mono/sgen/sgen-alloc.c

   1 /**
   2  * \file
   3  * Object allocation routines + managed allocators
   4  *
   5  * Author:
   6  *      Paolo Molaro (lupus@ximian.com)
   7  *  Rodrigo Kumpera (kumpera@gmail.com)
   8  *
   9  * Copyright 2005-2011 Novell, Inc (http://www.novell.com)
  10  * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
  11  * Copyright 2011 Xamarin, Inc.
  12  * Copyright (C) 2012 Xamarin Inc
  13  *
  14  * Licensed under the MIT license. See LICENSE file in the project root for full license information.
  15  */
  16
  17 /*
  18  * ######################################################################
  19  * ########  Object allocation
  20  * ######################################################################
  21  * This section of code deals with allocating memory for objects.
  22  * There are several ways:
  23  * *) allocate large objects
  24  * *) allocate normal objects
  25  * *) fast lock-free allocation
  26  * *) allocation of pinned objects
  27  */
  28
  29 #include "config.h"
  30 #ifdef HAVE_SGEN_GC
  31
  32 #include <string.h>
  33
  34 #include "mono/sgen/sgen-gc.h"
  35 #include "mono/sgen/sgen-protocol.h"
  36 #include "mono/sgen/sgen-memory-governor.h"
  37 #include "mono/sgen/sgen-client.h"
  38 #include "mono/utils/mono-memory-model.h"
  39 #include "mono/utils/mono-tls-inline.h"
  40
  41 #define ALIGN_UP                SGEN_ALIGN_UP
  42 #define ALLOC_ALIGN             SGEN_ALLOC_ALIGN
  43 #define MAX_SMALL_OBJ_SIZE      SGEN_MAX_SMALL_OBJ_SIZE
  44
  45 #ifdef HEAVY_STATISTICS
  46 static guint64 stat_objects_alloced = 0;
  47 static guint64 stat_bytes_alloced = 0;
  48 static guint64 stat_bytes_alloced_los = 0;
  49 #endif
  50
  51 /* The total number of bytes allocated so far in program execution by all attached threads.
  52  * This is not constantly syncrhonized, but only updated on each GC. */
  53 static guint64 bytes_allocated_attached = 0;
  54
  55 /* Total bytes allocated so far in program execution by detached threads */
  56 static guint64 bytes_allocated_detached = 0;
  57
  58 /*
  59  * Allocation is done from a Thread Local Allocation Buffer (TLAB). TLABs are allocated
  60  * from nursery fragments.
  61  * tlab_next is the pointer to the space inside the TLAB where the next object will
  62  * be allocated.
  63  * tlab_temp_end is the pointer to the end of the temporary space reserved for
  64  * the allocation: it allows us to set the scan starts at reasonable intervals.
  65  * tlab_real_end points to the end of the TLAB.
  66  */
  67
  68 #define TLAB_START      (__thread_info__->tlab_start)
  69 #define TLAB_NEXT       (__thread_info__->tlab_next)
  70 #define TLAB_TEMP_END   (__thread_info__->tlab_temp_end)
  71 #define TLAB_REAL_END   (__thread_info__->tlab_real_end)
  72
  73 static void
  74 increment_thread_allocation_counter (size_t byte_size)
  75 {
  76         mono_thread_info_current ()->total_bytes_allocated += byte_size;
  77 }
  78
  79 static GCObject*
  80 alloc_degraded (GCVTable vtable, size_t size, gboolean for_mature)
  81 {
  82         GCObject *p;
  83         increment_thread_allocation_counter (size);
  84
  85         if (!for_mature) {
  86                 sgen_client_degraded_allocation ();
  87                 SGEN_ATOMIC_ADD_P (sgen_degraded_mode, size);
  88                 sgen_ensure_free_space (size, GENERATION_OLD);
  89         } else {
  90                 gboolean forced;
  91                 if (sgen_need_major_collection (size, &forced))
  92                         sgen_perform_collection (size, GENERATION_OLD, "mature allocation failure", !for_mature || forced, TRUE);
  93         }
  94
  95
  96         p = sgen_major_collector.alloc_degraded (vtable, size);
  97
  98         if (!for_mature)
  99                 sgen_binary_protocol_alloc_degraded (p, vtable, size, sgen_client_get_provenance ());
 100
 101         return p;
 102 }
 103
 104 static void
 105 zero_tlab_if_necessary (void *p, size_t size)
 106 {
 107         if (sgen_nursery_clear_policy == CLEAR_AT_TLAB_CREATION || sgen_nursery_clear_policy == CLEAR_AT_TLAB_CREATION_DEBUG) {
 108                 memset (p, 0, size);
 109         } else {
 110                 /*
 111                  * This function is called for all allocations in
 112                  * TLABs.  TLABs originate from fragments, which are
 113                  * initialized to be faux arrays.  The remainder of
 114                  * the fragments are zeroed out at initialization for
 115                  * CLEAR_AT_GC, so here we just need to make sure that
 116                  * the array header is zeroed.  Since we don't know
 117                  * whether we're called for the start of a fragment or
 118                  * for somewhere in between, we zero in any case, just
 119                  * to make sure.
