1MAKEDUMPFILE(8)       Linux System Administrator's Manual      MAKEDUMPFILE(8)
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NAME

6       makedumpfile - make a small dumpfile of kdump
7

SYNOPSIS

9       makedumpfile    [OPTION] [-x VMLINUX|-i VMCOREINFO] VMCORE DUMPFILE
10       makedumpfile -F [OPTION] [-x VMLINUX|-i VMCOREINFO] VMCORE
11       makedumpfile   [OPTION] -x VMLINUX [--config FILTERCONFIGFILE] [--eppic
12       EPPICMACRO] VMCORE DUMPFILE
13       makedumpfile -R DUMPFILE
14       makedumpfile --split [OPTION] [-x VMLINUX|-i VMCOREINFO]  VMCORE  DUMP‐
15       FILE1 DUMPFILE2 [DUMPFILE3 ..]
16       makedumpfile  [OPTION] [-x VMLINUX|-i VMCOREINFO] --num-threads THREAD‐
17       NUM VMCORE DUMPFILE
18       makedumpfile --reassemble DUMPFILE1 DUMPFILE2 [DUMPFILE3 ..] DUMPFILE
19       makedumpfile -g VMCOREINFO -x VMLINUX
20       makedumpfile    [OPTION] [--xen-syms XEN-SYMS|--xen-vmcoreinfo  VMCORE‐
21       INFO] VMCORE DUMPFILE
22       makedumpfile  --dump-dmesg [--partial-dmesg] [-x VMLINUX|-i VMCOREINFO]
23       VMCORE LOGFILE
24       makedumpfile    [OPTION] -x VMLINUX --diskset=VMCORE1 --diskset=VMCORE2
25       [--diskset=VMCORE3 ..] DUMPFILE
26       makedumpfile -h
27       makedumpfile -v
28

