makedumpfile memmory usage seems high with option -E

[Vivek Goyal]

Hi Atsushi/Hatayama,

We noticed in our testing that makedumpfile gets OOM killed if we happen
to use -E option. Saving to compressed kdump format works just fine.

Also we noticed that with -E if we disable cyclic mode then it works just
fine.

So looks like something is going on with -E and cyclic mode enabled. I am
not sure what it is.

Do you suspect something?

Thanks
Vivek