Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 2001, 2009, 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.

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  */

 class HeapRegion;

 class HeapRegionClosure;

 class HeapRegionSeq: public CHeapObj {

   // _regions is kept sorted by start address order, and no two regions are

   // overlapping.

   GrowableArray<HeapRegion*> _regions;

   // The index in "_regions" at which to start the next allocation search.

   // (For efficiency only; private to obj_allocate after initialization.)

   int _alloc_search_start;

   // Attempts to allocate a block of the (assumed humongous) word_size,

   // starting at the region "ind".

   HeapWord* alloc_obj_from_region_index(int ind, size_t word_size);

   // Currently, we're choosing collection sets in a round-robin fashion,

   // starting here.

   int _next_rr_candidate;

   // The bottom address of the bottom-most region, or else NULL if there

   // are no regions in the sequence.

   char* _seq_bottom;

  public:

   // Initializes "this" to the empty sequence of regions.

   HeapRegionSeq(const size_t max_size);

   // Adds "hr" to "this" sequence.  Requires "hr" not to overlap with

   // any region already in "this".  (Will perform better if regions are

   // inserted in ascending address order.)

   void insert(HeapRegion* hr);

   // Given a HeapRegion*, returns its index within _regions,

   // or returns -1 if not found.

   int find(HeapRegion* hr);

   // Requires the index to be valid, and return the region at the index.

   HeapRegion* at(size_t i) { return _regions.at((int)i); }

   // Return the number of regions in the sequence.

   size_t length();

   // Returns the number of contiguous regions at the end of the sequence

   // that are available for allocation.

   size_t free_suffix();

   // Requires "word_size" to be humongous (in the technical sense).  If

   // possible, allocates a contiguous subsequence of the heap regions to

   // satisfy the allocation, and returns the address of the beginning of

   // that sequence, otherwise returns NULL.

   HeapWord* obj_allocate(size_t word_size);

   // Apply the "doHeapRegion" method of "blk" to all regions in "this",

   // in address order, terminating the iteration early

   // if the "doHeapRegion" method returns "true".

   void iterate(HeapRegionClosure* blk);

   // Apply the "doHeapRegion" method of "blk" to all regions in "this",

   // starting at "r" (or first region, if "r" is NULL), in a circular

   // manner, terminating the iteration early if the "doHeapRegion" method

   // returns "true".

   void iterate_from(HeapRegion* r, HeapRegionClosure* blk);

   // As above, but start from a given index in the sequence

   // instead of a given heap region.

   void iterate_from(int idx, HeapRegionClosure* blk);

   // Requires "shrink_bytes" to be a multiple of the page size and heap

   // region granularity.  Deletes as many "rightmost" completely free heap

   // regions from the sequence as comprise shrink_bytes bytes.  Returns the

   // MemRegion indicating the region those regions comprised, and sets

   // "num_regions_deleted" to the number of regions deleted.

   MemRegion shrink_by(size_t shrink_bytes, size_t& num_regions_deleted);

   // If "addr" falls within a region in the sequence, return that region,

   // or else NULL.

   HeapRegion* addr_to_region(const void* addr);

   void print();

   // Prints out runs of empty regions.

   void print_empty_runs();

 };