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
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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);
80 /* GC trigger heuristics. */
83 sgen_memgov_try_calculate_minor_collection_allowance (gboolean overwrite)
85 int num_major_sections, num_major_sections_saved;
86 mword los_memory_saved, new_major, new_heap_size, save_target, allowance_target;
89 g_assert (need_calculate_minor_collection_allowance);
91 if (!need_calculate_minor_collection_allowance)
94 if (!*major_collector.have_swept) {
96 minor_collection_allowance = MIN_MINOR_COLLECTION_ALLOWANCE;
100 num_major_sections = major_collector.get_num_major_sections ();
102 num_major_sections_saved = MAX (last_collection_old_num_major_sections - num_major_sections, 0);
103 los_memory_saved = MAX (last_collection_old_los_memory_usage - last_collection_los_memory_usage, 1);
105 new_major = num_major_sections * major_collector.section_size;
106 new_heap_size = new_major + last_collection_los_memory_usage;
108 save_target = (mword)((new_major + last_collection_los_memory_usage) * SGEN_DEFAULT_SAVE_TARGET_RATIO);
111 * We aim to allow the allocation of as many sections as is
112 * necessary to reclaim save_target sections in the next
113 * collection. We assume the collection pattern won't change.
114 * In the last cycle, we had num_major_sections_saved for
115 * minor_collection_sections_alloced. Assuming things won't
116 * change, this must be the same ratio as save_target for
117 * allowance_target, i.e.
119 * num_major_sections_saved save_target
120 * --------------------------------- == ----------------
121 * minor_collection_sections_alloced allowance_target
125 allowance_target = (mword)((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));
127 minor_collection_allowance = MAX (MIN (allowance_target, num_major_sections * major_collector.section_size + los_memory_usage), MIN_MINOR_COLLECTION_ALLOWANCE);
129 if (new_heap_size + minor_collection_allowance > soft_heap_limit) {
130 if (new_heap_size > soft_heap_limit)
131 minor_collection_allowance = MIN_MINOR_COLLECTION_ALLOWANCE;
133 minor_collection_allowance = MAX (soft_heap_limit - new_heap_size, MIN_MINOR_COLLECTION_ALLOWANCE);
136 if (debug_print_allowance) {
137 mword old_major = last_collection_old_num_major_sections * major_collector.section_size;
139 fprintf (gc_debug_file, "Before collection: %td bytes (%td major, %td LOS)\n",
140 old_major + last_collection_old_los_memory_usage, old_major, last_collection_old_los_memory_usage);
141 fprintf (gc_debug_file, "After collection: %td bytes (%td major, %td LOS)\n",
142 new_heap_size, new_major, last_collection_los_memory_usage);
143 fprintf (gc_debug_file, "Allowance: %td bytes\n", minor_collection_allowance);
146 if (major_collector.have_computed_minor_collection_allowance)
147 major_collector.have_computed_minor_collection_allowance ();
149 need_calculate_minor_collection_allowance = FALSE;
154 sgen_need_major_collection (mword space_needed)
156 mword los_alloced = los_memory_usage - MIN (last_collection_los_memory_usage, los_memory_usage);
157 return (space_needed > sgen_memgov_available_free_space ()) ||
158 minor_collection_sections_alloced * major_collector.section_size + los_alloced > minor_collection_allowance;
162 sgen_memgov_minor_collection_start (void)
164 sgen_memgov_try_calculate_minor_collection_allowance (FALSE);
168 sgen_memgov_minor_collection_end (void)
173 sgen_memgov_major_collection_start (void)
175 last_collection_old_num_major_sections = sgen_get_major_collector ()->get_num_major_sections ();
178 * A domain could have been freed, resulting in
179 * los_memory_usage being less than last_collection_los_memory_usage.
