worker(uint worker_i, uint num_workers, uint num_regions) const;
+
+ // Find a contiguous set of empty or uncommitted regions of length num and return
+ // the index of the first region or G1_NO_HRM_INDEX if the search was unsuccessful.
+ // If only_empty is true, only empty regions are considered.
+ // Searches from bottom to top of the heap, doing a first-fit.
+ uint find_contiguous(size_t num, bool only_empty);
+ // Finds the next sequence of unavailable regions starting from start_idx. Returns the
+ // length of the sequence found. If this result is zero, no such sequence could be found,
+ // otherwise res_idx indicates the start index of these regions.
+ uint find_unavailable_from_idx(uint start_idx, uint* res_idx) const;
+ // Finds the next sequence of empty regions starting from start_idx, going backwards in
+ // the heap. Returns the length of the sequence found. If this value is zero, no
+ // sequence could be found, otherwise res_idx contains the start index of this range.
+ uint find_empty_from_idx_reverse(uint start_idx, uint* res_idx) const;
+ // Allocate a new HeapRegion for the given index.
+ HeapRegion* new_heap_region(uint hrm_index);
+#ifdef ASSERT
+public:
+ bool is_free(HeapRegion* hr) const;
+#endif
+ // Returns whether the given region is available for allocation.
+ bool is_available(uint region) const;
+
+ public:
+ // Empty constructor, we'll initialize it with the initialize() method.
+ HeapRegionManager() : _regions(), _heap_mapper(NULL), _num_committed(0),
+ _next_bitmap_mapper(NULL), _prev_bitmap_mapper(NULL), _bot_mapper(NULL),
+ _allocated_heapregions_length(0), _available_map(),
+ _free_list("Free list", new MasterFreeRegionListMtSafeChecker())
+ { }
+
+ void initialize(G1RegionToSpaceMapper* heap_storage,
+ G1RegionToSpaceMapper* prev_bitmap,
+ G1RegionToSpaceMapper* next_bitmap,
+ G1RegionToSpaceMapper* bot,
+ G1RegionToSpaceMapper* cardtable,
+ G1RegionToSpaceMapper* card_counts);
+
+ // Return the "dummy" region used for G1AllocRegion. This is currently a hardwired
+ // new HeapRegion that owns HeapRegion at index 0. Since at the moment we commit
+ // the heap from the lowest address, this region (and its associated data
+ // structures) are available and we do not need to check further.
+ HeapRegion* get_dummy_region() { return new_heap_region(0); }
+
+ // Return the HeapRegion at the given index. Assume that the index
+ // is valid.
+ inline HeapRegion* at(uint index) const;
+
+ // If addr is within the committed space return its corresponding
+ // HeapRegion, otherwise return NULL.
+ inline HeapRegion* addr_to_region(HeapWord* addr) const;
+
+ // Insert the given region into the free region list.
+ inline void insert_into_free_list(HeapRegion* hr);
+
+ // Insert the given region list into the global free region list.
+ void insert_list_into_free_list(FreeRegionList* list) {
+ _free_list.add_ordered(list);
+ }
+
+ HeapRegion* allocate_free_region(bool is_old) {
+ HeapRegion* hr = _free_list.remove_region(is_old);
+
+ if (hr != NULL) {
+ assert(hr->next() == NULL, "Single region should not have next");
+ assert(is_available(hr->hrm_index()), "Must be committed");
+ }
+ return hr;
+ }
+
+ inline void allocate_free_regions_starting_at(uint first, uint num_regions);
+
+ // Remove all regions from the free list.
+ void remove_all_free_regions() {
+ _free_list.remove_all();
+ }
+
+ // Return the number of committed free regions in the heap.
+ uint num_free_regions() const {
+ return _free_list.length();
+ }
+
+ size_t total_capacity_bytes() const {
+ return num_free_regions() * HeapRegion::GrainBytes;
+ }
+
+ // Return the number of available (uncommitted) regions.
+ uint available() const { return max_length() - length(); }
+
+ // Return the number of regions that have been committed in the heap.
+ uint length() const { return _num_committed; }
+
+ // Return the maximum number of regions in the heap.
+ uint max_length() const { return (uint)_regions.length(); }
+
+ MemRegion reserved() const { return MemRegion(heap_bottom(), heap_end()); }
+
+ // Expand the sequence to reflect that the heap has grown. Either create new
+ // HeapRegions, or re-use existing ones. Returns the number of regions the
+ // sequence was expanded by. If a HeapRegion allocation fails, the resulting
+ // number of regions might be smaller than what's desired.
+ uint expand_by(uint num_regions);
+
+ // Makes sure that the regions from start to start+num_regions-1 are available
+ // for allocation. Returns the number of regions that were committed to achieve
+ // this.
+ uint expand_at(uint start, uint num_regions);
+
+ // Find a contiguous set of empty regions of length num. Returns the start index of
+ // that set, or G1_NO_HRM_INDEX.
+ uint find_contiguous_only_empty(size_t num) { return find_contiguous(num, true); }
+ // Find a contiguous set of empty or unavailable regions of length num. Returns the
+ // start index of that set, or G1_NO_HRM_INDEX.
+ uint find_contiguous_empty_or_unavailable(size_t num) { return find_contiguous(num, false); }
+
+ HeapRegion* next_region_in_heap(const HeapRegion* r) const;
+
+ // Apply blk->doHeapRegion() on all committed regions in address order,
+ // terminating the iteration early if doHeapRegion() returns true.
+ void iterate(HeapRegionClosure* blk) const;
+
+ void par_iterate(HeapRegionClosure* blk, uint worker_id, uint no_of_par_workers, jint claim_value) const;
+
+ // Uncommit up to num_regions_to_remove regions that are completely free.
+ // Return the actual number of uncommitted regions.
+ uint shrink_by(uint num_regions_to_remove);
+
+ void verify();
+
+ // Do some sanity checking.
+ void verify_optional() PRODUCT_RETURN;
+};
+
+#endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONMANAGER_HPP
+