On 03/10/2017 05:20 AM, Yisheng Xie wrote:
> If the migrate target is a large free page and we ignore suitable,
> it may not good for defrag. So move the ignore block suitable after
> check large free page.
Right. But in practice I expect close to no impact, because direct
compaction shouldn't have to be called if there's a >=pageblock_order
page already available.
> Signed-off-by: Yisheng Xie <xieyishe...@huawei.com>
> ---
> mm/compaction.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 0fdfde0..4bf2a5d 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -991,9 +991,6 @@ static bool too_many_isolated(struct zone *zone)
> static bool suitable_migration_target(struct compact_control *cc,
> struct page *page)
> {
> - if (cc->ignore_block_suitable)
> - return true;
> -
> /* If the page is a large free page, then disallow migration */
> if (PageBuddy(page)) {
> /*
> @@ -1005,6 +1002,9 @@ static bool suitable_migration_target(struct
> compact_control *cc,
> return false;
> }
>
> + if (cc->ignore_block_suitable)
> + return true;
> +
> /* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */
> if (migrate_async_suitable(get_pageblock_migratetype(page)))
> return true;
>
