2 * sgen-cardtable.c: Card table implementation for sgen
5 * Rodrigo Kumpera (rkumpera@novell.com)
7 * SGen is licensed under the terms of the MIT X11 license
9 * Copyright 2001-2003 Ximian, Inc
10 * Copyright 2003-2010 Novell, Inc.
11 * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
13 * Permission is hereby granted, free of charge, to any person obtaining
14 * a copy of this software and associated documentation files (the
15 * "Software"), to deal in the Software without restriction, including
16 * without limitation the rights to use, copy, modify, merge, publish,
17 * distribute, sublicense, and/or sell copies of the Software, and to
18 * permit persons to whom the Software is furnished to do so, subject to
19 * the following conditions:
21 * The above copyright notice and this permission notice shall be
22 * included in all copies or substantial portions of the Software.
24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
28 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
29 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
30 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
36 #include "metadata/sgen-gc.h"
37 #include "metadata/sgen-memory-governor.h"
38 #include "metadata/mono-gc.h"
40 #include "utils/mono-counters.h"
41 #include "utils/mono-mmap.h"
42 #include "utils/mono-logger-internal.h"
44 #define MIN_MINOR_COLLECTION_ALLOWANCE ((mword)(DEFAULT_NURSERY_SIZE * default_allowance_nursery_size_ratio))
46 /*Heap limits and allocation knobs*/
47 static mword max_heap_size = ((mword)0)- ((mword)1);
48 static mword soft_heap_limit = ((mword)0) - ((mword)1);
50 static double default_allowance_nursery_size_ratio = SGEN_DEFAULT_ALLOWANCE_NURSERY_SIZE_RATIO;
51 static double save_target_ratio = SGEN_DEFAULT_SAVE_TARGET_RATIO;
54 static mword allocated_heap;
55 static mword total_alloc = 0;
59 static gboolean debug_print_allowance = FALSE;
62 /* use this to tune when to do a major/minor collection */
63 static mword memory_pressure = 0;
64 static mword minor_collection_allowance;
65 static int minor_collection_sections_alloced = 0;
67 static int last_major_num_sections = 0;
68 static int last_los_memory_usage = 0;
70 static gboolean need_calculate_minor_collection_allowance;
72 static int last_collection_old_num_major_sections;
73 static mword last_collection_los_memory_usage = 0;
74 static mword last_collection_old_los_memory_usage;
75 static mword last_collection_los_memory_alloced;
77 static mword sgen_memgov_available_free_space (void);
81 double_to_mword_with_saturation (double value)
83 if (value >= (double)MWORD_MAX_VALUE)
84 return MWORD_MAX_VALUE;
88 /* GC trigger heuristics. */
91 sgen_memgov_try_calculate_minor_collection_allowance (gboolean overwrite)
93 int num_major_sections, num_major_sections_saved;
94 mword los_memory_saved, new_major, new_heap_size, save_target, allowance_target;
97 g_assert (need_calculate_minor_collection_allowance);
99 if (!need_calculate_minor_collection_allowance)
102 if (!*major_collector.have_swept) {
104 minor_collection_allowance = MIN_MINOR_COLLECTION_ALLOWANCE;
108 num_major_sections = major_collector.get_num_major_sections ();
110 num_major_sections_saved = MAX (last_collection_old_num_major_sections - num_major_sections, 0);
111 los_memory_saved = MAX (last_collection_old_los_memory_usage - last_collection_los_memory_usage, 1);
113 new_major = num_major_sections * major_collector.section_size;
114 new_heap_size = new_major + last_collection_los_memory_usage;
116 save_target = (mword)((new_major + last_collection_los_memory_usage) * SGEN_DEFAULT_SAVE_TARGET_RATIO);
119 * We aim to allow the allocation of as many sections as is
120 * necessary to reclaim save_target sections in the next
121 * collection. We assume the collection pattern won't change.
122 * In the last cycle, we had num_major_sections_saved for
123 * minor_collection_sections_alloced. Assuming things won't
124 * change, this must be the same ratio as save_target for
125 * allowance_target, i.e.
