mono/metadata/sgen-los.c

   1 /*
   2  * sgen-los.c: Simple generational GC.
   3  *
   4  * Author:
   5  *      Paolo Molaro (lupus@ximian.com)
   6  *
   7  * Copyright 2005-2010 Novell, Inc (http://www.novell.com)
   8  *
   9  * Thread start/stop adapted from Boehm's GC:
  10  * Copyright (c) 1994 by Xerox Corporation.  All rights reserved.
  11  * Copyright (c) 1996 by Silicon Graphics.  All rights reserved.
  12  * Copyright (c) 1998 by Fergus Henderson.  All rights reserved.
  13  * Copyright (c) 2000-2004 by Hewlett-Packard Company.  All rights reserved.
  14  *
  15  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
  16  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
  17  *
  18  * Permission is hereby granted to use or copy this program
  19  * for any purpose,  provided the above notices are retained on all copies.
  20  * Permission to modify the code and to distribute modified code is granted,
  21  * provided the above notices are retained, and a notice that the code was
  22  * modified is included with the above copyright notice.
  23  *
  24  *
  25  * Copyright 2001-2003 Ximian, Inc
  26  * Copyright 2003-2010 Novell, Inc.
  27  *
  28  * Permission is hereby granted, free of charge, to any person obtaining
  29  * a copy of this software and associated documentation files (the
  30  * "Software"), to deal in the Software without restriction, including
  31  * without limitation the rights to use, copy, modify, merge, publish,
  32  * distribute, sublicense, and/or sell copies of the Software, and to
  33  * permit persons to whom the Software is furnished to do so, subject to
  34  * the following conditions:
  35  *
  36  * The above copyright notice and this permission notice shall be
  37  * included in all copies or substantial portions of the Software.
  38  *
  39  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  40  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  41  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  42  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  43  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  44  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  45  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  46  */
  47
  48 #include "config.h"
  49
  50 #ifdef HAVE_SGEN_GC
  51
  52 #include "metadata/sgen-gc.h"
  53 #include "metadata/sgen-protocol.h"
  54 #include "metadata/sgen-cardtable.h"
  55 #include "utils/mono-mmap.h"
  56
  57 #define LOS_SECTION_SIZE        (1024 * 1024)
  58
  59 /*
  60  * This shouldn't be much smaller or larger than MAX_SMALL_OBJ_SIZE.
  61  * Must be at least sizeof (LOSSection).
  62  */
  63 #define LOS_CHUNK_SIZE          4096
  64 #define LOS_CHUNK_BITS          12
  65
  66 /* Largest object that can be allocated in a section. */
  67 #define LOS_SECTION_OBJECT_LIMIT        (LOS_SECTION_SIZE - LOS_CHUNK_SIZE - sizeof (LOSObject))
  68 //#define LOS_SECTION_OBJECT_LIMIT      0
  69 #define LOS_SECTION_NUM_CHUNKS          ((LOS_SECTION_SIZE >> LOS_CHUNK_BITS) - 1)
  70
  71 #define LOS_SECTION_FOR_OBJ(obj)        ((LOSSection*)((mword)(obj) & ~(mword)(LOS_SECTION_SIZE - 1)))
  72 #define LOS_CHUNK_INDEX(obj,section)    (((char*)(obj) - (char*)(section)) >> LOS_CHUNK_BITS)
  73
  74 #define LOS_NUM_FAST_SIZES              32
  75
  76 typedef struct _LOSFreeChunks LOSFreeChunks;
  77 struct _LOSFreeChunks {
  78         LOSFreeChunks *next_size;
  79         size_t size;
  80 };
  81
  82 typedef struct _LOSSection LOSSection;
  83 struct _LOSSection {
  84         LOSSection *next;
  85         int num_free_chunks;
  86         unsigned char *free_chunk_map;
  87 };
  88
  89 LOSObject *los_object_list = NULL;
  90 mword los_memory_usage = 0;
  91
