Re: [PATCH v9 4/8] mm: Use zone and order instead of free area in free_list manipulators

Michal Hocko
2019-09-10T12:27:19Z

On Sat 07-09-19 10:25:36, Alexander Duyck wrote:
> From: Alexander Duyck <alexander.h.duyck@linux.intel.com>
>
> In order to enable the use of the zone from the list manipulator functions
> I will need access to the zone pointer. As it turns out most of the
> accessors were always just being directly passed &zone->free_area[order]
> anyway so it would make sense to just fold that into the function itself
> and pass the zone and order as arguments instead of the free area.

Yes this makes the interface better.

> In order to be able to reference the zone we need to move the declaration
> of the functions down so that we have the zone defined before we define the
> list manipulation functions.
>
> Reviewed-by: Dan Williams <dan.j.williams@intel.com>
> Reviewed-by: David Hildenbrand <david@redhat.com>
> Reviewed-by: Pankaj Gupta <pagupta@redhat.com>
> Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
> include/linux/mmzone.h | 70 ++++++++++++++++++++++++++----------------------
> mm/page_alloc.c | 30 ++++++++-------------
> 2 files changed, 49 insertions(+), 51 deletions(-)
>
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 125f300981c6..2ddf1f1971c0 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -100,29 +100,6 @@ struct free_area {
> unsigned long nr_free;
> };
>
> -/* Used for pages not on another list */
> -static inline void add_to_free_area(struct page *page, struct free_area *area,
> - int migratetype)
> -{
> - list_add(&page->lru, &area->free_list[migratetype]);
> - area->nr_free++;
> -}
> -
> -/* Used for pages not on another list */
> -static inline void add_to_free_area_tail(struct page *page, struct free_area *area,
> - int migratetype)
> -{
> - list_add_tail(&page->lru, &area->free_list[migratetype]);
> - area->nr_free++;
> -}
> -
> -/* Used for pages which are on another list */
> -static inline void move_to_free_area(struct page *page, struct free_area *area,
> - int migratetype)
> -{
> - list_move(&page->lru, &area->free_list[migratetype]);
> -}
> -
> static inline struct page *get_page_from_free_area(struct free_area *area,
> int migratetype)
> {
> @@ -130,15 +107,6 @@ static inline struct page *get_page_from_free_area(struct free_area *area,
> struct page, lru);
> }
>
> -static inline void del_page_from_free_area(struct page *page,
> - struct free_area *area)
> -{
> - list_del(&page->lru);
> - __ClearPageBuddy(page);
> - set_page_private(page, 0);
> - area->nr_free--;
> -}
> -
> static inline bool free_area_empty(struct free_area *area, int migratetype)
> {
> return list_empty(&area->free_list[migratetype]);
> @@ -796,6 +764,44 @@ static inline bool pgdat_is_empty(pg_data_t *pgdat)
> return !pgdat->node_start_pfn && !pgdat->node_spanned_pages;
> }
>
> +/* Used for pages not on another list */
> +static inline void add_to_free_list(struct page *page, struct zone *zone,
> + unsigned int order, int migratetype)
> +{
> + struct free_area *area = &zone->free_area[order];
> +
> + list_add(&page->lru, &area->free_list[migratetype]);
> + area->nr_free++;
> +}
> +
> +/* Used for pages not on another list */
> +static inline void add_to_free_list_tail(struct page *page, struct zone *zone,
> + unsigned int order, int migratetype)
> +{
> + struct free_area *area = &zone->free_area[order];
> +
> + list_add_tail(&page->lru, &area->free_list[migratetype]);
> + area->nr_free++;
> +}
> +
> +/* Used for pages which are on another list */
> +static inline void move_to_free_list(struct page *page, struct zone *zone,
> + unsigned int order, int migratetype)
> +{
> + struct free_area *area = &zone->free_area[order];
> +
> + list_move(&page->lru, &area->free_list[migratetype]);
> +}
> +
> +static inline void del_page_from_free_list(struct page *page, struct zone *zone,
> + unsigned int order)
> +{
> + list_del(&page->lru);
> + __ClearPageBuddy(page);
> + set_page_private(page, 0);
> + zone->free_area[order].nr_free--;
> +}
> +
> #include <linux/memory_hotplug.h>
>
> void build_all_zonelists(pg_data_t *pgdat);
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index a791f2baeeeb..f85dc1561b85 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -921,7 +921,6 @@ static inline void __free_one_page(struct page *page,
