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.
22 #include "glibconfig.h"
24 #if defined HAVE_POSIX_MEMALIGN && defined POSIX_MEMALIGN_WITH_COMPLIANT_ALLOCS
25 # define HAVE_COMPLIANT_POSIX_MEMALIGN 1
28 #if defined(HAVE_COMPLIANT_POSIX_MEMALIGN) && !defined(_XOPEN_SOURCE)
29 #define _XOPEN_SOURCE 600 /* posix_memalign() */
31 #include <stdlib.h> /* posix_memalign() */
36 #include <unistd.h> /* sysconf() */
43 #include <stdio.h> /* fputs/fprintf */
48 #include "gmem.h" /* gslice.h */
49 #include "gstrfuncs.h"
51 #include "gtrashstack.h"
52 #include "gtestutils.h"
54 #include "glib_trace.h"
56 /* the GSlice allocator is split up into 4 layers, roughly modelled after the slab
57 * allocator and magazine extensions as outlined in:
58 * + [Bonwick94] Jeff Bonwick, The slab allocator: An object-caching kernel
59 * memory allocator. USENIX 1994, http://citeseer.ist.psu.edu/bonwick94slab.html
60 * + [Bonwick01] Bonwick and Jonathan Adams, Magazines and vmem: Extending the
61 * slab allocator to many cpu's and arbitrary resources.
62 * USENIX 2001, http://citeseer.ist.psu.edu/bonwick01magazines.html
64 * - the thread magazines. for each (aligned) chunk size, a magazine (a list)
65 * of recently freed and soon to be allocated chunks is maintained per thread.
66 * this way, most alloc/free requests can be quickly satisfied from per-thread
67 * free lists which only require one g_private_get() call to retrive the
69 * - the magazine cache. allocating and freeing chunks to/from threads only
70 * occours at magazine sizes from a global depot of magazines. the depot
71 * maintaines a 15 second working set of allocated magazines, so full
72 * magazines are not allocated and released too often.
73 * the chunk size dependent magazine sizes automatically adapt (within limits,
74 * see [3]) to lock contention to properly scale performance across a variety
76 * - the slab allocator. this allocator allocates slabs (blocks of memory) close
77 * to the system page size or multiples thereof which have to be page aligned.
78 * the blocks are divided into smaller chunks which are used to satisfy
79 * allocations from the upper layers. the space provided by the reminder of
80 * the chunk size division is used for cache colorization (random distribution
81 * of chunk addresses) to improve processor cache utilization. multiple slabs
82 * with the same chunk size are kept in a partially sorted ring to allow O(1)
83 * freeing and allocation of chunks (as long as the allocation of an entirely
84 * new slab can be avoided).
85 * - the page allocator. on most modern systems, posix_memalign(3) or
86 * memalign(3) should be available, so this is used to allocate blocks with
87 * system page size based alignments and sizes or multiples thereof.
88 * if no memalign variant is provided, valloc() is used instead and
89 * block sizes are limited to the system page size (no multiples thereof).
90 * as a fallback, on system without even valloc(), a malloc(3)-based page
91 * allocator with alloc-only behaviour is used.
94 * [1] some systems memalign(3) implementations may rely on boundary tagging for
95 * the handed out memory chunks. to avoid excessive page-wise fragmentation,
96 * we reserve 2 * sizeof (void*) per block size for the systems memalign(3),
97 * specified in NATIVE_MALLOC_PADDING.
98 * [2] using the slab allocator alone already provides for a fast and efficient
99 * allocator, it doesn't properly scale beyond single-threaded uses though.
100 * also, the slab allocator implements eager free(3)-ing, i.e. does not
101 * provide any form of caching or working set maintenance. so if used alone,
102 * it's vulnerable to trashing for sequences of balanced (alloc, free) pairs
103 * at certain thresholds.
104 * [3] magazine sizes are bound by an implementation specific minimum size and
105 * a chunk size specific maximum to limit magazine storage sizes to roughly
107 * [4] allocating ca. 8 chunks per block/page keeps a good balance between
108 * external and internal fragmentation (<= 12.5%). [Bonwick94]
111 /* --- macros and constants --- */
112 #define LARGEALIGNMENT (256)
113 #define P2ALIGNMENT (2 * sizeof (gsize)) /* fits 2 pointers (assumed to be 2 * GLIB_SIZEOF_SIZE_T below) */
114 #define ALIGN(size, base) ((base) * (gsize) (((size) + (base) - 1) / (base)))
115 #define NATIVE_MALLOC_PADDING P2ALIGNMENT /* per-page padding left for native malloc(3) see [1] */
116 #define SLAB_INFO_SIZE P2ALIGN (sizeof (SlabInfo) + NATIVE_MALLOC_PADDING)
117 #define MAX_MAGAZINE_SIZE (256) /* see [3] and allocator_get_magazine_threshold() for this */
118 #define MIN_MAGAZINE_SIZE (4)
119 #define MAX_STAMP_COUNTER (7) /* distributes the load of gettimeofday() */
120 #define MAX_SLAB_CHUNK_SIZE(al) (((al)->max_page_size - SLAB_INFO_SIZE) / 8) /* we want at last 8 chunks per page, see [4] */
121 #define MAX_SLAB_INDEX(al) (SLAB_INDEX (al, MAX_SLAB_CHUNK_SIZE (al)) + 1)
122 #define SLAB_INDEX(al, asize) ((asize) / P2ALIGNMENT - 1) /* asize must be P2ALIGNMENT aligned */
123 #define SLAB_CHUNK_SIZE(al, ix) (((ix) + 1) * P2ALIGNMENT)
124 #define SLAB_BPAGE_SIZE(al,csz) (8 * (csz) + SLAB_INFO_SIZE)
126 /* optimized version of ALIGN (size, P2ALIGNMENT) */
127 #if GLIB_SIZEOF_SIZE_T * 2 == 8 /* P2ALIGNMENT */
