tree f444d157d56583e034d3384a0102b5cb22d08743
parent 8d936626dd00bd47cf574add458fea8a23b79611
author Mel Gorman <mel@csn.ul.ie> 1197937205 -0800
committer Linus Torvalds <torvalds@woody.linux-foundation.org> 1197948496 -0800

mm: fix page allocation for larger I/O segments

In some cases the IO subsystem is able to merge requests if the pages are
adjacent in physical memory.  This was achieved in the allocator by having
expand() return pages in physically contiguous order in situations were a
large buddy was split.  However, list-based anti-fragmentation changed the
order pages were returned in to avoid searching in buffered_rmqueue() for a
page of the appropriate migrate type.

This patch restores behaviour of rmqueue_bulk() preserving the physical
order of pages returned by the allocator without incurring increased search
costs for anti-fragmentation.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Mark Lord <mlord@pobox.com
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>