]> git.karo-electronics.de Git - linux-beck.git/commit
mm: check if any page in a pageblock is reserved before marking it MIGRATE_RESERVE
authorArve Hjønnevåg <arve@android.com>
Wed, 25 May 2011 00:12:24 +0000 (17:12 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 25 May 2011 15:39:24 +0000 (08:39 -0700)
commit6d3163ce86dd386b4f7bda80241d7fea2bc0bb1d
tree169f74df152fa593e5dc9adfff7f6f7e31061028
parent0091a47da0b720ca39511c7d90dcc768cafcaf58
mm: check if any page in a pageblock is reserved before marking it MIGRATE_RESERVE

This fixes a problem where the first pageblock got marked MIGRATE_RESERVE
even though it only had a few free pages.  eg, On current ARM port, The
kernel starts at offset 0x8000 to leave room for boot parameters, and the
memory is freed later.

This in turn caused no contiguous memory to be reserved and frequent
kswapd wakeups that emptied the caches to get more contiguous memory.

Unfortunatelly, ARM needs order-2 allocation for pgd (see
arm/mm/pgd.c#pgd_alloc()).  Therefore the issue is not minor nor easy
avoidable.

[kosaki.motohiro@jp.fujitsu.com: added some explanation]
[kosaki.motohiro@jp.fujitsu.com: add !pfn_valid_within() to check]
[minchan.kim@gmail.com: check end_pfn in pageblock_is_reserved]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/page_alloc.c