 120                  */
 121                 sgen_client_zero_array_fill_header (p, size);
 122         }
 123 }
 124
 125 /*
 126  * Provide a variant that takes just the vtable for small fixed-size objects.
 127  * The aligned size is already computed and stored in vt->gc_descr.
 128  * Note: every SGEN_SCAN_START_SIZE or so we are given the chance to do some special
 129  * processing. We can keep track of where objects start, for example,
 130  * so when we scan the thread stacks for pinned objects, we can start
 131  * a search for the pinned object in SGEN_SCAN_START_SIZE chunks.
 132  */
 133 GCObject*
 134 sgen_alloc_obj_nolock (GCVTable vtable, size_t size)
 135 {
 136         /* FIXME: handle OOM */
 137         void **p;
 138         char *new_next;
 139         size_t real_size = size;
 140         TLAB_ACCESS_INIT;
 141
 142         CANARIFY_SIZE(size);
 143
 144         HEAVY_STAT (++stat_objects_alloced);
 145         if (real_size <= SGEN_MAX_SMALL_OBJ_SIZE)
 146                 HEAVY_STAT (stat_bytes_alloced += size);
 147         else
 148                 HEAVY_STAT (stat_bytes_alloced_los += size);
 149
 150         size = ALIGN_UP (size);
 151
 152         SGEN_ASSERT (6, sgen_vtable_get_descriptor (vtable), "VTable without descriptor");
 153
 154         if (G_UNLIKELY (sgen_has_per_allocation_action)) {
 155                 static int alloc_count;
 156                 int current_alloc = mono_atomic_inc_i32 (&alloc_count);
 157
 158                 if (sgen_collect_before_allocs) {
 159                         if (((current_alloc % sgen_collect_before_allocs) == 0) && sgen_nursery_section) {
 160                                 sgen_perform_collection (0, GENERATION_NURSERY, "collect-before-alloc-triggered", TRUE, TRUE);
 161                                 if (!sgen_degraded_mode && sgen_can_alloc_size (size) && real_size <= SGEN_MAX_SMALL_OBJ_SIZE) {
 162                                         // FIXME:
 163                                         g_assert_not_reached ();
 164                                 }
 165                         }
 166                 } else if (sgen_verify_before_allocs) {
 167                         if ((current_alloc % sgen_verify_before_allocs) == 0)
 168                                 sgen_check_whole_heap_stw ();
 169                 }
 170         }
 171
 172         /*
 173          * We must already have the lock here instead of after the
 174          * fast path because we might be interrupted in the fast path
 175          * (after confirming that new_next < TLAB_TEMP_END) by the GC,
 176          * and we'll end up allocating an object in a fragment which
 177          * no longer belongs to us.
 178          *
 179          * The managed allocator does not do this, but it's treated
 180          * specially by the world-stopping code.