> struct capture_control *capc = task_capc(zone);
> unsigned long uninitialized_var(buddy_pfn);
> unsigned long combined_pfn;
> - struct free_area *area;
> unsigned int max_order;
> struct page *buddy;
>
> @@ -958,7 +957,7 @@ static inline void __free_one_page(struct page *page,
> if (page_is_guard(buddy))
> clear_page_guard(zone, buddy, order, migratetype);
> else
> - del_page_from_free_area(buddy, &zone->free_area[order]);
> + del_page_from_free_list(buddy, zone, order);
> combined_pfn = buddy_pfn & pfn;
> page = page + (combined_pfn - pfn);
> pfn = combined_pfn;
> @@ -992,12 +991,11 @@ static inline void __free_one_page(struct page *page,
> done_merging:
> set_page_order(page, order);
>
> - area = &zone->free_area[order];
> if (is_shuffle_order(order) ? shuffle_pick_tail() :
> buddy_merge_likely(pfn, buddy_pfn, page, order))
> - add_to_free_area_tail(page, area, migratetype);
> + add_to_free_list_tail(page, zone, order, migratetype);
> else
> - add_to_free_area(page, area, migratetype);
> + add_to_free_list(page, zone, order, migratetype);
> }
>
> /*
> @@ -2001,13 +1999,11 @@ void __init init_cma_reserved_pageblock(struct page *page)
> * -- nyc
> */
> static inline void expand(struct zone *zone, struct page *page,
> - int low, int high, struct free_area *area,
> - int migratetype)
> + int low, int high, int migratetype)
> {
> unsigned long size = 1 << high;
>
> while (high > low) {
> - area--;
> high--;
> size >>= 1;
> VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]);
> @@ -2021,7 +2017,7 @@ static inline void expand(struct zone *zone, struct page *page,
> if (set_page_guard(zone, &page[size], high, migratetype))
> continue;
>
> - add_to_free_area(&page[size], area, migratetype);
> + add_to_free_list(&page[size], zone, high, migratetype);
> set_page_order(&page[size], high);
> }
> }
> @@ -2179,8 +2175,8 @@ struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
> page = get_page_from_free_area(area, migratetype);
> if (!page)
> continue;
> - del_page_from_free_area(page, area);
> - expand(zone, page, order, current_order, area, migratetype);
> + del_page_from_free_list(page, zone, current_order);
> + expand(zone, page, order, current_order, migratetype);
> set_pcppage_migratetype(page, migratetype);
> return page;
> }
> @@ -2188,7 +2184,6 @@ struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
> return NULL;
> }
>
> -
> /*
> * This array describes the order lists are fallen back to when
> * the free lists for the desirable migrate type are depleted
> @@ -2254,7 +2249,7 @@ static int move_freepages(struct zone *zone,
> VM_BUG_ON_PAGE(page_zone(page) != zone, page);
>
> order = page_order(page);
> - move_to_free_area(page, &zone->free_area[order], migratetype);
> + move_to_free_list(page, zone, order, migratetype);
> page += 1 << order;
> pages_moved += 1 << order;
> }
> @@ -2370,7 +2365,6 @@ static void steal_suitable_fallback(struct zone *zone, struct page *page,
> unsigned int alloc_flags, int start_type, bool whole_block)
> {
> unsigned int current_order = page_order(page);
> - struct free_area *area;
> int free_pages, movable_pages, alike_pages;
> int old_block_type;
>
> @@ -2441,8 +2435,7 @@ static void steal_suitable_fallback(struct zone *zone, struct page *page,
> return;
>
> single_page:
> - area = &zone->free_area[current_order];
> - move_to_free_area(page, area, start_type);
> + move_to_free_list(page, zone, current_order, start_type);
> }
>
> /*
> @@ -3113,7 +3106,6 @@ void split_page(struct page *page, unsigned int order)
>
> int __isolate_free_page(struct page *page, unsigned int order)
> {
> - struct free_area *area = &page_zone(page)->free_area[order];
> unsigned long watermark;
> struct zone *zone;
> int mt;
> @@ -3139,7 +3131,7 @@ int __isolate_free_page(struct page *page, unsigned int order)
>
> /* Remove page from free list */
>
> - del_page_from_free_area(page, area);
> + del_page_from_free_list(page, zone, order);
>
> /*
> * Set the pageblock if the isolated page is at least half of a
> @@ -8560,7 +8552,7 @@ void zone_pcp_reset(struct zone *zone)
> pr_info("remove from free list %lx %d %lx\n",
> pfn, 1 << order, end_pfn);
> #endif
> - del_page_from_free_area(page, &zone->free_area[order]);
> + del_page_from_free_list(page, zone, order);
> for (i = 0; i < (1 << order); i++)
> SetPageReserved((page+i));
> pfn += (1 << order);

--
Michal Hocko
SUSE Labs