This is a backport of the following upstream commit:
commit a895dc8
Author: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Date: Thu Dec 12 16:40:12 2013 +0900
[PATCH] Add --non-mmap option to disable mmap() manually.
When --non-mmap option is specified, makedumpfile doesn't use
mmap() even if /proc/vmcore supports mmap().
Signed-off-by: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Having this patch, user can switch between mmap() and read() when
accessing vmcore. Whenever user feels necessary to use readmem on vmcore
(buggy code in mmap path, debug purpose, etc.), --non-mmap can do this
favor.
Signed-off-by: WANG Chao <chaowang@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>