 181          */
 182
 183         if (real_size > SGEN_MAX_SMALL_OBJ_SIZE) {
 184                 p = (void **)sgen_los_alloc_large_inner (vtable, ALIGN_UP (real_size));
 185                 if (p) {
 186                         increment_thread_allocation_counter (size);
 187                 }
 188         } else {
 189                 /* tlab_next and tlab_temp_end are TLS vars so accessing them might be expensive */
 190
 191                 p = (void**)TLAB_NEXT;
 192                 /* FIXME: handle overflow */
 193                 new_next = (char*)p + size;
 194                 TLAB_NEXT = new_next;
 195
 196                 if (G_LIKELY (new_next < TLAB_TEMP_END)) {
 197                         /* Fast path */
 198
 199                         CANARIFY_ALLOC(p,real_size);
 200                         SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, sgen_client_vtable_get_name (vtable), size);
 201                         sgen_binary_protocol_alloc (p , vtable, size, sgen_client_get_provenance ());
 202                         g_assert (*p == NULL);
 203                         mono_atomic_store_seq (p, vtable);
 204
 205                         return (GCObject*)p;
 206                 }
 207
 208                 /* Slow path */
 209
 210                 /* there are two cases: the object is too big or we run out of space in the TLAB */
 211                 /* we also reach here when the thread does its first allocation after a minor
 212                  * collection, since the tlab_ variables are initialized to NULL.
 213                  * there can be another case (from ORP), if we cooperate with the runtime a bit:
 214                  * objects that need finalizers can have the high bit set in their size
 215                  * so the above check fails and we can readily add the object to the queue.
 216                  * This avoids taking again the GC lock when registering, but this is moot when
 217                  * doing thread-local allocation, so it may not be a good idea.
 218                  */
 219                 if (TLAB_NEXT >= TLAB_REAL_END) {
 220                         int available_in_tlab;
 221                         /*
 222                          * Run out of space in the TLAB. When this happens, some amount of space
 223                          * remains in the TLAB, but not enough to satisfy the current allocation
 224                          * request. We keep the TLAB for future allocations if the remaining
 225                          * space is above a treshold, and satisfy the allocation directly
 226                          * from the nursery. Otherwise, we attempt to get a new TLAB from the
 227                          * nursery and allocate into it.
 228                          */
 229                         TLAB_NEXT -= size;
 230                         /* when running in degraded mode, we continue allocing that way
 231                          * for a while, to decrease the number of useless nursery collections.
 232                          */
 233                         if (sgen_degraded_mode && sgen_degraded_mode < sgen_nursery_size)
 234                                 return alloc_degraded (vtable, size, FALSE);
 235
 236                         available_in_tlab = (int)(TLAB_REAL_END - TLAB_NEXT);//We'll never have tlabs > 2Gb
 237                         if (size > sgen_tlab_size || available_in_tlab > SGEN_MAX_NURSERY_WASTE) {
 238                                 /* Allocate directly from the nursery */
 239                                 p = (void **)sgen_nursery_alloc (size);
 240                                 if (!p) {
 241                                         /*
 242                                          * We couldn't allocate from the nursery, so we try
 243                                          * collecting.  Even after the collection, we might
 244                                          * still not have enough memory to allocate the
 245                                          * object.  The reason will most likely be that we've
 246                                          * run out of memory, but there is the theoretical
 247                                          * possibility that other threads might have consumed
 248                                          * the freed up memory ahead of us.
 249                                          *
 250                                          * What we do in this case is allocate degraded, i.e.,
 251                                          * from the major heap.
 252                                          *
 253                                          * Ideally we'd like to detect the case of other
 254                                          * threads allocating ahead of us and loop (if we
 255                                          * always loop we will loop endlessly in the case of
 256                                          * OOM).