127 * num_major_sections_saved save_target
128 * --------------------------------- == ----------------
129 * minor_collection_sections_alloced allowance_target
133 allowance_target = double_to_mword_with_saturation ((double)save_target * (double)(minor_collection_sections_alloced * major_collector.section_size + last_collection_los_memory_alloced) / (double)(num_major_sections_saved * major_collector.section_size + los_memory_saved));
135 minor_collection_allowance = MAX (MIN (allowance_target, num_major_sections * major_collector.section_size + los_memory_usage), MIN_MINOR_COLLECTION_ALLOWANCE);
137 if (new_heap_size + minor_collection_allowance > soft_heap_limit) {
138 if (new_heap_size > soft_heap_limit)
139 minor_collection_allowance = MIN_MINOR_COLLECTION_ALLOWANCE;
141 minor_collection_allowance = MAX (soft_heap_limit - new_heap_size, MIN_MINOR_COLLECTION_ALLOWANCE);
144 if (debug_print_allowance) {
145 mword old_major = last_collection_old_num_major_sections * major_collector.section_size;
147 fprintf (gc_debug_file, "Before collection: %td bytes (%td major, %td LOS)\n",
148 old_major + last_collection_old_los_memory_usage, old_major, last_collection_old_los_memory_usage);
149 fprintf (gc_debug_file, "After collection: %td bytes (%td major, %td LOS)\n",
150 new_heap_size, new_major, last_collection_los_memory_usage);
151 fprintf (gc_debug_file, "Allowance: %td bytes\n", minor_collection_allowance);
154 if (major_collector.have_computed_minor_collection_allowance)
155 major_collector.have_computed_minor_collection_allowance ();
157 need_calculate_minor_collection_allowance = FALSE;
162 sgen_need_major_collection (mword space_needed)
164 mword los_alloced = los_memory_usage - MIN (last_collection_los_memory_usage, los_memory_usage);
165 return (space_needed > sgen_memgov_available_free_space ()) ||
166 minor_collection_sections_alloced * major_collector.section_size + los_alloced > minor_collection_allowance;
170 sgen_memgov_minor_collection_start (void)
172 sgen_memgov_try_calculate_minor_collection_allowance (FALSE);
176 sgen_memgov_minor_collection_end (void)
181 sgen_memgov_major_collection_start (void)
183 last_collection_old_num_major_sections = sgen_get_major_collector ()->get_num_major_sections ();
186 * A domain could have been freed, resulting in
187 * los_memory_usage being less than last_collection_los_memory_usage.
189 last_collection_los_memory_alloced = los_memory_usage - MIN (last_collection_los_memory_usage, los_memory_usage);
190 last_collection_old_los_memory_usage = los_memory_usage;
192 need_calculate_minor_collection_allowance = TRUE;
196 sgen_memgov_major_collection_end (void)
198 sgen_memgov_try_calculate_minor_collection_allowance (TRUE);
200 minor_collection_sections_alloced = 0;
201 last_collection_los_memory_usage = los_memory_usage;
205 sgen_memgov_collection_start (int generation)
207 last_major_num_sections = major_collector.get_num_major_sections ();
208 last_los_memory_usage = los_memory_usage;
212 log_timming (GGTimingInfo *info)
214 //unsigned long stw_time, unsigned long bridge_time, gboolean is_overflow
215 int num_major_sections = major_collector.get_num_major_sections ();
216 char full_timing_buff [1024];
217 full_timing_buff [0] = '\0';
219 if (!info->is_overflow)
220 sprintf (full_timing_buff, "total %.2fms, bridge %.2f", info->stw_time / 1000.0f, (int)info->bridge_time / 1000.0f);
221 if (info->generation == GENERATION_OLD)
222 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "GC_MAJOR%s: (%s) pause %.2fms, %s major %dK/%dK los %dK/%dK",
223 info->is_overflow ? "_OVERFLOW" : "",
225 (int)info->total_time / 1000.0f,
227 major_collector.section_size * num_major_sections / 1024,
228 major_collector.section_size * last_major_num_sections / 1024,
229 los_memory_usage / 1024,
230 last_los_memory_usage / 1024);
232 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "GC_MINOR%s: (%s) pause %.2fms, %s promoted %dK major %dK los %dK",
233 info->is_overflow ? "_OVERFLOW" : "",
235 (int)info->total_time / 1000.0f,
237 (num_major_sections - last_major_num_sections) * major_collector.section_size / 1024,
238 major_collector.section_size * num_major_sections / 1024,
239 los_memory_usage / 1024);
243 sgen_memgov_collection_end (int generation, GGTimingInfo* info, int info_count)
246 for (i = 0; i < info_count; ++i) {
247 if (info->generation != -1)
248 log_timming (&info [i]);
253 sgen_register_major_sections_alloced (int num_sections)
255 minor_collection_sections_alloced += num_sections;
259 sgen_get_minor_collection_allowance (void)
261 return minor_collection_allowance;
264 /* Memory pressure API */
266 /* Negative value to remove */
268 mono_gc_add_memory_pressure (gint64 value)
270 /* FIXME: Use interlocked functions */
272 memory_pressure += value;