  92 static LOSSection *los_sections = NULL;
  93 static LOSFreeChunks *los_fast_free_lists [LOS_NUM_FAST_SIZES]; /* 0 is for larger sizes */
  94 static mword los_num_objects = 0;
  95 static int los_num_sections = 0;
  96 static mword next_los_collection = 2*1024*1024; /* 2 MB, need to tune */
  97
  98 //#define USE_MALLOC
  99 //#define LOS_CONSISTENCY_CHECK
 100 //#define LOS_DUMMY
 101
 102 #ifdef LOS_DUMMY
 103 #define LOS_SEGMENT_SIZE        (4096 * 1024)
 104
 105 static char *los_segment = NULL;
 106 static int los_segment_index = 0;
 107 #endif
 108
 109 #ifdef LOS_CONSISTENCY_CHECK
 110 static void
 111 los_consistency_check (void)
 112 {
 113         LOSSection *section;
 114         LOSObject *obj;
 115         int i;
 116         mword memory_usage = 0;
 117
 118         for (obj = los_object_list; obj; obj = obj->next) {
 119                 char *end = obj->data + obj->size;
 120                 int start_index, num_chunks;
 121
 122                 memory_usage += obj->size;
 123
 124                 if (obj->size > LOS_SECTION_OBJECT_LIMIT)
 125                         continue;
 126
 127                 section = LOS_SECTION_FOR_OBJ (obj);
 128
 129                 g_assert (end <= (char*)section + LOS_SECTION_SIZE);
 130
 131                 start_index = LOS_CHUNK_INDEX (obj, section);
 132                 num_chunks = (obj->size + sizeof (LOSObject) + LOS_CHUNK_SIZE - 1) >> LOS_CHUNK_BITS;
 133                 for (i = start_index; i < start_index + num_chunks; ++i)
 134                         g_assert (!section->free_chunk_map [i]);
 135         }
 136
 137         for (i = 0; i < LOS_NUM_FAST_SIZES; ++i) {
 138                 LOSFreeChunks *size_chunks;
 139                 for (size_chunks = los_fast_free_lists [i]; size_chunks; size_chunks = size_chunks->next_size) {
 140                         LOSSection *section = LOS_SECTION_FOR_OBJ (size_chunks);
 141                         int j, num_chunks, start_index;
 142
 143                         if (i == 0)
 144                                 g_assert (size_chunks->size >= LOS_NUM_FAST_SIZES * LOS_CHUNK_SIZE);
 145                         else
 146                                 g_assert (size_chunks->size == i * LOS_CHUNK_SIZE);
 147
 148                         num_chunks = size_chunks->size >> LOS_CHUNK_BITS;
 149                         start_index = LOS_CHUNK_INDEX (size_chunks, section);
 150                         for (j = start_index; j < start_index + num_chunks; ++j)
 151                                 g_assert (section->free_chunk_map [j]);
 152                 }
 153         }
 154
 155         g_assert (los_memory_usage == memory_usage);
 156 }
 157 #endif
 158
 159 static void
 160 add_free_chunk (LOSFreeChunks *free_chunks, size_t size)
 161 {
 162         int num_chunks = size >> LOS_CHUNK_BITS;
 163
 164         free_chunks->size = size;
 165
 166         if (num_chunks >= LOS_NUM_FAST_SIZES)
 167                 num_chunks = 0;
 168         free_chunks->next_size = los_fast_free_lists [num_chunks];
 169         los_fast_free_lists [num_chunks] = free_chunks;
 170 }
 171
 172 static LOSFreeChunks*
 173 get_from_size_list (LOSFreeChunks **list, size_t size)
 174 {
 175         LOSFreeChunks *free_chunks = NULL;
 176         LOSSection *section;
 177         int num_chunks, i, start_index;
 178
 179         g_assert ((size & (LOS_CHUNK_SIZE - 1)) == 0);
 180
 181         while (*list) {
 182                 free_chunks = *list;
 183                 if (free_chunks->size >= size)
 184                         break;
 185                 list = &(*list)->next_size;
 186         }
 187
 188         if (!*list)
 189                 return NULL;
 190
 191         *list = free_chunks->next_size;
 192
