rev 7084 : [mq]: demacro

   1 /*
   2  * Copyright (c) 2000, 2012, 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_MEMORY_SPACE_INLINE_HPP
  26 #define SHARE_VM_MEMORY_SPACE_INLINE_HPP
  27 



  28 #include "gc_interface/collectedHeap.hpp"
  29 #include "memory/space.hpp"
  30 #include "memory/universe.hpp"
  31 #include "runtime/prefetch.inline.hpp"
  32 #include "runtime/safepoint.hpp"
  33 
  34 inline HeapWord* Space::block_start(const void* p) {
  35   return block_start_const(p);
  36 }
  37 
  38 #define SCAN_AND_FORWARD(cp,scan_limit,block_is_obj,block_size) {            \
  39   /* Compute the new addresses for the live objects and store it in the mark \
  40    * Used by universe::mark_sweep_phase2()                                   \
  41    */                                                                        \
  42   HeapWord* compact_top; /* This is where we are currently compacting to. */ \
  43                                                                              \
  44   /* We're sure to be here before any objects are compacted into this        \
  45    * space, so this is a good time to initialize this:                       \
  46    */                                                                        \
  47   set_compaction_top(bottom());                                              \
  48                                                                              \
  49   if (cp->space == NULL) {                                                   \
  50     assert(cp->gen != NULL, "need a generation");                            \
  51     assert(cp->threshold == NULL, "just checking");                          \
  52     assert(cp->gen->first_compaction_space() == this, "just checking");      \
  53     cp->space = cp->gen->first_compaction_space();                           \
  54     compact_top = cp->space->bottom();                                       \
  55     cp->space->set_compaction_top(compact_top);                              \
  56     cp->threshold = cp->space->initialize_threshold();                       \
  57   } else {                                                                   \
  58     compact_top = cp->space->compaction_top();                               \
  59   }                                                                          \
  60                                                                              \
  61   /* We allow some amount of garbage towards the bottom of the space, so     \
  62    * we don't start compacting before there is a significant gain to be made.\
  63    * Occasionally, we want to ensure a full compaction, which is determined  \
  64    * by the MarkSweepAlwaysCompactCount parameter.                           \
  65    */                                                                        \
  66   uint invocations = MarkSweep::total_invocations();                         \
  67   bool skip_dead = ((invocations % MarkSweepAlwaysCompactCount) != 0);       \
  68                                                                              \
  69   size_t allowed_deadspace = 0;                                              \
  70   if (skip_dead) {                                                           \
  71     const size_t ratio = allowed_dead_ratio();                               \
  72     allowed_deadspace = (capacity() * ratio / 100) / HeapWordSize;           \
  73   }                                                                          \
  74                                                                              \
  75   HeapWord* q = bottom();                                                    \
  76   HeapWord* t = scan_limit();                                                \
  77                                                                              \
  78   HeapWord*  end_of_live= q;    /* One byte beyond the last byte of the last \
  79                                    live object. */                           \
  80   HeapWord*  first_dead = end();/* The first dead object. */                 \
  81   LiveRange* liveRange  = NULL; /* The current live range, recorded in the   \
  82                                    first header of preceding free area. */   \
  83   _first_dead = first_dead;                                                  \
  84                                                                              \
  85   const intx interval = PrefetchScanIntervalInBytes;                         \
  86                                                                              \
  87   while (q < t) {                                                            \
  88     assert(!block_is_obj(q) ||                                               \
  89            oop(q)->mark()->is_marked() || oop(q)->mark()->is_unlocked() ||   \
  90            oop(q)->mark()->has_bias_pattern(),                               \
  91            "these are the only valid states during a mark sweep");           \
  92     if (block_is_obj(q) && oop(q)->is_gc_marked()) {                         \
  93       /* prefetch beyond q */                                                \
  94       Prefetch::write(q, interval);                                          \
  95       size_t size = block_size(q);                                           \
  96       compact_top = cp->space->forward(oop(q), size, cp, compact_top);       \
  97       q += size;                                                             \
  98       end_of_live = q;                                                       \
  99     } else {                                                                 \
 100       /* run over all the contiguous dead objects */                         \
 101       HeapWord* end = q;                                                     \
 102       do {                                                                   \
 103         /* prefetch beyond end */                                            \
 104         Prefetch::write(end, interval);                                      \
