1 /* GLIB sliced memory - fast concurrent memory chunk allocator
2 * Copyright (C) 2005 Tim Janik
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
23 #if defined HAVE_POSIX_MEMALIGN && defined POSIX_MEMALIGN_WITH_COMPLIANT_ALLOCS
24 # define HAVE_COMPLIANT_POSIX_MEMALIGN 1
27 #ifdef HAVE_COMPLIANT_POSIX_MEMALIGN
28 #define _XOPEN_SOURCE 600 /* posix_memalign() */
30 #include <stdlib.h> /* posix_memalign() */
35 #include <unistd.h> /* sysconf() */
42 #include <stdio.h> /* fputs/fprintf */
46 #include "gmem.h" /* gslice.h */
48 #include "gtestutils.h"
50 #include "gthreadprivate.h"
51 #include "glib_trace.h"
53 /* the GSlice allocator is split up into 4 layers, roughly modelled after the slab
54 * allocator and magazine extensions as outlined in:
55 * + [Bonwick94] Jeff Bonwick, The slab allocator: An object-caching kernel
56 * memory allocator. USENIX 1994, http://citeseer.ist.psu.edu/bonwick94slab.html
57 * + [Bonwick01] Bonwick and Jonathan Adams, Magazines and vmem: Extending the
58 * slab allocator to many cpu's and arbitrary resources.
59 * USENIX 2001, http://citeseer.ist.psu.edu/bonwick01magazines.html
61 * - the thread magazines. for each (aligned) chunk size, a magazine (a list)
62 * of recently freed and soon to be allocated chunks is maintained per thread.
63 * this way, most alloc/free requests can be quickly satisfied from per-thread
64 * free lists which only require one g_private_get() call to retrive the
66 * - the magazine cache. allocating and freeing chunks to/from threads only
67 * occours at magazine sizes from a global depot of magazines. the depot
68 * maintaines a 15 second working set of allocated magazines, so full
69 * magazines are not allocated and released too often.
70 * the chunk size dependent magazine sizes automatically adapt (within limits,
71 * see [3]) to lock contention to properly scale performance across a variety
73 * - the slab allocator. this allocator allocates slabs (blocks of memory) close
74 * to the system page size or multiples thereof which have to be page aligned.
75 * the blocks are divided into smaller chunks which are used to satisfy
76 * allocations from the upper layers. the space provided by the reminder of
77 * the chunk size division is used for cache colorization (random distribution
78 * of chunk addresses) to improve processor cache utilization. multiple slabs
79 * with the same chunk size are kept in a partially sorted ring to allow O(1)
80 * freeing and allocation of chunks (as long as the allocation of an entirely
81 * new slab can be avoided).
82 * - the page allocator. on most modern systems, posix_memalign(3) or
83 * memalign(3) should be available, so this is used to allocate blocks with
84 * system page size based alignments and sizes or multiples thereof.
85 * if no memalign variant is provided, valloc() is used instead and
86 * block sizes are limited to the system page size (no multiples thereof).
87 * as a fallback, on system without even valloc(), a malloc(3)-based page
88 * allocator with alloc-only behaviour is used.
91 * [1] some systems memalign(3) implementations may rely on boundary tagging for
92 * the handed out memory chunks. to avoid excessive page-wise fragmentation,
93 * we reserve 2 * sizeof (void*) per block size for the systems memalign(3),
94 * specified in NATIVE_MALLOC_PADDING.
95 * [2] using the slab allocator alone already provides for a fast and efficient
96 * allocator, it doesn't properly scale beyond single-threaded uses though.
97 * also, the slab allocator implements eager free(3)-ing, i.e. does not
98 * provide any form of caching or working set maintenance. so if used alone,
99 * it's vulnerable to trashing for sequences of balanced (alloc, free) pairs
100 * at certain thresholds.
101 * [3] magazine sizes are bound by an implementation specific minimum size and
102 * a chunk size specific maximum to limit magazine storage sizes to roughly
104 * [4] allocating ca. 8 chunks per block/page keeps a good balance between
105 * external and internal fragmentation (<= 12.5%). [Bonwick94]
108 /* --- macros and constants --- */
109 #define LARGEALIGNMENT (256)
110 #define P2ALIGNMENT (2 * sizeof (gsize)) /* fits 2 pointers (assumed to be 2 * GLIB_SIZEOF_SIZE_T below) */
111 #define ALIGN(size, base) ((base) * (gsize) (((size) + (base) - 1) / (base)))
112 #define NATIVE_MALLOC_PADDING P2ALIGNMENT /* per-page padding left for native malloc(3) see [1] */
113 #define SLAB_INFO_SIZE P2ALIGN (sizeof (SlabInfo) + NATIVE_MALLOC_PADDING)
114 #define MAX_MAGAZINE_SIZE (256) /* see [3] and allocator_get_magazine_threshold() for this */
115 #define MIN_MAGAZINE_SIZE (4)
116 #define MAX_STAMP_COUNTER (7) /* distributes the load of gettimeofday() */
117 #define MAX_SLAB_CHUNK_SIZE(al) (((al)->max_page_size - SLAB_INFO_SIZE) / 8) /* we want at last 8 chunks per page, see [4] */
118 #define MAX_SLAB_INDEX(al) (SLAB_INDEX (al, MAX_SLAB_CHUNK_SIZE (al)) + 1)
119 #define SLAB_INDEX(al, asize) ((asize) / P2ALIGNMENT - 1) /* asize must be P2ALIGNMENT aligned */
120 #define SLAB_CHUNK_SIZE(al, ix) (((ix) + 1) * P2ALIGNMENT)
121 #define SLAB_BPAGE_SIZE(al,csz) (8 * (csz) + SLAB_INFO_SIZE)
