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"
38 #include "utils/dtrace.h"
40 #define MIN_MINOR_COLLECTION_ALLOWANCE ((mword)(DEFAULT_NURSERY_SIZE * default_allowance_nursery_size_ratio))
42 /*Heap limits and allocation knobs*/
43 static mword max_heap_size = ((mword)0)- ((mword)1);
44 static mword soft_heap_limit = ((mword)0) - ((mword)1);
46 static double default_allowance_nursery_size_ratio = SGEN_DEFAULT_ALLOWANCE_NURSERY_SIZE_RATIO;
47 static double save_target_ratio = SGEN_DEFAULT_SAVE_TARGET_RATIO;
50 static mword allocated_heap;
51 static mword total_alloc = 0;
52 static mword total_alloc_max = 0;
56 static gboolean debug_print_allowance = FALSE;
59 /* use this to tune when to do a major/minor collection */
60 static mword memory_pressure = 0;
61 static mword major_collection_trigger_size;
63 static mword last_major_num_sections = 0;
64 static mword last_los_memory_usage = 0;
66 static gboolean need_calculate_minor_collection_allowance;
68 /* The size of the LOS after the last major collection, after sweeping. */
69 static mword last_collection_los_memory_usage = 0;
71 static mword sgen_memgov_available_free_space (void);
74 /* GC trigger heuristics. */
77 sgen_memgov_calculate_minor_collection_allowance (void)
79 size_t new_major, new_heap_size, allowance_target, allowance;
81 if (!need_calculate_minor_collection_allowance)
84 SGEN_ASSERT (0, major_collector.have_swept (), "Can only calculate allowance if heap is swept");
86 new_major = major_collector.get_bytes_survived_last_sweep ();
87 new_heap_size = new_major + last_collection_los_memory_usage;
90 * We allow the heap to grow by one third its current size before we start the next
93 allowance_target = new_heap_size / 3;
95 allowance = MAX (allowance_target, MIN_MINOR_COLLECTION_ALLOWANCE);
97 if (new_heap_size + allowance > soft_heap_limit) {
98 if (new_heap_size > soft_heap_limit)
99 allowance = MIN_MINOR_COLLECTION_ALLOWANCE;
101 allowance = MAX (soft_heap_limit - new_heap_size, MIN_MINOR_COLLECTION_ALLOWANCE);
104 /* FIXME: Why is this here? */
105 if (major_collector.free_swept_blocks)
106 major_collector.free_swept_blocks (allowance);
108 major_collection_trigger_size = new_heap_size + allowance;
110 need_calculate_minor_collection_allowance = FALSE;
112 if (debug_print_allowance) {
113 SGEN_LOG (0, "Surviving sweep: %ld bytes (%ld major, %ld LOS)", (long)new_heap_size, (long)new_major, (long)last_collection_los_memory_usage);
114 SGEN_LOG (0, "Allowance: %ld bytes", (long)allowance);
115 SGEN_LOG (0, "Trigger size: %ld bytes", (long)major_collection_trigger_size);
120 sgen_need_major_collection (mword space_needed)
124 if (sgen_concurrent_collection_in_progress ())
127 /* FIXME: This is a cop-out. We should have some way of figuring this out. */
128 if (!major_collector.have_swept ())
131 if (space_needed > sgen_memgov_available_free_space ())
134 sgen_memgov_calculate_minor_collection_allowance ();
136 heap_size = major_collector.get_num_major_sections () * major_collector.section_size + los_memory_usage;
138 return heap_size > major_collection_trigger_size;
142 sgen_memgov_minor_collection_start (void)
147 sgen_memgov_minor_collection_end (void)
152 sgen_memgov_major_collection_start (void)
154 need_calculate_minor_collection_allowance = TRUE;
156 if (debug_print_allowance) {
157 SGEN_LOG (0, "Starting collection with heap size %ld bytes", (long)(major_collector.get_num_major_sections () * major_collector.section_size + los_memory_usage));
162 sgen_memgov_major_collection_end (gboolean forced)
164 last_collection_los_memory_usage = los_memory_usage;
167 sgen_get_major_collector ()->finish_sweeping ();
168 sgen_memgov_calculate_minor_collection_allowance ();
173 log_timming (GGTimingInfo *info)
175 //unsigned long stw_time, unsigned long bridge_time, gboolean is_overflow
176 mword num_major_sections = major_collector.get_num_major_sections ();
177 char full_timing_buff [1024];
178 full_timing_buff [0] = '\0';
180 if (!info->is_overflow)
181 sprintf (full_timing_buff, "total %.2fms, bridge %.2fms", info->stw_time / 10000.0f, (int)info->bridge_time / 10000.0f);
182 if (info->generation == GENERATION_OLD)
183 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "GC_MAJOR%s: (%s) pause %.2fms, %s major %dK/%dK los %dK/%dK",
184 info->is_overflow ? "_OVERFLOW" : "",
185 info->reason ? info->reason : "",
186 (int)info->total_time / 10000.0f,
188 major_collector.section_size * num_major_sections / 1024,
189 major_collector.section_size * last_major_num_sections / 1024,
190 los_memory_usage / 1024,
191 last_los_memory_usage / 1024);
193 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "GC_MINOR%s: (%s) pause %.2fms, %s promoted %dK major %dK los %dK",
194 info->is_overflow ? "_OVERFLOW" : "",
195 info->reason ? info->reason : "",
196 (int)info->total_time / 10000.0f,
198 (num_major_sections - last_major_num_sections) * major_collector.section_size / 1024,
199 major_collector.section_size * num_major_sections / 1024,
200 los_memory_usage / 1024);
203 /* FIXME: Remove either these or the specialized ones above. */
205 sgen_memgov_collection_start (int generation)
210 sgen_memgov_collection_end (int generation, GGTimingInfo* info, int info_count)
213 for (i = 0; i < info_count; ++i) {
214 if (info[i].generation != -1)
215 log_timming (&info [i]);
219 /* Memory pressure API */
221 /* Negative value to remove */
223 mono_gc_add_memory_pressure (gint64 value)
225 /* FIXME: Use interlocked functions */
227 memory_pressure += value;
233 Global GC memory tracking.
234 This tracks the total usage of memory by the GC. This includes
235 managed and unmanaged memory.