 105         end += block_size(end);                                              \
 106       } while (end < t && (!block_is_obj(end) || !oop(end)->is_gc_marked()));\
 107                                                                              \
 108       /* see if we might want to pretend this object is alive so that        \
 109        * we don't have to compact quite as often.                            \
 110        */                                                                    \
 111       if (allowed_deadspace > 0 && q == compact_top) {                       \
 112         size_t sz = pointer_delta(end, q);                                   \
 113         if (insert_deadspace(allowed_deadspace, q, sz)) {                    \
 114           compact_top = cp->space->forward(oop(q), sz, cp, compact_top);     \
 115           q = end;                                                           \
 116           end_of_live = end;                                                 \
 117           continue;                                                          \
 118         }                                                                    \
 119       }                                                                      \
 120                                                                              \
 121       /* otherwise, it really is a free region. */                           \
 122                                                                              \
 123       /* for the previous LiveRange, record the end of the live objects. */  \
 124       if (liveRange) {                                                       \
 125         liveRange->set_end(q);                                               \
 126       }                                                                      \
 127                                                                              \
 128       /* record the current LiveRange object.                                \
 129        * liveRange->start() is overlaid on the mark word.                    \
 130        */                                                                    \
 131       liveRange = (LiveRange*)q;                                             \
 132       liveRange->set_start(end);                                             \
 133       liveRange->set_end(end);                                               \
 134                                                                              \
 135       /* see if this is the first dead region. */                            \
 136       if (q < first_dead) {                                                  \
 137         first_dead = q;                                                      \
 138       }                                                                      \
 139                                                                              \
 140       /* move on to the next object */                                       \
 141       q = end;                                                               \
 142     }                                                                        \
 143   }                                                                          \
 144                                                                              \
 145   assert(q == t, "just checking");                                           \
 146   if (liveRange != NULL) {                                                   \
 147     liveRange->set_end(q);                                                   \
 148   }                                                                          \
 149   _end_of_live = end_of_live;                                                \
 150   if (end_of_live < first_dead) {                                            \
 151     first_dead = end_of_live;                                                \
 152   }                                                                          \
 153   _first_dead = first_dead;                                                  \
 154                                                                              \
 155   /* save the compaction_top of the compaction space. */                     \
 156   cp->space->set_compaction_top(compact_top);                                \
 157 }
 158 
 159 #define SCAN_AND_ADJUST_POINTERS(adjust_obj_size) {                             \
 160   /* adjust all the interior pointers to point at the new locations of objects  \
 161    * Used by MarkSweep::mark_sweep_phase3() */                                  \
 162                                                                                 \
 163   HeapWord* q = bottom();                                                       \
 164   HeapWord* t = _end_of_live;  /* Established by "prepare_for_compaction". */   \
 165                                                                                 \
 166   assert(_first_dead <= _end_of_live, "Stands to reason, no?");                 \
 167                                                                                 \
 168   if (q < t && _first_dead > q &&                                               \
 169       !oop(q)->is_gc_marked()) {                                                \
 170     /* we have a chunk of the space which hasn't moved and we've                \
 171      * reinitialized the mark word during the previous pass, so we can't        \
 172      * use is_gc_marked for the traversal. */                                   \
 173     HeapWord* end = _first_dead;                                                \
 174                                                                                 \
 175     while (q < end) {                                                           \
 176       /* I originally tried to conjoin "block_start(q) == q" to the             \
 177        * assertion below, but that doesn't work, because you can't              \
 178        * accurately traverse previous objects to get to the current one         \