128 #define P2ALIGN(size) (((size) + 0x7) & ~(gsize) 0x7)
129 #elif GLIB_SIZEOF_SIZE_T * 2 == 16 /* P2ALIGNMENT */
130 #define P2ALIGN(size) (((size) + 0xf) & ~(gsize) 0xf)
132 #define P2ALIGN(size) ALIGN (size, P2ALIGNMENT)
135 /* special helpers to avoid gmessage.c dependency */
136 static void mem_error (const char *format, ...) G_GNUC_PRINTF (1,2);
137 #define mem_assert(cond) do { if (G_LIKELY (cond)) ; else mem_error ("assertion failed: %s", #cond); } while (0)
139 /* --- structures --- */
140 typedef struct _ChunkLink ChunkLink;
141 typedef struct _SlabInfo SlabInfo;
142 typedef struct _CachedMagazine CachedMagazine;
150 SlabInfo *next, *prev;
154 gsize count; /* approximative chunks list length */
157 Magazine *magazine1; /* array of MAX_SLAB_INDEX (allocator) */
158 Magazine *magazine2; /* array of MAX_SLAB_INDEX (allocator) */
161 gboolean always_malloc;
162 gboolean bypass_magazines;
163 gboolean debug_blocks;
164 gsize working_set_msecs;
165 guint color_increment;
168 /* const after initialization */
169 gsize min_page_size, max_page_size;
171 gsize max_slab_chunk_size_for_magazine_cache;
173 GMutex magazine_mutex;
174 ChunkLink **magazines; /* array of MAX_SLAB_INDEX (allocator) */
175 guint *contention_counters; /* array of MAX_SLAB_INDEX (allocator) */
181 SlabInfo **slab_stack; /* array of MAX_SLAB_INDEX (allocator) */
185 /* --- g-slice prototypes --- */
186 static gpointer slab_allocator_alloc_chunk (gsize chunk_size);
187 static void slab_allocator_free_chunk (gsize chunk_size,
189 static void private_thread_memory_cleanup (gpointer data);
190 static gpointer allocator_memalign (gsize alignment,
192 static void allocator_memfree (gsize memsize,
194 static inline void magazine_cache_update_stamp (void);
195 static inline gsize allocator_get_magazine_threshold (Allocator *allocator,
198 /* --- g-slice memory checker --- */
199 static void smc_notify_alloc (void *pointer,
201 static int smc_notify_free (void *pointer,
204 /* --- variables --- */
205 static GPrivate private_thread_memory = G_PRIVATE_INIT (private_thread_memory_cleanup);
206 static gsize sys_page_size = 0;
207 static Allocator allocator[1] = { { 0, }, };
208 static SliceConfig slice_config = {
209 FALSE, /* always_malloc */
210 FALSE, /* bypass_magazines */
211 FALSE, /* debug_blocks */
212 15 * 1000, /* working_set_msecs */
213 1, /* color increment, alt: 0x7fffffff */
215 static GMutex smc_tree_mutex; /* mutex for G_SLICE=debug-blocks */
217 /* --- auxiliary funcitons --- */
219 g_slice_set_config (GSliceConfig ckey,
222 g_return_if_fail (sys_page_size == 0);
225 case G_SLICE_CONFIG_ALWAYS_MALLOC:
226 slice_config.always_malloc = value != 0;
228 case G_SLICE_CONFIG_BYPASS_MAGAZINES:
229 slice_config.bypass_magazines = value != 0;
231 case G_SLICE_CONFIG_WORKING_SET_MSECS:
232 slice_config.working_set_msecs = value;
234 case G_SLICE_CONFIG_COLOR_INCREMENT:
235 slice_config.color_increment = value;
241 g_slice_get_config (GSliceConfig ckey)
245 case G_SLICE_CONFIG_ALWAYS_MALLOC:
246 return slice_config.always_malloc;
247 case G_SLICE_CONFIG_BYPASS_MAGAZINES:
248 return slice_config.bypass_magazines;
249 case G_SLICE_CONFIG_WORKING_SET_MSECS:
250 return slice_config.working_set_msecs;
251 case G_SLICE_CONFIG_CHUNK_SIZES:
252 return MAX_SLAB_INDEX (allocator);
253 case G_SLICE_CONFIG_COLOR_INCREMENT:
254 return slice_config.color_increment;
261 g_slice_get_config_state (GSliceConfig ckey,
266 g_return_val_if_fail (n_values != NULL, NULL);
271 case G_SLICE_CONFIG_CONTENTION_COUNTER:
272 array[i++] = SLAB_CHUNK_SIZE (allocator, address);
273 array[i++] = allocator->contention_counters[address];
274 array[i++] = allocator_get_magazine_threshold (allocator, address);
276 return g_memdup (array, sizeof (array[0]) * *n_values);
283 getenv_nomalloc (const gchar *variable,
286 const gchar *retval = getenv (variable);
287 if (retval && retval[0])
289 gint l = strlen (retval);
292 strncpy (buffer, retval, l);
301 slice_config_init (SliceConfig *config)
303 /* don't use g_malloc/g_message here */
305 const gchar *val = getenv_nomalloc ("G_SLICE", buffer);
306 const GDebugKey keys[] = {
307 { "always-malloc", 1 << 0 },
308 { "debug-blocks", 1 << 1 },
310 gint flags = !val ? 0 : g_parse_debug_string (val, keys, G_N_ELEMENTS (keys));
311 *config = slice_config;
312 if (flags & (1 << 0)) /* always-malloc */
313 config->always_malloc = TRUE;
314 if (flags & (1 << 1)) /* debug-blocks */
315 config->debug_blocks = TRUE;
319 g_slice_init_nomessage (void)
321 /* we may not use g_error() or friends here */
322 mem_assert (sys_page_size == 0);
323 mem_assert (MIN_MAGAZINE_SIZE >= 4);
327 SYSTEM_INFO system_info;
328 GetSystemInfo (&system_info);
329 sys_page_size = system_info.dwPageSize;
332 sys_page_size = sysconf (_SC_PAGESIZE); /* = sysconf (_SC_PAGE_SIZE); = getpagesize(); */
334 mem_assert (sys_page_size >= 2 * LARGEALIGNMENT);
335 mem_assert ((sys_page_size & (sys_page_size - 1)) == 0);
336 slice_config_init (&allocator->config);
337 allocator->min_page_size = sys_page_size;
338 #if HAVE_COMPLIANT_POSIX_MEMALIGN || HAVE_MEMALIGN
339 /* allow allocation of pages up to 8KB (with 8KB alignment).
340 * this is useful because many medium to large sized structures
341 * fit less than 8 times (see [4]) into 4KB pages.