 257                                          */
 258                                         sgen_ensure_free_space (real_size, GENERATION_NURSERY);
 259                                         if (!sgen_degraded_mode)
 260                                                 p = (void **)sgen_nursery_alloc (size);
 261
 262                                         if (p)
 263                                                 increment_thread_allocation_counter (size);
 264
 265                                 }
 266                                 if (!p)
 267                                         return alloc_degraded (vtable, size, TRUE);
 268
 269                                 zero_tlab_if_necessary (p, size);
 270                         } else {
 271                                 size_t alloc_size = 0;
 272                                 if (TLAB_START)
 273                                         SGEN_LOG (3, "Retire TLAB: %p-%p [%ld]", TLAB_START, TLAB_REAL_END, (long)(TLAB_REAL_END - TLAB_NEXT - size));
 274                                 sgen_nursery_retire_region (p, available_in_tlab);
 275
 276                                 p = (void **)sgen_nursery_alloc_range (sgen_tlab_size, size, &alloc_size);
 277                                 if (!p) {
 278                                         /* See comment above in similar case. */
 279                                         sgen_ensure_free_space (sgen_tlab_size, GENERATION_NURSERY);
 280                                         if (!sgen_degraded_mode)
 281                                                 p = (void **)sgen_nursery_alloc_range (sgen_tlab_size, size, &alloc_size);
 282                                 }
 283                                 if (!p)
 284                                         return alloc_degraded (vtable, size, TRUE);
 285
 286                                 increment_thread_allocation_counter (TLAB_NEXT - TLAB_START);
 287
 288                                 /* Allocate a new TLAB from the current nursery fragment */
 289                                 TLAB_START = (char*)p;
 290                                 TLAB_NEXT = TLAB_START;
 291                                 TLAB_REAL_END = TLAB_START + alloc_size;
 292                                 TLAB_TEMP_END = TLAB_START + MIN (SGEN_SCAN_START_SIZE, alloc_size);
 293
 294                                 zero_tlab_if_necessary (TLAB_START, alloc_size);
 295
 296                                 /* Allocate from the TLAB */
 297                                 p = (void **)TLAB_NEXT;
 298                                 TLAB_NEXT += size;
 299                                 sgen_set_nursery_scan_start ((char*)p);
 300                         }
 301                 } else {
 302                         /* Reached tlab_temp_end */
 303
 304                         /* record the scan start so we can find pinned objects more easily */
 305                         sgen_set_nursery_scan_start ((char*)p);
 306                         /* we just bump tlab_temp_end as well */
 307                         TLAB_TEMP_END = MIN (TLAB_REAL_END, TLAB_NEXT + SGEN_SCAN_START_SIZE);
 308                         SGEN_LOG (5, "Expanding local alloc: %p-%p", TLAB_NEXT, TLAB_TEMP_END);
 309                 }
 310                 CANARIFY_ALLOC(p,real_size);
 311         }
 312
 313         if (G_LIKELY (p)) {
 314                 SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, sgen_client_vtable_get_name (vtable), size);
 315                 sgen_binary_protocol_alloc (p, vtable, size, sgen_client_get_provenance ());
 316                 mono_atomic_store_seq (p, vtable);
 317         }
 318
 319         return (GCObject*)p;
 320 }
 321
 322 GCObject*
 323 sgen_try_alloc_obj_nolock (GCVTable vtable, size_t size)
 324 {
 325         void **p;
 326         char *new_next;
 327         size_t real_size = size;
 328         TLAB_ACCESS_INIT;
 329
 330         CANARIFY_SIZE(size);
 331
 332         size = ALIGN_UP (size);
 333         SGEN_ASSERT (9, real_size >= SGEN_CLIENT_MINIMUM_OBJECT_SIZE, "Object too small");
 334
 335         SGEN_ASSERT (6, sgen_vtable_get_descriptor (vtable), "VTable without descriptor");
 336
 337         if (real_size > SGEN_MAX_SMALL_OBJ_SIZE)
 338                 return NULL;
 339
 340         if (G_UNLIKELY (size > sgen_tlab_size)) {
 341                 /* Allocate directly from the nursery */
 342
 343                 p = (void **)sgen_nursery_alloc (size);
 344                 if (!p)
 345                         return NULL;
 346
 347                 increment_thread_allocation_counter (size);
 348                 sgen_set_nursery_scan_start ((char*)p);
 349
 350                 /*FIXME we should use weak memory ops here. Should help specially on x86. */
 351                 zero_tlab_if_necessary (p, size);
 352         } else {
