1 /*

     2  * copyright (c) 2011, 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_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP

    26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP

    27 

    28 #include "gc_implementation/g1/heapRegion.hpp"

    29 

    30 // Large buffer for some cases where the output might be larger than normal.

    31 #define HRL_ERR_MSG_BUFSZ 512

    32 typedef FormatBuffer<HRL_ERR_MSG_BUFSZ> hrl_err_msg;

    33 

    34 // Set verification will be forced either if someone defines

    35 // HEAP_REGION_SET_FORCE_VERIFY to be 1, or in builds in which

    36 // asserts are compiled in.

    37 #ifndef HEAP_REGION_SET_FORCE_VERIFY

    38 #define HEAP_REGION_SET_FORCE_VERIFY defined(ASSERT)

    39 #endif // HEAP_REGION_SET_FORCE_VERIFY

    40 

    41 //////////////////// HeapRegionSetBase ////////////////////

    42 

    43 // Base class for all the classes that represent heap region sets. It

    44 // contains the basic attributes that each set needs to maintain

    45 // (e.g., length, region num, used bytes sum) plus any shared

    46 // functionality (e.g., verification).

    47 

    48 class hrl_ext_msg;

    49 

    50 class HeapRegionSetBase VALUE_OBJ_CLASS_SPEC {

    51   friend class hrl_ext_msg;

    52 

    53 protected:

    54   static size_t calculate_region_num(HeapRegion* hr);

    55 

    56   static size_t _unrealistically_long_length;

    57 

    58   // The number of regions added to the set. If the set contains

    59   // only humongous regions, this reflects only 'starts humongous'

    60   // regions and does not include 'continues humongous' ones.

    61   size_t _length;

    62 

    63   // The total number of regions represented by the set. If the set

    64   // does not contain humongous regions, this should be the same as

    65   // _length. If the set contains only humongous regions, this will

    66   // include the 'continues humongous' regions.

    67   size_t _region_num;

    68 

    69   // We don't keep track of the total capacity explicitly, we instead

    70   // recalculate it based on _region_num and the heap region size.

    71 

    72   // The sum of used bytes in the all the regions in the set.

    73   size_t _total_used_bytes;

    74 

    75   const char* _name;

    76 

    77   bool        _verify_in_progress;

    78   size_t      _calc_length;

    79   size_t      _calc_region_num;

    80   size_t      _calc_total_capacity_bytes;

    81   size_t      _calc_total_used_bytes;

    82 

    83   // verify_region() is used to ensure that the contents of a region

    84   // added to / removed from a set are consistent. Different sets

    85   // make different assumptions about the regions added to them. So

    86   // each set can override verify_region_extra(), which is called

    87   // from verify_region(), and do any extra verification it needs to

    88   // perform in that.

    89   virtual const char* verify_region_extra(HeapRegion* hr) { return NULL; }

    90   bool verify_region(HeapRegion* hr,

    91                      HeapRegionSetBase* expected_containing_set);

    92 

    93   // Indicates whether all regions in the set should be humongous or

    94   // not. Only used during verification.

    95   virtual bool regions_humongous() = 0;

    96 

    97   // Indicates whether all regions in the set should be empty or

    98   // not. Only used during verification.

    99   virtual bool regions_empty() = 0;

   100 

   101   // Subclasses can optionally override this to do MT safety protocol

   102   // checks. It is called in an assert from all methods that perform

   103   // updates on the set (and subclasses should also call it too).

   104   virtual bool check_mt_safety() { return true; }

   105 

   106   // fill_in_ext_msg() writes the the values of the set's attributes

   107   // in the custom err_msg (hrl_ext_msg). fill_in_ext_msg_extra()

   108   // allows subclasses to append further information.

   109   virtual void fill_in_ext_msg_extra(hrl_ext_msg* msg) { }

   110   void fill_in_ext_msg(hrl_ext_msg* msg, const char* message);

   111 

   112   // It updates the fields of the set to reflect hr being added to

   113   // the set.

   114   inline void update_for_addition(HeapRegion* hr);

   115 

   116   // It updates the fields of the set to reflect hr being added to

   117   // the set and tags the region appropriately.

   118   inline void add_internal(HeapRegion* hr);

   119 

   120   // It updates the fields of the set to reflect hr being removed

   121   // from the set.