342 * we allow very small page sizes here, to reduce wastage in
343 * threads if only small allocations are required (this does
344 * bear the risk of incresing allocation times and fragmentation
347 allocator->min_page_size = MAX (allocator->min_page_size, 4096);
348 allocator->max_page_size = MAX (allocator->min_page_size, 8192);
349 allocator->min_page_size = MIN (allocator->min_page_size, 128);
351 /* we can only align to system page size */
352 allocator->max_page_size = sys_page_size;
354 if (allocator->config.always_malloc)
356 allocator->contention_counters = NULL;
357 allocator->magazines = NULL;
358 allocator->slab_stack = NULL;
362 allocator->contention_counters = g_new0 (guint, MAX_SLAB_INDEX (allocator));
363 allocator->magazines = g_new0 (ChunkLink*, MAX_SLAB_INDEX (allocator));
364 allocator->slab_stack = g_new0 (SlabInfo*, MAX_SLAB_INDEX (allocator));
367 g_mutex_init (&allocator->magazine_mutex);
368 allocator->mutex_counter = 0;
369 allocator->stamp_counter = MAX_STAMP_COUNTER; /* force initial update */
370 allocator->last_stamp = 0;
371 g_mutex_init (&allocator->slab_mutex);
372 allocator->color_accu = 0;
373 magazine_cache_update_stamp();
374 /* values cached for performance reasons */
375 allocator->max_slab_chunk_size_for_magazine_cache = MAX_SLAB_CHUNK_SIZE (allocator);
376 if (allocator->config.always_malloc || allocator->config.bypass_magazines)
377 allocator->max_slab_chunk_size_for_magazine_cache = 0; /* non-optimized cases */
381 allocator_categorize (gsize aligned_chunk_size)
383 /* speed up the likely path */
384 if (G_LIKELY (aligned_chunk_size && aligned_chunk_size <= allocator->max_slab_chunk_size_for_magazine_cache))
385 return 1; /* use magazine cache */
387 if (!allocator->config.always_malloc &&
388 aligned_chunk_size &&
389 aligned_chunk_size <= MAX_SLAB_CHUNK_SIZE (allocator))
391 if (allocator->config.bypass_magazines)
392 return 2; /* use slab allocator, see [2] */
393 return 1; /* use magazine cache */
395 return 0; /* use malloc() */
399 g_mutex_lock_a (GMutex *mutex,
400 guint *contention_counter)
402 gboolean contention = FALSE;
403 if (!g_mutex_trylock (mutex))
405 g_mutex_lock (mutex);
410 allocator->mutex_counter++;
411 if (allocator->mutex_counter >= 1) /* quickly adapt to contention */
413 allocator->mutex_counter = 0;
414 *contention_counter = MIN (*contention_counter + 1, MAX_MAGAZINE_SIZE);
417 else /* !contention */
419 allocator->mutex_counter--;
420 if (allocator->mutex_counter < -11) /* moderately recover magazine sizes */
422 allocator->mutex_counter = 0;
423 *contention_counter = MAX (*contention_counter, 1) - 1;
428 static inline ThreadMemory*
429 thread_memory_from_self (void)
431 ThreadMemory *tmem = g_private_get (&private_thread_memory);
432 if (G_UNLIKELY (!tmem))
434 static GMutex init_mutex;
437 g_mutex_lock (&init_mutex);
438 if G_UNLIKELY (sys_page_size == 0)
439 g_slice_init_nomessage ();
440 g_mutex_unlock (&init_mutex);
442 n_magazines = MAX_SLAB_INDEX (allocator);
443 tmem = g_malloc0 (sizeof (ThreadMemory) + sizeof (Magazine) * 2 * n_magazines);
444 tmem->magazine1 = (Magazine*) (tmem + 1);
445 tmem->magazine2 = &tmem->magazine1[n_magazines];
446 g_private_set (&private_thread_memory, tmem);
451 static inline ChunkLink*
452 magazine_chain_pop_head (ChunkLink **magazine_chunks)
454 /* magazine chains are linked via ChunkLink->next.
455 * each ChunkLink->data of the toplevel chain may point to a subchain,
456 * linked via ChunkLink->next. ChunkLink->data of the subchains just
457 * contains uninitialized junk.
459 ChunkLink *chunk = (*magazine_chunks)->data;
460 if (G_UNLIKELY (chunk))
462 /* allocating from freed list */
463 (*magazine_chunks)->data = chunk->next;
467 chunk = *magazine_chunks;
468 *magazine_chunks = chunk->next;
473 #if 0 /* useful for debugging */
475 magazine_count (ChunkLink *head)
482 ChunkLink *child = head->data;
484 for (child = head->data; child; child = child->next)
493 allocator_get_magazine_threshold (Allocator *allocator,
496 /* the magazine size calculated here has a lower bound of MIN_MAGAZINE_SIZE,
497 * which is required by the implementation. also, for moderately sized chunks
498 * (say >= 64 bytes), magazine sizes shouldn't be much smaller then the number
499 * of chunks available per page/2 to avoid excessive traffic in the magazine
500 * cache for small to medium sized structures.
501 * the upper bound of the magazine size is effectively provided by
502 * MAX_MAGAZINE_SIZE. for larger chunks, this number is scaled down so that
503 * the content of a single magazine doesn't exceed ca. 16KB.