DESCRIPTION

30       With kdump, the memory image of the first kernel (called "panicked ker‐
31       nel") can be taken as /proc/vmcore  while  the  second  kernel  (called
32       "kdump  kernel"  or  "capture kernel") is running. This document repre‐
33       sents /proc/vmcore as VMCORE. makedumpfile makes a  small  DUMPFILE  by
34       compressing  dump  data or by excluding unnecessary pages for analysis,
35       or both. makedumpfile needs the first kernel's  debug  information,  so
36       that  it  can  distinguish unnecessary pages by analyzing how the first
37       kernel uses the memory.  The information can be taken from  VMLINUX  or
38       VMCOREINFO.
39
40       makedumpfile can exclude the following types of pages while copying VM‐
41       CORE to DUMPFILE, and a user can choose which type of pages will be ex‐
42       cluded.
43       - Pages filled with zero
44       - Cache pages without private flag (non-private cache)
45       - Cache pages with private flag (private cache)
46       - User process data pages
47       - Free pages
48
49       makedumpfile  provides  two  DUMPFILE  formats  (the ELF format and the
50       kdump-compressed format). By default, makedumpfile makes a DUMPFILE  in
51       the  kdump-compressed  format.  The kdump-compressed format is readable
52       only with the crash utility, and it can be smaller than the ELF  format
53       because of the compression support. The ELF format is readable with GDB
54       and the crash utility.  If a user wants to use GDB, DUMPFILE format has
55       to be explicitly specified to be the ELF format.
56
57       Apart  from  the  exclusion of unnecessary pages mentioned above, make‐
58       dumpfile allows user to filter out targeted  kernel  data.  The  filter
59       config  file  can be used to specify kernel/module symbols and its mem‐
60       bers that need to be filtered out through  the  erase  command  syntax.
61       makedumpfile  reads the filter config and builds the list of memory ad‐
62       dresses and its sizes after processing filter commands. The memory  lo‐
63       cations  that require to be filtered out are then poisoned with charac‐
64       ter 'X' (58 in Hex). Refer to makedumpfile.conf(5) for file format.
65
66       Eppic macros can also be used to specify kernel symbols and its members
67       that need to be filtered. Eppic provides C semantics including language
68       constructs such as conditional statements, logical and arithmetic oper‐
69       ators, functions, nested loops to traverse and erase kernel data. --ep‐
70       pic requires eppic_makedumpfile.so and eppic  library.  eppic_makedump‐
71       file.so   can   be   built   from   makedumpfile   source.   Refer   to
72       http://code.google.com/p/eppic/ to build eppic library  libeppic.a  and
73       for more information on writing eppic macros.
74
75       To  analyze  the first kernel's memory usage, makedumpfile can refer to
76       VMCOREINFO instead of VMLINUX. VMCOREINFO contains the  first  kernel's
77       information  (structure  size,  field  offset, etc.), and VMCOREINFO is
78       small enough to be included into the second kernel's initrd.
79       If the second kernel is running on its initrd without mounting  a  root
80       file  system,  makedumpfile  cannot refer to VMLINUX because the second
81       kernel's initrd cannot include a large file like VMLINUX. To solve  the
82       problem, makedumpfile makes VMCOREINFO beforehand, and it refers to VM‐
83       COREINFO instead of VMLINUX while the second kernel is running.
84       VMCORE has contained VMCOREINFO since linux-2.6.24, and a user does not
85       need to specify neither -x nor -i option.
86
87       If the second kernel is running on its initrd without mounting any file
88       system, a user needs to transport the dump data to a  remote  host.  To
89       transport  the  dump data by SSH, makedumpfile outputs the dump data in
90       the intermediate format (the flattened format) to the standard  output.
91       By piping the output data to SSH, a user can transport the dump data to
92       a remote host. Note that analysis tools (crash utility  before  version
93       5.1.2 or GDB) cannot read the flattened format directly, so on a remote
94       host the received data in the flattened format needs to  be  rearranged
95       to a readable DUMPFILE format by makedumpfile (or makedumpfile-R.pl).
96
97       makedumpfile can read a DUMPFILE in the kdump-compressed format instead
98       of VMCORE and re-filter it. This feature is useful  in  situation  that
99       users need to reduce the file size of DUMPFILE for sending it somewhere
100       by ftp/scp/etc. (If all of the page types, which are specified by a new
101       dump_level, are excluded from an original DUMPFILE already, a new DUMP‐
102       FILE is the same as an original DUMPFILE.)
103       For example, makedumpfile can create a DUMPFILE of dump_level  31  from
104       the one of dump_level 3 like the following:
105       Example:
106       # makedumpfile -c -d 3 /proc/vmcore dumpfile.1
107       # makedumpfile -c -d 31 dumpfile.1 dumpfile.2
108
109       makedumpfile  can read VMCORE(s) in three kinds of sadump formats: sin‐
110       gle partition format, diskset format and media backup format,  and  can
111       convert  each  of  them into kdump-compressed format with filtering and
112       compression processing. Note that for VMCORE(s) created by sadump,  you
113       always  need to pass VMLINUX with -x option. Also, to pass multiple VM‐
114       COREs created on diskset configuration, you need to use  --diskset  op‐
115       tion.
116
117

OPTIONS

119       -c,-l,-p,-z
120              Compress  dump  data by the page using the following compression
121              library respectively:
122                   -c : zlib
123                   -l : lzo
124                   -p : snappy
125                   -z : zstd
126              (-l,  -p  and  -z  option  need  USELZO=on,   USESNAPPY=on   and
127              USEZSTD=on respectively when building makedumpfile)
128              A  user  cannot  specify this option with -E option, because the
129              ELF format does not support compressed data.
130              Example:
131              # makedumpfile -c -d 31 -x vmlinux /proc/vmcore dumpfile
132
133
134       -d dump_level
135              Specify the type of unnecessary page for analysis.
136              Pages of the specified type are not copied to DUMPFILE. The page
137              type marked in the following table is excluded. A user can spec‐
138              ify multiple page types by setting the sum of each page type for
139              dump_level.  The  maximum  of  dump_level  is  31.  Note  that a
140              dump_level for Xen dump filtering is 0 or 1 on a  machine  other
141              than  x86_64.  On  a x86_64 machine, even 2 or bigger dump level
142              will be effective if you specify domain-0's vmlinux with -x  op‐
143              tion.  Then the pages are excluded only from domain-0.
144              If specifying multiple dump_levels with the delimiter ',', make‐
145              dumpfile retries to create DUMPFILE using  the  next  dump_level
146              when  the  size  of  a dumpfile exceeds the limit specified with
147              '-L' or when a "No space on device" error happens. For  example,
148              if  dump_level is "11,31" and makedumpfile fails with dump_level
149              11, makedumpfile retries with dump_level 31.
150              Example:
151              # makedumpfile -d 11 -x vmlinux /proc/vmcore dumpfile
152              # makedumpfile -d 11,31 -x vmlinux /proc/vmcore dumpfile
153              Base level:
154              dump_level consists of five bits, so there are five base  levels
155              to specify the type of unnecessary page.
156                    1 : Exclude the pages filled with zero.
157                    2 : Exclude the non-private cache pages.
158                    4 : Exclude all cache pages.
159                    8 : Exclude the user process data pages.
160                   16 : Exclude the free pages.
161
162              Here is the all combinations of the bits.
163
164                     |      |non-   |       |      |
165                dump | zero |private|private| user | free
166               level | page |cache  |cache  | data | page
167              -------+------+-------+-------+------+------
168                   0 |      |       |       |      |
169                   1 |  X   |       |       |      |
170                   2 |      |   X   |       |      |
171                   3 |  X   |   X   |       |      |
172                   4 |      |   X   |   X   |      |
173                   5 |  X   |   X   |   X   |      |
174                   6 |      |   X   |   X   |      |
175                   7 |  X   |   X   |   X   |      |
176                   8 |      |       |       |  X   |
177                   9 |  X   |       |       |  X   |
178                  10 |      |   X   |       |  X   |
179                  11 |  X   |   X   |       |  X   |
180                  12 |      |   X   |   X   |  X   |
181                  13 |  X   |   X   |   X   |  X   |
182                  14 |      |   X   |   X   |  X   |
183                  15 |  X   |   X   |   X   |  X   |
184                  16 |      |       |       |      |  X
185                  17 |  X   |       |       |      |  X
186                  18 |      |   X   |       |      |  X
187                  19 |  X   |   X   |       |      |  X
188                  20 |      |   X   |   X   |      |  X
189                  21 |  X   |   X   |   X   |      |  X
190                  22 |      |   X   |   X   |      |  X
191                  23 |  X   |   X   |   X   |      |  X
192                  24 |      |       |       |  X   |  X
193                  25 |  X   |       |       |  X   |  X
194                  26 |      |   X   |       |  X   |  X
195                  27 |  X   |   X   |       |  X   |  X
196                  28 |      |   X   |   X   |  X   |  X
197                  29 |  X   |   X   |   X   |  X   |  X
198                  30 |      |   X   |   X   |  X   |  X
199                  31 |  X   |   X   |   X   |  X   |  X
200
201
202       -L SIZE
203              Limit  the  size of the output file to SIZE bytes. An incomplete
204              DUMPFILE or LOGFILE is written if the size would  otherwise  ex‐
205              ceed SIZE.
206
207
208       -E     Create DUMPFILE in the ELF format.
209              This  option  cannot be specified with the -c, -l or -p options,
210              because the ELF format does not support compressed data.
211              Example:
212              # makedumpfile -E -d 31 -x vmlinux /proc/vmcore dumpfile
213
214
215       -f     Force existing DUMPFILE to be overwritten and mem-usage to  work
216              with older kernel as well.
217              Example:
218              # makedumpfile -f -d 31 -x vmlinux /proc/vmcore dumpfile
219              This command overwrites DUMPFILE even if it already exists.
220              # makedumpfile -f --mem-usage /proc/kcore
221              Kernel  version lesser than v4.11 will not work with --mem-usage
222              functionality until it has been  patched  with  upstream  commit
223              464920104bf7.   Therefore  if you have patched your older kernel
224              then use -f.
225
226
227       -x VMLINUX
228              Specify the first kernel's VMLINUX with debug information to an‐
229              alyze the first kernel's memory usage.
230              This  option is necessary if VMCORE does not contain VMCOREINFO,
231              [-i VMCOREINFO] is not specified, and dump_level is 2 or more.
232              The page size of the first kernel and the second  kernel  should
233              match.
234              Example:
235              # makedumpfile -d 31 -x vmlinux /proc/vmcore dumpfile
236
237
238       -i VMCOREINFO
239              Specify  VMCOREINFO  instead  of VMLINUX for analyzing the first
240              kernel's memory usage.
241              VMCOREINFO should be made beforehand by makedumpfile with -g op‐
242              tion, and it contains the first kernel's information.
243              This  option is necessary if VMCORE does not contain VMCOREINFO,
244              [-x VMLINUX] is not specified, and dump_level is 2 or more.
245              Example:
246              # makedumpfile -d 31 -i vmcoreinfo /proc/vmcore dumpfile
247
248
249       -g VMCOREINFO
250              Generate VMCOREINFO from the first kernel's VMLINUX  with  debug
251              information.
252              VMCOREINFO  must  be generated on the system that is running the
253              first kernel. With -i option, a user can specify VMCOREINFO gen‐
254              erated  on  the other system that is running the same first ker‐
255              nel. [-x VMLINUX] must be specified.
256              Example:
257              # makedumpfile -g vmcoreinfo -x vmlinux
258
259
260       --config FILTERCONFIGFILE
261              Used in conjunction with -x VMLINUX option, to specify the  fil‐
262              ter config file FILTERCONFIGFILE that contains erase commands to
263              filter out desired kernel data from vmcore while creating  DUMP‐
264              FILE.  For  filter  command  syntax  please  refer  to makedump‐
265              file.conf(5).
266
267
268       --eppic EPPICMACRO
269              Used in conjunction with -x VMLINUX option, to specify the eppic
270              macro file that contains filter rules or directory that contains
271              eppic macro files to filter out desired kernel data from  vmcore
272              while  creating  DUMPFILE.  When directory is specified, all the
273              eppic macros in the directory are processed.
274
275
276       -F     Output the dump data in the flattened  format  to  the  standard
277              output for transporting the dump data by SSH.
278              Analysis  tools (crash utility before version 5.1.2 or GDB) can‐
279              not read the flattened format directly. For analysis,  the  dump
280              data  in  the  flattened format should be rearranged to a normal
281              DUMPFILE (readable with analysis tools) by -R option.  By  which
282              option is specified with -F option, the format of the rearranged
283              DUMPFILE is fixed.  In other words, it is impossible to  specify
284              the DUMPFILE format when the dump data is rearranged with -R op‐
285              tion. If specifying -E option with -F option, the format of  the
286              rearranged  DUMPFILE  is  the  ELF  format. Otherwise, it is the
287              kdump-compressed format. All the messages are output to standard
288              error  output  by  -F option because standard output is used for
289              the dump data.
290              Example:
291              # makedumpfile -F -c -d 31 -x vmlinux /proc/vmcore \
292              | ssh user@host "cat > dumpfile.tmp"
293              # makedumpfile -F -c -d 31 -x vmlinux /proc/vmcore \
294              | ssh user@host "makedumpfile -R dumpfile"
295              # makedumpfile -F -E -d 31 -i vmcoreinfo  /proc/vmcore \
296              | ssh user@host "makedumpfile -R dumpfile"
297              # makedumpfile -F -E --xen-vmcoreinfo VMCOREINFO /proc/vmcore \
298              | ssh user@host "makedumpfile -R dumpfile"
299
300
301       -R     Rearrange the dump data in the flattened format from  the  stan‐
302              dard input to a normal DUMPFILE (readable with analysis tools).
303              Example:
304              # makedumpfile -R dumpfile < dumpfile.tmp
305              # makedumpfile -F -d 31 -x vmlinux /proc/vmcore \
306              | ssh user@host "makedumpfile -R dumpfile"
307
308              Instead  of  using  -R option, a perl script "makedumpfile-R.pl"
309              rearranges the dump data in the flattened  format  to  a  normal
310              DUMPFILE,  too. The perl script does not depend on architecture,
311              and most systems have perl command.  Even if a remote host  does
312              not have makedumpfile, it is possible to rearrange the dump data
313              in the flattened format to a readable DUMPFILE on a remote  host
314              by running this script.
315              Example:
316              # makedumpfile -F -d 31 -x vmlinux /proc/vmcore \
317              | ssh user@host "makedumpfile-R.pl dumpfile"
318
319
320       --split
321              Split the dump data to multiple DUMPFILEs in parallel. If speci‐
322              fying DUMPFILEs on different storage devices, a device can share
323              I/O  load  with other devices and it reduces time for saving the
324              dump data. The file size of each DUMPFILE is  smaller  than  the
325              system  memory size which is divided by the number of DUMPFILEs.
326              This feature supports only the kdump-compressed format.
327              Example:
328              # makedumpfile --split -d 31 -x vmlinux  /proc/vmcore  dumpfile1
329              dumpfile2
330
331
332       --num-threads THREADNUM
333              Using multiple threads to read and compress data of each page in
334              parallel.  And it will reduces time for saving  DUMPFILE.   Note
335              that if the usable cpu number is less than the thread number, it
336              may lead to great performance degradation.   This  feature  only
337              supports creating DUMPFILE in kdump-comressed format from VMCORE
338              in kdump-compressed format or elf format.
339              Example:
340              # makedumpfile -d 31 --num-threads 4 /proc/vmcore dumpfile
341
342
343       --reassemble
344              Reassemble multiple DUMPFILEs, which are created by --split  op‐
345              tion, into one DUMPFILE. dumpfile1 and dumpfile2 are reassembled
346              into dumpfile on the following example.
347              Example:
348              # makedumpfile --reassemble dumpfile1 dumpfile2 dumpfile
349
350
351       -b <order>
352              Cache 2^order pages in ram when generating DUMPFILE before writ‐
353              ing to output.  The default value is 4.
354
355
356       --cyclic-buffer buffer_size
357              Specify  the buffer size in kilo bytes for bitmap data.  Filter‐
358              ing processing will be divided into multi cycles to fix the mem‐
359              ory consumption, the number of cycles is represented as:
360
361                  num_of_cycles  =  system_memory  /  (buffer_size  *  1024  *
362              bit_per_bytes * page_size )
363
364              The lesser number of cycles, the faster  working  speed  is  ex‐
365              pected.   By  default,  buffer_size will be calculated automati‐
366              cally depending on system memory size, so ordinary  users  don't
367              need to specify this option.
368
369              Example:
370              #  makedumpfile  --cyclic-buffer 1024 -d 31 -x vmlinux /proc/vm‐
371              core dumpfile
372
373
374       --splitblock-size splitblock_size
375              Specify the splitblock size in  kilo  bytes  for  analysis  with
376              --split.   If  --splitblock  N  is specified, difference of each
377              splitted dumpfile size is at most N kilo bytes.
378              Example:
379              # makedumpfile --splitblock-size 1024 -d 31 -x  vmlinux  --split
380              /proc/vmcore dumpfile1 dumpfile2
381
382
383
384       --work-dir
385              Specify the working directory for the temporary bitmap file.  If
386              this option isn't specified, the bitmap will be saved on memory.
387              Filtering processing has to do 2 pass scanning to fix the memory
388              consumption, but it can be avoided by using working directory on
389              file system.  So if you specify this option, the filtering speed
390              may be bit faster.
391
392              Example:
393              # makedumpfile --work-dir /tmp -d  31  -x  vmlinux  /proc/vmcore
394              dumpfile
395
396
397       --non-mmap
398              Never  use  mmap(2)  to read VMCORE even if it supports mmap(2).
399              Generally, reading VMCORE with mmap(2) is  faster  than  without
400              it,  so  ordinary users don't need to specify this option.  This
401              option is mainly for debugging.
