[PATCH] remove static variable mm/page-writeback.c:total_pages

[PATCH] remove static variable mm/page-writeback.c:total_pages

page-writeback.c has a static local variable "total_pages", which is the
total number of pages in the system.

There is a global variable "vm_total_pages", which is the total number of
pages the VM controls.

Both are assigned from the return value of nr_free_pagecache_pages().

This patch removes the local variable and uses the global variable in that
place.

One more issue with the local static variable "total_pages" is that it is
not updated when new pages are hot-added.  Since vm_total_pages is updated
when new pages are hot-added, this patch fixes that problem too.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>