181 last_collection_los_memory_alloced = los_memory_usage - MIN (last_collection_los_memory_usage, los_memory_usage);
182 last_collection_old_los_memory_usage = los_memory_usage;
184 need_calculate_minor_collection_allowance = TRUE;
188 sgen_memgov_major_collection_end (void)
190 sgen_memgov_try_calculate_minor_collection_allowance (TRUE);
192 minor_collection_sections_alloced = 0;
193 last_collection_los_memory_usage = los_memory_usage;
197 sgen_memgov_collection_start (int generation)
199 last_major_num_sections = major_collector.get_num_major_sections ();
200 last_los_memory_usage = los_memory_usage;
204 log_timming (GGTimingInfo *info)
206 //unsigned long stw_time, unsigned long bridge_time, gboolean is_overflow
207 int num_major_sections = major_collector.get_num_major_sections ();
208 char full_timing_buff [1024];
209 full_timing_buff [0] = '\0';
211 if (!info->is_overflow)
212 sprintf (full_timing_buff, "total %.2fms, bridge %.2f", info->stw_time / 1000.0f, (int)info->bridge_time / 1000.0f);
213 if (info->generation == GENERATION_OLD)
214 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "GC_MAJOR%s: (%s) pause %.2fms, %s major %dK/%dK los %dK/%dK",
215 info->is_overflow ? "_OVERFLOW" : "",
217 (int)info->total_time / 1000.0f,
219 major_collector.section_size * num_major_sections / 1024,
220 major_collector.section_size * last_major_num_sections / 1024,
221 los_memory_usage / 1024,
222 last_los_memory_usage / 1024);
224 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "GC_MINOR%s: (%s) pause %.2fms, %s promoted %dK major %dK los %dK",
225 info->is_overflow ? "_OVERFLOW" : "",
227 (int)info->total_time / 1000.0f,
229 (num_major_sections - last_major_num_sections) * major_collector.section_size / 1024,
230 major_collector.section_size * num_major_sections / 1024,
231 los_memory_usage / 1024);
235 sgen_memgov_collection_end (int generation, GGTimingInfo* info, int info_count)
238 for (i = 0; i < info_count; ++i) {
239 if (info->generation != -1)
240 log_timming (&info [i]);
245 sgen_register_major_sections_alloced (int num_sections)
247 minor_collection_sections_alloced += num_sections;
251 sgen_get_minor_collection_allowance (void)
253 return minor_collection_allowance;
256 /* Memory pressure API */
258 /* Negative value to remove */
260 mono_gc_add_memory_pressure (gint64 value)
262 /* FIXME: Use interlocked functions */
264 memory_pressure += value;
270 Global GC memory tracking.
271 This tracks the total usage of memory by the GC. This includes
272 managed and unmanaged memory.
276 prot_flags_for_activate (int activate)
278 unsigned long prot_flags = activate? MONO_MMAP_READ|MONO_MMAP_WRITE: MONO_MMAP_NONE;
279 return prot_flags | MONO_MMAP_PRIVATE | MONO_MMAP_ANON;
283 * Allocate a big chunk of memory from the OS (usually 64KB to several megabytes).
284 * This must not require any lock.
287 sgen_alloc_os_memory (size_t size, int activate)
289 void *ptr = mono_valloc (0, size, prot_flags_for_activate (activate));
291 SGEN_ATOMIC_ADD_P (total_alloc, size);
295 /* size must be a power of 2 */
297 sgen_alloc_os_memory_aligned (size_t size, mword alignment, gboolean activate)
299 void *ptr = mono_valloc_aligned (size, alignment, prot_flags_for_activate (activate));
301 SGEN_ATOMIC_ADD_P (total_alloc, size);
306 * Free the memory returned by sgen_alloc_os_memory (), returning it to the OS.
309 sgen_free_os_memory (void *addr, size_t size)
311 mono_vfree (addr, size);
312 SGEN_ATOMIC_ADD_P (total_alloc, -size);
316 mono_gc_get_heap_size (void)
324 This limit the max size of the heap. It takes into account
325 only memory actively in use to hold heap objects and not
326 for other parts of the GC.
329 sgen_memgov_available_free_space (void)
331 return max_heap_size - MIN (allocated_heap, max_heap_size);
335 sgen_memgov_release_space (mword size, int space)
337 SGEN_ATOMIC_ADD_P (allocated_heap, -size);
341 sgen_memgov_try_alloc_space (mword size, int space)
343 if (sgen_memgov_available_free_space () < size)
346 SGEN_ATOMIC_ADD_P (allocated_heap, size);
347 mono_runtime_resource_check_limit (MONO_RESOURCE_GC_HEAP, allocated_heap);
352 sgen_memgov_init (glong max_heap, glong soft_limit, gboolean debug_allowance, double allowance_ratio, double save_target)
355 soft_heap_limit = soft_limit;
357 debug_print_allowance = debug_allowance;
362 if (max_heap < soft_limit) {
363 fprintf (stderr, "max-heap-size must be at least as large as soft-heap-limit.\n");
367 if (max_heap < sgen_nursery_size * 4) {
368 fprintf (stderr, "max-heap-size must be at least 4 times larger than nursery size.\n");
371 max_heap_size = max_heap - sgen_nursery_size;
373 minor_collection_allowance = MIN_MINOR_COLLECTION_ALLOWANCE;
376 default_allowance_nursery_size_ratio = allowance_ratio;
379 save_target_ratio = save_target;