   122   inline void update_for_removal(HeapRegion* hr);

   123 

   124   // It updates the fields of the set to reflect hr being removed

   125   // from the set and tags the region appropriately.

   126   inline void remove_internal(HeapRegion* hr);

   127 

   128   // It clears all the fields of the sets. Note: it will not iterate

   129   // over the set and remove regions from it. It assumes that the

   130   // caller has already done so. It will literally just clear the fields.

   131   virtual void clear();

   132 

   133   HeapRegionSetBase(const char* name);

   134 

   135 public:

   136   static void set_unrealistically_long_length(size_t len);

   137 

   138   const char* name() { return _name; }

   139 

   140   size_t length() { return _length; }

   141 

   142   bool is_empty() { return _length == 0; }

   143 

   144   size_t region_num() { return _region_num; }

   145 

   146   size_t total_capacity_bytes() {

   147     return region_num() << HeapRegion::LogOfHRGrainBytes;

   148   }

   149 

   150   size_t total_used_bytes() { return _total_used_bytes; }

   151 

   152   virtual void verify();

   153   void verify_start();

   154   void verify_next_region(HeapRegion* hr);

   155   void verify_end();

   156 

   157 #if HEAP_REGION_SET_FORCE_VERIFY

   158   void verify_optional() {

   159     verify();

   160   }

   161 #else // HEAP_REGION_SET_FORCE_VERIFY

   162   void verify_optional() { }

   163 #endif // HEAP_REGION_SET_FORCE_VERIFY

   164 

   165   virtual void print_on(outputStream* out, bool print_contents = false);

   166 };

   167 

   168 // Customized err_msg for heap region sets. Apart from a

   169 // assert/guarantee-specific message it also prints out the values of

   170 // the fields of the associated set. This can be very helpful in

   171 // diagnosing failures.

   172 

   173 class hrl_ext_msg : public hrl_err_msg {

   174 public:

   175   hrl_ext_msg(HeapRegionSetBase* set, const char* message) : hrl_err_msg("") {

   176     set->fill_in_ext_msg(this, message);

   177   }

   178 };

   179 

   180 // These two macros are provided for convenience, to keep the uses of

   181 // these two asserts a bit more concise.

   182 

   183 #define hrl_assert_mt_safety_ok(_set_)                                        \

   184   do {                                                                        \

   185     assert((_set_)->check_mt_safety(), hrl_ext_msg((_set_), "MT safety"));    \

   186   } while (0)

   187 

   188 #define hrl_assert_region_ok(_set_, _hr_, _expected_)                         \

   189   do {                                                                        \

   190     assert((_set_)->verify_region((_hr_), (_expected_)),                      \

   191            hrl_ext_msg((_set_), "region verification"));                      \

   192   } while (0)

   193 

   194 //////////////////// HeapRegionSet ////////////////////

   195 

   196 #define hrl_assert_sets_match(_set1_, _set2_)                                 \

   197   do {                                                                        \

   198     assert(((_set1_)->regions_humongous() ==                                  \

   199                                             (_set2_)->regions_humongous()) && \

   200            ((_set1_)->regions_empty() == (_set2_)->regions_empty()),          \

   201            hrl_err_msg("the contents of set %s and set %s should match",      \

   202                        (_set1_)->name(), (_set2_)->name()));                  \

   203   } while (0)

   204 

   205 // This class represents heap region sets whose members are not

   206 // explicitly tracked. It's helpful to group regions using such sets

   207 // so that we can reason about all the region groups in the heap using

   208 // the same interface (namely, the HeapRegionSetBase API).

   209 

   210 class HeapRegionSet : public HeapRegionSetBase {

   211 protected:

   212   virtual const char* verify_region_extra(HeapRegion* hr) {

   213     if (hr->next() != NULL) {

   214       return "next() should always be NULL as we do not link the regions";

   215     }

   216 

   217     return HeapRegionSetBase::verify_region_extra(hr);

   218   }

   219 

   220   HeapRegionSet(const char* name) : HeapRegionSetBase(name) {

   221     clear();

   222   }

   223 

   224 public:

   225   // It adds hr to the set. The region should not be a member of

   226   // another set.

   227   inline void add(HeapRegion* hr);

   228 

   229   // It removes hr from the set. The region should be a member of

   230   // this set.