505 gsize chunk_size = SLAB_CHUNK_SIZE (allocator, ix);
506 guint threshold = MAX (MIN_MAGAZINE_SIZE, allocator->max_page_size / MAX (5 * chunk_size, 5 * 32));
507 guint contention_counter = allocator->contention_counters[ix];
508 if (G_UNLIKELY (contention_counter)) /* single CPU bias */
510 /* adapt contention counter thresholds to chunk sizes */
511 contention_counter = contention_counter * 64 / chunk_size;
512 threshold = MAX (threshold, contention_counter);
517 /* --- magazine cache --- */
519 magazine_cache_update_stamp (void)
521 if (allocator->stamp_counter >= MAX_STAMP_COUNTER)
524 g_get_current_time (&tv);
525 allocator->last_stamp = tv.tv_sec * 1000 + tv.tv_usec / 1000; /* milli seconds */
526 allocator->stamp_counter = 0;
529 allocator->stamp_counter++;
532 static inline ChunkLink*
533 magazine_chain_prepare_fields (ChunkLink *magazine_chunks)
539 /* checked upon initialization: mem_assert (MIN_MAGAZINE_SIZE >= 4); */
540 /* ensure a magazine with at least 4 unused data pointers */
541 chunk1 = magazine_chain_pop_head (&magazine_chunks);
542 chunk2 = magazine_chain_pop_head (&magazine_chunks);
543 chunk3 = magazine_chain_pop_head (&magazine_chunks);
544 chunk4 = magazine_chain_pop_head (&magazine_chunks);
545 chunk4->next = magazine_chunks;
546 chunk3->next = chunk4;
547 chunk2->next = chunk3;
548 chunk1->next = chunk2;
552 /* access the first 3 fields of a specially prepared magazine chain */
553 #define magazine_chain_prev(mc) ((mc)->data)
554 #define magazine_chain_stamp(mc) ((mc)->next->data)
555 #define magazine_chain_uint_stamp(mc) GPOINTER_TO_UINT ((mc)->next->data)
556 #define magazine_chain_next(mc) ((mc)->next->next->data)
557 #define magazine_chain_count(mc) ((mc)->next->next->next->data)
560 magazine_cache_trim (Allocator *allocator,
564 /* g_mutex_lock (allocator->mutex); done by caller */
565 /* trim magazine cache from tail */
566 ChunkLink *current = magazine_chain_prev (allocator->magazines[ix]);
567 ChunkLink *trash = NULL;
568 while (ABS (stamp - magazine_chain_uint_stamp (current)) >= allocator->config.working_set_msecs)
571 ChunkLink *prev = magazine_chain_prev (current);
572 ChunkLink *next = magazine_chain_next (current);
573 magazine_chain_next (prev) = next;
574 magazine_chain_prev (next) = prev;
575 /* clear special fields, put on trash stack */
576 magazine_chain_next (current) = NULL;
577 magazine_chain_count (current) = NULL;
578 magazine_chain_stamp (current) = NULL;
579 magazine_chain_prev (current) = trash;
581 /* fixup list head if required */
582 if (current == allocator->magazines[ix])
584 allocator->magazines[ix] = NULL;
589 g_mutex_unlock (&allocator->magazine_mutex);
593 const gsize chunk_size = SLAB_CHUNK_SIZE (allocator, ix);
594 g_mutex_lock (&allocator->slab_mutex);
598 trash = magazine_chain_prev (current);
599 magazine_chain_prev (current) = NULL; /* clear special field */
602 ChunkLink *chunk = magazine_chain_pop_head (¤t);
603 slab_allocator_free_chunk (chunk_size, chunk);
606 g_mutex_unlock (&allocator->slab_mutex);
611 magazine_cache_push_magazine (guint ix,
612 ChunkLink *magazine_chunks,
613 gsize count) /* must be >= MIN_MAGAZINE_SIZE */
615 ChunkLink *current = magazine_chain_prepare_fields (magazine_chunks);
616 ChunkLink *next, *prev;
617 g_mutex_lock (&allocator->magazine_mutex);
618 /* add magazine at head */
619 next = allocator->magazines[ix];
621 prev = magazine_chain_prev (next);
623 next = prev = current;
624 magazine_chain_next (prev) = current;
625 magazine_chain_prev (next) = current;
626 magazine_chain_prev (current) = prev;
627 magazine_chain_next (current) = next;
628 magazine_chain_count (current) = (gpointer) count;
630 magazine_cache_update_stamp();
631 magazine_chain_stamp (current) = GUINT_TO_POINTER (allocator->last_stamp);
632 allocator->magazines[ix] = current;
633 /* free old magazines beyond a certain threshold */
634 magazine_cache_trim (allocator, ix, allocator->last_stamp);
635 /* g_mutex_unlock (allocator->mutex); was done by magazine_cache_trim() */
639 magazine_cache_pop_magazine (guint ix,
642 g_mutex_lock_a (&allocator->magazine_mutex, &allocator->contention_counters[ix]);
643 if (!allocator->magazines[ix])
645 guint magazine_threshold = allocator_get_magazine_threshold (allocator, ix);
646 gsize i, chunk_size = SLAB_CHUNK_SIZE (allocator, ix);
647 ChunkLink *chunk, *head;
648 g_mutex_unlock (&allocator->magazine_mutex);
649 g_mutex_lock (&allocator->slab_mutex);
650 head = slab_allocator_alloc_chunk (chunk_size);
653 for (i = 1; i < magazine_threshold; i++)
655 chunk->next = slab_allocator_alloc_chunk (chunk_size);
660 g_mutex_unlock (&allocator->slab_mutex);
666 ChunkLink *current = allocator->magazines[ix];
667 ChunkLink *prev = magazine_chain_prev (current);
668 ChunkLink *next = magazine_chain_next (current);
670 magazine_chain_next (prev) = next;
671 magazine_chain_prev (next) = prev;
672 allocator->magazines[ix] = next == current ? NULL : next;
673 g_mutex_unlock (&allocator->magazine_mutex);
674 /* clear special fields and hand out */
675 *countp = (gsize) magazine_chain_count (current);
676 magazine_chain_prev (current) = NULL;
677 magazine_chain_next (current) = NULL;
678 magazine_chain_count (current) = NULL;
679 magazine_chain_stamp (current) = NULL;
684 /* --- thread magazines --- */
686 private_thread_memory_cleanup (gpointer data)
688 ThreadMemory *tmem = data;
689 const guint n_magazines = MAX_SLAB_INDEX (allocator);
691 for (ix = 0; ix < n_magazines; ix++)
695 mags[0] = &tmem->magazine1[ix];
696 mags[1] = &tmem->magazine2[ix];
697 for (j = 0; j < 2; j++)
699 Magazine *mag = mags[j];
700 if (mag->count >= MIN_MAGAZINE_SIZE)
701 magazine_cache_push_magazine (ix, mag->chunks, mag->count);
704 const gsize chunk_size = SLAB_CHUNK_SIZE (allocator, ix);
705 g_mutex_lock (&allocator->slab_mutex);
708 ChunkLink *chunk = magazine_chain_pop_head (&mag->chunks);
709 slab_allocator_free_chunk (chunk_size, chunk);
711 g_mutex_unlock (&allocator->slab_mutex);
719 thread_memory_magazine1_reload (ThreadMemory *tmem,
722 Magazine *mag = &tmem->magazine1[ix];
723 mem_assert (mag->chunks == NULL); /* ensure that we may reset mag->count */
725 mag->chunks = magazine_cache_pop_magazine (ix, &mag->count);
729 thread_memory_magazine2_unload (ThreadMemory *tmem,
732 Magazine *mag = &tmem->magazine2[ix];
733 magazine_cache_push_magazine (ix, mag->chunks, mag->count);
739 thread_memory_swap_magazines (ThreadMemory *tmem,
742 Magazine xmag = tmem->magazine1[ix];
743 tmem->magazine1[ix] = tmem->magazine2[ix];
744 tmem->magazine2[ix] = xmag;
747 static inline gboolean
748 thread_memory_magazine1_is_empty (ThreadMemory *tmem,
751 return tmem->magazine1[ix].chunks == NULL;
754 static inline gboolean
755 thread_memory_magazine2_is_full (ThreadMemory *tmem,
758 return tmem->magazine2[ix].count >= allocator_get_magazine_threshold (allocator, ix);
761 static inline gpointer
762 thread_memory_magazine1_alloc (ThreadMemory *tmem,
765 Magazine *mag = &tmem->magazine1[ix];
766 ChunkLink *chunk = magazine_chain_pop_head (&mag->chunks);
767 if (G_LIKELY (mag->count > 0))
773 thread_memory_magazine2_free (ThreadMemory *tmem,
777 Magazine *mag = &tmem->magazine2[ix];
778 ChunkLink *chunk = mem;
780 chunk->next = mag->chunks;
785 /* --- API functions --- */
787 g_slice_alloc (gsize mem_size)
794 /* This gets the private structure for this thread. If the private
795 * structure does not yet exist, it is created.
