tree 06dbbc2c38d55f8eacab09c55a68c736156b9540
parent 594fe1a044325bb0a1a49ca7d086e3df4f1df59a
author KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> 1231281633 -0800
committer Linus Torvalds <torvalds@linux-foundation.org> 1231286350 -0800

mm: stop kswapd's infinite loop at high order allocation

Wassim Dagash reported following kswapd infinite loop problem.

  kswapd runs in some infinite loop trying to swap until order 10 of zone
  highmem is OK.... kswapd will continue to try to balance order 10 of zone
  highmem forever (or until someone release a very large chunk of highmem).

For non order-0 allocations, the system may never be balanced due to
fragmentation but kswapd should not infinitely loop as a result.

Instead, recheck all watermarks at order-0 as they are the most important.
If watermarks are ok, kswapd will go back to sleep.

[akpm@linux-foundation.org: fix comment]
Reported-by: wassim dagash <wassim.dagash@gmail.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>