   231   inline void remove(HeapRegion* hr);

   232 

   233   // It removes a region from the set. Instead of updating the fields

   234   // of the set to reflect this removal, it accumulates the updates

   235   // in proxy_set. The idea is that proxy_set is thread-local to

   236   // avoid multiple threads updating the fields of the set

   237   // concurrently and having to synchronize. The method

   238   // update_from_proxy() will update the fields of the set from the

   239   // proxy_set.

   240   inline void remove_with_proxy(HeapRegion* hr, HeapRegionSet* proxy_set);

   241 

   242   // After multiple calls to remove_with_proxy() the updates to the

   243   // fields of the set are accumulated in proxy_set. This call

   244   // updates the fields of the set from proxy_set.

   245   void update_from_proxy(HeapRegionSet* proxy_set);

   246 };

   247 

   248 //////////////////// HeapRegionLinkedList ////////////////////

   249 

   250 // A set that links all the regions added to it in a singly-linked

   251 // list. We should try to avoid doing operations that iterate over

   252 // such lists in performance critical paths. Typically we should

   253 // add / remove one region at a time or concatenate two lists. All

   254 // those operations are done in constant time.

   255 

   256 class HeapRegionLinkedListIterator;

   257 

   258 class HeapRegionLinkedList : public HeapRegionSetBase {

   259   friend class HeapRegionLinkedListIterator;

   260 

   261 private:

   262   HeapRegion* _head;

   263   HeapRegion* _tail;

   264 

   265   // These are provided for use by the friend classes.

   266   HeapRegion* head() { return _head; }

   267   HeapRegion* tail() { return _tail; }

   268 

   269 protected:

   270   virtual void fill_in_ext_msg_extra(hrl_ext_msg* msg);

   271 

   272   // See the comment for HeapRegionSetBase::clear()

   273   virtual void clear();

   274 

   275   HeapRegionLinkedList(const char* name) : HeapRegionSetBase(name) {

   276     clear();

   277   }

   278 

   279 public:

   280   // It adds hr to the list as the new tail. The region should not be

   281   // a member of another set.

   282   inline void add_as_tail(HeapRegion* hr);

   283 

   284   // It removes and returns the head of the list. It assumes that the

   285   // list is not empty so it will return a non-NULL value.

   286   inline HeapRegion* remove_head();

   287 

   288   // Convenience method.

   289   inline HeapRegion* remove_head_or_null();

   290 

   291   // It moves the regions from from_list to this list and empties

   292   // from_list. The new regions will appear in the same order as they

   293   // were in from_list and be linked in the end of this list.

   294   void add_as_tail(HeapRegionLinkedList* from_list);

   295 

   296   // It empties the list by removing all regions from it.

   297   void remove_all();

   298 

   299   // It removes all regions in the list that are pending for removal

   300   // (i.e., they have been tagged with "pending_removal"). The list

   301   // must not be empty, target_count should reflect the exact number

   302   // of regions that are pending for removal in the list, and

   303   // target_count should be > 1 (currently, we never need to remove a

   304   // single region using this).

   305   void remove_all_pending(size_t target_count);

   306 

   307   virtual void verify();

   308 

   309   virtual void print_on(outputStream* out, bool print_contents = false);

   310 };

   311 

   312 //////////////////// HeapRegionLinkedList ////////////////////

   313 

   314 // Iterator class that provides a convenient way to iterator over the

   315 // regions in a HeapRegionLinkedList instance.

   316 

   317 class HeapRegionLinkedListIterator : public StackObj {

   318 private:

   319   HeapRegionLinkedList* _list;

   320   HeapRegion*           _curr;

   321 

   322 public:

   323   bool more_available() {

   324     return _curr != NULL;

   325   }

   326 

   327   HeapRegion* get_next() {

   328     assert(more_available(),

   329            "get_next() should be called when more regions are available");

   330 

   331     // If we are going to introduce a count in the iterator we should

   332     // do the "cycle" check.

   333 

   334     HeapRegion* hr = _curr;

   335     assert(_list->verify_region(hr, _list), "region verification");

   336     _curr = hr->next();

   337     return hr;

   338   }

   339 

   340   HeapRegionLinkedListIterator(HeapRegionLinkedList* list)

   341     : _curr(NULL), _list(list) {

   342     _curr = list->head();

   343   }

   344 };

   345 

   346 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP