memory hotplug: allocate usemap on the section with pgdat
commit48c906823f3927b981db9f0b03c2e2499977ee93
authorYasunori Goto <y-goto@jp.fujitsu.com>
Thu, 24 Jul 2008 04:28:15 +0000 (23 21:28 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 24 Jul 2008 17:47:21 +0000 (24 10:47 -0700)
treef01270b14dbc8e0816e966e1aed1e3294e1c1d4a
parentf84f9504bddeec33a72d64ebe95143d3aaeb3f9b
memory hotplug: allocate usemap on the section with pgdat

Usemaps are allocated on the section which has pgdat by this.

Because usemap size is very small, many other sections usemaps are
allocated on only one page.  If a section has usemap, it can't be removed
until removing other sections.  This dependency is not desirable for
memory removing.

Pgdat has similar feature.  When a section has pgdat area, it must be the
last section for removing on the node.  So, if section A has pgdat and
section B has usemap for section A, Both sections can't be removed due to
dependency each other.

To solve this issue, this patch collects usemap on same section with pgdat
as much as possible.  If other sections doesn't have any dependency, this
section will be able to be removed finally.

Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: David Miller <davem@davemloft.net>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hiroyuki KAMEZAWA <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/sparse.c