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"
43 #include "utils/dtrace.h"
45 #define MIN_MINOR_COLLECTION_ALLOWANCE ((mword)(DEFAULT_NURSERY_SIZE * default_allowance_nursery_size_ratio))
47 /*Heap limits and allocation knobs*/
48 static mword max_heap_size = ((mword)0)- ((mword)1);
49 static mword soft_heap_limit = ((mword)0) - ((mword)1);
51 static double default_allowance_nursery_size_ratio = SGEN_DEFAULT_ALLOWANCE_NURSERY_SIZE_RATIO;
52 static double save_target_ratio = SGEN_DEFAULT_SAVE_TARGET_RATIO;
55 static mword allocated_heap;
56 static mword total_alloc = 0;
60 static gboolean debug_print_allowance = FALSE;
63 /* use this to tune when to do a major/minor collection */
64 static mword memory_pressure = 0;
65 static mword minor_collection_allowance;
66 static int minor_collection_sections_alloced = 0;
68 static int last_major_num_sections = 0;
69 static int last_los_memory_usage = 0;
71 static gboolean need_calculate_minor_collection_allowance;
73 static int last_collection_old_num_major_sections;
74 static mword last_collection_los_memory_usage = 0;
75 static mword last_collection_old_los_memory_usage;
76 static mword last_collection_los_memory_alloced;
78 static mword sgen_memgov_available_free_space (void);
82 double_to_mword_with_saturation (double value)
84 if (value >= (double)MWORD_MAX_VALUE)
85 return MWORD_MAX_VALUE;
89 /* GC trigger heuristics. */
92 sgen_memgov_try_calculate_minor_collection_allowance (gboolean overwrite)
94 int num_major_sections, num_major_sections_saved;
95 mword los_memory_saved, new_major, new_heap_size, save_target, allowance_target;
98 g_assert (need_calculate_minor_collection_allowance);
100 if (!need_calculate_minor_collection_allowance)
103 if (!*major_collector.have_swept) {
105 minor_collection_allowance = MIN_MINOR_COLLECTION_ALLOWANCE;
109 num_major_sections = major_collector.get_num_major_sections ();
111 num_major_sections_saved = MAX (last_collection_old_num_major_sections - num_major_sections, 0);
112 los_memory_saved = MAX (last_collection_old_los_memory_usage - last_collection_los_memory_usage, 1);
114 new_major = num_major_sections * major_collector.section_size;
115 new_heap_size = new_major + last_collection_los_memory_usage;
117 save_target = (mword)((new_major + last_collection_los_memory_usage) * SGEN_DEFAULT_SAVE_TARGET_RATIO);
120 * We aim to allow the allocation of as many sections as is
121 * necessary to reclaim save_target sections in the next
122 * collection. We assume the collection pattern won't change.
123 * In the last cycle, we had num_major_sections_saved for
124 * minor_collection_sections_alloced. Assuming things won't
125 * change, this must be the same ratio as save_target for
126 * allowance_target, i.e.
128 * num_major_sections_saved save_target
129 * --------------------------------- == ----------------
130 * minor_collection_sections_alloced allowance_target
134 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));
136 minor_collection_allowance = MAX (MIN (allowance_target, num_major_sections * major_collector.section_size + los_memory_usage), MIN_MINOR_COLLECTION_ALLOWANCE);
138 if (new_heap_size + minor_collection_allowance > soft_heap_limit) {
139 if (new_heap_size > soft_heap_limit)
140 minor_collection_allowance = MIN_MINOR_COLLECTION_ALLOWANCE;
142 minor_collection_allowance = MAX (soft_heap_limit - new_heap_size, MIN_MINOR_COLLECTION_ALLOWANCE);
145 if (debug_print_allowance) {
146 mword old_major = last_collection_old_num_major_sections * major_collector.section_size;
148 fprintf (gc_debug_file, "Before collection: %td bytes (%td major, %td LOS)\n",
149 old_major + last_collection_old_los_memory_usage, old_major, last_collection_old_los_memory_usage);
150 fprintf (gc_debug_file, "After collection: %td bytes (%td major, %td LOS)\n",
151 new_heap_size, new_major, last_collection_los_memory_usage);
152 fprintf (gc_debug_file, "Allowance: %td bytes\n", minor_collection_allowance);
155 if (major_collector.have_computed_minor_collection_allowance)
156 major_collector.have_computed_minor_collection_allowance ();
158 need_calculate_minor_collection_allowance = FALSE;
163 sgen_need_major_collection (mword space_needed)
165 mword los_alloced = los_memory_usage - MIN (last_collection_los_memory_usage, los_memory_usage);
166 return (space_needed > sgen_memgov_available_free_space ()) ||
167 minor_collection_sections_alloced * major_collector.section_size + los_alloced > minor_collection_allowance;
171 sgen_memgov_minor_collection_start (void)
173 sgen_memgov_try_calculate_minor_collection_allowance (FALSE);
177 sgen_memgov_minor_collection_end (void)
182 sgen_memgov_major_collection_start (void)
184 last_collection_old_num_major_sections = sgen_get_major_collector ()->get_num_major_sections ();
187 * A domain could have been freed, resulting in
188 * los_memory_usage being less than last_collection_los_memory_usage.
