[Crash-utility] [PATCH v2] kmem: Introduce -m option

[Dave Anderson]

Aaron Tomlin and I have been collaborating offline/in-house with respect
to this patch, and we've finally come up with an implementation that is
queued for crash-7.1.1:

  https://github.com/crash-utility/crash/commit/a8e7fc1e580122fac032c80f789026dfe3f1fc4d

  - Implemented a new "kmem -m" option that is similar to "kmem -p",
    but it allows the user to specify the page struct members to be
    displayed.  The option takes a comma-separated list of one or
    more page struct members, which will be displayed following the
    page structure address.  The "flags" member will always be expressed
    in hexadecimal format, and the "_count" and "_mapcount" members will
    always be expressed in decimal format.  Otherwise, all other members
    will be displayed in hexadecimal format unless the current output
    radix is 10 and the member is a signed/unsigned integer.  Members
    that are data structures may be specified by the data structure's
    member name, or expanded to specify a member of that data structure.
    For example, "-m lru" refers to a list_head data structure, in which
    case both the list_head.next and list_head.prev pointer values will
    be displayed; if "-m lru.next" is specified, just the list_head.next
    value will be displayed.
    (atomlin at redhat.com, anderson at redhat.com)