797 * This has a side effect of causing GSlice to be initialised, so it
800 tmem = thread_memory_from_self ();
802 chunk_size = P2ALIGN (mem_size);
803 acat = allocator_categorize (chunk_size);
804 if (G_LIKELY (acat == 1)) /* allocate through magazine layer */
806 guint ix = SLAB_INDEX (allocator, chunk_size);
807 if (G_UNLIKELY (thread_memory_magazine1_is_empty (tmem, ix)))
809 thread_memory_swap_magazines (tmem, ix);
810 if (G_UNLIKELY (thread_memory_magazine1_is_empty (tmem, ix)))
811 thread_memory_magazine1_reload (tmem, ix);
813 mem = thread_memory_magazine1_alloc (tmem, ix);
815 else if (acat == 2) /* allocate through slab allocator */
817 g_mutex_lock (&allocator->slab_mutex);
818 mem = slab_allocator_alloc_chunk (chunk_size);
819 g_mutex_unlock (&allocator->slab_mutex);
821 else /* delegate to system malloc */
822 mem = g_malloc (mem_size);
823 if (G_UNLIKELY (allocator->config.debug_blocks))
824 smc_notify_alloc (mem, mem_size);
826 TRACE (GLIB_SLICE_ALLOC((void*)mem, mem_size));
832 g_slice_alloc0 (gsize mem_size)
834 gpointer mem = g_slice_alloc (mem_size);
836 memset (mem, 0, mem_size);
841 g_slice_copy (gsize mem_size,
842 gconstpointer mem_block)
844 gpointer mem = g_slice_alloc (mem_size);
846 memcpy (mem, mem_block, mem_size);
851 g_slice_free1 (gsize mem_size,
854 gsize chunk_size = P2ALIGN (mem_size);
855 guint acat = allocator_categorize (chunk_size);
856 if (G_UNLIKELY (!mem_block))
858 if (G_UNLIKELY (allocator->config.debug_blocks) &&
859 !smc_notify_free (mem_block, mem_size))
861 if (G_LIKELY (acat == 1)) /* allocate through magazine layer */
863 ThreadMemory *tmem = thread_memory_from_self();
864 guint ix = SLAB_INDEX (allocator, chunk_size);
865 if (G_UNLIKELY (thread_memory_magazine2_is_full (tmem, ix)))
867 thread_memory_swap_magazines (tmem, ix);
868 if (G_UNLIKELY (thread_memory_magazine2_is_full (tmem, ix)))
869 thread_memory_magazine2_unload (tmem, ix);
871 if (G_UNLIKELY (g_mem_gc_friendly))
872 memset (mem_block, 0, chunk_size);
873 thread_memory_magazine2_free (tmem, ix, mem_block);
875 else if (acat == 2) /* allocate through slab allocator */
877 if (G_UNLIKELY (g_mem_gc_friendly))
878 memset (mem_block, 0, chunk_size);
879 g_mutex_lock (&allocator->slab_mutex);
880 slab_allocator_free_chunk (chunk_size, mem_block);
881 g_mutex_unlock (&allocator->slab_mutex);
883 else /* delegate to system malloc */
885 if (G_UNLIKELY (g_mem_gc_friendly))
886 memset (mem_block, 0, mem_size);
889 TRACE (GLIB_SLICE_FREE((void*)mem_block, mem_size));
893 g_slice_free_chain_with_offset (gsize mem_size,
897 gpointer slice = mem_chain;
898 /* while the thread magazines and the magazine cache are implemented so that
899 * they can easily be extended to allow for free lists containing more free
900 * lists for the first level nodes, which would allow O(1) freeing in this
901 * function, the benefit of such an extension is questionable, because:
902 * - the magazine size counts will become mere lower bounds which confuses
903 * the code adapting to lock contention;
904 * - freeing a single node to the thread magazines is very fast, so this
905 * O(list_length) operation is multiplied by a fairly small factor;
906 * - memory usage histograms on larger applications seem to indicate that
907 * the amount of released multi node lists is negligible in comparison
908 * to single node releases.
909 * - the major performance bottle neck, namely g_private_get() or
910 * g_mutex_lock()/g_mutex_unlock() has already been moved out of the
911 * inner loop for freeing chained slices.