190 last_collection_los_memory_alloced = los_memory_usage - MIN (last_collection_los_memory_usage, los_memory_usage);
191 last_collection_old_los_memory_usage = los_memory_usage;
193 need_calculate_minor_collection_allowance = TRUE;
197 sgen_memgov_major_collection_end (void)
199 sgen_memgov_try_calculate_minor_collection_allowance (TRUE);
201 minor_collection_sections_alloced = 0;
202 last_collection_los_memory_usage = los_memory_usage;
206 sgen_memgov_collection_start (int generation)
208 last_major_num_sections = major_collector.get_num_major_sections ();
209 last_los_memory_usage = los_memory_usage;
213 log_timming (GGTimingInfo *info)
215 //unsigned long stw_time, unsigned long bridge_time, gboolean is_overflow
216 int num_major_sections = major_collector.get_num_major_sections ();
217 char full_timing_buff [1024];
218 full_timing_buff [0] = '\0';
220 if (!info->is_overflow)
221 sprintf (full_timing_buff, "total %.2fms, bridge %.2f", info->stw_time / 1000.0f, (int)info->bridge_time / 1000.0f);
222 if (info->generation == GENERATION_OLD)
223 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "GC_MAJOR%s: (%s) pause %.2fms, %s major %dK/%dK los %dK/%dK",
224 info->is_overflow ? "_OVERFLOW" : "",
226 (int)info->total_time / 1000.0f,
228 major_collector.section_size * num_major_sections / 1024,
229 major_collector.section_size * last_major_num_sections / 1024,
230 los_memory_usage / 1024,
231 last_los_memory_usage / 1024);
233 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "GC_MINOR%s: (%s) pause %.2fms, %s promoted %dK major %dK los %dK",
234 info->is_overflow ? "_OVERFLOW" : "",
236 (int)info->total_time / 1000.0f,
238 (num_major_sections - last_major_num_sections) * major_collector.section_size / 1024,
239 major_collector.section_size * num_major_sections / 1024,
240 los_memory_usage / 1024);
244 sgen_memgov_collection_end (int generation, GGTimingInfo* info, int info_count)
247 for (i = 0; i < info_count; ++i) {
248 if (info->generation != -1)
249 log_timming (&info [i]);
254 sgen_register_major_sections_alloced (int num_sections)
256 minor_collection_sections_alloced += num_sections;
260 sgen_get_minor_collection_allowance (void)
262 return minor_collection_allowance;
265 /* Memory pressure API */
267 /* Negative value to remove */
269 mono_gc_add_memory_pressure (gint64 value)
271 /* FIXME: Use interlocked functions */
273 memory_pressure += value;
279 Global GC memory tracking.
280 This tracks the total usage of memory by the GC. This includes
281 managed and unmanaged memory.
285 prot_flags_for_activate (int activate)
287 unsigned long prot_flags = activate? MONO_MMAP_READ|MONO_MMAP_WRITE: MONO_MMAP_NONE;
288 return prot_flags | MONO_MMAP_PRIVATE | MONO_MMAP_ANON;
292 sgen_assert_memory_alloc (void *ptr, const char *assert_description)
294 if (ptr || !assert_description)
296 fprintf (stderr, "Error: Garbage collector could not allocate memory for %s.\n", assert_description);
301 * Allocate a big chunk of memory from the OS (usually 64KB to several megabytes).
302 * This must not require any lock.
305 sgen_alloc_os_memory (size_t size, int activate, gboolean is_heap_memory, const char *assert_description)
307 void *ptr = mono_valloc (0, size, prot_flags_for_activate (activate));
308 sgen_assert_memory_alloc (ptr, assert_description);
310 SGEN_ATOMIC_ADD_P (total_alloc, size);
312 MONO_GC_HEAP_ALLOC (ptr, size);
317 /* size must be a power of 2 */
319 sgen_alloc_os_memory_aligned (size_t size, mword alignment, gboolean activate, gboolean is_heap_memory, const char *assert_description)
321 void *ptr = mono_valloc_aligned (size, alignment, prot_flags_for_activate (activate));
322 sgen_assert_memory_alloc (ptr, assert_description);
324 SGEN_ATOMIC_ADD_P (total_alloc, size);
326 MONO_GC_HEAP_ALLOC (ptr, size);
332 * Free the memory returned by sgen_alloc_os_memory (), returning it to the OS.
335 sgen_free_os_memory (void *addr, size_t size, gboolean is_heap_memory)
337 mono_vfree (addr, size);
338 SGEN_ATOMIC_ADD_P (total_alloc, -size);
340 MONO_GC_HEAP_FREE (addr, size);
344 mono_gc_get_heap_size (void)
352 This limit the max size of the heap. It takes into account
353 only memory actively in use to hold heap objects and not
354 for other parts of the GC.
357 sgen_memgov_available_free_space (void)
359 return max_heap_size - MIN (allocated_heap, max_heap_size);
363 sgen_memgov_release_space (mword size, int space)
365 SGEN_ATOMIC_ADD_P (allocated_heap, -size);
369 sgen_memgov_try_alloc_space (mword size, int space)
371 if (sgen_memgov_available_free_space () < size)
374 SGEN_ATOMIC_ADD_P (allocated_heap, size);
375 mono_runtime_resource_check_limit (MONO_RESOURCE_GC_HEAP, allocated_heap);
380 sgen_memgov_init (glong max_heap, glong soft_limit, gboolean debug_allowance, double allowance_ratio, double save_target)
383 soft_heap_limit = soft_limit;
385 debug_print_allowance = debug_allowance;
390 if (max_heap < soft_limit) {
391 fprintf (stderr, "max-heap-size must be at least as large as soft-heap-limit.\n");
395 if (max_heap < sgen_nursery_size * 4) {
396 fprintf (stderr, "max-heap-size must be at least 4 times larger than nursery size.\n");
399 max_heap_size = max_heap - sgen_nursery_size;
401 minor_collection_allowance = MIN_MINOR_COLLECTION_ALLOWANCE;
404 default_allowance_nursery_size_ratio = allowance_ratio;
407 save_target_ratio = save_target;