2 * sgen-los.c: Simple generational GC.
5 * Paolo Molaro (lupus@ximian.com)
7 * Copyright 2005-2010 Novell, Inc (http://www.novell.com)
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.
15 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
16 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
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.
25 * Copyright 2001-2003 Ximian, Inc
26 * Copyright 2003-2010 Novell, Inc.
28 * Permission is hereby granted, free of charge, to any person obtaining
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50 #include "metadata/sgen-gc.h"
51 #include "metadata/sgen-protocol.h"
52 #include "metadata/sgen-cardtable.h"
53 #include "utils/mono-mmap.h"
55 #define LOS_SECTION_SIZE (1024 * 1024)
58 * This shouldn't be much smaller or larger than MAX_SMALL_OBJ_SIZE.
59 * Must be at least sizeof (LOSSection).
61 #define LOS_CHUNK_SIZE 4096
62 #define LOS_CHUNK_BITS 12
64 /* Largest object that can be allocated in a section. */
65 #define LOS_SECTION_OBJECT_LIMIT (LOS_SECTION_SIZE - LOS_CHUNK_SIZE - sizeof (LOSObject))
66 //#define LOS_SECTION_OBJECT_LIMIT 0
67 #define LOS_SECTION_NUM_CHUNKS ((LOS_SECTION_SIZE >> LOS_CHUNK_BITS) - 1)
69 #define LOS_SECTION_FOR_OBJ(obj) ((LOSSection*)((mword)(obj) & ~(mword)(LOS_SECTION_SIZE - 1)))
70 #define LOS_CHUNK_INDEX(obj,section) (((char*)(obj) - (char*)(section)) >> LOS_CHUNK_BITS)
72 #define LOS_NUM_FAST_SIZES 32
74 typedef struct _LOSFreeChunks LOSFreeChunks;
75 struct _LOSFreeChunks {
76 LOSFreeChunks *next_size;
80 typedef struct _LOSSection LOSSection;
84 unsigned char *free_chunk_map;
87 LOSObject *los_object_list = NULL;
88 mword los_memory_usage = 0;
89 mword last_los_memory_usage = 0;
91 static LOSSection *los_sections = NULL;
92 static LOSFreeChunks *los_fast_free_lists [LOS_NUM_FAST_SIZES]; /* 0 is for larger sizes */
93 static mword los_num_objects = 0;
94 static int los_num_sections = 0;
95 static mword next_los_collection = 2*1024*1024; /* 2 MB, need to tune */
98 //#define LOS_CONSISTENCY_CHECK
102 #define LOS_SEGMENT_SIZE (4096 * 1024)
104 static char *los_segment = NULL;
105 static int los_segment_index = 0;
108 #ifdef LOS_CONSISTENCY_CHECK
110 los_consistency_check (void)
115 mword memory_usage = 0;
117 for (obj = los_object_list; obj; obj = obj->next) {
118 char *end = obj->data + obj->size;
119 int start_index, num_chunks;
121 memory_usage += obj->size;
123 if (obj->size > LOS_SECTION_OBJECT_LIMIT)
126 section = LOS_SECTION_FOR_OBJ (obj);
128 g_assert (end <= (char*)section + LOS_SECTION_SIZE);
130 start_index = LOS_CHUNK_INDEX (obj, section);
131 num_chunks = (obj->size + sizeof (LOSObject) + LOS_CHUNK_SIZE - 1) >> LOS_CHUNK_BITS;
132 for (i = start_index; i < start_index + num_chunks; ++i)
133 g_assert (!section->free_chunk_map [i]);
136 for (i = 0; i < LOS_NUM_FAST_SIZES; ++i) {
137 LOSFreeChunks *size_chunks;
138 for (size_chunks = los_fast_free_lists [i]; size_chunks; size_chunks = size_chunks->next_size) {
139 LOSSection *section = LOS_SECTION_FOR_OBJ (size_chunks);
140 int j, num_chunks, start_index;
143 g_assert (size_chunks->size >= LOS_NUM_FAST_SIZES * LOS_CHUNK_SIZE);
145 g_assert (size_chunks->size == i * LOS_CHUNK_SIZE);
147 num_chunks = size_chunks->size >> LOS_CHUNK_BITS;
148 start_index = LOS_CHUNK_INDEX (size_chunks, section);
149 for (j = start_index; j < start_index + num_chunks; ++j)
150 g_assert (section->free_chunk_map [j]);
154 g_assert (los_memory_usage == memory_usage);
159 add_free_chunk (LOSFreeChunks *free_chunks, size_t size)
161 int num_chunks = size >> LOS_CHUNK_BITS;
163 free_chunks->size = size;
165 if (num_chunks >= LOS_NUM_FAST_SIZES)
167 free_chunks->next_size = los_fast_free_lists [num_chunks];
168 los_fast_free_lists [num_chunks] = free_chunks;
171 static LOSFreeChunks*
172 get_from_size_list (LOSFreeChunks **list, size_t size)