 179        * after their pointers have been                                         \
 180        * updated, until the actual compaction is done.  dld, 4/00 */            \
 181       assert(block_is_obj(q),                                                   \
 182              "should be at block boundaries, and should be looking at objs");   \
 183                                                                                 \
 184       /* point all the oops to the new location */                              \
 185       size_t size = oop(q)->adjust_pointers();                                  \
 186       size = adjust_obj_size(size);                                             \
 187                                                                                 \
 188       q += size;                                                                \
 189     }                                                                           \
 190                                                                                 \
 191     if (_first_dead == t) {                                                     \
 192       q = t;                                                                    \
 193     } else {                                                                    \
 194       /* $$$ This is funky.  Using this to read the previously written          \
 195        * LiveRange.  See also use below. */                                     \
 196       q = (HeapWord*)oop(_first_dead)->mark()->decode_pointer();                \
 197     }                                                                           \
 198   }                                                                             \
 199                                                                                 \
 200   const intx interval = PrefetchScanIntervalInBytes;                            \
 201                                                                                 \
 202   debug_only(HeapWord* prev_q = NULL);                                          \
 203   while (q < t) {                                                               \
 204     /* prefetch beyond q */                                                     \
 205     Prefetch::write(q, interval);                                               \
 206     if (oop(q)->is_gc_marked()) {                                               \
 207       /* q is alive */                                                          \
 208       /* point all the oops to the new location */                              \
 209       size_t size = oop(q)->adjust_pointers();                                  \
 210       size = adjust_obj_size(size);                                             \
 211       debug_only(prev_q = q);                                                   \
 212       q += size;                                                                \
 213     } else {                                                                    \
 214       /* q is not a live object, so its mark should point at the next           \
 215        * live object */                                                         \
 216       debug_only(prev_q = q);                                                   \
 217       q = (HeapWord*) oop(q)->mark()->decode_pointer();                         \
 218       assert(q > prev_q, "we should be moving forward through memory");         \
 219     }                                                                           \
 220   }                                                                             \
 221                                                                                 \
 222   assert(q == t, "just checking");                                              \
 223 }
 224 
 225 #define SCAN_AND_COMPACT(obj_size) {                                            \
 226   /* Copy all live objects to their new location                                \
 227    * Used by MarkSweep::mark_sweep_phase4() */                                  \
 228                                                                                 \
 229   HeapWord*       q = bottom();                                                 \
 230   HeapWord* const t = _end_of_live;                                             \
 231   debug_only(HeapWord* prev_q = NULL);                                          \
 232                                                                                 \
 233   if (q < t && _first_dead > q &&                                               \
 234       !oop(q)->is_gc_marked()) {                                                \
 235     debug_only(                                                                 \
 236     /* we have a chunk of the space which hasn't moved and we've reinitialized  \
 237      * the mark word during the previous pass, so we can't use is_gc_marked for \
 238      * the traversal. */                                                        \
 239     HeapWord* const end = _first_dead;                                          \
 240                                                                                 \
 241     while (q < end) {                                                           \
 242       size_t size = obj_size(q);                                                \
 243       assert(!oop(q)->is_gc_marked(),                                           \
 244              "should be unmarked (special dense prefix handling)");             \
 245       debug_only(prev_q = q);                                                   \
 246       q += size;                                                                \
 247     }                                                                           \
 248     )  /* debug_only */                                                         \
 249                                                                                 \
 250     if (_first_dead == t) {                                                     \
 251       q = t;                                                                    \
