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src/hotspot/share/memory/metaspace/virtualSpaceNode.hpp

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rev 60538 : imported patch jep387-all.patch
   1 /*
   2  * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.

   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP
  26 #define SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP
  27 
  28 #include "memory/virtualspace.hpp"





  29 #include "memory/memRegion.hpp"

  30 #include "utilities/debug.hpp"

  31 #include "utilities/globalDefinitions.hpp"
  32 

  33 class outputStream;
  34 
  35 namespace metaspace {
  36 
  37 class Metachunk;
  38 class ChunkManager;
  39 class OccupancyMap;







































  40 
  41 // A VirtualSpaceList node.
  42 class VirtualSpaceNode : public CHeapObj<mtClass> {
  43   friend class VirtualSpaceList;
  44 
  45   // Link to next VirtualSpaceNode
  46   VirtualSpaceNode* _next;
  47 
  48   // Whether this node is contained in class or metaspace.
  49   const bool _is_class;
  50 
  51   // total in the VirtualSpace
  52   ReservedSpace _rs;
  53   VirtualSpace _virtual_space;
  54   MetaWord* _top;
  55   // count of chunks contained in this VirtualSpace
  56   uintx _container_count;
  57 
  58   OccupancyMap* _occupancy_map;
  59 
  60   // Convenience functions to access the _virtual_space
  61   char* low()  const { return virtual_space()->low(); }
  62   char* high() const { return virtual_space()->high(); }
  63   char* low_boundary()  const { return virtual_space()->low_boundary(); }
  64   char* high_boundary() const { return virtual_space()->high_boundary(); }
  65 
  66   // The first Metachunk will be allocated at the bottom of the
  67   // VirtualSpace
  68   Metachunk* first_chunk() { return (Metachunk*) bottom(); }
  69 
  70   // Committed but unused space in the virtual space
  71   size_t free_words_in_vs() const;
  72 
  73   // True if this node belongs to class metaspace.
  74   bool is_class() const { return _is_class; }
  75 
  76   // Helper function for take_from_committed: allocate padding chunks
  77   // until top is at the given address.
  78   void allocate_padding_chunks_until_top_is_at(MetaWord* target_top);
  79 
  80  public:
  81 
  82   VirtualSpaceNode(bool is_class, size_t byte_size);
  83   VirtualSpaceNode(bool is_class, ReservedSpace rs) :
  84     _next(NULL), _is_class(is_class), _rs(rs), _top(NULL), _container_count(0), _occupancy_map(NULL) {}
  85   ~VirtualSpaceNode();
  86 
  87   // Convenience functions for logical bottom and (committed) end
  88   MetaWord* bottom() const { return (MetaWord*) _virtual_space.low(); }
  89   MetaWord* end() const { return (MetaWord*) _virtual_space.high(); }
  90 
  91   const OccupancyMap* occupancy_map() const { return _occupancy_map; }
  92   OccupancyMap* occupancy_map() { return _occupancy_map; }
  93 
  94   bool contains(const void* ptr) { return ptr >= low() && ptr < high(); }
  95 
  96   size_t reserved_words() const  { return _virtual_space.reserved_size() / BytesPerWord; }
  97   size_t committed_words() const { return _virtual_space.actual_committed_size() / BytesPerWord; }
  98 
  99   bool is_pre_committed() const { return _virtual_space.special(); }

 100 
 101   // address of next available space in _virtual_space;
 102   // Accessors
 103   VirtualSpaceNode* next() { return _next; }
 104   void set_next(VirtualSpaceNode* v) { _next = v; }
 105 
 106   void set_top(MetaWord* v) { _top = v; }

























