123 /* optimized version of ALIGN (size, P2ALIGNMENT) */
124 #if GLIB_SIZEOF_SIZE_T * 2 == 8 /* P2ALIGNMENT */
125 #define P2ALIGN(size) (((size) + 0x7) & ~(gsize) 0x7)
126 #elif GLIB_SIZEOF_SIZE_T * 2 == 16 /* P2ALIGNMENT */
127 #define P2ALIGN(size) (((size) + 0xf) & ~(gsize) 0xf)
129 #define P2ALIGN(size) ALIGN (size, P2ALIGNMENT)
132 /* special helpers to avoid gmessage.c dependency */
133 static void mem_error (const char *format, ...) G_GNUC_PRINTF (1,2);
134 #define mem_assert(cond) do { if (G_LIKELY (cond)) ; else mem_error ("assertion failed: %s", #cond); } while (0)
136 /* --- structures --- */
137 typedef struct _ChunkLink ChunkLink;
138 typedef struct _SlabInfo SlabInfo;
139 typedef struct _CachedMagazine CachedMagazine;
147 SlabInfo *next, *prev;
151 gsize count; /* approximative chunks list length */
154 Magazine *magazine1; /* array of MAX_SLAB_INDEX (allocator) */
155 Magazine *magazine2; /* array of MAX_SLAB_INDEX (allocator) */
158 gboolean always_malloc;
159 gboolean bypass_magazines;
160 gboolean debug_blocks;
161 gsize working_set_msecs;
162 guint color_increment;
165 /* const after initialization */
166 gsize min_page_size, max_page_size;
168 gsize max_slab_chunk_size_for_magazine_cache;
170 GMutex *magazine_mutex;
171 ChunkLink **magazines; /* array of MAX_SLAB_INDEX (allocator) */
172 guint *contention_counters; /* array of MAX_SLAB_INDEX (allocator) */
178 SlabInfo **slab_stack; /* array of MAX_SLAB_INDEX (allocator) */
182 /* --- g-slice prototypes --- */
183 static gpointer slab_allocator_alloc_chunk (gsize chunk_size);
184 static void slab_allocator_free_chunk (gsize chunk_size,
186 static void private_thread_memory_cleanup (gpointer data);
187 static gpointer allocator_memalign (gsize alignment,
189 static void allocator_memfree (gsize memsize,
191 static inline void magazine_cache_update_stamp (void);
192 static inline gsize allocator_get_magazine_threshold (Allocator *allocator,
195 /* --- g-slice memory checker --- */
196 static void smc_notify_alloc (void *pointer,
198 static int smc_notify_free (void *pointer,
201 /* --- variables --- */
202 static GPrivate *private_thread_memory = NULL;
203 static gsize sys_page_size = 0;
204 static Allocator allocator[1] = { { 0, }, };
205 static SliceConfig slice_config = {
206 FALSE, /* always_malloc */
207 FALSE, /* bypass_magazines */
208 FALSE, /* debug_blocks */
209 15 * 1000, /* working_set_msecs */
210 1, /* color increment, alt: 0x7fffffff */
212 static GMutex *smc_tree_mutex = NULL; /* mutex for G_SLICE=debug-blocks */
214 /* --- auxillary funcitons --- */
216 g_slice_set_config (GSliceConfig ckey,
219 g_return_if_fail (sys_page_size == 0);
222 case G_SLICE_CONFIG_ALWAYS_MALLOC:
223 slice_config.always_malloc = value != 0;
225 case G_SLICE_CONFIG_BYPASS_MAGAZINES:
226 slice_config.bypass_magazines = value != 0;
228 case G_SLICE_CONFIG_WORKING_SET_MSECS:
229 slice_config.working_set_msecs = value;
231 case G_SLICE_CONFIG_COLOR_INCREMENT:
232 slice_config.color_increment = value;
238 g_slice_get_config (GSliceConfig ckey)
242 case G_SLICE_CONFIG_ALWAYS_MALLOC:
243 return slice_config.always_malloc;
244 case G_SLICE_CONFIG_BYPASS_MAGAZINES:
245 return slice_config.bypass_magazines;
246 case G_SLICE_CONFIG_WORKING_SET_MSECS:
247 return slice_config.working_set_msecs;
248 case G_SLICE_CONFIG_CHUNK_SIZES:
249 return MAX_SLAB_INDEX (allocator);
250 case G_SLICE_CONFIG_COLOR_INCREMENT:
251 return slice_config.color_increment;
258 g_slice_get_config_state (GSliceConfig ckey,
263 g_return_val_if_fail (n_values != NULL, NULL);
268 case G_SLICE_CONFIG_CONTENTION_COUNTER:
269 array[i++] = SLAB_CHUNK_SIZE (allocator, address);
270 array[i++] = allocator->contention_counters[address];
271 array[i++] = allocator_get_magazine_threshold (allocator, address);
273 return g_memdup (array, sizeof (array[0]) * *n_values);
280 slice_config_init (SliceConfig *config)
282 /* don't use g_malloc/g_message here */
284 const gchar *val = _g_getenv_nomalloc ("G_SLICE", buffer);
285 const GDebugKey keys[] = {
286 { "always-malloc", 1 << 0 },
287 { "debug-blocks", 1 << 1 },
289 gint flags = !val ? 0 : g_parse_debug_string (val, keys, G_N_ELEMENTS (keys));
290 *config = slice_config;
291 if (flags & (1 << 0)) /* always-malloc */
292 config->always_malloc = TRUE;
293 if (flags & (1 << 1)) /* debug-blocks */
294 config->debug_blocks = TRUE;
298 g_slice_init_nomessage (void)
300 /* we may not use g_error() or friends here */
301 mem_assert (sys_page_size == 0);
302 mem_assert (MIN_MAGAZINE_SIZE >= 4);
306 SYSTEM_INFO system_info;
307 GetSystemInfo (&system_info);
308 sys_page_size = system_info.dwPageSize;
311 sys_page_size = sysconf (_SC_PAGESIZE); /* = sysconf (_SC_PAGE_SIZE); = getpagesize(); */
313 mem_assert (sys_page_size >= 2 * LARGEALIGNMENT);
314 mem_assert ((sys_page_size & (sys_page_size - 1)) == 0);
315 slice_config_init (&allocator->config);
316 allocator->min_page_size = sys_page_size;
317 #if HAVE_COMPLIANT_POSIX_MEMALIGN || HAVE_MEMALIGN
318 /* allow allocation of pages up to 8KB (with 8KB alignment).
319 * this is useful because many medium to large sized structures
320 * fit less than 8 times (see [4]) into 4KB pages.
321 * we allow very small page sizes here, to reduce wastage in
322 * threads if only small allocations are required (this does
323 * bear the risk of incresing allocation times and fragmentation
326 allocator->min_page_size = MAX (allocator->min_page_size, 4096);
327 allocator->max_page_size = MAX (allocator->min_page_size, 8192);
328 allocator->min_page_size = MIN (allocator->min_page_size, 128);
330 /* we can only align to system page size */
331 allocator->max_page_size = sys_page_size;
333 if (allocator->config.always_malloc)
335 allocator->contention_counters = NULL;
336 allocator->magazines = NULL;
337 allocator->slab_stack = NULL;
341 allocator->contention_counters = g_new0 (guint, MAX_SLAB_INDEX (allocator));
342 allocator->magazines = g_new0 (ChunkLink*, MAX_SLAB_INDEX (allocator));
343 allocator->slab_stack = g_new0 (SlabInfo*, MAX_SLAB_INDEX (allocator));
346 allocator->magazine_mutex = NULL; /* _g_slice_thread_init_nomessage() */
347 allocator->mutex_counter = 0;
348 allocator->stamp_counter = MAX_STAMP_COUNTER; /* force initial update */
349 allocator->last_stamp = 0;
350 allocator->slab_mutex = NULL; /* _g_slice_thread_init_nomessage() */
351 allocator->color_accu = 0;
352 magazine_cache_update_stamp();
353 /* values cached for performance reasons */
354 allocator->max_slab_chunk_size_for_magazine_cache = MAX_SLAB_CHUNK_SIZE (allocator);
355 if (allocator->config.always_malloc || allocator->config.bypass_magazines)
356 allocator->max_slab_chunk_size_for_magazine_cache = 0; /* non-optimized cases */
357 /* at this point, g_mem_gc_friendly() should be initialized, this
358 * should have been accomplished by the above g_malloc/g_new calls
363 allocator_categorize (gsize aligned_chunk_size)
365 /* speed up the likely path */
366 if (G_LIKELY (aligned_chunk_size && aligned_chunk_size <= allocator->max_slab_chunk_size_for_magazine_cache))
367 return 1; /* use magazine cache */
369 /* the above will fail (max_slab_chunk_size_for_magazine_cache == 0) if the
370 * allocator is still uninitialized, or if we are not configured to use the
374 g_slice_init_nomessage ();
375 if (!allocator->config.always_malloc &&
376 aligned_chunk_size &&
377 aligned_chunk_size <= MAX_SLAB_CHUNK_SIZE (allocator))
379 if (allocator->config.bypass_magazines)
380 return 2; /* use slab allocator, see [2] */
381 return 1; /* use magazine cache */
383 return 0; /* use malloc() */
387 _g_slice_thread_init_nomessage (void)
389 /* we may not use g_error() or friends here */
391 g_slice_init_nomessage();
394 /* g_slice_init_nomessage() has been called already, probably due
395 * to a g_slice_alloc1() before g_thread_init().
398 private_thread_memory = g_private_new (private_thread_memory_cleanup);
399 allocator->magazine_mutex = g_mutex_new();
400 allocator->slab_mutex = g_mutex_new();
401 if (allocator->config.debug_blocks)
402 smc_tree_mutex = g_mutex_new();
406 g_mutex_lock_a (GMutex *mutex,
407 guint *contention_counter)
409 gboolean contention = FALSE;
410 if (!g_mutex_trylock (mutex))
412 g_mutex_lock (mutex);
417 allocator->mutex_counter++;
418 if (allocator->mutex_counter >= 1) /* quickly adapt to contention */
420 allocator->mutex_counter = 0;
421 *contention_counter = MIN (*contention_counter + 1, MAX_MAGAZINE_SIZE);
424 else /* !contention */
426 allocator->mutex_counter--;
427 if (allocator->mutex_counter < -11) /* moderately recover magazine sizes */
429 allocator->mutex_counter = 0;
430 *contention_counter = MAX (*contention_counter, 1) - 1;
435 static inline ThreadMemory*
436 thread_memory_from_self (void)
438 ThreadMemory *tmem = g_private_get (private_thread_memory);
439 if (G_UNLIKELY (!tmem))
441 static ThreadMemory *single_thread_memory = NULL; /* remember single-thread info for multi-threaded case */
442 if (single_thread_memory && g_thread_supported ())
444 g_mutex_lock (allocator->slab_mutex);
445 if (single_thread_memory)
447 /* GSlice has been used before g_thread_init(), and now
448 * we are running threaded. to cope with it, use the saved
449 * thread memory structure from when we weren't threaded.
451 tmem = single_thread_memory;
452 single_thread_memory = NULL; /* slab_mutex protected when multi-threaded */
454 g_mutex_unlock (allocator->slab_mutex);
458 const guint n_magazines = MAX_SLAB_INDEX (allocator);
459 tmem = g_malloc0 (sizeof (ThreadMemory) + sizeof (Magazine) * 2 * n_magazines);
460 tmem->magazine1 = (Magazine*) (tmem + 1);
461 tmem->magazine2 = &tmem->magazine1[n_magazines];
463 /* g_private_get/g_private_set works in the single-threaded xor the multi-
464 * threaded case. but not *across* g_thread_init(), after multi-thread
465 * initialization it returns NULL for previously set single-thread data.
467 g_private_set (private_thread_memory, tmem);
468 /* save single-thread thread memory structure, in case we need to
469 * pick it up again after multi-thread initialization happened.
471 if (!single_thread_memory && !g_thread_supported ())
472 single_thread_memory = tmem; /* no slab_mutex created yet */
477 static inline ChunkLink*
478 magazine_chain_pop_head (ChunkLink **magazine_chunks)
480 /* magazine chains are linked via ChunkLink->next.
481 * each ChunkLink->data of the toplevel chain may point to a subchain,
482 * linked via ChunkLink->next. ChunkLink->data of the subchains just
483 * contains uninitialized junk.
485 ChunkLink *chunk = (*magazine_chunks)->data;
486 if (G_UNLIKELY (chunk))
488 /* allocating from freed list */
489 (*magazine_chunks)->data = chunk->next;
493 chunk = *magazine_chunks;
494 *magazine_chunks = chunk->next;
499 #if 0 /* useful for debugging */
501 magazine_count (ChunkLink *head)
508 ChunkLink *child = head->data;
510 for (child = head->data; child; child = child->next)
519 allocator_get_magazine_threshold (Allocator *allocator,
522 /* the magazine size calculated here has a lower bound of MIN_MAGAZINE_SIZE,
523 * which is required by the implementation. also, for moderately sized chunks
524 * (say >= 64 bytes), magazine sizes shouldn't be much smaller then the number
525 * of chunks available per page/2 to avoid excessive traffic in the magazine
526 * cache for small to medium sized structures.
527 * the upper bound of the magazine size is effectively provided by
528 * MAX_MAGAZINE_SIZE. for larger chunks, this number is scaled down so that
529 * the content of a single magazine doesn't exceed ca. 16KB.
531 gsize chunk_size = SLAB_CHUNK_SIZE (allocator, ix);
532 guint threshold = MAX (MIN_MAGAZINE_SIZE, allocator->max_page_size / MAX (5 * chunk_size, 5 * 32));
533 guint contention_counter = allocator->contention_counters[ix];
534 if (G_UNLIKELY (contention_counter)) /* single CPU bias */
536 /* adapt contention counter thresholds to chunk sizes */
537 contention_counter = contention_counter * 64 / chunk_size;
538 threshold = MAX (threshold, contention_counter);
543 /* --- magazine cache --- */
545 magazine_cache_update_stamp (void)
547 if (allocator->stamp_counter >= MAX_STAMP_COUNTER)
550 g_get_current_time (&tv);
551 allocator->last_stamp = tv.tv_sec * 1000 + tv.tv_usec / 1000; /* milli seconds */
552 allocator->stamp_counter = 0;
555 allocator->stamp_counter++;
558 static inline ChunkLink*
559 magazine_chain_prepare_fields (ChunkLink *magazine_chunks)
565 /* checked upon initialization: mem_assert (MIN_MAGAZINE_SIZE >= 4); */
566 /* ensure a magazine with at least 4 unused data pointers */
567 chunk1 = magazine_chain_pop_head (&magazine_chunks);
568 chunk2 = magazine_chain_pop_head (&magazine_chunks);
569 chunk3 = magazine_chain_pop_head (&magazine_chunks);
570 chunk4 = magazine_chain_pop_head (&magazine_chunks);
571 chunk4->next = magazine_chunks;
572 chunk3->next = chunk4;
573 chunk2->next = chunk3;
574 chunk1->next = chunk2;
578 /* access the first 3 fields of a specially prepared magazine chain */
579 #define magazine_chain_prev(mc) ((mc)->data)
580 #define magazine_chain_stamp(mc) ((mc)->next->data)
581 #define magazine_chain_uint_stamp(mc) GPOINTER_TO_UINT ((mc)->next->data)
582 #define magazine_chain_next(mc) ((mc)->next->next->data)
583 #define magazine_chain_count(mc) ((mc)->next->next->next->data)
586 magazine_cache_trim (Allocator *allocator,
590 /* g_mutex_lock (allocator->mutex); done by caller */
591 /* trim magazine cache from tail */
592 ChunkLink *current = magazine_chain_prev (allocator->magazines[ix]);
593 ChunkLink *trash = NULL;
594 while (ABS (stamp - magazine_chain_uint_stamp (current)) >= allocator->config.working_set_msecs)
597 ChunkLink *prev = magazine_chain_prev (current);
598 ChunkLink *next = magazine_chain_next (current);
599 magazine_chain_next (prev) = next;
600 magazine_chain_prev (next) = prev;
601 /* clear special fields, put on trash stack */
602 magazine_chain_next (current) = NULL;
603 magazine_chain_count (current) = NULL;
604 magazine_chain_stamp (current) = NULL;
605 magazine_chain_prev (current) = trash;
607 /* fixup list head if required */
608 if (current == allocator->magazines[ix])
610 allocator->magazines[ix] = NULL;
615 g_mutex_unlock (allocator->magazine_mutex);
619 const gsize chunk_size = SLAB_CHUNK_SIZE (allocator, ix);
620 g_mutex_lock (allocator->slab_mutex);
624 trash = magazine_chain_prev (current);
625 magazine_chain_prev (current) = NULL; /* clear special field */
628 ChunkLink *chunk = magazine_chain_pop_head (¤t);
629 slab_allocator_free_chunk (chunk_size, chunk);
632 g_mutex_unlock (allocator->slab_mutex);
637 magazine_cache_push_magazine (guint ix,
638 ChunkLink *magazine_chunks,
639 gsize count) /* must be >= MIN_MAGAZINE_SIZE */
641 ChunkLink *current = magazine_chain_prepare_fields (magazine_chunks);
642 ChunkLink *next, *prev;
643 g_mutex_lock (allocator->magazine_mutex);
644 /* add magazine at head */
645 next = allocator->magazines[ix];
647 prev = magazine_chain_prev (next);
649 next = prev = current;
650 magazine_chain_next (prev) = current;
651 magazine_chain_prev (next) = current;
652 magazine_chain_prev (current) = prev;
653 magazine_chain_next (current) = next;
654 magazine_chain_count (current) = (gpointer) count;
656 magazine_cache_update_stamp();
657 magazine_chain_stamp (current) = GUINT_TO_POINTER (allocator->last_stamp);
658 allocator->magazines[ix] = current;
659 /* free old magazines beyond a certain threshold */
660 magazine_cache_trim (allocator, ix, allocator->last_stamp);
661 /* g_mutex_unlock (allocator->mutex); was done by magazine_cache_trim() */
665 magazine_cache_pop_magazine (guint ix,
668 g_mutex_lock_a (allocator->magazine_mutex, &allocator->contention_counters[ix]);
669 if (!allocator->magazines[ix])
671 guint magazine_threshold = allocator_get_magazine_threshold (allocator, ix);
672 gsize i, chunk_size = SLAB_CHUNK_SIZE (allocator, ix);
673 ChunkLink *chunk, *head;
674 g_mutex_unlock (allocator->magazine_mutex);
675 g_mutex_lock (allocator->slab_mutex);
676 head = slab_allocator_alloc_chunk (chunk_size);
679 for (i = 1; i < magazine_threshold; i++)
681 chunk->next = slab_allocator_alloc_chunk (chunk_size);
686 g_mutex_unlock (allocator->slab_mutex);
692 ChunkLink *current = allocator->magazines[ix];
693 ChunkLink *prev = magazine_chain_prev (current);
694 ChunkLink *next = magazine_chain_next (current);
696 magazine_chain_next (prev) = next;
697 magazine_chain_prev (next) = prev;
698 allocator->magazines[ix] = next == current ? NULL : next;
699 g_mutex_unlock (allocator->magazine_mutex);
700 /* clear special fields and hand out */
701 *countp = (gsize) magazine_chain_count (current);
702 magazine_chain_prev (current) = NULL;
703 magazine_chain_next (current) = NULL;
704 magazine_chain_count (current) = NULL;
705 magazine_chain_stamp (current) = NULL;
710 /* --- thread magazines --- */
712 private_thread_memory_cleanup (gpointer data)
714 ThreadMemory *tmem = data;
715 const guint n_magazines = MAX_SLAB_INDEX (allocator);
717 for (ix = 0; ix < n_magazines; ix++)
721 mags[0] = &tmem->magazine1[ix];
722 mags[1] = &tmem->magazine2[ix];
723 for (j = 0; j < 2; j++)
725 Magazine *mag = mags[j];
726 if (mag->count >= MIN_MAGAZINE_SIZE)
727 magazine_cache_push_magazine (ix, mag->chunks, mag->count);
730 const gsize chunk_size = SLAB_CHUNK_SIZE (allocator, ix);
731 g_mutex_lock (allocator->slab_mutex);
734 ChunkLink *chunk = magazine_chain_pop_head (&mag->chunks);
735 slab_allocator_free_chunk (chunk_size, chunk);
737 g_mutex_unlock (allocator->slab_mutex);
745 thread_memory_magazine1_reload (ThreadMemory *tmem,
748 Magazine *mag = &tmem->magazine1[ix];
749 mem_assert (mag->chunks == NULL); /* ensure that we may reset mag->count */
751 mag->chunks = magazine_cache_pop_magazine (ix, &mag->count);
755 thread_memory_magazine2_unload (ThreadMemory *tmem,
758 Magazine *mag = &tmem->magazine2[ix];
759 magazine_cache_push_magazine (ix, mag->chunks, mag->count);
765 thread_memory_swap_magazines (ThreadMemory *tmem,
768 Magazine xmag = tmem->magazine1[ix];
769 tmem->magazine1[ix] = tmem->magazine2[ix];
770 tmem->magazine2[ix] = xmag;
773 static inline gboolean
774 thread_memory_magazine1_is_empty (ThreadMemory *tmem,
777 return tmem->magazine1[ix].chunks == NULL;
780 static inline gboolean
781 thread_memory_magazine2_is_full (ThreadMemory *tmem,
784 return tmem->magazine2[ix].count >= allocator_get_magazine_threshold (allocator, ix);
787 static inline gpointer
788 thread_memory_magazine1_alloc (ThreadMemory *tmem,
791 Magazine *mag = &tmem->magazine1[ix];
792 ChunkLink *chunk = magazine_chain_pop_head (&mag->chunks);
793 if (G_LIKELY (mag->count > 0))
799 thread_memory_magazine2_free (ThreadMemory *tmem,
803 Magazine *mag = &tmem->magazine2[ix];
804 ChunkLink *chunk = mem;
806 chunk->next = mag->chunks;
811 /* --- API functions --- */
813 g_slice_alloc (gsize mem_size)
818 chunk_size = P2ALIGN (mem_size);
819 acat = allocator_categorize (chunk_size);
820 if (G_LIKELY (acat == 1)) /* allocate through magazine layer */
822 ThreadMemory *tmem = thread_memory_from_self();
823 guint ix = SLAB_INDEX (allocator, chunk_size);
824 if (G_UNLIKELY (thread_memory_magazine1_is_empty (tmem, ix)))
826 thread_memory_swap_magazines (tmem, ix);
827 if (G_UNLIKELY (thread_memory_magazine1_is_empty (tmem, ix)))
828 thread_memory_magazine1_reload (tmem, ix);
830 mem = thread_memory_magazine1_alloc (tmem, ix);
832 else if (acat == 2) /* allocate through slab allocator */
834 g_mutex_lock (allocator->slab_mutex);
835 mem = slab_allocator_alloc_chunk (chunk_size);
836 g_mutex_unlock (allocator->slab_mutex);
838 else /* delegate to system malloc */
839 mem = g_malloc (mem_size);
840 if (G_UNLIKELY (allocator->config.debug_blocks))
841 smc_notify_alloc (mem, mem_size);
843 TRACE (GLIB_SLICE_ALLOC((void*)mem, mem_size));
849 g_slice_alloc0 (gsize mem_size)
851 gpointer mem = g_slice_alloc (mem_size);
853 memset (mem, 0, mem_size);
858 g_slice_copy (gsize mem_size,
859 gconstpointer mem_block)
861 gpointer mem = g_slice_alloc (mem_size);
863 memcpy (mem, mem_block, mem_size);
868 g_slice_free1 (gsize mem_size,
871 gsize chunk_size = P2ALIGN (mem_size);
872 guint acat = allocator_categorize (chunk_size);
873 if (G_UNLIKELY (!mem_block))
875 if (G_UNLIKELY (allocator->config.debug_blocks) &&
876 !smc_notify_free (mem_block, mem_size))
878 if (G_LIKELY (acat == 1)) /* allocate through magazine layer */
880 ThreadMemory *tmem = thread_memory_from_self();
881 guint ix = SLAB_INDEX (allocator, chunk_size);
882 if (G_UNLIKELY (thread_memory_magazine2_is_full (tmem, ix)))
884 thread_memory_swap_magazines (tmem, ix);
885 if (G_UNLIKELY (thread_memory_magazine2_is_full (tmem, ix)))
886 thread_memory_magazine2_unload (tmem, ix);
888 if (G_UNLIKELY (g_mem_gc_friendly))
889 memset (mem_block, 0, chunk_size);
890 thread_memory_magazine2_free (tmem, ix, mem_block);
892 else if (acat == 2) /* allocate through slab allocator */
894 if (G_UNLIKELY (g_mem_gc_friendly))
895 memset (mem_block, 0, chunk_size);
896 g_mutex_lock (allocator->slab_mutex);
897 slab_allocator_free_chunk (chunk_size, mem_block);
898 g_mutex_unlock (allocator->slab_mutex);
900 else /* delegate to system malloc */
902 if (G_UNLIKELY (g_mem_gc_friendly))
903 memset (mem_block, 0, mem_size);
906 TRACE (GLIB_SLICE_FREE((void*)mem_block, mem_size));
910 g_slice_free_chain_with_offset (gsize mem_size,
914 gpointer slice = mem_chain;
915 /* while the thread magazines and the magazine cache are implemented so that
916 * they can easily be extended to allow for free lists containing more free
917 * lists for the first level nodes, which would allow O(1) freeing in this
918 * function, the benefit of such an extension is questionable, because:
919 * - the magazine size counts will become mere lower bounds which confuses
920 * the code adapting to lock contention;
921 * - freeing a single node to the thread magazines is very fast, so this
922 * O(list_length) operation is multiplied by a fairly small factor;
923 * - memory usage histograms on larger applications seem to indicate that
924 * the amount of released multi node lists is negligible in comparison
925 * to single node releases.
926 * - the major performance bottle neck, namely g_private_get() or
927 * g_mutex_lock()/g_mutex_unlock() has already been moved out of the
928 * inner loop for freeing chained slices.
930 gsize chunk_size = P2ALIGN (mem_size);
931 guint acat = allocator_categorize (chunk_size);
932 if (G_LIKELY (acat == 1)) /* allocate through magazine layer */
934 ThreadMemory *tmem = thread_memory_from_self();
935 guint ix = SLAB_INDEX (allocator, chunk_size);
938 guint8 *current = slice;
939 slice = *(gpointer*) (current + next_offset);
940 if (G_UNLIKELY (allocator->config.debug_blocks) &&
941 !smc_notify_free (current, mem_size))
943 if (G_UNLIKELY (thread_memory_magazine2_is_full (tmem, ix)))
945 thread_memory_swap_magazines (tmem, ix);
946 if (G_UNLIKELY (thread_memory_magazine2_is_full (tmem, ix)))
947 thread_memory_magazine2_unload (tmem, ix);
949 if (G_UNLIKELY (g_mem_gc_friendly))
950 memset (current, 0, chunk_size);
951 thread_memory_magazine2_free (tmem, ix, current);
954 else if (acat == 2) /* allocate through slab allocator */
956 g_mutex_lock (allocator->slab_mutex);
959 guint8 *current = slice;
960 slice = *(gpointer*) (current + next_offset);
961 if (G_UNLIKELY (allocator->config.debug_blocks) &&
962 !smc_notify_free (current, mem_size))
964 if (G_UNLIKELY (g_mem_gc_friendly))
965 memset (current, 0, chunk_size);
966 slab_allocator_free_chunk (chunk_size, current);
968 g_mutex_unlock (allocator->slab_mutex);
970 else /* delegate to system malloc */
973 guint8 *current = slice;
974 slice = *(gpointer*) (current + next_offset);
975 if (G_UNLIKELY (allocator->config.debug_blocks) &&
976 !smc_notify_free (current, mem_size))
978 if (G_UNLIKELY (g_mem_gc_friendly))
979 memset (current, 0, mem_size);
984 /* --- single page allocator --- */
986 allocator_slab_stack_push (Allocator *allocator,
990 /* insert slab at slab ring head */
991 if (!allocator->slab_stack[ix])
998 SlabInfo *next = allocator->slab_stack[ix], *prev = next->prev;
1004 allocator->slab_stack[ix] = sinfo;
1008 allocator_aligned_page_size (Allocator *allocator,
1011 gsize val = 1 << g_bit_storage (n_bytes - 1);
1012 val = MAX (val, allocator->min_page_size);
1017 allocator_add_slab (Allocator *allocator,
1023 gsize addr, padding, n_chunks, color = 0;
1024 gsize page_size = allocator_aligned_page_size (allocator, SLAB_BPAGE_SIZE (allocator, chunk_size));
1025 /* allocate 1 page for the chunks and the slab */
1026 gpointer aligned_memory = allocator_memalign (page_size, page_size - NATIVE_MALLOC_PADDING);
1027 guint8 *mem = aligned_memory;
1031 const gchar *syserr = "unknown error";
1033 syserr = strerror (errno);
1035 mem_error ("failed to allocate %u bytes (alignment: %u): %s\n",
1036 (guint) (page_size - NATIVE_MALLOC_PADDING), (guint) page_size, syserr);
1038 /* mask page adress */
1039 addr = ((gsize) mem / page_size) * page_size;
1040 /* assert alignment */
1041 mem_assert (aligned_memory == (gpointer) addr);
1042 /* basic slab info setup */
1043 sinfo = (SlabInfo*) (mem + page_size - SLAB_INFO_SIZE);
1044 sinfo->n_allocated = 0;
1045 sinfo->chunks = NULL;
1046 /* figure cache colorization */
1047 n_chunks = ((guint8*) sinfo - mem) / chunk_size;
1048 padding = ((guint8*) sinfo - mem) - n_chunks * chunk_size;
1051 color = (allocator->color_accu * P2ALIGNMENT) % padding;
1052 allocator->color_accu += allocator->config.color_increment;
1054 /* add chunks to free list */
1055 chunk = (ChunkLink*) (mem + color);
1056 sinfo->chunks = chunk;
1057 for (i = 0; i < n_chunks - 1; i++)
1059 chunk->next = (ChunkLink*) ((guint8*) chunk + chunk_size);
1060 chunk = chunk->next;
1062 chunk->next = NULL; /* last chunk */
1063 /* add slab to slab ring */
1064 allocator_slab_stack_push (allocator, ix, sinfo);
1068 slab_allocator_alloc_chunk (gsize chunk_size)
1071 guint ix = SLAB_INDEX (allocator, chunk_size);
1072 /* ensure non-empty slab */
1073 if (!allocator->slab_stack[ix] || !allocator->slab_stack[ix]->chunks)
1074 allocator_add_slab (allocator, ix, chunk_size);
1075 /* allocate chunk */
1076 chunk = allocator->slab_stack[ix]->chunks;
1077 allocator->slab_stack[ix]->chunks = chunk->next;
1078 allocator->slab_stack[ix]->n_allocated++;
1079 /* rotate empty slabs */
1080 if (!allocator->slab_stack[ix]->chunks)
1081 allocator->slab_stack[ix] = allocator->slab_stack[ix]->next;
1086 slab_allocator_free_chunk (gsize chunk_size,
1091 guint ix = SLAB_INDEX (allocator, chunk_size);
1092 gsize page_size = allocator_aligned_page_size (allocator, SLAB_BPAGE_SIZE (allocator, chunk_size));
1093 gsize addr = ((gsize) mem / page_size) * page_size;
1094 /* mask page adress */
1095 guint8 *page = (guint8*) addr;
1096 SlabInfo *sinfo = (SlabInfo*) (page + page_size - SLAB_INFO_SIZE);
1097 /* assert valid chunk count */
1098 mem_assert (sinfo->n_allocated > 0);
1099 /* add chunk to free list */
1100 was_empty = sinfo->chunks == NULL;
1101 chunk = (ChunkLink*) mem;
1102 chunk->next = sinfo->chunks;
1103 sinfo->chunks = chunk;
1104 sinfo->n_allocated--;
1105 /* keep slab ring partially sorted, empty slabs at end */
1109 SlabInfo *next = sinfo->next, *prev = sinfo->prev;
1112 if (allocator->slab_stack[ix] == sinfo)
1113 allocator->slab_stack[ix] = next == sinfo ? NULL : next;
1114 /* insert slab at head */
1115 allocator_slab_stack_push (allocator, ix, sinfo);
1117 /* eagerly free complete unused slabs */
1118 if (!sinfo->n_allocated)
1121 SlabInfo *next = sinfo->next, *prev = sinfo->prev;
1124 if (allocator->slab_stack[ix] == sinfo)
1125 allocator->slab_stack[ix] = next == sinfo ? NULL : next;
1127 allocator_memfree (page_size, page);
1131 /* --- memalign implementation --- */
1132 #ifdef HAVE_MALLOC_H
1133 #include <malloc.h> /* memalign() */
1137 * define HAVE_POSIX_MEMALIGN 1 // if free(posix_memalign(3)) works, <stdlib.h>
1138 * define HAVE_COMPLIANT_POSIX_MEMALIGN 1 // if free(posix_memalign(3)) works for sizes != 2^n, <stdlib.h>
1139 * define HAVE_MEMALIGN 1 // if free(memalign(3)) works, <malloc.h>
1140 * define HAVE_VALLOC 1 // if free(valloc(3)) works, <stdlib.h> or <malloc.h>
1141 * if none is provided, we implement malloc(3)-based alloc-only page alignment
1144 #if !(HAVE_COMPLIANT_POSIX_MEMALIGN || HAVE_MEMALIGN || HAVE_VALLOC)
1145 static GTrashStack *compat_valloc_trash = NULL;
1149 allocator_memalign (gsize alignment,
1152 gpointer aligned_memory = NULL;
1154 #if HAVE_COMPLIANT_POSIX_MEMALIGN
1155 err = posix_memalign (&aligned_memory, alignment, memsize);
1158 aligned_memory = memalign (alignment, memsize);
1162 aligned_memory = valloc (memsize);
1165 /* simplistic non-freeing page allocator */
1166 mem_assert (alignment == sys_page_size);
1167 mem_assert (memsize <= sys_page_size);
1168 if (!compat_valloc_trash)
1170 const guint n_pages = 16;
1171 guint8 *mem = malloc (n_pages * sys_page_size);
1176 guint8 *amem = (guint8*) ALIGN ((gsize) mem, sys_page_size);
1178 i--; /* mem wasn't page aligned */
1180 g_trash_stack_push (&compat_valloc_trash, amem + i * sys_page_size);
1183 aligned_memory = g_trash_stack_pop (&compat_valloc_trash);
1185 if (!aligned_memory)
1187 return aligned_memory;
1191 allocator_memfree (gsize memsize,
1194 #if HAVE_COMPLIANT_POSIX_MEMALIGN || HAVE_MEMALIGN || HAVE_VALLOC
1197 mem_assert (memsize <= sys_page_size);
1198 g_trash_stack_push (&compat_valloc_trash, mem);
1203 mem_error (const char *format,
1208 /* at least, put out "MEMORY-ERROR", in case we segfault during the rest of the function */
1209 fputs ("\n***MEMORY-ERROR***: ", stderr);
1210 pname = g_get_prgname();
1211 fprintf (stderr, "%s[%ld]: GSlice: ", pname ? pname : "", (long)getpid());
1212 va_start (args, format);
1213 vfprintf (stderr, format, args);
1215 fputs ("\n", stderr);
1220 /* --- g-slice memory checker tree --- */
1221 typedef size_t SmcKType; /* key type */
1222 typedef size_t SmcVType; /* value type */
1227 static void smc_tree_insert (SmcKType key,
1229 static gboolean smc_tree_lookup (SmcKType key,
1231 static gboolean smc_tree_remove (SmcKType key);
1234 /* --- g-slice memory checker implementation --- */
1236 smc_notify_alloc (void *pointer,
1239 size_t adress = (size_t) pointer;
1241 smc_tree_insert (adress, size);
1246 smc_notify_ignore (void *pointer)
1248 size_t adress = (size_t) pointer;
1250 smc_tree_remove (adress);
1255 smc_notify_free (void *pointer,
1258 size_t adress = (size_t) pointer;
1263 return 1; /* ignore */
1264 found_one = smc_tree_lookup (adress, &real_size);
1267 fprintf (stderr, "GSlice: MemChecker: attempt to release non-allocated block: %p size=%" G_GSIZE_FORMAT "\n", pointer, size);
1270 if (real_size != size && (real_size || size))
1272 fprintf (stderr, "GSlice: MemChecker: attempt to release block with invalid size: %p size=%" G_GSIZE_FORMAT " invalid-size=%" G_GSIZE_FORMAT "\n", pointer, real_size, size);
1275 if (!smc_tree_remove (adress))
1277 fprintf (stderr, "GSlice: MemChecker: attempt to release non-allocated block: %p size=%" G_GSIZE_FORMAT "\n", pointer, size);
1280 return 1; /* all fine */
1283 /* --- g-slice memory checker tree implementation --- */
1284 #define SMC_TRUNK_COUNT (4093 /* 16381 */) /* prime, to distribute trunk collisions (big, allocated just once) */
1285 #define SMC_BRANCH_COUNT (511) /* prime, to distribute branch collisions */
1286 #define SMC_TRUNK_EXTENT (SMC_BRANCH_COUNT * 2039) /* key adress space per trunk, should distribute uniformly across BRANCH_COUNT */
1287 #define SMC_TRUNK_HASH(k) ((k / SMC_TRUNK_EXTENT) % SMC_TRUNK_COUNT) /* generate new trunk hash per megabyte (roughly) */
1288 #define SMC_BRANCH_HASH(k) (k % SMC_BRANCH_COUNT)
1292 unsigned int n_entries;
1295 static SmcBranch **smc_tree_root = NULL;
1298 smc_tree_abort (int errval)
1300 const char *syserr = "unknown error";
1302 syserr = strerror (errval);
1304 mem_error ("MemChecker: failure in debugging tree: %s", syserr);
1307 static inline SmcEntry*
1308 smc_tree_branch_grow_L (SmcBranch *branch,
1311 unsigned int old_size = branch->n_entries * sizeof (branch->entries[0]);
