2 * sgen-memory-governor.c: When to schedule collections based on
6 * Rodrigo Kumpera (rkumpera@novell.com)
8 * Copyright 2001-2003 Ximian, Inc
9 * Copyright 2003-2010 Novell, Inc.
10 * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
11 * Copyright (C) 2012 Xamarin Inc
13 * This library is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU Library General Public
15 * License 2.0 as published by the Free Software Foundation;
17 * This library is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * Library General Public License for more details.
22 * You should have received a copy of the GNU Library General Public
23 * License 2.0 along with this library; if not, write to the Free
24 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
30 #include "metadata/sgen-gc.h"
31 #include "metadata/sgen-memory-governor.h"
32 #include "metadata/sgen-thread-pool.h"
33 #include "metadata/mono-gc.h"
35 #include "utils/mono-counters.h"
36 #include "utils/mono-mmap.h"
37 #include "utils/mono-logger-internal.h"
39 #define MIN_MINOR_COLLECTION_ALLOWANCE ((mword)(DEFAULT_NURSERY_SIZE * default_allowance_nursery_size_ratio))
41 /*Heap limits and allocation knobs*/
42 static mword max_heap_size = ((mword)0)- ((mword)1);
43 static mword soft_heap_limit = ((mword)0) - ((mword)1);
45 static double default_allowance_nursery_size_ratio = SGEN_DEFAULT_ALLOWANCE_NURSERY_SIZE_RATIO;
46 static double save_target_ratio = SGEN_DEFAULT_SAVE_TARGET_RATIO;
49 static mword allocated_heap;
50 static mword total_alloc = 0;
51 static mword total_alloc_max = 0;
55 static gboolean debug_print_allowance = FALSE;
58 /* use this to tune when to do a major/minor collection */
59 static mword memory_pressure = 0;
60 static mword major_collection_trigger_size;
62 static mword last_major_num_sections = 0;
63 static mword last_los_memory_usage = 0;
65 static gboolean need_calculate_minor_collection_allowance;
67 /* The size of the LOS after the last major collection, after sweeping. */
68 static mword last_collection_los_memory_usage = 0;
70 static mword sgen_memgov_available_free_space (void);
73 /* GC trigger heuristics. */
76 sgen_memgov_calculate_minor_collection_allowance (void)
78 size_t new_major, new_heap_size, allowance_target, allowance;
80 if (!need_calculate_minor_collection_allowance)
83 SGEN_ASSERT (0, major_collector.have_swept (), "Can only calculate allowance if heap is swept");
85 new_major = major_collector.get_bytes_survived_last_sweep ();
86 new_heap_size = new_major + last_collection_los_memory_usage;
89 * We allow the heap to grow by one third its current size before we start the next
92 allowance_target = new_heap_size / 3;
94 allowance = MAX (allowance_target, MIN_MINOR_COLLECTION_ALLOWANCE);
96 if (new_heap_size + allowance > soft_heap_limit) {
97 if (new_heap_size > soft_heap_limit)
98 allowance = MIN_MINOR_COLLECTION_ALLOWANCE;
100 allowance = MAX (soft_heap_limit - new_heap_size, MIN_MINOR_COLLECTION_ALLOWANCE);
103 /* FIXME: Why is this here? */
104 if (major_collector.free_swept_blocks)
105 major_collector.free_swept_blocks (allowance);
107 major_collection_trigger_size = new_heap_size + allowance;
109 need_calculate_minor_collection_allowance = FALSE;
111 if (debug_print_allowance) {
112 SGEN_LOG (0, "Surviving sweep: %ld bytes (%ld major, %ld LOS)", (long)new_heap_size, (long)new_major, (long)last_collection_los_memory_usage);
113 SGEN_LOG (0, "Allowance: %ld bytes", (long)allowance);
114 SGEN_LOG (0, "Trigger size: %ld bytes", (long)major_collection_trigger_size);
119 sgen_need_major_collection (mword space_needed)
