When viewing page owner information, we may be more concerned about the
total memory rather than the times of stack appears.  Therefore, the
following adjustments are made:

1. Added the statistics on the total number of pages.

2. Added the optional parameter "-m" to configure the program to sort by
   memory (total pages).

The general output of page_owner is as follows:

	Page allocated via order XXX, ...
	PFN XXX ...
	 // Detailed stack

	Page allocated via order XXX, ...
	PFN XXX ...
	 // Detailed stack

The original page_owner_sort ignores PFN rows, puts the remaining rows
in buf, counts the times of buf, and finally sorts them according to the
times.  General output:

	XXX times:
	Page allocated via order XXX, ...
	 // Detailed stack

Now, we use regexp to extract the page order value from the buf, and
count the total pages for the buf.  General output:

	XXX times, XXX pages:
	Page allocated via order XXX, ...
	 // Detailed stack

By default, it is still sorted by the times of buf; If you want to sort
by the pages nums of buf, use the new -m parameter.

Link: https://lkml.kernel.org/r/1631678242-41033-1-git-send-email-weizhenliang@huawei.comSigned-off-by: Zhenliang Wei <weizhenliang@huawei.com>
Cc: Tang Bin <tangbin@cmss.chinamobile.com>
Cc: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Cc: Zhenliang Wei <weizhenliang@huawei.com>
Cc: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>