aboutsummaryrefslogtreecommitdiff
path: root/malloc/memusage.c
blob: 16fa09060a8d8984cf852a7a66aa7d32289bcfeb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
/* Profile heap and stack memory usage of running program.
   Copyright (C) 1998-2002, 2004, 2005, 2006 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <atomic.h>
#include <dlfcn.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/time.h>

#include <memusage.h>

/* Pointer to the real functions.  These are determined used `dlsym'
   when really needed.  */
static void *(*mallocp) (size_t);
static void *(*reallocp) (void *, size_t);
static void *(*callocp) (size_t, size_t);
static void (*freep) (void *);

static void *(*mmapp) (void *, size_t, int, int, int, off_t);
static void *(*mmap64p) (void *, size_t, int, int, int, off64_t);
static int (*munmapp) (void *, size_t);
static void *(*mremapp) (void *, size_t, size_t, int, void *);

enum
{
  idx_malloc = 0,
  idx_realloc,
  idx_calloc,
  idx_free,
  idx_mmap_r,
  idx_mmap_w,
  idx_mmap_a,
  idx_mremap,
  idx_munmap,
  idx_last
};


struct header
{
  size_t length;
  size_t magic;
};

#define MAGIC 0xfeedbeaf


static memusage_cntr_t calls[idx_last];
static memusage_cntr_t failed[idx_last];
static memusage_size_t total[idx_last];
static memusage_size_t grand_total;
static memusage_cntr_t histogram[65536 / 16];
static memusage_cntr_t large;
static memusage_cntr_t calls_total;
static memusage_cntr_t inplace;
static memusage_cntr_t decreasing;
static memusage_cntr_t realloc_free;
static memusage_cntr_t inplace_mremap;
static memusage_cntr_t decreasing_mremap;
static memusage_size_t current_heap;
static memusage_size_t peak_use[3];
static __thread uintptr_t start_sp;

/* A few macros to make the source more readable.  */
#define peak_heap	peak_use[0]
#define peak_stack	peak_use[1]
#define peak_total	peak_use[2]

#define DEFAULT_BUFFER_SIZE	1024
static size_t buffer_size;

static int fd = -1;

static bool not_me;
static int initialized;
static bool trace_mmap;
extern const char *__progname;

struct entry
{
  uint64_t heap;
  uint64_t stack;
  uint32_t time_low;
  uint32_t time_high;
};

static struct entry buffer[2 * DEFAULT_BUFFER_SIZE];
static uatomic32_t buffer_cnt;
static struct entry first;


/* Update the global data after a successful function call.  */
static void
update_data (struct header *result, size_t len, size_t old_len)
{
  if (result != NULL)
    {
      /* Record the information we need and mark the block using a
         magic number.  */
      result->length = len;
      result->magic = MAGIC;
    }

  /* Compute current heap usage and compare it with the maximum value.  */
  memusage_size_t heap
    = atomic_exchange_and_add (&current_heap, len - old_len) + len - old_len;
  atomic_max (&peak_heap, heap);

  /* Compute current stack usage and compare it with the maximum
     value.  The base stack pointer might not be set if this is not
     the main thread and it is the first call to any of these
     functions.  */
  if (__builtin_expect (!start_sp, 0))
    start_sp = GETSP ();

  uintptr_t sp = GETSP ();
#ifdef STACK_GROWS_UPWARD
  /* This can happen in threads where we didn't catch the thread's
     stack early enough.  */
  if (__builtin_expect (sp < start_sp, 0))
    start_sp = sp;
  size_t current_stack = sp - start_sp;
#else
  /* This can happen in threads where we didn't catch the thread's
     stack early enough.  */
  if (__builtin_expect (sp > start_sp, 0))
    start_sp = sp;
  size_t current_stack = start_sp - sp;
#endif
  atomic_max (&peak_stack, current_stack);

  /* Add up heap and stack usage and compare it with the maximum value.  */
  atomic_max (&peak_total, heap + current_stack);

  /* Store the value only if we are writing to a file.  */
  if (fd != -1)
    {
      uatomic32_t idx = atomic_exchange_and_add (&buffer_cnt, 1);
      if (idx >= 2 * buffer_size)
	{
	  /* We try to reset the counter to the correct range.  If
	     this fails because of another thread increasing the
	     counter it does not matter since that thread will take
	     care of the correction.  */
	  unsigned int reset = idx - 2 * buffer_size;
	  atomic_compare_and_exchange_val_acq (&buffer_size, reset, idx);
	  idx = reset;
	}

      buffer[idx].heap = current_heap;
      buffer[idx].stack = current_stack;
      GETTIME (buffer[idx].time_low, buffer[idx].time_high);

      /* Write out buffer if it is full.  */
      if (idx + 1 == buffer_size)
	write (fd, buffer, buffer_size * sizeof (struct entry));
      else if (idx + 1 == 2 * buffer_size)
	write (fd, &buffer[buffer_size], buffer_size * sizeof (struct entry));
    }
}


/* Interrupt handler.  */
static void
int_handler (int signo)
{
  /* Nothing gets allocated.  Just record the stack pointer position.  */
  update_data (NULL, 0, 0);
}


/* Find out whether this is the program we are supposed to profile.
   For this the name in the variable `__progname' must match the one
   given in the environment variable MEMUSAGE_PROG_NAME.  If the variable
   is not present every program assumes it should be profiling.

   If this is the program open a file descriptor to the output file.
   We will write to it whenever the buffer overflows.  The name of the
   output file is determined by the environment variable MEMUSAGE_OUTPUT.

   If the environment variable MEMUSAGE_BUFFER_SIZE is set its numerical
   value determines the size of the internal buffer.  The number gives
   the number of elements in the buffer.  By setting the number to one
   one effectively selects unbuffered operation.

   If MEMUSAGE_NO_TIMER is not present an alarm handler is installed
   which at the highest possible frequency records the stack pointer.  */
static void
me (void)
{
  const char *env = getenv ("MEMUSAGE_PROG_NAME");
  size_t prog_len = strlen (__progname);

  initialized = -1;
  mallocp = (void *(*) (size_t)) dlsym (RTLD_NEXT, "malloc");
  reallocp = (void *(*) (void *, size_t)) dlsym (RTLD_NEXT, "realloc");
  callocp = (void *(*) (size_t, size_t)) dlsym (RTLD_NEXT, "calloc");
  freep = (void (*) (void *)) dlsym (RTLD_NEXT, "free");

  mmapp = (void *(*) (void *, size_t, int, int, int, off_t)) dlsym (RTLD_NEXT,
								    "mmap");
  mmap64p =
    (void *(*) (void *, size_t, int, int, int, off64_t)) dlsym (RTLD_NEXT,
								"mmap64");
  mremapp = (void *(*) (void *, size_t, size_t, int, void *)) dlsym (RTLD_NEXT,
								     "mremap");
  munmapp = (int (*) (void *, size_t)) dlsym (RTLD_NEXT, "munmap");
  initialized = 1;

  if (env != NULL)
    {
      /* Check for program name.  */
      size_t len = strlen (env);
      if (len > prog_len || strcmp (env, &__progname[prog_len - len]) != 0
	  || (prog_len != len && __progname[prog_len - len - 1] != '/'))
	not_me = true;
    }

  /* Only open the file if it's really us.  */
  if (!not_me && fd == -1)
    {
      const char *outname;

      if (!start_sp)
	start_sp = GETSP ();

      outname = getenv ("MEMUSAGE_OUTPUT");
      if (outname != NULL && outname[0] != '\0'
	  && (access (outname, R_OK | W_OK) == 0 || errno == ENOENT))
	{
	  fd = creat64 (outname, 0666);

	  if (fd == -1)
	    /* Don't do anything in future calls if we cannot write to
	       the output file.  */
	    not_me = true;
	  else
	    {
	      /* Write the first entry.  */
	      first.heap = 0;
	      first.stack = 0;
	      GETTIME (first.time_low, first.time_high);
	      /* Write it two times since we need the starting and end time. */
	      write (fd, &first, sizeof (first));
	      write (fd, &first, sizeof (first));

	      /* Determine the buffer size.  We use the default if the
		 environment variable is not present.  */
	      buffer_size = DEFAULT_BUFFER_SIZE;
	      if (getenv ("MEMUSAGE_BUFFER_SIZE") != NULL)
		{
		  buffer_size = atoi (getenv ("MEMUSAGE_BUFFER_SIZE"));
		  if (buffer_size == 0 || buffer_size > DEFAULT_BUFFER_SIZE)
		    buffer_size = DEFAULT_BUFFER_SIZE;
		}

	      /* Possibly enable timer-based stack pointer retrieval.  */
	      if (getenv ("MEMUSAGE_NO_TIMER") == NULL)
		{
		  struct sigaction act;

		  act.sa_handler = (sighandler_t) &int_handler;
		  act.sa_flags = SA_RESTART;
		  sigfillset (&act.sa_mask);

		  if (sigaction (SIGPROF, &act, NULL) >= 0)
		    {
		      struct itimerval timer;

		      timer.it_value.tv_sec = 0;
		      timer.it_value.tv_usec = 1;
		      timer.it_interval = timer.it_value;
		      setitimer (ITIMER_PROF, &timer, NULL);
		    }
		}
	    }
	}

      if (!not_me && getenv ("MEMUSAGE_TRACE_MMAP") != NULL)
	trace_mmap = true;
    }
}


/* Record the initial stack position.  */
static void
__attribute__ ((constructor))
init (void)
{
  start_sp = GETSP ();
  if (! initialized)
    me ();
}


/* `malloc' replacement.  We keep track of the memory usage if this is the
   correct program.  */
void *
malloc (size_t len)
{
  struct header *result = NULL;

  /* Determine real implementation if not already happened.  */
  if (__builtin_expect (initialized <= 0, 0))
    {
      if (initialized == -1)
	return NULL;
      me ();
    }

  /* If this is not the correct program just use the normal function.  */
  if (not_me)
    return (*mallocp) (len);

  /* Keep track of number of calls.  */
  atomic_increment (&calls[idx_malloc]);
  /* Keep track of total memory consumption for `malloc'.  */
  atomic_add (&total[idx_malloc], len);
  /* Keep track of total memory requirement.  */
  atomic_add (&grand_total, len);
  /* Remember the size of the request.  */
  if (len < 65536)
    atomic_increment (&histogram[len / 16]);
  else
    atomic_increment (&large);
  /* Total number of calls of any of the functions.  */
  atomic_increment (&calls_total);

  /* Do the real work.  */
  result = (struct header *) (*mallocp) (len + sizeof (struct header));
  if (result == NULL)
    {
      atomic_increment (&failed[idx_malloc]);
      return NULL;
    }

  /* Update the allocation data and write out the records if necessary.  */
  update_data (result, len, 0);

  /* Return the pointer to the user buffer.  */
  return (void *) (result + 1);
}


/* `realloc' replacement.  We keep track of the memory usage if this is the
   correct program.  */
void *
realloc (void *old, size_t len)
{
  struct header *result = NULL;
  struct header *real;
  size_t old_len;

  /* Determine real implementation if not already happened.  */
  if (__builtin_expect (initialized <= 0, 0))
    {
      if (initialized == -1)
	return NULL;
      me ();
    }

  /* If this is not the correct program just use the normal function.  */
  if (not_me)
    return (*reallocp) (old, len);

  if (old == NULL)
    {
      /* This is really a `malloc' call.  */
      real = NULL;
      old_len = 0;
    }
  else
    {
      real = ((struct header *) old) - 1;
      if (real->magic != MAGIC)
	/* This is no memory allocated here.  */
	return (*reallocp) (old, len);
      old_len = real->length;
    }

  /* Keep track of number of calls.  */
  atomic_increment (&calls[idx_realloc]);
  if (len > old_len)
    {
      /* Keep track of total memory consumption for `realloc'.  */
      atomic_add (&total[idx_realloc], len - old_len);
      /* Keep track of total memory requirement.  */
      atomic_add (&grand_total, len - old_len);
    }

  if (len == 0 && old != NULL)
    {
      /* Special case.  */
      atomic_increment (&realloc_free);
      /* Keep track of total memory freed using `free'.  */
      atomic_add (&total[idx_free], real->length);

      /* Update the allocation data and write out the records if necessary.  */
      update_data (NULL, 0, old_len);

      /* Do the real work.  */
      (*freep) (real);

      return NULL;
    }

  /* Remember the size of the request.  */
  if (len < 65536)
    atomic_increment (&histogram[len / 16]);
  else
    atomic_increment (&large);
  /* Total number of calls of any of the functions.  */
  atomic_increment (&calls_total);

  /* Do the real work.  */
  result = (struct header *) (*reallocp) (real, len + sizeof (struct header));
  if (result == NULL)
    {
      atomic_increment (&failed[idx_realloc]);
      return NULL;
    }

  /* Record whether the reduction/increase happened in place.  */
  if (real == result)
    atomic_increment (&inplace);
  /* Was the buffer increased?  */
  if (old_len > len)
    atomic_increment (&decreasing);

  /* Update the allocation data and write out the records if necessary.  */
  update_data (result, len, old_len);

  /* Return the pointer to the user buffer.  */
  return (void *) (result + 1);
}


/* `calloc' replacement.  We keep track of the memory usage if this is the
   correct program.  */
void *
calloc (size_t n, size_t len)
{
  struct header *result;
  size_t size = n * len;

  /* Determine real implementation if not already happened.  */
  if (__builtin_expect (initialized <= 0, 0))
    {
      if (initialized == -1)
	return NULL;
      me ();
    }

  /* If this is not the correct program just use the normal function.  */
  if (not_me)
    return (*callocp) (n, len);

  /* Keep track of number of calls.  */
  atomic_increment (&calls[idx_calloc]);
  /* Keep track of total memory consumption for `calloc'.  */
  atomic_add (&total[idx_calloc], size);
  /* Keep track of total memory requirement.  */
  atomic_add (&grand_total, size);
  /* Remember the size of the request.  */
  if (size < 65536)
    atomic_increment (&histogram[size / 16]);
  else
    atomic_increment (&large);
  /* Total number of calls of any of the functions.  */
  ++calls_total;

  /* Do the real work.  */
  result = (struct header *) (*mallocp) (size + sizeof (struct header));
  if (result == NULL)
    {
      atomic_increment (&failed[idx_calloc]);
      return NULL;
    }

  /* Update the allocation data and write out the records if necessary.  */
  update_data (result, size, 0);

  /* Do what `calloc' would have done and return the buffer to the caller.  */
  return memset (result + 1, '\0', size);
}


/* `free' replacement.  We keep track of the memory usage if this is the
   correct program.  */
void
free (void *ptr)
{
  struct header *real;

  /* Determine real implementation if not already happened.  */
  if (__builtin_expect (initialized <= 0, 0))
    {
      if (initialized == -1)
	return;
      me ();
    }

  /* If this is not the correct program just use the normal function.  */
  if (not_me)
    {
      (*freep) (ptr);
      return;
    }

  /* `free (NULL)' has no effect.  */
  if (ptr == NULL)
    {
      atomic_increment (&calls[idx_free]);
      return;
    }

  /* Determine the pointer to the header.  */
  real = ((struct header *) ptr) - 1;
  if (real->magic != MAGIC)
    {
      /* This block wasn't allocated here.  */
      (*freep) (ptr);
      return;
    }

  /* Keep track of number of calls.  */
  atomic_increment (&calls[idx_free]);
  /* Keep track of total memory freed using `free'.  */
  atomic_add (&total[idx_free], real->length);

  /* Update the allocation data and write out the records if necessary.  */
  update_data (NULL, 0, real->length);

  /* Do the real work.  */
  (*freep) (real);
}


/* `mmap' replacement.  We do not have to keep track of the sizesince
   `munmap' will get it as a parameter.  */
void *
mmap (void *start, size_t len, int prot, int flags, int fd, off_t offset)
{
  void *result = NULL;

  /* Determine real implementation if not already happened.  */
  if (__builtin_expect (initialized <= 0, 0))
    {
      if (initialized == -1)
	return NULL;
      me ();
    }