913 gsize chunk_size = P2ALIGN (mem_size);
914 guint acat = allocator_categorize (chunk_size);
915 if (G_LIKELY (acat == 1)) /* allocate through magazine layer */
917 ThreadMemory *tmem = thread_memory_from_self();
918 guint ix = SLAB_INDEX (allocator, chunk_size);
921 guint8 *current = slice;
922 slice = *(gpointer*) (current + next_offset);
923 if (G_UNLIKELY (allocator->config.debug_blocks) &&
924 !smc_notify_free (current, mem_size))
926 if (G_UNLIKELY (thread_memory_magazine2_is_full (tmem, ix)))
928 thread_memory_swap_magazines (tmem, ix);
929 if (G_UNLIKELY (thread_memory_magazine2_is_full (tmem, ix)))
930 thread_memory_magazine2_unload (tmem, ix);
932 if (G_UNLIKELY (g_mem_gc_friendly))
933 memset (current, 0, chunk_size);
934 thread_memory_magazine2_free (tmem, ix, current);
937 else if (acat == 2) /* allocate through slab allocator */
939 g_mutex_lock (&allocator->slab_mutex);
942 guint8 *current = slice;
943 slice = *(gpointer*) (current + next_offset);
944 if (G_UNLIKELY (allocator->config.debug_blocks) &&
945 !smc_notify_free (current, mem_size))
947 if (G_UNLIKELY (g_mem_gc_friendly))
948 memset (current, 0, chunk_size);
949 slab_allocator_free_chunk (chunk_size, current);
951 g_mutex_unlock (&allocator->slab_mutex);
953 else /* delegate to system malloc */
956 guint8 *current = slice;
957 slice = *(gpointer*) (current + next_offset);
958 if (G_UNLIKELY (allocator->config.debug_blocks) &&
959 !smc_notify_free (current, mem_size))
961 if (G_UNLIKELY (g_mem_gc_friendly))
962 memset (current, 0, mem_size);
967 /* --- single page allocator --- */
969 allocator_slab_stack_push (Allocator *allocator,
973 /* insert slab at slab ring head */
974 if (!allocator->slab_stack[ix])
981 SlabInfo *next = allocator->slab_stack[ix], *prev = next->prev;
987 allocator->slab_stack[ix] = sinfo;
991 allocator_aligned_page_size (Allocator *allocator,
994 gsize val = 1 << g_bit_storage (n_bytes - 1);
995 val = MAX (val, allocator->min_page_size);
1000 allocator_add_slab (Allocator *allocator,
1006 gsize addr, padding, n_chunks, color = 0;
1007 gsize page_size = allocator_aligned_page_size (allocator, SLAB_BPAGE_SIZE (allocator, chunk_size));
1008 /* allocate 1 page for the chunks and the slab */
1009 gpointer aligned_memory = allocator_memalign (page_size, page_size - NATIVE_MALLOC_PADDING);
1010 guint8 *mem = aligned_memory;
1014 const gchar *syserr = "unknown error";
1016 syserr = strerror (errno);
1018 mem_error ("failed to allocate %u bytes (alignment: %u): %s\n",
1019 (guint) (page_size - NATIVE_MALLOC_PADDING), (guint) page_size, syserr);
1021 /* mask page address */
1022 addr = ((gsize) mem / page_size) * page_size;
1023 /* assert alignment */
1024 mem_assert (aligned_memory == (gpointer) addr);
1025 /* basic slab info setup */
1026 sinfo = (SlabInfo*) (mem + page_size - SLAB_INFO_SIZE);
1027 sinfo->n_allocated = 0;
1028 sinfo->chunks = NULL;
1029 /* figure cache colorization */
1030 n_chunks = ((guint8*) sinfo - mem) / chunk_size;
1031 padding = ((guint8*) sinfo - mem) - n_chunks * chunk_size;
1034 color = (allocator->color_accu * P2ALIGNMENT) % padding;
1035 allocator->color_accu += allocator->config.color_increment;
1037 /* add chunks to free list */
1038 chunk = (ChunkLink*) (mem + color);
1039 sinfo->chunks = chunk;
1040 for (i = 0; i < n_chunks - 1; i++)
1042 chunk->next = (ChunkLink*) ((guint8*) chunk + chunk_size);
1043 chunk = chunk->next;
1045 chunk->next = NULL; /* last chunk */
1046 /* add slab to slab ring */
1047 allocator_slab_stack_push (allocator, ix, sinfo);
1051 slab_allocator_alloc_chunk (gsize chunk_size)
1054 guint ix = SLAB_INDEX (allocator, chunk_size);
1055 /* ensure non-empty slab */
1056 if (!allocator->slab_stack[ix] || !allocator->slab_stack[ix]->chunks)
1057 allocator_add_slab (allocator, ix, chunk_size);
1058 /* allocate chunk */
1059 chunk = allocator->slab_stack[ix]->chunks;
1060 allocator->slab_stack[ix]->chunks = chunk->next;
1061 allocator->slab_stack[ix]->n_allocated++;
1062 /* rotate empty slabs */
1063 if (!allocator->slab_stack[ix]->chunks)
1064 allocator->slab_stack[ix] = allocator->slab_stack[ix]->next;
1069 slab_allocator_free_chunk (gsize chunk_size,
1074 guint ix = SLAB_INDEX (allocator, chunk_size);
1075 gsize page_size = allocator_aligned_page_size (allocator, SLAB_BPAGE_SIZE (allocator, chunk_size));
1076 gsize addr = ((gsize) mem / page_size) * page_size;
1077 /* mask page address */
1078 guint8 *page = (guint8*) addr;
1079 SlabInfo *sinfo = (SlabInfo*) (page + page_size - SLAB_INFO_SIZE);
1080 /* assert valid chunk count */
1081 mem_assert (sinfo->n_allocated > 0);
1082 /* add chunk to free list */
1083 was_empty = sinfo->chunks == NULL;
1084 chunk = (ChunkLink*) mem;
1085 chunk->next = sinfo->chunks;
1086 sinfo->chunks = chunk;
1087 sinfo->n_allocated--;
1088 /* keep slab ring partially sorted, empty slabs at end */