 107 
 108   // Accessors
 109   VirtualSpace* virtual_space() const { return (VirtualSpace*) &_virtual_space; }
 110 
 111   // Returns true if "word_size" is available in the VirtualSpace
 112   bool is_available(size_t word_size) { return word_size <= pointer_delta(end(), _top, sizeof(MetaWord)); }
 113 
 114   MetaWord* top() const { return _top; }
 115   void inc_top(size_t word_size) { _top += word_size; }
 116 
 117   uintx container_count() { return _container_count; }
 118   void inc_container_count();
 119   void dec_container_count();
 120 
 121   // used and capacity in this single entry in the list
 122   size_t used_words_in_vs() const;
 123   size_t capacity_words_in_vs() const;
 124 
 125   bool initialize();
 126 
 127   // get space from the virtual space
 128   Metachunk* take_from_committed(size_t chunk_word_size);
 129 
 130   // Allocate a chunk from the virtual space and return it.
 131   Metachunk* get_chunk_vs(size_t chunk_word_size);
 132 
 133   // Expands the committed space by at least min_words words.
 134   bool expand_by(size_t min_words, size_t preferred_words);
 135 
 136   // In preparation for deleting this node, remove all the chunks
 137   // in the node from any freelist.
 138   void purge(ChunkManager* chunk_manager);
 139 
 140   // If an allocation doesn't fit in the current node a new node is created.
 141   // Allocate chunks out of the remaining committed space in this node
 142   // to avoid wasting that memory.
 143   // This always adds up because all the chunk sizes are multiples of
 144   // the smallest chunk size.
 145   void retire(ChunkManager* chunk_manager);
 146 
 147   void print_on(outputStream* st) const                 { print_on(st, K); }
 148   void print_on(outputStream* st, size_t scale) const;
 149   void print_map(outputStream* st, bool is_class) const;
 150 
 151   // Debug support
 152   DEBUG_ONLY(void mangle();)
 153   // Verify counters and basic structure. Slow mode: verify all chunks in depth and occupancy map.
 154   DEBUG_ONLY(void verify(bool slow);)
 155   // Verify that all free chunks in this node are ideally merged
 156   // (there should not be multiple small chunks where a large chunk could exist.)
 157   DEBUG_ONLY(void verify_free_chunks_are_ideally_merged();)







































































































 158 
 159 };

 160 
 161 } // namespace metaspace
 162 
 163 #endif // SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP
   1 /*
   2  * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2018, 2020 SAP SE. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #ifndef SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP
  27 #define SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP
  28 
  29 
  30 #include "memory/allocation.hpp"
  31 #include "memory/metaspace/counter.hpp"
  32 #include "memory/metaspace/commitMask.hpp"
  33 #include "memory/metaspace/rootChunkArea.hpp"
  34 #include "memory/metaspace/settings.hpp"
  35 #include "memory/memRegion.hpp"
  36 #include "memory/virtualspace.hpp"
  37 #include "utilities/debug.hpp"
  38 #include "utilities/bitMap.hpp"
  39 #include "utilities/globalDefinitions.hpp"
  40 
  41 
  42 class outputStream;
  43 
  44 namespace metaspace {
  45 
  46 class CommitLimiter;
  47 class FreeChunkListVector;
  48 
  49 // VirtualSpaceNode manages a single contiguous address range of metaspace. Logically that memory
  50 //  region is split up into a sequence of "root chunk areas", each one containing one root chunk
  51 //  or splinters of a root chunk.
  52 //
  53 // The underlying memory is also logically divided into a number of "commit granules", units of memory
  54 //  which may be committed or uncommitted independently from each other.
  55 //
  56 // (Both root chunk areas and commit granules have not much to do with each other - one is a way to
  57 //   reserve memory for the upper regions, see ChunkManager. One is a way to manage commited memory.)
  58 //
  59 // VirtualSpaceNode:
  60 //  - exposes a function to allocate a new root chunk (see VirtualSpaceNode::allocate_root_chunk()).
  61 //
  62 //  - knows about the commit state of the memory region - which commit granule are committed, which
  63 //    are not. It exposes functions to commit and uncommit regions (without actively committing
  64 //    itself)
  65 //
  66 //  - It has a reference to a "CommitLimiter", an interface to query whether committing is
  67 //    possible. That interface hides the various ways committing may be limited (GC threshold,
  68 //    MaxMetaspaceSize, ...)
  69 //
  70 //  - It uses ReservedSpace to reserve its memory. It either owns the ReservedSpace or that
  71 //    space got handed in from outside (ccs).
  72 //
  73 //
  74 //
  75 //
  76 // | root chunk area               | root chunk area               | root chunk area               | <-- root chunk areas
  77 //
  78 // +-----------------------------------------------------------------------------------------------+
  79 // |                                                                                               |
  80 // |                                   `VirtualSpaceNode` memory                                   |
  81 // |                                                                                               |
  82 // +-----------------------------------------------------------------------------------------------+
  83 //
  84 // |x| |x|x|x| | | | |x|x|x| | | |x|x| | | |x|x|x|x| | | | | | | | |x| | | |x|x|x|x| | | |x| | | |x| <-- commit granules
  85 //
  86 // (x = committed)
  87 //
  88 

  89 class VirtualSpaceNode : public CHeapObj<mtClass> {

  90 
  91   // Link to next VirtualSpaceNode
  92   VirtualSpaceNode* _next;
  93 
  94   // The underlying space. This has been either created by this node
  95   //  and is owned by it, or has been handed in from outside (e.g. in
  96   //  case of CompressedClassSpace).