402              Example:
403              # makedumpfile --non-mmap -d 31 -x vmlinux /proc/vmcore dumpfile
404
405
406       --xen-syms XEN-SYMS
407              Specify the XEN-SYMS with debug information to analyze the xen's
408              memory  usage.   This  option  extracts  the part of xen and do‐
409              main-0.
410              Example:
411              # makedumpfile -E --xen-syms xen-syms /proc/vmcore dumpfile
412
413
414       --xen-vmcoreinfo VMCOREINFO
415              Specify VMCOREINFO instead of XEN-SYMS for analyzing  the  xen's
416              memory usage.
417              VMCOREINFO should be made beforehand by makedumpfile with -g op‐
418              tion, and it contains the xen's information.
419              Example:
420              # makedumpfile -E --xen-vmcoreinfo VMCOREINFO /proc/vmcore dump‐
421              file
422
423
424       -X     Exclude  all  the user domain pages from Xen kdump's VMCORE, and
425              extracts the part of xen and domain-0. If VMCORE contains VMCOR‐
426              EINFO  for  Xen,  it  is not necessary to specify --xen-syms and
427              --xen-vmcoreinfo.
428              Example:
429              # makedumpfile -E -X /proc/vmcore dumpfile
430
431
432       --xen_phys_start xen_phys_start_address
433              This option is only for x86_64.  Specify the  xen_phys_start_ad‐
434              dress,  if  the xen code/data is relocatable and VMCORE does not
435              contain     xen_phys_start_address     in     the     CRASHINFO.
436              xen_phys_start_address can be taken from the line of "Hypervisor
437              code and data" in /proc/iomem. For example,  specify  0xcee00000
438              as xen_phys_start_address if /proc/iomem is the following:
439                -------------------------------------------------------
440                # cat /proc/iomem
441                ...
442                  cee00000-cfd99999 : Hypervisor code and data
443                ...
444                -------------------------------------------------------
445
446              Example:
447              #  makedumpfile  -E  -X --xen_phys_start 0xcee00000 /proc/vmcore
448              dumpfile
449
450
451       --message-level message_level
452              Specify the message types.
453              Users can restrict outputs printed by  specifying  message_level
454              with  this option. The message type marked with an X in the fol‐
455              lowing table is printed. For example, according  to  the  table,
456              specifying  7  as message_level means progress indicator, common
457              message, and error message are printed, and this  is  a  default
458              value. Note that the maximum value of message_level is 31.
459
460               message | progress | common  | error   | debug   | report
461               level   | indicator| message | message | message | message
462              ---------+----------+---------+---------+---------+---------
463                     0 |          |         |         |         |
464                     1 |    X     |         |         |         |
465                     2 |          |    X    |         |         |
466                     3 |    X     |    X    |         |         |
467                     4 |          |         |    X    |         |
468                     5 |    X     |         |    X    |         |
469                     6 |          |    X    |    X    |         |
470                   * 7 |    X     |    X    |    X    |         |
471                     8 |          |         |         |    X    |
472                     9 |    X     |         |         |    X    |
473                    10 |          |    X    |         |    X    |
474                    11 |    X     |    X    |         |    X    |
475                    12 |          |         |    X    |    X    |
476                    13 |    X     |         |    X    |    X    |
477                    14 |          |    X    |    X    |    X    |
478                    15 |    X     |    X    |    X    |    X    |
479                    16 |          |         |         |         |    X
480                    17 |    X     |         |         |         |    X
481                    18 |          |    X    |         |         |    X
482                    19 |    X     |    X    |         |         |    X
483                    20 |          |         |    X    |         |    X
484                    21 |    X     |         |    X    |         |    X
485                    22 |          |    X    |    X    |         |    X
486                    23 |    X     |    X    |    X    |         |    X
487                    24 |          |         |         |    X    |    X
488                    25 |    X     |         |         |    X    |    X
489                    26 |          |    X    |         |    X    |    X
490                    27 |    X     |    X    |         |    X    |    X