278 Global GC memory tracking.
279 This tracks the total usage of memory by the GC. This includes
280 managed and unmanaged memory.
284 prot_flags_for_activate (int activate)
286 unsigned long prot_flags = activate? MONO_MMAP_READ|MONO_MMAP_WRITE: MONO_MMAP_NONE;
287 return prot_flags | MONO_MMAP_PRIVATE | MONO_MMAP_ANON;
291 sgen_assert_memory_alloc (void *ptr, const char *assert_description)
293 if (ptr || !assert_description)
295 fprintf (stderr, "Error: Garbage collector could not allocate memory for %s.\n", assert_description);
300 * Allocate a big chunk of memory from the OS (usually 64KB to several megabytes).
301 * This must not require any lock.
304 sgen_alloc_os_memory (size_t size, int activate, const char *assert_description)
306 void *ptr = mono_valloc (0, size, prot_flags_for_activate (activate));
307 sgen_assert_memory_alloc (ptr, assert_description);
309 SGEN_ATOMIC_ADD_P (total_alloc, size);
313 /* size must be a power of 2 */
315 sgen_alloc_os_memory_aligned (size_t size, mword alignment, gboolean activate, const char *assert_description)
317 void *ptr = mono_valloc_aligned (size, alignment, prot_flags_for_activate (activate));
318 sgen_assert_memory_alloc (ptr, assert_description);
320 SGEN_ATOMIC_ADD_P (total_alloc, size);
325 * Free the memory returned by sgen_alloc_os_memory (), returning it to the OS.
328 sgen_free_os_memory (void *addr, size_t size)
330 mono_vfree (addr, size);
331 SGEN_ATOMIC_ADD_P (total_alloc, -size);
335 mono_gc_get_heap_size (void)
343 This limit the max size of the heap. It takes into account
344 only memory actively in use to hold heap objects and not
345 for other parts of the GC.
348 sgen_memgov_available_free_space (void)
350 return max_heap_size - MIN (allocated_heap, max_heap_size);
354 sgen_memgov_release_space (mword size, int space)
356 SGEN_ATOMIC_ADD_P (allocated_heap, -size);
360 sgen_memgov_try_alloc_space (mword size, int space)
362 if (sgen_memgov_available_free_space () < size)
365 SGEN_ATOMIC_ADD_P (allocated_heap, size);
366 mono_runtime_resource_check_limit (MONO_RESOURCE_GC_HEAP, allocated_heap);
371 sgen_memgov_init (glong max_heap, glong soft_limit, gboolean debug_allowance, double allowance_ratio, double save_target)
374 soft_heap_limit = soft_limit;
376 debug_print_allowance = debug_allowance;
381 if (max_heap < soft_limit) {
382 fprintf (stderr, "max-heap-size must be at least as large as soft-heap-limit.\n");
386 if (max_heap < sgen_nursery_size * 4) {
387 fprintf (stderr, "max-heap-size must be at least 4 times larger than nursery size.\n");
390 max_heap_size = max_heap - sgen_nursery_size;
392 minor_collection_allowance = MIN_MINOR_COLLECTION_ALLOWANCE;
395 default_allowance_nursery_size_ratio = allowance_ratio;
398 save_target_ratio = save_target;