 252     } else {                                                                    \
 253       /* $$$ Funky */                                                           \
 254       q = (HeapWord*) oop(_first_dead)->mark()->decode_pointer();               \
 255     }                                                                           \
 256   }                                                                             \
 257                                                                                 \
 258   const intx scan_interval = PrefetchScanIntervalInBytes;                       \
 259   const intx copy_interval = PrefetchCopyIntervalInBytes;                       \
 260   while (q < t) {                                                               \
 261     if (!oop(q)->is_gc_marked()) {                                              \
 262       /* mark is pointer to next marked oop */                                  \
 263       debug_only(prev_q = q);                                                   \
 264       q = (HeapWord*) oop(q)->mark()->decode_pointer();                         \
 265       assert(q > prev_q, "we should be moving forward through memory");         \
 266     } else {                                                                    \
 267       /* prefetch beyond q */                                                   \
 268       Prefetch::read(q, scan_interval);                                         \
 269                                                                                 \
 270       /* size and destination */                                                \
 271       size_t size = obj_size(q);                                                \
 272       HeapWord* compaction_top = (HeapWord*)oop(q)->forwardee();                \
 273                                                                                 \
 274       /* prefetch beyond compaction_top */                                      \
 275       Prefetch::write(compaction_top, copy_interval);                           \
 276                                                                                 \
 277       /* copy object and reinit its mark */                                     \
 278       assert(q != compaction_top, "everything in this pass should be moving");  \
 279       Copy::aligned_conjoint_words(q, compaction_top, size);                    \
 280       oop(compaction_top)->init_mark();                                         \
 281       assert(oop(compaction_top)->klass() != NULL, "should have a class");      \
 282                                                                                 \
 283       debug_only(prev_q = q);                                                   \
 284       q += size;                                                                \
 285     }                                                                           \
 286   }                                                                             \
 287                                                                                 \
 288   /* Let's remember if we were empty before we did the compaction. */           \
 289   bool was_empty = used_region().is_empty();                                    \
 290   /* Reset space after compaction is complete */                                \
 291   reset_after_compaction();                                                     \
 292   /* We do this clear, below, since it has overloaded meanings for some */      \
 293   /* space subtypes.  For example, OffsetTableContigSpace's that were   */      \
 294   /* compacted into will have had their offset table thresholds updated */      \
 295   /* continuously, but those that weren't need to have their thresholds */      \
 296   /* re-initialized.  Also mangles unused area for debugging.           */      \
 297   if (used_region().is_empty()) {                                               \
 298     if (!was_empty) clear(SpaceDecorator::Mangle);                              \
 299   } else {                                                                      \
 300     if (ZapUnusedHeapArea) mangle_unused_area();                                \
 301   }                                                                             \
 302 }
 303 
 304 inline HeapWord* OffsetTableContigSpace::allocate(size_t size) {
 305   HeapWord* res = ContiguousSpace::allocate(size);
 306   if (res != NULL) {
 307     _offsets.alloc_block(res, size);
 308   }
 309   return res;
 310 }
 311 
 312 // Because of the requirement of keeping "_offsets" up to date with the
 313 // allocations, we sequentialize these with a lock.  Therefore, best if
 314 // this is used for larger LAB allocations only.
 315 inline HeapWord* OffsetTableContigSpace::par_allocate(size_t size) {
 316   MutexLocker x(&_par_alloc_lock);
 317   // This ought to be just "allocate", because of the lock above, but that
 318   // ContiguousSpace::allocate asserts that either the allocating thread
 319   // holds the heap lock or it is the VM thread and we're at a safepoint.
 320   // The best I (dld) could figure was to put a field in ContiguousSpace
 321   // meaning "locking at safepoint taken care of", and set/reset that
 322   // here.  But this will do for now, especially in light of the comment
 323   // above.  Perhaps in the future some lock-free manner of keeping the
 324   // coordination.
 325   HeapWord* res = ContiguousSpace::par_allocate(size);
 326   if (res != NULL) {
 327     _offsets.alloc_block(res, size);
 328   }
 329   return res;
 330 }
 331 
 332 inline HeapWord*
 333 OffsetTableContigSpace::block_start_const(const void* p) const {
 334   return _offsets.block_start(p);
 335 }
 336 



































































































































































































































































 337 #endif // SHARE_VM_MEMORY_SPACE_INLINE_HPP
--- EOF ---