123 if (sgen_concurrent_collection_in_progress ())
126 /* FIXME: This is a cop-out. We should have some way of figuring this out. */
127 if (!major_collector.have_swept ())
130 if (space_needed > sgen_memgov_available_free_space ())
133 sgen_memgov_calculate_minor_collection_allowance ();
135 heap_size = major_collector.get_num_major_sections () * major_collector.section_size + los_memory_usage;
137 return heap_size > major_collection_trigger_size;
141 sgen_memgov_minor_collection_start (void)
146 sgen_memgov_minor_collection_end (void)
151 sgen_memgov_major_collection_start (void)
153 need_calculate_minor_collection_allowance = TRUE;
155 if (debug_print_allowance) {
156 SGEN_LOG (0, "Starting collection with heap size %ld bytes", (long)(major_collector.get_num_major_sections () * major_collector.section_size + los_memory_usage));
161 sgen_memgov_major_collection_end (gboolean forced)
163 last_collection_los_memory_usage = los_memory_usage;
166 sgen_get_major_collector ()->finish_sweeping ();
167 sgen_memgov_calculate_minor_collection_allowance ();
172 log_timming (GGTimingInfo *info)
174 //unsigned long stw_time, unsigned long bridge_time, gboolean is_overflow
175 mword num_major_sections = major_collector.get_num_major_sections ();
176 char full_timing_buff [1024];
177 full_timing_buff [0] = '\0';
179 if (!info->is_overflow)
180 sprintf (full_timing_buff, "total %.2fms, bridge %.2fms", info->stw_time / 10000.0f, (int)info->bridge_time / 10000.0f);
181 if (info->generation == GENERATION_OLD)
182 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "GC_MAJOR%s: (%s) pause %.2fms, %s major %dK/%dK los %dK/%dK",
183 info->is_overflow ? "_OVERFLOW" : "",
184 info->reason ? info->reason : "",
185 (int)info->total_time / 10000.0f,
187 major_collector.section_size * num_major_sections / 1024,
188 major_collector.section_size * last_major_num_sections / 1024,
189 los_memory_usage / 1024,
190 last_los_memory_usage / 1024);
192 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "GC_MINOR%s: (%s) pause %.2fms, %s promoted %dK major %dK los %dK",
193 info->is_overflow ? "_OVERFLOW" : "",
194 info->reason ? info->reason : "",
195 (int)info->total_time / 10000.0f,
197 (num_major_sections - last_major_num_sections) * major_collector.section_size / 1024,
198 major_collector.section_size * num_major_sections / 1024,
199 los_memory_usage / 1024);
202 /* FIXME: Remove either these or the specialized ones above. */
204 sgen_memgov_collection_start (int generation)
209 sgen_memgov_collection_end (int generation, GGTimingInfo* info, int info_count)
212 for (i = 0; i < info_count; ++i) {
213 if (info[i].generation != -1)
214 log_timming (&info [i]);
218 /* Memory pressure API */
220 /* Negative value to remove */
222 mono_gc_add_memory_pressure (gint64 value)
224 /* FIXME: Use interlocked functions */
226 memory_pressure += value;
232 Global GC memory tracking.
233 This tracks the total usage of memory by the GC. This includes
234 managed and unmanaged memory.
238 prot_flags_for_activate (int activate)
240 unsigned long prot_flags = activate? MONO_MMAP_READ|MONO_MMAP_WRITE: MONO_MMAP_NONE;
241 return prot_flags | MONO_MMAP_PRIVATE | MONO_MMAP_ANON;
245 sgen_assert_memory_alloc (void *ptr, size_t requested_size, const char *assert_description)
247 if (ptr || !assert_description)
249 fprintf (stderr, "Error: Garbage collector could not allocate %zu bytes of memory for %s.\n", requested_size, assert_description);
254 * Allocate a big chunk of memory from the OS (usually 64KB to several megabytes).
255 * This must not require any lock.
