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
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25 * Copyright 2001-2003 Ximian, Inc
26 * Copyright 2003-2010 Novell, Inc.
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48 #define LOS_SECTION_SIZE (1024 * 1024)
51 * This shouldn't be much smaller or larger than MAX_SMALL_OBJ_SIZE.
52 * Must be at least sizeof (LOSSection).
54 #define LOS_CHUNK_SIZE 4096
55 #define LOS_CHUNK_BITS 12
57 /* Largest object that can be allocated in a section. */
58 #define LOS_SECTION_OBJECT_LIMIT (LOS_SECTION_SIZE - LOS_CHUNK_SIZE - sizeof (LOSObject))
59 //#define LOS_SECTION_OBJECT_LIMIT 0
60 #define LOS_SECTION_NUM_CHUNKS ((LOS_SECTION_SIZE >> LOS_CHUNK_BITS) - 1)
62 #define LOS_SECTION_FOR_OBJ(obj) ((LOSSection*)((mword)(obj) & ~(mword)(LOS_SECTION_SIZE - 1)))
63 #define LOS_CHUNK_INDEX(obj,section) (((char*)(obj) - (char*)(section)) >> LOS_CHUNK_BITS)
65 #define LOS_NUM_FAST_SIZES 32
67 typedef struct _LOSObject LOSObject;
70 mword size; /* this is the object size */
72 int dummy; /* to have a sizeof (LOSObject) a multiple of ALLOC_ALIGN and data starting at same alignment */
73 char data [MONO_ZERO_LEN_ARRAY];
76 typedef struct _LOSFreeChunks LOSFreeChunks;
77 struct _LOSFreeChunks {
78 LOSFreeChunks *next_size;
82 typedef struct _LOSSection LOSSection;
86 unsigned char *free_chunk_map;
89 static LOSSection *los_sections = NULL;
90 static LOSObject *los_object_list = NULL;
91 static LOSFreeChunks *los_fast_free_lists [LOS_NUM_FAST_SIZES]; /* 0 is for larger sizes */
92 static mword los_memory_usage = 0;
93 static mword last_los_memory_usage = 0;
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 */
99 //#define LOS_CONSISTENCY_CHECK
103 #define LOS_SEGMENT_SIZE (4096 * 1024)
105 static char *los_segment = NULL;
106 static int los_segment_index = 0;
109 #ifdef LOS_CONSISTENCY_CHECK
111 los_consistency_check (void)
116 mword memory_usage = 0;
118 for (obj = los_object_list; obj; obj = obj->next) {
119 char *end = obj->data + obj->size;
120 int start_index, num_chunks;
122 memory_usage += obj->size;
124 if (obj->size > LOS_SECTION_OBJECT_LIMIT)
127 section = LOS_SECTION_FOR_OBJ (obj);
129 g_assert (end <= (char*)section + LOS_SECTION_SIZE);
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]);
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;
144 g_assert (size_chunks->size >= LOS_NUM_FAST_SIZES * LOS_CHUNK_SIZE);
146 g_assert (size_chunks->size == i * LOS_CHUNK_SIZE);
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]);
155 g_assert (los_memory_usage == memory_usage);
160 add_free_chunk (LOSFreeChunks *free_chunks, size_t size)
162 int num_chunks = size >> LOS_CHUNK_BITS;
164 free_chunks->size = size;
166 if (num_chunks >= LOS_NUM_FAST_SIZES)
168 free_chunks->next_size = los_fast_free_lists [num_chunks];
169 los_fast_free_lists [num_chunks] = free_chunks;
172 static LOSFreeChunks*
173 get_from_size_list (LOSFreeChunks **list, size_t size)
175 LOSFreeChunks *free_chunks = NULL;
177 int num_chunks, i, start_index;
179 g_assert ((size & (LOS_CHUNK_SIZE - 1)) == 0);
183 if (free_chunks->size >= size)
185 list = &(*list)->next_size;
191 *list = free_chunks->next_size;
193 if (free_chunks->size > size)
194 add_free_chunk ((LOSFreeChunks*)((char*)free_chunks + size), free_chunks->size - size);
196 num_chunks = size >> LOS_CHUNK_BITS;
198 section = LOS_SECTION_FOR_OBJ (free_chunks);
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;
206 section->num_free_chunks -= size >> LOS_CHUNK_BITS;
207 g_assert (section->num_free_chunks >= 0);
213 get_los_section_memory (size_t size)
216 LOSFreeChunks *free_chunks;
219 size += LOS_CHUNK_SIZE - 1;
220 size &= ~(LOS_CHUNK_SIZE - 1);
222 num_chunks = size >> LOS_CHUNK_BITS;
224 g_assert (size > 0 && size - sizeof (LOSObject) <= LOS_SECTION_OBJECT_LIMIT);
225 g_assert (num_chunks > 0);
228 if (num_chunks >= LOS_NUM_FAST_SIZES) {
229 free_chunks = get_from_size_list (&los_fast_free_lists [0], size);
232 for (i = num_chunks; i < LOS_NUM_FAST_SIZES; ++i) {
233 free_chunks = get_from_size_list (&los_fast_free_lists [i], size);
238 free_chunks = get_from_size_list (&los_fast_free_lists [0], size);
242 return (LOSObject*)free_chunks;
244 section = get_os_memory_aligned (LOS_SECTION_SIZE, LOS_SECTION_SIZE, TRUE);
246 total_alloc += LOS_SECTION_SIZE;
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);
301 free_large_object (LOSObject *obj)
304 size_t size = obj->size;
305 DEBUG (4, fprintf (gc_debug_file, "Freed large object %p, size %lu\n", obj->data, (unsigned long)obj->size));
306 binary_protocol_empty (obj->data, obj->size);
308 los_memory_usage -= size;
314 if (size > LOS_SECTION_OBJECT_LIMIT) {
315 size += sizeof (LOSObject);
316 size += pagesize - 1;
317 size &= ~(pagesize - 1);
319 free_os_memory (obj, size);
321 free_los_section_memory (obj, size + sizeof (LOSObject));
322 #ifdef LOS_CONSISTENCY_CHECKS
323 los_consistency_check ();
331 * Objects with size >= MAX_SMALL_SIZE are allocated in the large object space.