 353                 int available_in_tlab;
 354                 char *real_end;
 355                 /* tlab_next and tlab_temp_end are TLS vars so accessing them might be expensive */
 356
 357                 p = (void**)TLAB_NEXT;
 358                 /* FIXME: handle overflow */
 359                 new_next = (char*)p + size;
 360
 361                 real_end = TLAB_REAL_END;
 362                 available_in_tlab = (int)(real_end - (char*)p);//We'll never have tlabs > 2Gb
 363
 364                 if (G_LIKELY (new_next < real_end)) {
 365                         TLAB_NEXT = new_next;
 366
 367                         /* Second case, we overflowed temp end */
 368                         if (G_UNLIKELY (new_next >= TLAB_TEMP_END)) {
 369                                 sgen_set_nursery_scan_start (new_next);
 370                                 /* we just bump tlab_temp_end as well */
 371                                 TLAB_TEMP_END = MIN (TLAB_REAL_END, TLAB_NEXT + SGEN_SCAN_START_SIZE);
 372                                 SGEN_LOG (5, "Expanding local alloc: %p-%p", TLAB_NEXT, TLAB_TEMP_END);
 373                         }
 374                 } else if (available_in_tlab > SGEN_MAX_NURSERY_WASTE) {
 375                         /* Allocate directly from the nursery */
 376                         p = (void **)sgen_nursery_alloc (size);
 377                         if (!p)
 378                                 return NULL;
 379
 380                         increment_thread_allocation_counter (size);
 381                         zero_tlab_if_necessary (p, size);
 382                 } else {
 383                         size_t alloc_size = 0;
 384
 385                         sgen_nursery_retire_region (p, available_in_tlab);
 386                         new_next = (char *)sgen_nursery_alloc_range (sgen_tlab_size, size, &alloc_size);
 387                         p = (void**)new_next;
 388                         if (!p)
 389                                 return NULL;
 390
 391                         increment_thread_allocation_counter (TLAB_NEXT - TLAB_START);
 392
 393                         TLAB_START = (char*)new_next;
 394                         TLAB_NEXT = new_next + size;
 395                         TLAB_REAL_END = new_next + alloc_size;
 396                         TLAB_TEMP_END = new_next + MIN (SGEN_SCAN_START_SIZE, alloc_size);
 397                         sgen_set_nursery_scan_start ((char*)p);
 398
 399                         zero_tlab_if_necessary (new_next, alloc_size);
 400                 }
 401         }
 402
 403         HEAVY_STAT (++stat_objects_alloced);
 404         HEAVY_STAT (stat_bytes_alloced += size);
 405
 406         CANARIFY_ALLOC(p,real_size);
 407         SGEN_LOG (6, "Allocated object %p, vtable: %p (%s), size: %zd", p, vtable, sgen_client_vtable_get_name (vtable), size);
 408         sgen_binary_protocol_alloc (p, vtable, size, sgen_client_get_provenance ());
 409         g_assert (*p == NULL); /* FIXME disable this in non debug builds */
 410
 411         mono_atomic_store_seq (p, vtable);
 412
 413         return (GCObject*)p;
 414 }
 415
 416 GCObject*
 417 sgen_alloc_obj (GCVTable vtable, size_t size)
 418 {
 419         GCObject *res;
 420         TLAB_ACCESS_INIT;
 421
 422         if (!SGEN_CAN_ALIGN_UP (size))
 423                 return NULL;
 424
 425         if (G_UNLIKELY (sgen_has_per_allocation_action)) {
 426                 static int alloc_count;
 427                 int current_alloc = mono_atomic_inc_i32 (&alloc_count);
 428
 429                 if (sgen_verify_before_allocs) {
 430                         if ((current_alloc % sgen_verify_before_allocs) == 0) {
 431                                 LOCK_GC;
 432                                 sgen_check_whole_heap_stw ();
 433                                 UNLOCK_GC;
 434                         }
 435                 }
 436                 if (sgen_collect_before_allocs) {
 437                         if (((current_alloc % sgen_collect_before_allocs) == 0) && sgen_nursery_section) {
 438                                 LOCK_GC;
 439                                 sgen_perform_collection (0, GENERATION_NURSERY, "collect-before-alloc-triggered", TRUE, TRUE);
 440                                 UNLOCK_GC;
 441                         }
 442                 }
 443         }
 444
 445         ENTER_CRITICAL_REGION;
 446         res = sgen_try_alloc_obj_nolock (vtable, size);
 447         if (res) {
 448                 EXIT_CRITICAL_REGION;
 449                 return res;
 450         }
 451         EXIT_CRITICAL_REGION;
 452
 453         LOCK_GC;
 454         res = sgen_alloc_obj_nolock (vtable, size);
 455         UNLOCK_GC;
 456
 457         return res;
 458 }
 459
 460 /*
 461  * To be used for interned strings and possibly MonoThread, reflection handles.
 462  * We may want to explicitly free these objects.