1092 SlabInfo *next = sinfo->next, *prev = sinfo->prev;
1095 if (allocator->slab_stack[ix] == sinfo)
1096 allocator->slab_stack[ix] = next == sinfo ? NULL : next;
1097 /* insert slab at head */
1098 allocator_slab_stack_push (allocator, ix, sinfo);
1100 /* eagerly free complete unused slabs */
1101 if (!sinfo->n_allocated)
1104 SlabInfo *next = sinfo->next, *prev = sinfo->prev;
1107 if (allocator->slab_stack[ix] == sinfo)
1108 allocator->slab_stack[ix] = next == sinfo ? NULL : next;
1110 allocator_memfree (page_size, page);
1114 /* --- memalign implementation --- */
1115 #ifdef HAVE_MALLOC_H
1116 #include <malloc.h> /* memalign() */
1120 * define HAVE_POSIX_MEMALIGN 1 // if free(posix_memalign(3)) works, <stdlib.h>
1121 * define HAVE_COMPLIANT_POSIX_MEMALIGN 1 // if free(posix_memalign(3)) works for sizes != 2^n, <stdlib.h>
1122 * define HAVE_MEMALIGN 1 // if free(memalign(3)) works, <malloc.h>
1123 * define HAVE_VALLOC 1 // if free(valloc(3)) works, <stdlib.h> or <malloc.h>
1124 * if none is provided, we implement malloc(3)-based alloc-only page alignment
1127 #if !(HAVE_COMPLIANT_POSIX_MEMALIGN || HAVE_MEMALIGN || HAVE_VALLOC)
1128 static GTrashStack *compat_valloc_trash = NULL;
1132 allocator_memalign (gsize alignment,
1135 gpointer aligned_memory = NULL;
1137 #if HAVE_COMPLIANT_POSIX_MEMALIGN
1138 err = posix_memalign (&aligned_memory, alignment, memsize);
1141 aligned_memory = memalign (alignment, memsize);
1145 aligned_memory = valloc (memsize);
1148 /* simplistic non-freeing page allocator */
1149 mem_assert (alignment == sys_page_size);
1150 mem_assert (memsize <= sys_page_size);
1151 if (!compat_valloc_trash)
1153 const guint n_pages = 16;
1154 guint8 *mem = malloc (n_pages * sys_page_size);
1159 guint8 *amem = (guint8*) ALIGN ((gsize) mem, sys_page_size);
1161 i--; /* mem wasn't page aligned */
1163 g_trash_stack_push (&compat_valloc_trash, amem + i * sys_page_size);
1166 aligned_memory = g_trash_stack_pop (&compat_valloc_trash);
1168 if (!aligned_memory)
1170 return aligned_memory;
1174 allocator_memfree (gsize memsize,
1177 #if HAVE_COMPLIANT_POSIX_MEMALIGN || HAVE_MEMALIGN || HAVE_VALLOC
1180 mem_assert (memsize <= sys_page_size);
1181 g_trash_stack_push (&compat_valloc_trash, mem);
1186 mem_error (const char *format,
1191 /* at least, put out "MEMORY-ERROR", in case we segfault during the rest of the function */
1192 fputs ("\n***MEMORY-ERROR***: ", stderr);
1193 pname = g_get_prgname();
1194 fprintf (stderr, "%s[%ld]: GSlice: ", pname ? pname : "", (long)getpid());
1195 va_start (args, format);
1196 vfprintf (stderr, format, args);
1198 fputs ("\n", stderr);
1203 /* --- g-slice memory checker tree --- */
1204 typedef size_t SmcKType; /* key type */
1205 typedef size_t SmcVType; /* value type */
1210 static void smc_tree_insert (SmcKType key,
1212 static gboolean smc_tree_lookup (SmcKType key,
1214 static gboolean smc_tree_remove (SmcKType key);
1217 /* --- g-slice memory checker implementation --- */
1219 smc_notify_alloc (void *pointer,
1222 size_t adress = (size_t) pointer;
1224 smc_tree_insert (adress, size);
1229 smc_notify_ignore (void *pointer)
1231 size_t adress = (size_t) pointer;
1233 smc_tree_remove (adress);
1238 smc_notify_free (void *pointer,
1241 size_t adress = (size_t) pointer;
1246 return 1; /* ignore */
1247 found_one = smc_tree_lookup (adress, &real_size);
1250 fprintf (stderr, "GSlice: MemChecker: attempt to release non-allocated block: %p size=%" G_GSIZE_FORMAT "\n", pointer, size);
1253 if (real_size != size && (real_size || size))
1255 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);
1258 if (!smc_tree_remove (adress))
1260 fprintf (stderr, "GSlice: MemChecker: attempt to release non-allocated block: %p size=%" G_GSIZE_FORMAT "\n", pointer, size);
1263 return 1; /* all fine */
1266 /* --- g-slice memory checker tree implementation --- */
1267 #define SMC_TRUNK_COUNT (4093 /* 16381 */) /* prime, to distribute trunk collisions (big, allocated just once) */
1268 #define SMC_BRANCH_COUNT (511) /* prime, to distribute branch collisions */
1269 #define SMC_TRUNK_EXTENT (SMC_BRANCH_COUNT * 2039) /* key adress space per trunk, should distribute uniformly across BRANCH_COUNT */
1270 #define SMC_TRUNK_HASH(k) ((k / SMC_TRUNK_EXTENT) % SMC_TRUNK_COUNT) /* generate new trunk hash per megabyte (roughly) */
1271 #define SMC_BRANCH_HASH(k) (k % SMC_BRANCH_COUNT)
1275 unsigned int n_entries;
1278 static SmcBranch **smc_tree_root = NULL;
1281 smc_tree_abort (int errval)
1283 const char *syserr = "unknown error";
1285 syserr = strerror (errval);
1287 mem_error ("MemChecker: failure in debugging tree: %s", syserr);
1290 static inline SmcEntry*
1291 smc_tree_branch_grow_L (SmcBranch *branch,
1294 unsigned int old_size = branch->n_entries * sizeof (branch->entries[0]);
1295 unsigned int new_size = old_size + sizeof (branch->entries[0]);
1297 mem_assert (index <= branch->n_entries);
