tree 2c098ccf82bf853d78cb0ffb126b42b43f825a6e
parent c406515239376fc93a30d5d03192182160cbd3fb
author Joonsoo Kim <iamjoonsoo.kim@lge.com> 1415920747 -0800
committer Linus Torvalds <torvalds@linux-foundation.org> 1415924225 -0800

mm/compaction: skip the range until proper target pageblock is met

Commit 7d49d8868336 ("mm, compaction: reduce zone checking frequency in
the migration scanner") has a side-effect that changes the iteration
range calculation.  Before the change, block_end_pfn is calculated using
start_pfn, but now it blindly adds pageblock_nr_pages to the previous
value.

This causes the problem that isolation_start_pfn is larger than
block_end_pfn when we isolate the page with more than pageblock order.
In this case, isolation would fail due to an invalid range parameter.

To prevent this, this patch implements skipping the range until a proper
target pageblock is met.  Without this patch, CMA with more than
pageblock order always fails but with this patch it will succeed.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>