NAME | SYNOPSIS | DESCRIPTION | OPTIONS | RETURN CODES | EXAMPLES | SEE ALSO | AVAILABILITY | COLOPHON

CHMEM(8)                    System Administration                   CHMEM(8)

NAME         top

       chmem - configure memory

SYNOPSIS         top

       chmem [-h] [-V] [-v] [-e|-d] [SIZE|RANGE|-b BLOCKRANGE]

DESCRIPTION         top

       The chmem command sets a particular size or range of memory online or
       offline.

       ‐ Specify SIZE as <size>[m|M|g|G]. With m or M, <size> specifies the
         memory size in MiB (1024 x 1024 bytes). With g or G, <size>
         specifies the memory size in GiB (1024 x 1024 x 1024 bytes). The
         default unit is MiB.

       ‐ Specify RANGE in the form 0x<start>-0x<end> as shown in the output
         of the lsmem command. <start> is the hexadecimal address of the
         first byte and <end> is the hexadecimal address of the last byte in
         the memory range.

       ‐ Specify BLOCKRANGE in the form <first>-<last> or <block> as shown
         in the output of the lsmem command. <first> is the number of the
         first memory block and <last> is the number of the last memory
         block in the memory range. Alternatively a single block can be
         specified. BLOCKRANGE requires the --blocks option.

       SIZE and RANGE must be aligned to the Linux memory block size, as
       shown in the output of the lsmem command.

       Setting memory online can fail for various reasons. On virtualized
       systems it can fail if the hypervisor does not have enough memory
       left, for example because memory was overcommitted. Setting memory
       offline can fail if Linux cannot free the memory. If only part of the
       requested memory can be set online or offline, a message tells you
       how much memory was set online or offline instead of the requested
       amount.

       When setting memory online chmem starts with the lowest memory block
       numbers. When setting memory offline chmem starts with the highest
       memory block numbers.

OPTIONS         top

       -b, --blocks
              Use a BLOCKRANGE parameter instead of RANGE or SIZE for the
              --enable and --disable options.

       -d, --disable
              Set the specified RANGE, SIZE, or BLOCKRANGE of memory
              offline.

       -e, --enable
              Set the specified RANGE, SIZE, or BLOCKRANGE of memory online.

       -h, --help
              Print a short help text, then exit.

       -v, --verbose
              Verbose mode. Causes chmem to print debugging messages about
              it's progress.

       -V, --version
              Print the version number, then exit.

RETURN CODES         top

       chmem has the following return codes:

       0      success

       1      failure

       64     partial success

EXAMPLES         top

       chmem --enable 1024
              This command requests 1024 MiB of memory to be set online.

       chmem -e 2g
              This command requests 2 GiB of memory to be set online.

       chmem --disable 0x00000000e4000000-0x00000000f3ffffff
              This command requests the memory range starting with
              0x00000000e4000000 and ending with 0x00000000f3ffffff to be
              set offline.

       chmem -b -d 10
              This command requests the memory block number 10 to be set
              offline.

SEE ALSO         top

       lsmem(1)

AVAILABILITY         top

       The chmem command is part of the util-linux package and is available
       from Linux Kernel Archive 
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.

COLOPHON         top

       This page is part of the util-linux (a random collection of Linux
       utilities) project.  Information about the project can be found at 
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.  If you have a
       bug report for this manual page, send it to
       util-linux@vger.kernel.org.  This page was obtained from the
       project's upstream Git repository 
       ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
       2017-03-13.  If you discover any rendering problems in this HTML ver‐
       sion of the page, or you believe there is a better or more up-to-date
       source for the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original man‐
       ual page), send a mail to man-pages@man7.org

util-linux                      October 2016                        CHMEM(8)