1312 unsigned int new_size = old_size + sizeof (branch->entries[0]);
1314 mem_assert (index <= branch->n_entries);
1315 branch->entries = (SmcEntry*) realloc (branch->entries, new_size);
1316 if (!branch->entries)
1317 smc_tree_abort (errno);
1318 entry = branch->entries + index;
1319 g_memmove (entry + 1, entry, (branch->n_entries - index) * sizeof (entry[0]));
1320 branch->n_entries += 1;
1324 static inline SmcEntry*
1325 smc_tree_branch_lookup_nearest_L (SmcBranch *branch,
1328 unsigned int n_nodes = branch->n_entries, offs = 0;
1329 SmcEntry *check = branch->entries;
1331 while (offs < n_nodes)
1333 unsigned int i = (offs + n_nodes) >> 1;
1334 check = branch->entries + i;
1335 cmp = key < check->key ? -1 : key != check->key;
1337 return check; /* return exact match */
1340 else /* (cmp > 0) */
1343 /* check points at last mismatch, cmp > 0 indicates greater key */
1344 return cmp > 0 ? check + 1 : check; /* return insertion position for inexact match */
1348 smc_tree_insert (SmcKType key,
1351 unsigned int ix0, ix1;
1354 g_mutex_lock (smc_tree_mutex);
1355 ix0 = SMC_TRUNK_HASH (key);
1356 ix1 = SMC_BRANCH_HASH (key);
1359 smc_tree_root = calloc (SMC_TRUNK_COUNT, sizeof (smc_tree_root[0]));
1361 smc_tree_abort (errno);
1363 if (!smc_tree_root[ix0])
1365 smc_tree_root[ix0] = calloc (SMC_BRANCH_COUNT, sizeof (smc_tree_root[0][0]));
1366 if (!smc_tree_root[ix0])
1367 smc_tree_abort (errno);
1369 entry = smc_tree_branch_lookup_nearest_L (&smc_tree_root[ix0][ix1], key);
1370 if (!entry || /* need create */
1371 entry >= smc_tree_root[ix0][ix1].entries + smc_tree_root[ix0][ix1].n_entries || /* need append */
1372 entry->key != key) /* need insert */
1373 entry = smc_tree_branch_grow_L (&smc_tree_root[ix0][ix1], entry - smc_tree_root[ix0][ix1].entries);
1375 entry->value = value;
1376 g_mutex_unlock (smc_tree_mutex);
1380 smc_tree_lookup (SmcKType key,
1383 SmcEntry *entry = NULL;
1384 unsigned int ix0 = SMC_TRUNK_HASH (key), ix1 = SMC_BRANCH_HASH (key);
1385 gboolean found_one = FALSE;
1387 g_mutex_lock (smc_tree_mutex);
1388 if (smc_tree_root && smc_tree_root[ix0])
1390 entry = smc_tree_branch_lookup_nearest_L (&smc_tree_root[ix0][ix1], key);
1392 entry < smc_tree_root[ix0][ix1].entries + smc_tree_root[ix0][ix1].n_entries &&
1396 *value_p = entry->value;
1399 g_mutex_unlock (smc_tree_mutex);
1404 smc_tree_remove (SmcKType key)
1406 unsigned int ix0 = SMC_TRUNK_HASH (key), ix1 = SMC_BRANCH_HASH (key);
1407 gboolean found_one = FALSE;
1408 g_mutex_lock (smc_tree_mutex);
1409 if (smc_tree_root && smc_tree_root[ix0])
1411 SmcEntry *entry = smc_tree_branch_lookup_nearest_L (&smc_tree_root[ix0][ix1], key);
1413 entry < smc_tree_root[ix0][ix1].entries + smc_tree_root[ix0][ix1].n_entries &&
1416 unsigned int i = entry - smc_tree_root[ix0][ix1].entries;
1417 smc_tree_root[ix0][ix1].n_entries -= 1;
1418 g_memmove (entry, entry + 1, (smc_tree_root[ix0][ix1].n_entries - i) * sizeof (entry[0]));
1419 if (!smc_tree_root[ix0][ix1].n_entries)
1421 /* avoid useless pressure on the memory system */
1422 free (smc_tree_root[ix0][ix1].entries);
1423 smc_tree_root[ix0][ix1].entries = NULL;
1428 g_mutex_unlock (smc_tree_mutex);
1432 #ifdef G_ENABLE_DEBUG
1434 g_slice_debug_tree_statistics (void)
1436 g_mutex_lock (smc_tree_mutex);
1439 unsigned int i, j, t = 0, o = 0, b = 0, su = 0, ex = 0, en = 4294967295u;
1441 for (i = 0; i < SMC_TRUNK_COUNT; i++)
1442 if (smc_tree_root[i])
1445 for (j = 0; j < SMC_BRANCH_COUNT; j++)
1446 if (smc_tree_root[i][j].n_entries)
1449 su += smc_tree_root[i][j].n_entries;
1450 en = MIN (en, smc_tree_root[i][j].n_entries);
1451 ex = MAX (ex, smc_tree_root[i][j].n_entries);
1453 else if (smc_tree_root[i][j].entries)
1454 o++; /* formerly used, now empty */
1457 tf = MAX (t, 1.0); /* max(1) to be a valid divisor */
1458 bf = MAX (b, 1.0); /* max(1) to be a valid divisor */
1459 fprintf (stderr, "GSlice: MemChecker: %u trunks, %u branches, %u old branches\n", t, b, o);
1460 fprintf (stderr, "GSlice: MemChecker: %f branches per trunk, %.2f%% utilization\n",
1462 100.0 - (SMC_BRANCH_COUNT - b / tf) / (0.01 * SMC_BRANCH_COUNT));
1463 fprintf (stderr, "GSlice: MemChecker: %f entries per branch, %u minimum, %u maximum\n",
1467 fprintf (stderr, "GSlice: MemChecker: root=NULL\n");
1468 g_mutex_unlock (smc_tree_mutex);
1470 /* sample statistics (beast + GSLice + 24h scripted core & GUI activity):
1471 * PID %CPU %MEM VSZ RSS COMMAND
1472 * 8887 30.3 45.8 456068 414856 beast-0.7.1 empty.bse
1473 * $ cat /proc/8887/statm # total-program-size resident-set-size shared-pages text/code data/stack library dirty-pages
1474 * 114017 103714 2354 344 0 108676 0
1475 * $ cat /proc/8887/status
1486 * (gdb) print g_slice_debug_tree_statistics ()
1487 * GSlice: MemChecker: 422 trunks, 213068 branches, 0 old branches
1488 * GSlice: MemChecker: 504.900474 branches per trunk, 98.81% utilization
1489 * GSlice: MemChecker: 4.965039 entries per branch, 1 minimum, 37 maximum
1492 #endif /* G_ENABLE_DEBUG */