 193         if (free_chunks->size > size)
 194                 add_free_chunk ((LOSFreeChunks*)((char*)free_chunks + size), free_chunks->size - size);
 195
 196         num_chunks = size >> LOS_CHUNK_BITS;
 197
 198         section = LOS_SECTION_FOR_OBJ (free_chunks);
 199
 200         start_index = LOS_CHUNK_INDEX (free_chunks, section);
 201         for (i = start_index; i < start_index + num_chunks; ++i) {
 202                 g_assert (section->free_chunk_map [i]);
 203                 section->free_chunk_map [i] = 0;
 204         }
 205
 206         section->num_free_chunks -= size >> LOS_CHUNK_BITS;
 207         g_assert (section->num_free_chunks >= 0);
 208
 209         return free_chunks;
 210 }
 211
 212 static LOSObject*
 213 get_los_section_memory (size_t size)
 214 {
 215         LOSSection *section;
 216         LOSFreeChunks *free_chunks;
 217         int num_chunks;
 218
 219         size += LOS_CHUNK_SIZE - 1;
 220         size &= ~(LOS_CHUNK_SIZE - 1);
 221
 222         num_chunks = size >> LOS_CHUNK_BITS;
 223
 224         g_assert (size > 0 && size - sizeof (LOSObject) <= LOS_SECTION_OBJECT_LIMIT);
 225         g_assert (num_chunks > 0);
 226
 227  retry:
 228         if (num_chunks >= LOS_NUM_FAST_SIZES) {
 229                 free_chunks = get_from_size_list (&los_fast_free_lists [0], size);
 230         } else {
 231                 int i;
 232                 for (i = num_chunks; i < LOS_NUM_FAST_SIZES; ++i) {
 233                         free_chunks = get_from_size_list (&los_fast_free_lists [i], size);
 234                         if (free_chunks)
 235                                 break;
 236                 }
 237                 if (!free_chunks)
 238                         free_chunks = get_from_size_list (&los_fast_free_lists [0], size);
 239         }
 240
 241         if (free_chunks)
 242                 return (LOSObject*)free_chunks;
 243
 244         if (!mono_sgen_try_alloc_space (LOS_SECTION_SIZE, SPACE_LOS))
 245                 return NULL;
 246
 247         section = mono_sgen_alloc_os_memory_aligned (LOS_SECTION_SIZE, LOS_SECTION_SIZE, TRUE);
 248
 249         free_chunks = (LOSFreeChunks*)((char*)section + LOS_CHUNK_SIZE);
 250         free_chunks->size = LOS_SECTION_SIZE - LOS_CHUNK_SIZE;
 251         free_chunks->next_size = los_fast_free_lists [0];
 252         los_fast_free_lists [0] = free_chunks;
 253
 254         section->num_free_chunks = LOS_SECTION_NUM_CHUNKS;
 255
 256         section->free_chunk_map = (unsigned char*)section + sizeof (LOSSection);
 257         g_assert (sizeof (LOSSection) + LOS_SECTION_NUM_CHUNKS + 1 <= LOS_CHUNK_SIZE);
 258         section->free_chunk_map [0] = 0;
 259         memset (section->free_chunk_map + 1, 1, LOS_SECTION_NUM_CHUNKS);
 260
 261         section->next = los_sections;
 262         los_sections = section;
 263
 264         ++los_num_sections;
 265
 266         goto retry;
 267 }
 268
 269 static void
 270 free_los_section_memory (LOSObject *obj, size_t size)
 271 {
 272         LOSSection *section = LOS_SECTION_FOR_OBJ (obj);
 273         int num_chunks, i, start_index;
 274
 275         size += LOS_CHUNK_SIZE - 1;
 276         size &= ~(LOS_CHUNK_SIZE - 1);
 277
 278         num_chunks = size >> LOS_CHUNK_BITS;
 279
 280         g_assert (size > 0 && size - sizeof (LOSObject) <= LOS_SECTION_OBJECT_LIMIT);
 281         g_assert (num_chunks > 0);
 282
 283         section->num_free_chunks += num_chunks;
 284         g_assert (section->num_free_chunks <= LOS_SECTION_NUM_CHUNKS);
 285
 286         /*
 287          * We could free the LOS section here if it's empty, but we
 288          * can't unless we also remove its free chunks from the fast
 289          * free lists.  Instead, we do it in los_sweep().