174 LOSFreeChunks *free_chunks = NULL;
176 int num_chunks, i, start_index;
178 g_assert ((size & (LOS_CHUNK_SIZE - 1)) == 0);
182 if (free_chunks->size >= size)
184 list = &(*list)->next_size;
190 *list = free_chunks->next_size;
192 if (free_chunks->size > size)
193 add_free_chunk ((LOSFreeChunks*)((char*)free_chunks + size), free_chunks->size - size);
195 num_chunks = size >> LOS_CHUNK_BITS;
197 section = LOS_SECTION_FOR_OBJ (free_chunks);
199 start_index = LOS_CHUNK_INDEX (free_chunks, section);
200 for (i = start_index; i < start_index + num_chunks; ++i) {
201 g_assert (section->free_chunk_map [i]);
202 section->free_chunk_map [i] = 0;
205 section->num_free_chunks -= size >> LOS_CHUNK_BITS;
206 g_assert (section->num_free_chunks >= 0);
212 get_los_section_memory (size_t size)
215 LOSFreeChunks *free_chunks;
218 size += LOS_CHUNK_SIZE - 1;
219 size &= ~(LOS_CHUNK_SIZE - 1);
221 num_chunks = size >> LOS_CHUNK_BITS;
223 g_assert (size > 0 && size - sizeof (LOSObject) <= LOS_SECTION_OBJECT_LIMIT);
224 g_assert (num_chunks > 0);
227 if (num_chunks >= LOS_NUM_FAST_SIZES) {
228 free_chunks = get_from_size_list (&los_fast_free_lists [0], size);
231 for (i = num_chunks; i < LOS_NUM_FAST_SIZES; ++i) {
232 free_chunks = get_from_size_list (&los_fast_free_lists [i], size);
237 free_chunks = get_from_size_list (&los_fast_free_lists [0], size);
241 return (LOSObject*)free_chunks;
243 if (!mono_sgen_try_alloc_space (LOS_SECTION_SIZE, SPACE_LOS))
246 section = mono_sgen_alloc_os_memory_aligned (LOS_SECTION_SIZE, LOS_SECTION_SIZE, TRUE);
248 free_chunks = (LOSFreeChunks*)((char*)section + LOS_CHUNK_SIZE);
249 free_chunks->size = LOS_SECTION_SIZE - LOS_CHUNK_SIZE;
250 free_chunks->next_size = los_fast_free_lists [0];
251 los_fast_free_lists [0] = free_chunks;
253 section->num_free_chunks = LOS_SECTION_NUM_CHUNKS;
255 section->free_chunk_map = (unsigned char*)section + sizeof (LOSSection);
256 g_assert (sizeof (LOSSection) + LOS_SECTION_NUM_CHUNKS + 1 <= LOS_CHUNK_SIZE);
257 section->free_chunk_map [0] = 0;
258 memset (section->free_chunk_map + 1, 1, LOS_SECTION_NUM_CHUNKS);
260 section->next = los_sections;
261 los_sections = section;
269 free_los_section_memory (LOSObject *obj, size_t size)
271 LOSSection *section = LOS_SECTION_FOR_OBJ (obj);
272 int num_chunks, i, start_index;
274 size += LOS_CHUNK_SIZE - 1;
275 size &= ~(LOS_CHUNK_SIZE - 1);
277 num_chunks = size >> LOS_CHUNK_BITS;
279 g_assert (size > 0 && size - sizeof (LOSObject) <= LOS_SECTION_OBJECT_LIMIT);
280 g_assert (num_chunks > 0);
282 section->num_free_chunks += num_chunks;
283 g_assert (section->num_free_chunks <= LOS_SECTION_NUM_CHUNKS);
286 * We could free the LOS section here if it's empty, but we
287 * can't unless we also remove its free chunks from the fast
288 * free lists. Instead, we do it in los_sweep().
291 start_index = LOS_CHUNK_INDEX (obj, section);
292 for (i = start_index; i < start_index + num_chunks; ++i) {
293 g_assert (!section->free_chunk_map [i]);
294 section->free_chunk_map [i] = 1;
297 add_free_chunk ((LOSFreeChunks*)obj, size);
303 mono_sgen_los_free_object (LOSObject *obj)
306 size_t size = obj->size;
307 DEBUG (4, fprintf (gc_debug_file, "Freed large object %p, size %lu\n", obj->data, (unsigned long)obj->size));
308 binary_protocol_empty (obj->data, obj->size);
310 los_memory_usage -= size;
316 if (size > LOS_SECTION_OBJECT_LIMIT) {
318 pagesize = mono_pagesize ();
319 size += sizeof (LOSObject);
320 size += pagesize - 1;
321 size &= ~(pagesize - 1);
322 mono_sgen_free_os_memory (obj, size);
323 mono_sgen_release_space (size, SPACE_LOS);
325 free_los_section_memory (obj, size + sizeof (LOSObject));
326 #ifdef LOS_CONSISTENCY_CHECKS
327 los_consistency_check ();
335 * Objects with size >= MAX_SMALL_SIZE are allocated in the large object space.