  /* Always get a block.  We don't need extra memory.  */
  result = (*mmapp) (start, len, prot, flags, fd, offset);

  if (!not_me && trace_mmap)
    {
      int idx = (flags & MAP_ANON
		 ? idx_mmap_a : prot & PROT_WRITE ? idx_mmap_w : idx_mmap_r);

      /* Keep track of number of calls.  */
      atomic_increment (&calls[idx]);
      /* Keep track of total memory consumption for `malloc'.  */
      atomic_add (&total[idx], len);
      /* Keep track of total memory requirement.  */
      atomic_add (&grand_total, len);
      /* Remember the size of the request.  */
      if (len < 65536)
	atomic_increment (&histogram[len / 16]);
      else
	atomic_increment (&large);
      /* Total number of calls of any of the functions.  */
      atomic_increment (&calls_total);

      /* Check for failures.  */
      if (result == NULL)
	atomic_increment (&failed[idx]);
      else if (idx == idx_mmap_w)
	/* Update the allocation data and write out the records if
	   necessary.  Note the first parameter is NULL which means
	   the size is not tracked.  */
	update_data (NULL, len, 0);
    }

  /* Return the pointer to the user buffer.  */
  return result;
}


/* `mmap' replacement.  We do not have to keep track of the sizesince
   `munmap' will get it as a parameter.  */
void *
mmap64 (void *start, size_t len, int prot, int flags, int fd, off64_t offset)
{
  void *result = NULL;

  /* Determine real implementation if not already happened.  */
  if (__builtin_expect (initialized <= 0, 0))
    {
      if (initialized == -1)
	return NULL;
      me ();
    }

  /* Always get a block.  We don't need extra memory.  */
  result = (*mmap64p) (start, len, prot, flags, fd, offset);

  if (!not_me && trace_mmap)
    {
      int idx = (flags & MAP_ANON
		 ? idx_mmap_a : prot & PROT_WRITE ? idx_mmap_w : idx_mmap_r);

      /* Keep track of number of calls.  */
      atomic_increment (&calls[idx]);
      /* Keep track of total memory consumption for `malloc'.  */
      atomic_add (&total[idx], len);
      /* Keep track of total memory requirement.  */
      atomic_add (&grand_total, len);
      /* Remember the size of the request.  */
      if (len < 65536)
	atomic_increment (&histogram[len / 16]);
      else
	atomic_increment (&large);
      /* Total number of calls of any of the functions.  */
      atomic_increment (&calls_total);

      /* Check for failures.  */
      if (result == NULL)
	atomic_increment (&failed[idx]);
      else if (idx == idx_mmap_w)
	/* Update the allocation data and write out the records if
	   necessary.  Note the first parameter is NULL which means
	   the size is not tracked.  */
	update_data (NULL, len, 0);
    }

  /* Return the pointer to the user buffer.  */
  return result;
}


/* `mmap' replacement.  We do not have to keep track of the sizesince
   `munmap' will get it as a parameter.  */
void *
mremap (void *start, size_t old_len, size_t len, int flags,  ...)
{
  void *result = NULL;
  va_list ap;

  va_start (ap, flags);
  void *newaddr = (flags & MREMAP_FIXED) ? va_arg (ap, void *) : NULL;
  va_end (ap);

  /* Determine real implementation if not already happened.  */
  if (__builtin_expect (initialized <= 0, 0))
    {
      if (initialized == -1)
	return NULL;
      me ();
    }

  /* Always get a block.  We don't need extra memory.  */
  result = (*mremapp) (start, old_len, len, flags, newaddr);

  if (!not_me && trace_mmap)
    {
      /* Keep track of number of calls.  */
      atomic_increment (&calls[idx_mremap]);
      if (len > old_len)
	{
	  /* Keep track of total memory consumption for `malloc'.  */
	  atomic_add (&total[idx_mremap], len - old_len);
	  /* Keep track of total memory requirement.  */
	  atomic_add (&grand_total, len - old_len);
	}
      /* Remember the size of the request.  */
      if (len < 65536)
	atomic_increment (&histogram[len / 16]);
      else
	atomic_increment (&large);
      /* Total number of calls of any of the functions.  */
      atomic_increment (&calls_total);