258 sgen_alloc_os_memory (size_t size, SgenAllocFlags flags, const char *assert_description)
262 g_assert (!(flags & ~(SGEN_ALLOC_HEAP | SGEN_ALLOC_ACTIVATE)));
264 ptr = mono_valloc (0, size, prot_flags_for_activate (flags & SGEN_ALLOC_ACTIVATE));
265 sgen_assert_memory_alloc (ptr, size, assert_description);
267 SGEN_ATOMIC_ADD_P (total_alloc, size);
268 total_alloc_max = MAX (total_alloc_max, total_alloc);
273 /* size must be a power of 2 */
275 sgen_alloc_os_memory_aligned (size_t size, mword alignment, SgenAllocFlags flags, const char *assert_description)
279 g_assert (!(flags & ~(SGEN_ALLOC_HEAP | SGEN_ALLOC_ACTIVATE)));
281 ptr = mono_valloc_aligned (size, alignment, prot_flags_for_activate (flags & SGEN_ALLOC_ACTIVATE));
282 sgen_assert_memory_alloc (ptr, size, assert_description);
284 SGEN_ATOMIC_ADD_P (total_alloc, size);
285 total_alloc_max = MAX (total_alloc_max, total_alloc);
291 * Free the memory returned by sgen_alloc_os_memory (), returning it to the OS.
294 sgen_free_os_memory (void *addr, size_t size, SgenAllocFlags flags)
296 g_assert (!(flags & ~SGEN_ALLOC_HEAP));
298 mono_vfree (addr, size);
299 SGEN_ATOMIC_ADD_P (total_alloc, -(gssize)size);
300 total_alloc_max = MAX (total_alloc_max, total_alloc);
304 mono_gc_get_heap_size (void)
312 This limit the max size of the heap. It takes into account
313 only memory actively in use to hold heap objects and not
314 for other parts of the GC.
317 sgen_memgov_available_free_space (void)
319 return max_heap_size - MIN (allocated_heap, max_heap_size);
323 sgen_memgov_release_space (mword size, int space)
325 SGEN_ATOMIC_ADD_P (allocated_heap, -(gssize)size);
329 sgen_memgov_try_alloc_space (mword size, int space)
331 if (sgen_memgov_available_free_space () < size) {
332 SGEN_ASSERT (4, !sgen_thread_pool_is_thread_pool_thread (mono_native_thread_id_get ()), "Memory shouldn't run out in worker thread");
336 SGEN_ATOMIC_ADD_P (allocated_heap, size);
337 mono_runtime_resource_check_limit (MONO_RESOURCE_GC_HEAP, allocated_heap);
342 sgen_memgov_init (size_t max_heap, size_t soft_limit, gboolean debug_allowance, double allowance_ratio, double save_target)
345 soft_heap_limit = soft_limit;
347 debug_print_allowance = debug_allowance;
348 major_collection_trigger_size = MIN_MINOR_COLLECTION_ALLOWANCE;
350 mono_counters_register ("Memgov alloc", MONO_COUNTER_GC | MONO_COUNTER_WORD | MONO_COUNTER_BYTES | MONO_COUNTER_VARIABLE, &total_alloc);
351 mono_counters_register ("Memgov max alloc", MONO_COUNTER_GC | MONO_COUNTER_WORD | MONO_COUNTER_BYTES | MONO_COUNTER_MONOTONIC, &total_alloc_max);
356 if (max_heap < soft_limit) {
357 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Setting to minimum.", "`max-heap-size` must be at least as large as `soft-heap-limit`.");
358 max_heap = soft_limit;
361 if (max_heap < sgen_nursery_size * 4) {
362 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Setting to minimum.", "`max-heap-size` must be at least 4 times as large as `nursery size`.");
363 max_heap = sgen_nursery_size * 4;
365 max_heap_size = max_heap - sgen_nursery_size;
368 default_allowance_nursery_size_ratio = allowance_ratio;
371 save_target_ratio = save_target;