336 * They are currently kept track of with a linked list.
337 * They don't move, so there is no need to pin them during collection
338 * and we avoid the memcpy overhead.
341 mono_sgen_los_alloc_large_inner (MonoVTable *vtable, size_t size)
343 LOSObject *obj = NULL;
346 g_assert (size > SGEN_MAX_SMALL_OBJ_SIZE);
350 los_segment = mono_sgen_alloc_os_memory (LOS_SEGMENT_SIZE, TRUE);
351 los_segment_index = ALIGN_UP (los_segment_index);
353 obj = (LOSObject*)(los_segment + los_segment_index);
354 los_segment_index += size + sizeof (LOSObject);
355 g_assert (los_segment_index <= LOS_SEGMENT_SIZE);
357 if (mono_sgen_need_major_collection (size)) {
358 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));
359 sgen_collect_major_no_lock ("LOS overflow");
363 obj = malloc (size + sizeof (LOSObject));
364 memset (obj, 0, size + sizeof (LOSObject));
366 if (size > LOS_SECTION_OBJECT_LIMIT) {
367 size_t alloc_size = size;
369 pagesize = mono_pagesize ();
370 alloc_size += sizeof (LOSObject);
371 alloc_size += pagesize - 1;
372 alloc_size &= ~(pagesize - 1);
373 if (mono_sgen_try_alloc_space (alloc_size, SPACE_LOS)) {
374 obj = mono_sgen_alloc_os_memory (alloc_size, TRUE);
375 obj->huge_object = TRUE;
378 obj = get_los_section_memory (size + sizeof (LOSObject));
380 memset (obj, 0, size + sizeof (LOSObject));
386 g_assert (!((mword)obj->data & (SGEN_ALLOC_ALIGN - 1)));
388 vtslot = (void**)obj->data;
390 mono_sgen_update_heap_boundaries ((mword)obj->data, (mword)obj->data + size);
391 obj->next = los_object_list;
392 los_object_list = obj;
393 los_memory_usage += size;
395 DEBUG (4, fprintf (gc_debug_file, "Allocated large object %p, vtable: %p (%s), size: %zd\n", obj->data, vtable, vtable->klass->name, size));
396 binary_protocol_alloc (obj->data, vtable, size);
398 #ifdef LOS_CONSISTENCY_CHECK
399 los_consistency_check ();
406 mono_sgen_los_sweep (void)
408 LOSSection *section, *prev;
410 int num_sections = 0;
412 for (i = 0; i < LOS_NUM_FAST_SIZES; ++i)
413 los_fast_free_lists [i] = NULL;
416 section = los_sections;
418 if (section->num_free_chunks == LOS_SECTION_NUM_CHUNKS) {
419 LOSSection *next = section->next;
424 mono_sgen_free_os_memory (section, LOS_SECTION_SIZE);
425 mono_sgen_release_space (LOS_SECTION_SIZE, SPACE_LOS);
431 for (i = 0; i <= LOS_SECTION_NUM_CHUNKS; ++i) {
432 if (section->free_chunk_map [i]) {
434 for (j = i + 1; j <= LOS_SECTION_NUM_CHUNKS && section->free_chunk_map [j]; ++j)
436 add_free_chunk ((LOSFreeChunks*)((char*)section + (i << LOS_CHUNK_BITS)), (j - i) << LOS_CHUNK_BITS);
442 section = section->next;
447 #ifdef LOS_CONSISTENCY_CHECK
448 los_consistency_check ();
452 g_print ("LOS sections: %d objects: %d usage: %d\n", num_sections, los_num_objects, los_memory_usage);
453 for (i = 0; i < LOS_NUM_FAST_SIZES; ++i) {
455 LOSFreeChunks *free_chunks;
456 for (free_chunks = los_fast_free_lists [i]; free_chunks; free_chunks = free_chunks->next_size)
458 g_print (" %d: %d\n", i, num_chunks);
462 g_assert (los_num_sections == num_sections);
466 mono_sgen_ptr_is_in_los (char *ptr, char **start)
471 for (obj = los_object_list; obj; obj = obj->next) {
472 char *end = obj->data + obj->size;
474 if (ptr >= obj->data && ptr < end) {
483 mono_sgen_los_iterate_objects (IterateObjectCallbackFunc cb, void *user_data)
487 for (obj = los_object_list; obj; obj = obj->next)
488 cb (obj->data, obj->size, user_data);
492 mono_sgen_los_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
495 for (obj = los_object_list; obj; obj = obj->next) {
496 MonoVTable *vt = (MonoVTable*)SGEN_LOAD_VTABLE (obj->data);
497 if (vt->klass->has_references)
498 callback ((mword)obj->data, (mword)obj->size);
503 mono_sgen_los_scan_card_table (SgenGrayQueue *queue)
507 for (obj = los_object_list; obj; obj = obj->next) {
508 sgen_cardtable_scan_object (obj->data, obj->size, NULL, queue);
512 #endif /* HAVE_SGEN_GC */