      /* Check for failures.  */
      if (result == NULL)
	atomic_increment (&failed[idx_mremap]);
      else
	{
	  /* Record whether the reduction/increase happened in place.  */
	  if (start == result)
	    atomic_increment (&inplace_mremap);
	  /* Was the buffer increased?  */
	  if (old_len > len)
	    atomic_increment (&decreasing_mremap);

	  /* Update the allocation data and write out the records if
	     necessary.  Note the first parameter is NULL which means
	     the size is not tracked.  */
	  update_data (NULL, len, old_len);
	}
    }

  /* Return the pointer to the user buffer.  */
  return result;
}


/* `munmap' replacement.  */
int
munmap (void *start, size_t len)
{
  int result;

  /* Determine real implementation if not already happened.  */
  if (__builtin_expect (initialized <= 0, 0))
    {
      if (initialized == -1)
	return -1;
      me ();
    }

  /* Do the real work.  */
  result = (*munmapp) (start, len);

  if (!not_me && trace_mmap)
    {
      /* Keep track of number of calls.  */
      atomic_increment (&calls[idx_munmap]);

      if (__builtin_expect (result == 0, 1))
	{
	  /* Keep track of total memory freed using `free'.  */
	  atomic_add (&total[idx_munmap], len);

	  /* Update the allocation data and write out the records if
	     necessary.  */
	  update_data (NULL, 0, len);
	}
      else
	atomic_increment (&failed[idx_munmap]);
    }

  return result;
}


/* Write some statistics to standard error.  */
static void
__attribute__ ((destructor))
dest (void)
{
  int percent, cnt;
  unsigned long int maxcalls;

  /* If we haven't done anything here just return.  */
  if (not_me)
    return;
  /* If we should call any of the memory functions don't do any profiling.  */
  not_me = true;

  /* Finish the output file.  */
  if (fd != -1)
    {
      /* Write the partially filled buffer.  */
      if (buffer_cnt > buffer_size)
	write (fd, buffer + buffer_size,
	       (buffer_cnt - buffer_size) * sizeof (struct entry));
      else
	write (fd, buffer, buffer_cnt * sizeof (struct entry));

      /* Go back to the beginning of the file.  We allocated two records
	 here when we opened the file.  */
      lseek (fd, 0, SEEK_SET);
      /* Write out a record containing the total size.  */
      first.stack = peak_total;
      write (fd, &first, sizeof (struct entry));
      /* Write out another record containing the maximum for heap and
         stack.  */
      first.heap = peak_heap;
      first.stack = peak_stack;
      GETTIME (first.time_low, first.time_high);
      write (fd, &first, sizeof (struct entry));

      /* Close the file.  */
      close (fd);
      fd = -1;
    }

  /* Write a colorful statistic.  */
  fprintf (stderr, "\n\
\e[01;32mMemory usage summary:\e[0;0m heap total: %llu, heap peak: %lu, stack peak: %lu\n\
\e[04;34m         total calls   total memory   failed calls\e[0m\n\
\e[00;34m malloc|\e[0m %10lu   %12llu   %s%12lu\e[00;00m\n\
\e[00;34mrealloc|\e[0m %10lu   %12llu   %s%12lu\e[00;00m  (nomove:%ld, dec:%ld, free:%ld)\n\
\e[00;34m calloc|\e[0m %10lu   %12llu   %s%12lu\e[00;00m\n\
\e[00;34m   free|\e[0m %10lu   %12llu\n",
	   (unsigned long long int) grand_total, (unsigned long int) peak_heap,
	   (unsigned long int) peak_stack,
	   (unsigned long int) calls[idx_malloc],
	   (unsigned long long int) total[idx_malloc],
	   failed[idx_malloc] ? "\e[01;41m" : "",
	   (unsigned long int) failed[idx_malloc],
	   (unsigned long int) calls[idx_realloc],
	   (unsigned long long int) total[idx_realloc],
	   failed[idx_realloc] ? "\e[01;41m" : "",
	   (unsigned long int) failed[idx_realloc],
	   (unsigned long int) inplace,
	   (unsigned long int) decreasing,
	   (unsigned long int) realloc_free,
	   (unsigned long int) calls[idx_calloc],
	   (unsigned long long int) total[idx_calloc],
	   failed[idx_calloc] ? "\e[01;41m" : "",
	   (unsigned long int) failed[idx_calloc],
	   (unsigned long int) calls[idx_free],
	   (unsigned long long int) total[idx_free]);