1298 branch->entries = (SmcEntry*) realloc (branch->entries, new_size);
1299 if (!branch->entries)
1300 smc_tree_abort (errno);
1301 entry = branch->entries + index;
1302 g_memmove (entry + 1, entry, (branch->n_entries - index) * sizeof (entry[0]));
1303 branch->n_entries += 1;
1307 static inline SmcEntry*
1308 smc_tree_branch_lookup_nearest_L (SmcBranch *branch,
1311 unsigned int n_nodes = branch->n_entries, offs = 0;
1312 SmcEntry *check = branch->entries;
1314 while (offs < n_nodes)
1316 unsigned int i = (offs + n_nodes) >> 1;
1317 check = branch->entries + i;
1318 cmp = key < check->key ? -1 : key != check->key;
1320 return check; /* return exact match */
1323 else /* (cmp > 0) */
1326 /* check points at last mismatch, cmp > 0 indicates greater key */
1327 return cmp > 0 ? check + 1 : check; /* return insertion position for inexact match */
1331 smc_tree_insert (SmcKType key,
1334 unsigned int ix0, ix1;
1337 g_mutex_lock (&smc_tree_mutex);
1338 ix0 = SMC_TRUNK_HASH (key);
1339 ix1 = SMC_BRANCH_HASH (key);
1342 smc_tree_root = calloc (SMC_TRUNK_COUNT, sizeof (smc_tree_root[0]));
1344 smc_tree_abort (errno);
1346 if (!smc_tree_root[ix0])
1348 smc_tree_root[ix0] = calloc (SMC_BRANCH_COUNT, sizeof (smc_tree_root[0][0]));
1349 if (!smc_tree_root[ix0])
1350 smc_tree_abort (errno);
1352 entry = smc_tree_branch_lookup_nearest_L (&smc_tree_root[ix0][ix1], key);
1353 if (!entry || /* need create */
1354 entry >= smc_tree_root[ix0][ix1].entries + smc_tree_root[ix0][ix1].n_entries || /* need append */
1355 entry->key != key) /* need insert */
1356 entry = smc_tree_branch_grow_L (&smc_tree_root[ix0][ix1], entry - smc_tree_root[ix0][ix1].entries);
1358 entry->value = value;
1359 g_mutex_unlock (&smc_tree_mutex);
1363 smc_tree_lookup (SmcKType key,
1366 SmcEntry *entry = NULL;
1367 unsigned int ix0 = SMC_TRUNK_HASH (key), ix1 = SMC_BRANCH_HASH (key);
1368 gboolean found_one = FALSE;
1370 g_mutex_lock (&smc_tree_mutex);
1371 if (smc_tree_root && smc_tree_root[ix0])
1373 entry = smc_tree_branch_lookup_nearest_L (&smc_tree_root[ix0][ix1], key);
1375 entry < smc_tree_root[ix0][ix1].entries + smc_tree_root[ix0][ix1].n_entries &&
1379 *value_p = entry->value;
1382 g_mutex_unlock (&smc_tree_mutex);
1387 smc_tree_remove (SmcKType key)
1389 unsigned int ix0 = SMC_TRUNK_HASH (key), ix1 = SMC_BRANCH_HASH (key);
1390 gboolean found_one = FALSE;
1391 g_mutex_lock (&smc_tree_mutex);
1392 if (smc_tree_root && smc_tree_root[ix0])
1394 SmcEntry *entry = smc_tree_branch_lookup_nearest_L (&smc_tree_root[ix0][ix1], key);
1396 entry < smc_tree_root[ix0][ix1].entries + smc_tree_root[ix0][ix1].n_entries &&
1399 unsigned int i = entry - smc_tree_root[ix0][ix1].entries;
1400 smc_tree_root[ix0][ix1].n_entries -= 1;
1401 g_memmove (entry, entry + 1, (smc_tree_root[ix0][ix1].n_entries - i) * sizeof (entry[0]));
1402 if (!smc_tree_root[ix0][ix1].n_entries)
1404 /* avoid useless pressure on the memory system */
1405 free (smc_tree_root[ix0][ix1].entries);
1406 smc_tree_root[ix0][ix1].entries = NULL;
1411 g_mutex_unlock (&smc_tree_mutex);
1415 #ifdef G_ENABLE_DEBUG
1417 g_slice_debug_tree_statistics (void)
1419 g_mutex_lock (&smc_tree_mutex);
1422 unsigned int i, j, t = 0, o = 0, b = 0, su = 0, ex = 0, en = 4294967295u;
1424 for (i = 0; i < SMC_TRUNK_COUNT; i++)
1425 if (smc_tree_root[i])
1428 for (j = 0; j < SMC_BRANCH_COUNT; j++)
1429 if (smc_tree_root[i][j].n_entries)
1432 su += smc_tree_root[i][j].n_entries;
1433 en = MIN (en, smc_tree_root[i][j].n_entries);
1434 ex = MAX (ex, smc_tree_root[i][j].n_entries);
1436 else if (smc_tree_root[i][j].entries)
1437 o++; /* formerly used, now empty */
1440 tf = MAX (t, 1.0); /* max(1) to be a valid divisor */
1441 bf = MAX (b, 1.0); /* max(1) to be a valid divisor */
1442 fprintf (stderr, "GSlice: MemChecker: %u trunks, %u branches, %u old branches\n", t, b, o);
1443 fprintf (stderr, "GSlice: MemChecker: %f branches per trunk, %.2f%% utilization\n",
1445 100.0 - (SMC_BRANCH_COUNT - b / tf) / (0.01 * SMC_BRANCH_COUNT));
1446 fprintf (stderr, "GSlice: MemChecker: %f entries per branch, %u minimum, %u maximum\n",
1450 fprintf (stderr, "GSlice: MemChecker: root=NULL\n");
1451 g_mutex_unlock (&smc_tree_mutex);
1453 /* sample statistics (beast + GSLice + 24h scripted core & GUI activity):
1454 * PID %CPU %MEM VSZ RSS COMMAND
1455 * 8887 30.3 45.8 456068 414856 beast-0.7.1 empty.bse
1456 * $ cat /proc/8887/statm # total-program-size resident-set-size shared-pages text/code data/stack library dirty-pages
1457 * 114017 103714 2354 344 0 108676 0
1458 * $ cat /proc/8887/status
1469 * (gdb) print g_slice_debug_tree_statistics ()
1470 * GSlice: MemChecker: 422 trunks, 213068 branches, 0 old branches
1471 * GSlice: MemChecker: 504.900474 branches per trunk, 98.81% utilization
1472 * GSlice: MemChecker: 4.965039 entries per branch, 1 minimum, 37 maximum
1475 #endif /* G_ENABLE_DEBUG */