 290          */
 291
 292         start_index = LOS_CHUNK_INDEX (obj, section);
 293         for (i = start_index; i < start_index + num_chunks; ++i) {
 294                 g_assert (!section->free_chunk_map [i]);
 295                 section->free_chunk_map [i] = 1;
 296         }
 297
 298         add_free_chunk ((LOSFreeChunks*)obj, size);
 299 }
 300
 301 static int pagesize;
 302
 303 void
 304 mono_sgen_los_free_object (LOSObject *obj)
 305 {
 306 #ifndef LOS_DUMMY
 307         size_t size = obj->size;
 308         DEBUG (4, fprintf (gc_debug_file, "Freed large object %p, size %lu\n", obj->data, (unsigned long)obj->size));
 309         binary_protocol_empty (obj->data, obj->size);
 310
 311         los_memory_usage -= size;
 312         los_num_objects--;
 313
 314 #ifdef USE_MALLOC
 315         free (obj);
 316 #else
 317         if (size > LOS_SECTION_OBJECT_LIMIT) {
 318                 if (!pagesize)
 319                         pagesize = mono_pagesize ();
 320                 size += sizeof (LOSObject);
 321                 size += pagesize - 1;
 322                 size &= ~(pagesize - 1);
 323                 mono_sgen_free_os_memory (obj, size);
 324                 mono_sgen_release_space (size, SPACE_LOS);
 325         } else {
 326                 free_los_section_memory (obj, size + sizeof (LOSObject));
 327 #ifdef LOS_CONSISTENCY_CHECKS
 328                 los_consistency_check ();
 329 #endif
 330         }
 331 #endif
 332 #endif
 333 }
 334
 335 /*
 336  * Objects with size >= MAX_SMALL_SIZE are allocated in the large object space.
 337  * They are currently kept track of with a linked list.
 338  * They don't move, so there is no need to pin them during collection
 339  * and we avoid the memcpy overhead.
 340  */
 341 void*
 342 mono_sgen_los_alloc_large_inner (MonoVTable *vtable, size_t size)
 343 {
 344         LOSObject *obj = NULL;
 345         void **vtslot;
 346
 347         g_assert (size > SGEN_MAX_SMALL_OBJ_SIZE);
 348
 349 #ifdef LOS_DUMMY
 350         if (!los_segment)
 351                 los_segment = mono_sgen_alloc_os_memory (LOS_SEGMENT_SIZE, TRUE);
 352         los_segment_index = ALIGN_UP (los_segment_index);
 353
 354         obj = (LOSObject*)(los_segment + los_segment_index);
 355         los_segment_index += size + sizeof (LOSObject);
 356         g_assert (los_segment_index <= LOS_SEGMENT_SIZE);
 357 #else
 358         if (mono_sgen_need_major_collection (size)) {
 359                 DEBUG (4, fprintf (gc_debug_file, "Should trigger major collection: req size %zd (los already: %lu, limit: %lu)\n", size, (unsigned long)los_memory_usage, (unsigned long)next_los_collection));
 360                 sgen_collect_major_no_lock ("LOS overflow");
 361         }
 362
 363 #ifdef USE_MALLOC
 364         obj = malloc (size + sizeof (LOSObject));
 365         memset (obj, 0, size + sizeof (LOSObject));
 366 #else
 367         if (size > LOS_SECTION_OBJECT_LIMIT) {
 368                 size_t alloc_size = size;
 369                 if (!pagesize)
 370                         pagesize = mono_pagesize ();
 371                 alloc_size += sizeof (LOSObject);
 372                 alloc_size += pagesize - 1;
 373                 alloc_size &= ~(pagesize - 1);
 374                 if (mono_sgen_try_alloc_space (alloc_size, SPACE_LOS)) {
 375                         obj = mono_sgen_alloc_os_memory (alloc_size, TRUE);
 376                         obj->huge_object = TRUE;
 377                 }
 378         } else {
 379                 obj = get_los_section_memory (size + sizeof (LOSObject));
 380                 if (obj)
 381                         memset (obj, 0, size + sizeof (LOSObject));
 382         }
 383 #endif
 384 #endif
 385         if (!obj)
 386                 return NULL;
 387         g_assert (!((mword)obj->data & (SGEN_ALLOC_ALIGN - 1)));
 388         obj->size = size;
 389         vtslot = (void**)obj->data;
 390         *vtslot = vtable;
 391         mono_sgen_update_heap_boundaries ((mword)obj->data, (mword)obj->data + size);
 392         obj->next = los_object_list;
 393         los_object_list = obj;
 394         los_memory_usage += size;
 395         los_num_objects++;