491                    28 |          |         |    X    |    X    |    X
492                    29 |    X     |         |    X    |    X    |    X
493                    30 |          |    X    |    X    |    X    |    X
494                    31 |    X     |    X    |    X    |    X    |    X
495
496
497       --vtop virtual_address
498              This  option is useful, when user debugs the translation problem
499              of virtual address. If specifing virtual_address,  its  physical
500              address  is  printed.  It  makes debugging easy by comparing the
501              output of this option with the one of "vtop" subcommand  of  the
502              crash utility.  "--vtop" option only prints the translation out‐
503              put, and it does not affect the dumpfile creation.
504
505
506       --dump-dmesg
507              This option overrides the normal behavior of makedumpfile.   In‐
508              stead  of compressing and filtering a VMCORE to make it smaller,
509              it simply extracts the dmesg log from a VMCORE and writes it  to
510              the  specified  LOGFILE. If a VMCORE does not contain VMCOREINFO
511              for dmesg, it is necessary to specfiy [-x VMLINUX] or [-i VMCOR‐
512              EINFO].
513
514              Example:
515              # makedumpfile --dump-dmesg /proc/vmcore dmesgfile
516              # makedumpfile --dump-dmesg -x vmlinux /proc/vmcore dmesgfile
517
518
519
520       --partial-dmesg
521              This option will make --dump-dmesg extract only dmesg logs since
522              that buffer was last cleared  on  the  crashed  kernel,  through
523              "dmesg --clear" for example.
524
525
526
527       --mem-usage
528              This  option  is currently supported on x86_64, arm64, ppc64 and
529              s390x.  This option is used to show the page numbers of  current
530              system in different use. It should be executed in 1st kernel. By
531              the help of this, user can know how many pages is dumpable  when
532              different  dump_level is specified. It analyzes the 'System Ram'
533              and 'kernel text' program segment of /proc/kcore  excluding  the
534              crashkernel  range, then calculates the page number of different
535              kind per vmcoreinfo. So currently /proc/kcore need be  specified
536              explicitly.
537
538              Example:
539              # makedumpfile --mem-usage /proc/kcore
540
541
542
543       --diskset=VMCORE
544              Specify multiple VMCOREs created on sadump diskset configuration
545              the same number of times as the number of VMCOREs in  increasing
546              order  from  left to right.  VMCOREs are assembled into a single
547              DUMPFILE.
548
549              Example:
550              # makedumpfile -x  vmlinux  --diskset=vmcore1  --diskset=vmcore2
551              dumpfile
552
553
554       -D     Print debugging message.
555
556
557       -h (--help)
558              Show  help  message  and LZO/snappy support status (enabled/dis‐
559              abled).
560
561
562       -v     Show the version of makedumpfile.
563
564
565       --check-params
566              Only check whether the command-line parameters are valid or not,
567              and exit.  Preferable to be given as the first parameter.
568
569
570       --dry-run
571              Do  not write the output dump file while still performing opera‐
572              tions specified by other options.  This option  cannot  be  used
573              with the --dump-dmesg, --reassemble and -g options.
574
575
576       --show-stats
577              Display  report messages. This is an alternative to enabling bit
578              4 in the level provided to --message-level.
579
580

ENVIRONMENT VARIABLES

582       TMPDIR  This environment variable is used in 1st kernel environment for
583               a  temporary memory bitmap file.  If your machine has a lots of
584               memory and you use small tmpfs on /tmp, makedumpfile  can  fail
585               for  a  little  memory  because makedumpfile makes a very large
586               temporary memory bitmap file in this case. To avoid this  fail‐
587               ure, you should specify --work-dir option to use file system on
588               storage for the bitmap file.
589
590

DIAGNOSTICS

592       makedumpfile exits with the following value.
593
594       0 : makedumpfile succeeded.
595
596       1 : makedumpfile failed without the following reasons.
597
598       2 : makedumpfile failed due to the different version  between   VMLINUX
599       and VMCORE.
600
601

AUTHORS

603       Written by Masaki Tachibana, and Ken'ichi Ohmichi.
604
605

SEE ALSO

607       crash(8), gdb(1), kexec(8), makedumpfile.conf(5)
608
609
610
611
612makedumpfile v1.7.1               18 Apr 2022                  MAKEDUMPFILE(8)
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