239 prot_flags_for_activate (int activate)
241 unsigned long prot_flags = activate? MONO_MMAP_READ|MONO_MMAP_WRITE: MONO_MMAP_NONE;
242 return prot_flags | MONO_MMAP_PRIVATE | MONO_MMAP_ANON;
246 sgen_assert_memory_alloc (void *ptr, size_t requested_size, const char *assert_description)
248 if (ptr || !assert_description)
250 fprintf (stderr, "Error: Garbage collector could not allocate %zu bytes of memory for %s.\n", requested_size, assert_description);
255 * Allocate a big chunk of memory from the OS (usually 64KB to several megabytes).
256 * This must not require any lock.
259 sgen_alloc_os_memory (size_t size, SgenAllocFlags flags, const char *assert_description)
263 g_assert (!(flags & ~(SGEN_ALLOC_HEAP | SGEN_ALLOC_ACTIVATE)));
265 ptr = mono_valloc (0, size, prot_flags_for_activate (flags & SGEN_ALLOC_ACTIVATE));
266 sgen_assert_memory_alloc (ptr, size, assert_description);
268 SGEN_ATOMIC_ADD_P (total_alloc, size);
269 if (flags & SGEN_ALLOC_HEAP)
270 MONO_GC_HEAP_ALLOC ((mword)ptr, size);
271 total_alloc_max = MAX (total_alloc_max, total_alloc);
276 /* size must be a power of 2 */
278 sgen_alloc_os_memory_aligned (size_t size, mword alignment, SgenAllocFlags flags, const char *assert_description)
282 g_assert (!(flags & ~(SGEN_ALLOC_HEAP | SGEN_ALLOC_ACTIVATE)));
284 ptr = mono_valloc_aligned (size, alignment, prot_flags_for_activate (flags & SGEN_ALLOC_ACTIVATE));
285 sgen_assert_memory_alloc (ptr, size, assert_description);
287 SGEN_ATOMIC_ADD_P (total_alloc, size);
288 if (flags & SGEN_ALLOC_HEAP)
289 MONO_GC_HEAP_ALLOC ((mword)ptr, size);
290 total_alloc_max = MAX (total_alloc_max, total_alloc);
296 * Free the memory returned by sgen_alloc_os_memory (), returning it to the OS.
299 sgen_free_os_memory (void *addr, size_t size, SgenAllocFlags flags)
301 g_assert (!(flags & ~SGEN_ALLOC_HEAP));
303 mono_vfree (addr, size);
304 SGEN_ATOMIC_ADD_P (total_alloc, -(gssize)size);
305 if (flags & SGEN_ALLOC_HEAP)
306 MONO_GC_HEAP_FREE ((mword)addr, size);
307 total_alloc_max = MAX (total_alloc_max, total_alloc);
311 mono_gc_get_heap_size (void)
319 This limit the max size of the heap. It takes into account
320 only memory actively in use to hold heap objects and not
321 for other parts of the GC.
324 sgen_memgov_available_free_space (void)
326 return max_heap_size - MIN (allocated_heap, max_heap_size);
330 sgen_memgov_release_space (mword size, int space)
332 SGEN_ATOMIC_ADD_P (allocated_heap, -(gssize)size);
336 sgen_memgov_try_alloc_space (mword size, int space)
338 if (sgen_memgov_available_free_space () < size) {
339 SGEN_ASSERT (4, !sgen_thread_pool_is_thread_pool_thread (mono_native_thread_id_get ()), "Memory shouldn't run out in worker thread");
343 SGEN_ATOMIC_ADD_P (allocated_heap, size);
344 mono_runtime_resource_check_limit (MONO_RESOURCE_GC_HEAP, allocated_heap);
349 sgen_memgov_init (size_t max_heap, size_t soft_limit, gboolean debug_allowance, double allowance_ratio, double save_target)
352 soft_heap_limit = soft_limit;
354 debug_print_allowance = debug_allowance;
355 major_collection_trigger_size = MIN_MINOR_COLLECTION_ALLOWANCE;
357 mono_counters_register ("Memgov alloc", MONO_COUNTER_GC | MONO_COUNTER_WORD | MONO_COUNTER_BYTES | MONO_COUNTER_VARIABLE, &total_alloc);
358 mono_counters_register ("Memgov max alloc", MONO_COUNTER_GC | MONO_COUNTER_WORD | MONO_COUNTER_BYTES | MONO_COUNTER_MONOTONIC, &total_alloc_max);
363 if (max_heap < soft_limit) {
364 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Setting to minimum.", "`max-heap-size` must be at least as large as `soft-heap-limit`.");
365 max_heap = soft_limit;
368 if (max_heap < sgen_nursery_size * 4) {
369 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`.");
370 max_heap = sgen_nursery_size * 4;
372 max_heap_size = max_heap - sgen_nursery_size;
375 default_allowance_nursery_size_ratio = allowance_ratio;
378 save_target_ratio = save_target;