Implement a new "offline" internal crash variable that can be set to
either "show" (the default) or "hide".  When set to "hide", certain
command output associated with offline cpus will be hidden from view,
and the output will indicate that the cpu is "[OFFLINE]".  The new
variable can be set during invocation on the crash command line via
the option "--offline [show|hide]".  During runtime, or in a .crashrc
or other crash input file, the variable can be set by entering
"set offline [show|hide]".  The commands or options that are affected
when the variable is set to "hide" are as follows:

  o  On X86_64 machines, the "bt -E" option will not search exception
     stacks associated with offline cpus.
  o  On X86_64 machines, the "mach" command will append "[OFFLINE]"
     to the addresses of IRQ and exception stacks associated with
     offline cpus.
  o  On X86_64 machines, the "mach -c" command will not display the
     cpuinfo_x86 data structure associated with offline cpus.
  o  The "help -r" option has been fixed so as to not attempt to
     display register sets of offline cpus from ELF kdump vmcores,
     compressed kdump vmcores, and ELF kdump clones created by
     "virsh dump --memory-only".
  o  The "bt -c" option will not accept an offline cpu number.
  o  The "set -c" option will not accept an offline cpu number.
  o  The "irq -s" option will not display statistics associated with
     offline cpus.
  o  The "timer" command will not display hrtimer data associated
     with offline cpus.
  o  The "timer -r" option will not display hrtimer data associated
     with offline cpus.
  o  The "ptov" command will append "[OFFLINE]" when translating a
     per-cpu address offset to a virtal address of an offline cpu.
  o  The "kmem -o" option will append "[OFFLINE]" to the base per-cpu
     virtual address of an offline cpu.
  o  The "kmem -S" option in CONFIG_SLUB kernels will not display
     per-cpu data associated with offline cpus.
  o  When a per-cpu address reference is passed to the "struct"
     command, the data structure will not be displayed for offline
     cpus.
  o  When a per-cpu symbol and cpu reference is passed to the "p"
     command, the data will not be displayed for offline cpus.
  o  When the "ps -[l|m]" option is passed the optional "-C [cpus]"
     option, the tasks queued on offline cpus are not shown.
  o  The "runq" command and the "runq [-t/-m/-g/-d]" options will not
     display runqueue data for offline cpus.
  o  The "ps" command will replace the ">" active task indicator to
     a "-" for offline cpus.

The initial system information banner and the "sys" command will
display the total number of cpus as before, but will append the count
of offline cpus.  Lastly, a fix has been made for the initialization
time determination of the maximum number of per-cpu objects queued
in a CONFIG_SLAB kmem_cache so as to continue checking all cpus
higher than the first offline cpu.  These changes in behavior are not
dependent upon the setting of the crash "offline" variable.
(qiaonuohan@cn.fujitsu.com)