332 * They are currently kept track of with a linked list.
333 * They don't move, so there is no need to pin them during collection
334 * and we avoid the memcpy overhead.
336 static void* __attribute__((noinline))
337 alloc_large_inner (MonoVTable *vtable, size_t size)
342 g_assert (size > MAX_SMALL_OBJ_SIZE);
346 los_segment = get_os_memory (LOS_SEGMENT_SIZE, TRUE);
347 los_segment_index = ALIGN_UP (los_segment_index);
349 obj = (LOSObject*)(los_segment + los_segment_index);
350 los_segment_index += size + sizeof (LOSObject);
351 g_assert (los_segment_index <= LOS_SEGMENT_SIZE);
353 if (need_major_collection ()) {
354 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));
356 major_collection ("LOS overflow");
361 obj = malloc (size + sizeof (LOSObject));
362 memset (obj, 0, size + sizeof (LOSObject));
364 if (size > LOS_SECTION_OBJECT_LIMIT) {
365 size_t alloc_size = size;
366 alloc_size += sizeof (LOSObject);
367 alloc_size += pagesize - 1;
368 alloc_size &= ~(pagesize - 1);
369 /* FIXME: handle OOM */
370 obj = get_os_memory (alloc_size, TRUE);
371 total_alloc += alloc_size;
373 obj = get_los_section_memory (size + sizeof (LOSObject));
374 memset (obj, 0, size + sizeof (LOSObject));
379 g_assert (!((mword)obj->data & (ALLOC_ALIGN - 1)));
381 vtslot = (void**)obj->data;
383 update_heap_boundaries ((mword)obj->data, (mword)obj->data + size);
384 obj->next = los_object_list;
385 los_object_list = obj;
386 los_memory_usage += size;
388 DEBUG (4, fprintf (gc_debug_file, "Allocated large object %p, vtable: %p (%s), size: %zd\n", obj->data, vtable, vtable->klass->name, size));
389 binary_protocol_alloc (obj->data, vtable, size);
391 #ifdef LOS_CONSISTENCY_CHECK
392 los_consistency_check ();
401 LOSSection *section, *prev;
403 int num_sections = 0;
405 for (i = 0; i < LOS_NUM_FAST_SIZES; ++i)
406 los_fast_free_lists [i] = NULL;
409 section = los_sections;
411 if (section->num_free_chunks == LOS_SECTION_NUM_CHUNKS) {
412 LOSSection *next = section->next;
417 free_os_memory (section, LOS_SECTION_SIZE);
423 for (i = 0; i <= LOS_SECTION_NUM_CHUNKS; ++i) {
424 if (section->free_chunk_map [i]) {
426 for (j = i + 1; j <= LOS_SECTION_NUM_CHUNKS && section->free_chunk_map [j]; ++j)
428 add_free_chunk ((LOSFreeChunks*)((char*)section + (i << LOS_CHUNK_BITS)), (j - i) << LOS_CHUNK_BITS);
434 section = section->next;
439 #ifdef LOS_CONSISTENCY_CHECK
440 los_consistency_check ();
444 g_print ("LOS sections: %d objects: %d usage: %d\n", num_sections, los_num_objects, los_memory_usage);
445 for (i = 0; i < LOS_NUM_FAST_SIZES; ++i) {
447 LOSFreeChunks *free_chunks;
448 for (free_chunks = los_fast_free_lists [i]; free_chunks; free_chunks = free_chunks->next_size)
450 g_print (" %d: %d\n", i, num_chunks);
454 g_assert (los_num_sections == num_sections);