--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/heterogeneousHeapRegionManager.hpp Fri Dec 21 08:18:59 2018 -0800
@@ -0,0 +1,150 @@
+/*
+ * Copyright (c) 2018, 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_G1_HETEROGENEOUSHEAPREGIONMANAGER_HPP
+#define SHARE_VM_GC_G1_HETEROGENEOUSHEAPREGIONMANAGER_HPP
+
+#include "gc/g1/heapRegionManager.hpp"
+
+// This class manages heap regions on heterogenous memory comprising of dram and nv-dimm.
+// Regions in dram (dram_set) are used for young objects and archive regions (CDS).
+// Regions in nv-dimm (nvdimm_set) are used for old objects and humongous objects.
+// At any point there are some regions committed on dram and some on nv-dimm with the following guarantees:
+// 1. The total number of regions committed in dram and nv-dimm equals the current size of heap.
+// 2. Consequently, total number of regions committed is less than or equal to Xmx.
+// 3. To maintain the guarantee stated by 1., whenever one set grows (new regions committed), the other set shrinks (regions un-committed).
+// 3a. If more dram regions are needed (young generation expansion), corresponding number of regions in nv-dimm are un-committed.
+// 3b. When old generation or humongous set grows, and new regions need to be committed to nv-dimm, corresponding number of regions
+// are un-committed in dram.
+class HeterogeneousHeapRegionManager : public HeapRegionManager {
+ const uint _max_regions;
+ uint _max_dram_regions;
+ uint _max_nvdimm_regions;
+ uint _start_index_of_nvdimm;
+ uint _total_commited_before_full_gc;
+ uint _no_borrowed_regions;
+
+ uint total_regions_committed() const;
+ uint num_committed_dram() const;
+ uint num_committed_nvdimm() const;
+
+ // Similar to find_unavailable_from_idx() function from base class, difference is this function searches in range [start, end].
+ uint find_unavailable_in_range(uint start_idx, uint end_idx, uint* res_idx) const;
+
+ // Expand into dram. Maintains the invariant that total number of committed regions is less than current heap size.
+ uint expand_dram(uint num_regions, WorkGang* pretouch_workers);
+
+ // Expand into nv-dimm.
+ uint expand_nvdimm(uint num_regions, WorkGang* pretouch_workers);
+
+ // Expand by finding unavailable regions in [start, end] range.
+ uint expand_in_range(uint start, uint end, uint num_regions, WorkGang* pretouch_workers);
+
+ // Shrink dram set of regions.
+ uint shrink_dram(uint num_regions, bool update_free_list = true);
+
+ // Shrink nv-dimm set of regions.
+ uint shrink_nvdimm(uint num_regions, bool update_free_list = true);
+
+ // Shrink regions from [start, end] range.
+ uint shrink_in_range(uint start, uint end, uint num_regions, bool update_free_list = true);
+
+ // Similar to find_empty_from_idx_reverse() in base class. Only here it searches in a range.
+ uint find_empty_in_range_reverse(uint start_idx, uint end_idx, uint* res_idx);
+
+ // Similar to find_contiguous() in base class, with [start, end] range
+ uint find_contiguous(size_t start, size_t end, size_t num, bool empty_only);
+
+ // This function is called when there are no free nv-dimm regions.
+ // It borrows a region from the set of unavailable regions in nv-dimm for GC purpose.
+ HeapRegion* borrow_old_region_for_gc();
+
+ uint free_list_dram_length() const;
+ uint free_list_nvdimm_length() const;
+
+ // is region with given index in nv-dimm?
+ bool is_in_nvdimm(uint index) const;
+ bool is_in_dram(uint index) const;
+
+public:
+
+ // Empty constructor, we'll initialize it with the initialize() method.
+ HeterogeneousHeapRegionManager(uint num_regions) : _max_regions(num_regions), _max_dram_regions(0),
+ _max_nvdimm_regions(0), _start_index_of_nvdimm(0),
+ _total_commited_before_full_gc(0), _no_borrowed_regions(0)
+ {}
+
+ static HeterogeneousHeapRegionManager* manager();
+
+ virtual void initialize(G1RegionToSpaceMapper* heap_storage,
+ G1RegionToSpaceMapper* prev_bitmap,
+ G1RegionToSpaceMapper* next_bitmap,
+ G1RegionToSpaceMapper* bot,
+ G1RegionToSpaceMapper* cardtable,
+ G1RegionToSpaceMapper* card_counts);
+
+ uint start_index_of_nvdimm() const;
+ uint start_index_of_dram() const;
+ uint end_index_of_nvdimm() const;
+ uint end_index_of_dram() const;
+
+ // Override.
+ HeapRegion* get_dummy_region();
+
+ // Adjust dram_set to provision 'expected_num_regions' regions.
+ void adjust_dram_regions(uint expected_num_regions, WorkGang* pretouch_workers);
+
+ // Prepare heap regions before and after full collection.
+ void prepare_for_full_collection_start();
+ void prepare_for_full_collection_end();
+
+ virtual HeapRegion* allocate_free_region(HeapRegionType type);
+
+ // Return maximum number of regions that heap can expand to.
+ uint max_expandable_length() const;
+
+ // Override. Expand in nv-dimm.
+ uint expand_by(uint num_regions, WorkGang* pretouch_workers);
+
+ // Override.
+ uint expand_at(uint start, uint num_regions, WorkGang* pretouch_workers);
+
+ // Override. This function is called for humongous allocation, so we need to find empty regions in nv-dimm.
+ uint find_contiguous_only_empty(size_t num);
+
+ // Override. This function is called for humongous allocation, so we need to find empty or unavailable regions in nv-dimm.
+ uint find_contiguous_empty_or_unavailable(size_t num);
+
+ // Overrides base class implementation to find highest free region in dram.
+ uint find_highest_free(bool* expanded);
+
+ // Override. This fuction is called to shrink the heap, we shrink in dram first then in nv-dimm.
+ uint shrink_by(uint num_regions_to_remove);
+
+ bool has_borrowed_regions() const;
+
+ void verify();
+};
+
+#endif // SHARE_VM_GC_G1_HETEROGENEOUSHEAPREGIONMANAGER_HPP