  97   ReservedSpace _rs;










































  98 
  99   // True if the node owns the reserved space, false if not.
 100   const bool _owns_rs;
 101 
 102   // Start pointer of the area.
 103   MetaWord* const _base;
 104 
 105   // Size, in words, of the whole node
 106   const size_t _word_size;


 107 
 108   // Size, in words, of the range of this node which has been handed out in
 109   // the form of root chunks.
 110   size_t _used_words;
 111 
 112   // The bitmap describing the commit state of the region:
 113   // Each bit covers a region of 64K (see constants::commit_granule_size).
 114   CommitMask _commit_mask;
 115 
 116   // An array/lookup table of RootChunkArea objects. Each one describes a root chunk area.
 117   RootChunkAreaLUT _root_chunk_area_lut;
 118 
 119   // Limiter object to ask before expanding the committed size of this node.
 120   CommitLimiter* const _commit_limiter;
 121 
 122   // Points to outside size counters which we are to increase/decrease when we commit/uncommit
 123   // space from this node.
 124   SizeCounter* const _total_reserved_words_counter;
 125   SizeCounter* const _total_committed_words_counter;
 126 
 127   /// committing, uncommitting ///
 128 
 129   // Given a pointer into this node, calculate the start of the commit granule
 130   // the pointer points into.
 131   MetaWord* calc_start_of_granule(MetaWord* p) const {
 132     DEBUG_ONLY(check_pointer(p));
 133     return align_down(p, Settings::commit_granule_bytes());
 134   }
 135 
 136   // Given an address range, ensure it is committed.
 137   //
 138   // The range has to be aligned to granule size.
 139   //
 140   // Function will:
 141   // - check how many granules in that region are uncommitted; If all are committed, it
 142   //    returns true immediately.
 143   // - check if committing those uncommitted granules would bring us over the commit limit
 144   //    (GC threshold, MaxMetaspaceSize). If true, it returns false.
 145   // - commit the memory.
 146   // - mark the range as committed in the commit mask
 147   //
 148   // Returns true if success, false if it did hit a commit limit.
 149   bool commit_range(MetaWord* p, size_t word_size);
 150 
 151   //// creation ////
 152 
 153   // Create a new empty node spanning the given given reserved space.
 154   VirtualSpaceNode(ReservedSpace rs, bool owns_rs, CommitLimiter* limiter,
 155                    SizeCounter* reserve_counter, SizeCounter* commit_counter);
 156 
 157 public:
 158 
 159   // Create a node of a given size (it will create its own space).
 160   static VirtualSpaceNode* create_node(size_t word_size, CommitLimiter* limiter, SizeCounter* reserve_words_counter,
 161                                        SizeCounter* commit_words_counter);
 162 
 163   // Create a node over an existing space
 164   static VirtualSpaceNode* create_node(ReservedSpace rs, CommitLimiter* limiter, SizeCounter* reserve_words_counter,
 165                                        SizeCounter* commit_words_counter);
 166 
 167   ~VirtualSpaceNode();


























 168 
 169   // Note: public for gtests only, could be private.
 170   MetaWord* base() const        { return _base; }

 171 
 172   // Reserved size of the whole node.
 173   size_t word_size() const      { return _word_size; }




