Re: [PATCH 1/1 linux-next] mm,compaction: move suitable_migration_target() under CONFIG_COMPACTION

From: Vlastimil Babka
Date: Tue Jan 06 2015 - 12:21:28 EST


On 01/03/2015 05:04 PM, Fabian Frederick wrote:
> suitable_migration_target() is only used by isolate_freepages()
> Define it under CONFIG_COMPACTION || CONFIG_CMA is not needed.
>
> Fix the following warning:
> mm/compaction.c:311:13: warning: 'suitable_migration_target' defined
> but not used [-Wunused-function]
>
> Signed-off-by: Fabian Frederick <fabf@xxxxxxxxx>

I agree, I would just move it to the section where isolation_suitable() and
related others are, maybe at the end of this section below update_pageblock_skip()?

Vlastimil

> ---
> mm/compaction.c | 44 ++++++++++++++++++++++----------------------
> 1 file changed, 22 insertions(+), 22 deletions(-)
>
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 546e571..38b151c 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -307,28 +307,6 @@ static inline bool compact_should_abort(struct compact_control *cc)
> return false;
> }
>
> -/* Returns true if the page is within a block suitable for migration to */
> -static bool suitable_migration_target(struct page *page)
> -{
> - /* If the page is a large free page, then disallow migration */
> - if (PageBuddy(page)) {
> - /*
> - * We are checking page_order without zone->lock taken. But
> - * the only small danger is that we skip a potentially suitable
> - * pageblock, so it's not worth to check order for valid range.
> - */
> - if (page_order_unsafe(page) >= pageblock_order)
> - return false;
> - }
> -
> - /* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */
> - if (migrate_async_suitable(get_pageblock_migratetype(page)))
> - return true;
> -
> - /* Otherwise skip the block */
> - return false;
> -}
> -
> /*
> * Isolate free pages onto a private freelist. If @strict is true, will abort
> * returning 0 on any invalid PFNs or non-free pages inside of the pageblock
> @@ -802,6 +780,28 @@ isolate_migratepages_range(struct compact_control *cc, unsigned long start_pfn,
>
> #endif /* CONFIG_COMPACTION || CONFIG_CMA */
> #ifdef CONFIG_COMPACTION
> +/* Returns true if the page is within a block suitable for migration to */
> +static bool suitable_migration_target(struct page *page)
> +{
> + /* If the page is a large free page, then disallow migration */
> + if (PageBuddy(page)) {
> + /*
> + * We are checking page_order without zone->lock taken. But
> + * the only small danger is that we skip a potentially suitable
> + * pageblock, so it's not worth to check order for valid range.
> + */
> + if (page_order_unsafe(page) >= pageblock_order)
> + return false;
> + }
> +
> + /* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */
> + if (migrate_async_suitable(get_pageblock_migratetype(page)))
> + return true;
> +
> + /* Otherwise skip the block */
> + return false;
> +}
> +
> /*
> * Based on information in the current compact_control, find blocks
> * suitable for isolating free pages from and then isolate them.
>

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