[PATCH 7/7] add a new interface to show the memory usage of 1st kernel

[Vivek Goyal]

On Fri, Jul 11, 2014 at 03:16:04PM +0800, Baoquan He wrote:
> Recently people complained that they don't decide how much disk size
> need be reserved for kdump storing. E.g there are lots of machines
> with different memory size, if the memory usage information of current
> system can be shown, that can help them to make an estimate how much
> storage space need be reserved.
> 
> In this patch, a new interface is added into makedumpfile. With the
> help of this, people can know the page number of memory in different
> use. The implementation is analyzing the "System Ram" and "kernel text"
> program segment of /proc/kcore excluding the crashkernel range, then
> calculating the page number of different kind per vmcoreinfo.
> 
> The print is like below:
> ->$ ./makedumpfile  --mem-usage  /proc/kcore
> Excluding unnecessary pages        : [100.0 %] |
> 
> Page number of memory in different use
> --------------------------------------------------
> TYPE			PAGES			EXCLUDABLE	DESCRIPTION
> pfn_zero		0x0000000000000000	yes		Pages filled with zero
> pfn_cache		0x000000000002b19f	yes		Cache pages
> pfn_cache_private	0x0000000000042526	yes		Cache pages + private
> pfn_user		0x0000000000026bc3	yes		User process data pages
> pfn_free		0x0000000000133f79	yes		Free pages
> pfn_hwpoison		0x0000000000000000	yes		Hwpoison pages

Is there a need to display hwpoison pages? I think they are excluded by
default. Otherwise reading them might kill makedumpfile process.

Thanks
Vivek