Re: [PATCH 1/2] mm: use is_migrate_highatomic() to simplify the code
From: Michal Hocko
Date: Fri Mar 03 2017 - 10:52:48 EST
On Fri 03-03-17 19:10:13, Xishi Qiu wrote:
> Introduce two helpers, is_migrate_highatomic() and is_migrate_highatomic_page().
> Simplify the code, no functional changes.
static inline helpers would be nicer than macros
> Signed-off-by: Xishi Qiu <qiuxishi@xxxxxxxxxx>
OK this fits with other MIGRATE_$FOO types
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
> ---
> include/linux/mmzone.h | 5 +++++
> mm/page_alloc.c | 14 ++++++--------
> 2 files changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 8e02b37..8124440 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -66,6 +66,11 @@ enum {
> /* In mm/page_alloc.c; keep in sync also with show_migration_types() there */
> extern char * const migratetype_names[MIGRATE_TYPES];
>
> +#define is_migrate_highatomic(migratetype) \
> + (migratetype == MIGRATE_HIGHATOMIC)
> +#define is_migrate_highatomic_page(_page) \
> + (get_pageblock_migratetype(_page) == MIGRATE_HIGHATOMIC)
> +
> #ifdef CONFIG_CMA
> # define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
> # define is_migrate_cma_page(_page) (get_pageblock_migratetype(_page) == MIGRATE_CMA)
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 9f9623d..40d79a6 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -2040,8 +2040,8 @@ static void reserve_highatomic_pageblock(struct page *page, struct zone *zone,
>
> /* Yoink! */
> mt = get_pageblock_migratetype(page);
> - if (mt != MIGRATE_HIGHATOMIC &&
> - !is_migrate_isolate(mt) && !is_migrate_cma(mt)) {
> + if (!is_migrate_highatomic(mt) && !is_migrate_isolate(mt)
> + && !is_migrate_cma(mt)) {
> zone->nr_reserved_highatomic += pageblock_nr_pages;
> set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC);
> move_freepages_block(zone, page, MIGRATE_HIGHATOMIC);
> @@ -2098,8 +2098,7 @@ static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
> * from highatomic to ac->migratetype. So we should
> * adjust the count once.
> */
> - if (get_pageblock_migratetype(page) ==
> - MIGRATE_HIGHATOMIC) {
> + if (is_migrate_highatomic_page(page)) {
> /*
> * It should never happen but changes to
> * locking could inadvertently allow a per-cpu
> @@ -2156,8 +2155,7 @@ static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
>
> page = list_first_entry(&area->free_list[fallback_mt],
> struct page, lru);
> - if (can_steal &&
> - get_pageblock_migratetype(page) != MIGRATE_HIGHATOMIC)
> + if (can_steal && !is_migrate_highatomic_page(page))
> steal_suitable_fallback(zone, page, start_migratetype);
>
> /* Remove the page from the freelists */
> @@ -2494,7 +2492,7 @@ void free_hot_cold_page(struct page *page, bool cold)
> /*
> * We only track unmovable, reclaimable and movable on pcp lists.
> * Free ISOLATE pages back to the allocator because they are being
> - * offlined but treat RESERVE as movable pages so we can get those
> + * offlined but treat HIGHATOMIC as movable pages so we can get those
> * areas back if necessary. Otherwise, we may have to free
> * excessively into the page allocator
> */
> @@ -2605,7 +2603,7 @@ int __isolate_free_page(struct page *page, unsigned int order)
> for (; page < endpage; page += pageblock_nr_pages) {
> int mt = get_pageblock_migratetype(page);
> if (!is_migrate_isolate(mt) && !is_migrate_cma(mt)
> - && mt != MIGRATE_HIGHATOMIC)
> + && !is_migrate_highatomic(mt))
> set_pageblock_migratetype(page,
> MIGRATE_MOVABLE);
> }
> --
> 1.8.3.1
>
--
Michal Hocko
SUSE Labs