 174 
 175   //// Chunk allocation, splitting, merging /////


 176 
 177   // Allocate a root chunk from this node. Will fail and return NULL if the node is full
 178   //  - if we used up the whole address space of this node's memory region.
 179   //    (in case this node backs compressed class space, this is how we hit
 180   //     CompressedClassSpaceSize).
 181   // Note that this just returns reserved memory; caller must take care of committing this
 182   //  chunk before using it.
 183   Metachunk* allocate_root_chunk();
 184 
 185   // Given a chunk c, split it recursively until you get a chunk of the given target_level.
 186   //
 187   // The resulting target chunk resides at the same address as the original chunk.
 188   // The resulting splinters are added to freelists.
 189   void split(chunklevel_t target_level, Metachunk* c, FreeChunkListVector* freelists);
 190 
 191   // Given a chunk, attempt to merge it recursively with its neighboring chunks.
 192   //
 193   // If successful (merged at least once), returns address of
 194   // the merged chunk; NULL otherwise.
 195   //
 196   // The merged chunks are removed from the freelists.
 197   //
 198   // !!! Please note that if this method returns a non-NULL value, the
 199   // original chunk will be invalid and should not be accessed anymore! !!!
 200   Metachunk* merge(Metachunk* c, FreeChunkListVector* freelists);
 201 
 202   // Given a chunk c, which must be "in use" and must not be a root chunk, attempt to
 203   // enlarge it in place by claiming its trailing buddy.
 204   //
 205   // This will only work if c is the leader of the buddy pair and the trailing buddy is free.
 206   //
 207   // If successful, the follower chunk will be removed from the freelists, the leader chunk c will
 208   // double in size (level decreased by one).
 209   //
 210   // On success, true is returned, false otherwise.
 211   bool attempt_enlarge_chunk(Metachunk* c, FreeChunkListVector* freelists);
 212 
 213   // Attempts to purge the node:
 214   //
 215   // If all chunks living in this node are free, they will all be removed from
 216   //  the freelist they currently reside in. Then, the node will be deleted.
 217   //
 218   // Returns true if the node has been deleted, false if not.
 219   // !! If this returns true, do not access the node from this point on. !!
 220   bool attempt_purge(FreeChunkListVector* freelists);
 221 
 222   // Attempts to uncommit free areas according to the rules set in settings.
 223   // Returns number of words uncommitted.
 224   size_t uncommit_free_areas();
 225 
 226   /// misc /////
 227 
 228   // Returns size, in words, of the used space in this node alone.
 229   // (Notes:
 230   //  - This is the space handed out to the ChunkManager, so it is "used" from the viewpoint of this node,
 231   //    but not necessarily used for Metadata.
 232   //  - This may or may not be committed memory.
 233   size_t used_words() const             { return _used_words; }
 234 
 235   // Returns size, in words, of how much space is left in this node alone.
 236   size_t free_words() const             { return _word_size - _used_words; }
 237 
 238   // Returns size, in words, of committed space in this node alone.
 239   // Note: iterates over commit mask and hence may be a tad expensive on large nodes.
 240   size_t committed_words() const;
 241 
 242   //// Committing/uncommitting memory /////
 243 
 244   // Given an address range, ensure it is committed.
 245   //
 246   // The range does not have to be aligned to granule size. However, the function will always commit
 247   // whole granules.
 248   //
 249   // Function will:
 250   // - check how many granules in that region are uncommitted; If all are committed, it
 251   //    returns true immediately.
 252   // - check if committing those uncommitted granules would bring us over the commit limit
 253   //    (GC threshold, MaxMetaspaceSize). If true, it returns false.
 254   // - commit the memory.
 255   // - mark the range as committed in the commit mask
 256   //
 257   // Returns true if success, false if it did hit a commit limit.
 258   bool ensure_range_is_committed(MetaWord* p, size_t word_size);
 259 
 260   // Given an address range (which has to be aligned to commit granule size):
 261   //  - uncommit it
 262   //  - mark it as uncommitted in the commit mask
 263   void uncommit_range(MetaWord* p, size_t word_size);
 264 
 265   //// List stuff ////
 266   VirtualSpaceNode* next() const        { return _next; }
 267   void set_next(VirtualSpaceNode* vsn)  { _next = vsn; }
 268 
 269 
 270   /// Debug stuff ////
 271 
 272   // Print a description about this node.
 273   void print_on(outputStream* st) const;
 274 
 275   // Verify counters and basic structure. Slow mode: verify all chunks in depth
 276   bool contains(const MetaWord* p) const {
 277     return p >= _base && p < _base + _used_words;
 278   }
 279 
 280 #ifdef ASSERT
 281   void check_pointer(const MetaWord* p) const {
 282     assert(contains(p), "invalid pointer");
 283   }
 284   void verify(bool slow) const;
 285   void verify_locked(bool slow) const;
 286 #endif
 287 
 288 };
 289 
 290 
 291 } // namespace metaspace
 292 
 293 #endif // SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP
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