 396         DEBUG (4, fprintf (gc_debug_file, "Allocated large object %p, vtable: %p (%s), size: %zd\n", obj->data, vtable, vtable->klass->name, size));
 397         binary_protocol_alloc (obj->data, vtable, size);
 398
 399 #ifdef LOS_CONSISTENCY_CHECK
 400         los_consistency_check ();
 401 #endif
 402
 403         return obj->data;
 404 }
 405
 406 void
 407 mono_sgen_los_sweep (void)
 408 {
 409         LOSSection *section, *prev;
 410         int i;
 411         int num_sections = 0;
 412
 413         for (i = 0; i < LOS_NUM_FAST_SIZES; ++i)
 414                 los_fast_free_lists [i] = NULL;
 415
 416         prev = NULL;
 417         section = los_sections;
 418         while (section) {
 419                 if (section->num_free_chunks == LOS_SECTION_NUM_CHUNKS) {
 420                         LOSSection *next = section->next;
 421                         if (prev)
 422                                 prev->next = next;
 423                         else
 424                                 los_sections = next;
 425                         mono_sgen_free_os_memory (section, LOS_SECTION_SIZE);
 426                         mono_sgen_release_space (LOS_SECTION_SIZE, SPACE_LOS);
 427                         section = next;
 428                         --los_num_sections;
 429                         continue;
 430                 }
 431
 432                 for (i = 0; i <= LOS_SECTION_NUM_CHUNKS; ++i) {
 433                         if (section->free_chunk_map [i]) {
 434                                 int j;
 435                                 for (j = i + 1; j <= LOS_SECTION_NUM_CHUNKS && section->free_chunk_map [j]; ++j)
 436                                         ;
 437                                 add_free_chunk ((LOSFreeChunks*)((char*)section + (i << LOS_CHUNK_BITS)), (j - i) << LOS_CHUNK_BITS);
 438                                 i = j - 1;
 439                         }
 440                 }
 441
 442                 prev = section;
 443                 section = section->next;
 444
 445                 ++num_sections;
 446         }
 447
 448 #ifdef LOS_CONSISTENCY_CHECK
 449         los_consistency_check ();
 450 #endif
 451
 452         /*
 453         g_print ("LOS sections: %d  objects: %d  usage: %d\n", num_sections, los_num_objects, los_memory_usage);
 454         for (i = 0; i < LOS_NUM_FAST_SIZES; ++i) {
 455                 int num_chunks = 0;
 456                 LOSFreeChunks *free_chunks;
 457                 for (free_chunks = los_fast_free_lists [i]; free_chunks; free_chunks = free_chunks->next_size)
 458                         ++num_chunks;
 459                 g_print ("  %d: %d\n", i, num_chunks);
 460         }
 461         */
 462
 463         g_assert (los_num_sections == num_sections);
 464 }
 465
 466 gboolean
 467 mono_sgen_ptr_is_in_los (char *ptr, char **start)
 468 {
 469         LOSObject *obj;
 470
 471         *start = NULL;
 472         for (obj = los_object_list; obj; obj = obj->next) {
 473                 char *end = obj->data + obj->size;
 474
 475                 if (ptr >= obj->data && ptr < end) {
 476                         *start = obj->data;
 477                         return TRUE;
 478                 }
 479         }
 480         return FALSE;
 481 }
 482
 483 void
 484 mono_sgen_los_iterate_objects (IterateObjectCallbackFunc cb, void *user_data)
 485 {
 486         LOSObject *obj;
 487
 488         for (obj = los_object_list; obj; obj = obj->next)
 489                 cb (obj->data, obj->size, user_data);
 490 }
 491
 492 void
 493 mono_sgen_los_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
 494 {
 495         LOSObject *obj;
 496         for (obj = los_object_list; obj; obj = obj->next) {
 497                 MonoVTable *vt = (MonoVTable*)SGEN_LOAD_VTABLE (obj->data);
 498                 if (SGEN_VTABLE_HAS_REFERENCES (vt))
 499                         callback ((mword)obj->data, (mword)obj->size);
 500         }
 501 }
 502
 503 #ifdef SGEN_HAVE_CARDTABLE
 504 void
 505 mono_sgen_los_scan_card_table (SgenGrayQueue *queue)
 506 {
 507         LOSObject *obj;
 508
 509         for (obj = los_object_list; obj; obj = obj->next) {
 510                 sgen_cardtable_scan_object (obj->data, obj->size, NULL, queue);
 511         }
 512 }
 513 #endif
 514
 515 #endif /* HAVE_SGEN_GC */