  if (trace_mmap)
    fprintf (stderr, "\
\e[00;34mmmap(r)|\e[0m %10lu   %12llu   %s%12lu\e[00;00m\n\
\e[00;34mmmap(w)|\e[0m %10lu   %12llu   %s%12lu\e[00;00m\n\
\e[00;34mmmap(a)|\e[0m %10lu   %12llu   %s%12lu\e[00;00m\n\
\e[00;34m mremap|\e[0m %10lu   %12llu   %s%12lu\e[00;00m  (nomove: %ld, dec:%ld)\n\
\e[00;34m munmap|\e[0m %10lu   %12llu   %s%12lu\e[00;00m\n",
	     (unsigned long int) calls[idx_mmap_r],
	     (unsigned long long int) total[idx_mmap_r],
	     failed[idx_mmap_r] ? "\e[01;41m" : "",
	     (unsigned long int) failed[idx_mmap_r],
	     (unsigned long int) calls[idx_mmap_w],
	     (unsigned long long int) total[idx_mmap_w],
	     failed[idx_mmap_w] ? "\e[01;41m" : "",
	     (unsigned long int) failed[idx_mmap_w],
	     (unsigned long int) calls[idx_mmap_a],
	     (unsigned long long int) total[idx_mmap_a],
	     failed[idx_mmap_a] ? "\e[01;41m" : "",
	     (unsigned long int) failed[idx_mmap_a],
	     (unsigned long int) calls[idx_mremap],
	     (unsigned long long int) total[idx_mremap],
	     failed[idx_mremap] ? "\e[01;41m" : "",
	     (unsigned long int) failed[idx_mremap],
	     (unsigned long int) inplace_mremap,
	     (unsigned long int) decreasing_mremap,
	     (unsigned long int) calls[idx_munmap],
	     (unsigned long long int) total[idx_munmap],
	     failed[idx_munmap] ? "\e[01;41m" : "",
	     (unsigned long int) failed[idx_munmap]);

  /* Write out a histoogram of the sizes of the allocations.  */
  fprintf (stderr, "\e[01;32mHistogram for block sizes:\e[0;0m\n");

  /* Determine the maximum of all calls for each size range.  */
  maxcalls = large;
  for (cnt = 0; cnt < 65536; cnt += 16)
    if (histogram[cnt / 16] > maxcalls)
      maxcalls = histogram[cnt / 16];

  for (cnt = 0; cnt < 65536; cnt += 16)
    /* Only write out the nonzero entries.  */
    if (histogram[cnt / 16] != 0)
      {
	percent = (histogram[cnt / 16] * 100) / calls_total;
	fprintf (stderr, "%5d-%-5d%12lu ", cnt, cnt + 15,
		 (unsigned long int) histogram[cnt / 16]);
	if (percent == 0)
	  fputs (" <1% \e[41;37m", stderr);
	else
	  fprintf (stderr, "%3d%% \e[41;37m", percent);

	/* Draw a bar with a length corresponding to the current
           percentage.  */
	percent = (histogram[cnt / 16] * 50) / maxcalls;
	while (percent-- > 0)
	  fputc ('=', stderr);
	 fputs ("\e[0;0m\n", stderr);
      }

  if (large != 0)
    {
      percent = (large * 100) / calls_total;
      fprintf (stderr, "   large   %12lu ", (unsigned long int) large);
      if (percent == 0)
	fputs (" <1% \e[41;37m", stderr);
      else
	fprintf (stderr, "%3d%% \e[41;37m", percent);
      percent = (large * 50) / maxcalls;
      while (percent-- > 0)
        fputc ('=', stderr);
      fputs ("\e[0;0m\n", stderr);
    }

  /* Any following malloc/free etc. calls should generate statistics again,
     because otherwise freeing something that has been malloced before
     this destructor (including struct header in front of it) wouldn't
     be properly freed.  */
  not_me = false;
}