 463  */
 464 GCObject*
 465 sgen_alloc_obj_pinned (GCVTable vtable, size_t size)
 466 {
 467         GCObject *p;
 468
 469
 470         if (!SGEN_CAN_ALIGN_UP (size))
 471                 return NULL;
 472         size = ALIGN_UP (size);
 473
 474         LOCK_GC;
 475
 476         if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
 477                 /* large objects are always pinned anyway */
 478                 p = (GCObject *)sgen_los_alloc_large_inner (vtable, size);
 479         } else {
 480                 SGEN_ASSERT (9, sgen_client_vtable_is_inited (vtable), "class %s:%s is not initialized", sgen_client_vtable_get_namespace (vtable), sgen_client_vtable_get_name (vtable));
 481                 p = sgen_major_collector.alloc_small_pinned_obj (vtable, size, SGEN_VTABLE_HAS_REFERENCES (vtable));
 482         }
 483         if (G_LIKELY (p)) {
 484                 SGEN_LOG (6, "Allocated pinned object %p, vtable: %p (%s), size: %zd", p, vtable, sgen_client_vtable_get_name (vtable), size);
 485                 increment_thread_allocation_counter (size);
 486                 sgen_binary_protocol_alloc_pinned (p, vtable, size, sgen_client_get_provenance ());
 487         }
 488         UNLOCK_GC;
 489         return p;
 490 }
 491
 492 /*
 493  * Used to allocate thread objects during attach. Doesn't trigger collections since
 494  * the thread is not yet attached.
 495  */
 496 GCObject*
 497 sgen_alloc_obj_mature (GCVTable vtable, size_t size)
 498 {
 499         GCObject *res;
 500
 501         if (!SGEN_CAN_ALIGN_UP (size))
 502                 return NULL;
 503         size = ALIGN_UP (size);
 504
 505         LOCK_GC;
 506         res = sgen_major_collector.alloc_degraded (vtable, size);
 507         UNLOCK_GC;
 508
 509         if (res) {
 510                 increment_thread_allocation_counter (size);
 511         }
 512
 513         return res;
 514 }
 515
 516 /*
 517  * Clear the thread local TLAB variables for all threads.
 518  */
 519 void
 520 sgen_clear_tlabs (void)
 521 {
 522         guint64 total_bytes_allocated_globally = 0;
 523
 524         FOREACH_THREAD_ALL (info) {
 525                 /* A new TLAB will be allocated when the thread does its first allocation */
 526                 info->total_bytes_allocated += info->tlab_next - info->tlab_start;
 527                 total_bytes_allocated_globally += info->total_bytes_allocated;
 528                 info->tlab_start = NULL;
 529                 info->tlab_next = NULL;
 530                 info->tlab_temp_end = NULL;
 531                 info->tlab_real_end = NULL;
 532         } FOREACH_THREAD_END
 533
 534         sgen_set_bytes_allocated_attached (total_bytes_allocated_globally);
 535 }
 536
 537 void sgen_update_allocation_count (void)
 538 {
 539         guint64 total_bytes_allocated_globally = 0;
 540
 541         FOREACH_THREAD_ALL (info) {
 542                 total_bytes_allocated_globally += info->tlab_next - info->tlab_start;
 543                 total_bytes_allocated_globally += info->total_bytes_allocated;
 544         } FOREACH_THREAD_END
 545
 546         sgen_set_bytes_allocated_attached (total_bytes_allocated_globally);
 547 }
 548
 549 void
 550 sgen_set_bytes_allocated_attached (guint64 bytes)
 551 {
 552         bytes_allocated_attached = bytes;
 553 }
 554
 555 void
 556 sgen_increment_bytes_allocated_detached (guint64 bytes)
 557 {
 558         bytes_allocated_detached += bytes;
 559 }
 560
 561 guint64
 562 sgen_get_total_allocated_bytes (MonoBoolean precise)
 563 {
 564         if (precise) {
 565                 LOCK_GC;
 566                 sgen_stop_world (0, FALSE);
 567
 568                 sgen_update_allocation_count ();
 569
 570                 sgen_restart_world (0, FALSE);
 571                 UNLOCK_GC;
 572         }
 573
 574         return bytes_allocated_attached + bytes_allocated_detached;
 575 }
 576
 577
 578 void
 579 sgen_init_allocator (void)
 580 {
 581 #ifdef HEAVY_STATISTICS
 582         mono_counters_register ("# objects allocated", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_alloced);
 583         mono_counters_register ("bytes allocated", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced);
 584         mono_counters_register ("bytes allocated in LOS", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced_los);
 585 #endif
 586 }
 587
 588 #endif /*HAVE_SGEN_GC*/