From: Huan Yang link@vivo.com
mainline inclusion from mainline-v6.12-rc1 commit 94deaf69dcd33462c61fa8cabb0883e3085a1046 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IBC4T0
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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When page del from buddy and need expand, it will account free_pages in zone's migratetype.
The current way is to subtract the page number of the current order when deleting, and then add it back when expanding.
This is unnecessary, as when migrating the same type, we can directly record the difference between the high-order pages and the expand added, and then subtract it directly.
This patch merge that, only when del and expand done, then account free_pages.
Link: https://lkml.kernel.org/r/20240826064048.187790-1-link@vivo.com Signed-off-by: Huan Yang link@vivo.com Reviewed-by: Vlastimil Babka vbabka@suse.cz Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Liu Shixin liushixin2@huawei.com --- mm/page_alloc.c | 35 +++++++++++++++++++++++++---------- 1 file changed, 25 insertions(+), 10 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index e786cdd98bea..7734245d7870 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1327,11 +1327,11 @@ struct page *__pageblock_pfn_to_page(unsigned long start_pfn, * * -- nyc */ -static inline void expand(struct zone *zone, struct page *page, - int low, int high, int migratetype) +static inline unsigned int expand(struct zone *zone, struct page *page, int low, + int high, int migratetype) { - unsigned long size = 1 << high; - unsigned long nr_added = 0; + unsigned int size = 1 << high; + unsigned int nr_added = 0;
while (high > low) { high--; @@ -1351,7 +1351,19 @@ static inline void expand(struct zone *zone, struct page *page, set_buddy_order(&page[size], high); nr_added += size; } - account_freepages(zone, nr_added, migratetype); + + return nr_added; +} + +static __always_inline void page_del_and_expand(struct zone *zone, + struct page *page, int low, + int high, int migratetype) +{ + int nr_pages = 1 << high; + + __del_page_from_free_list(page, zone, high, migratetype); + nr_pages -= expand(zone, page, low, high, migratetype); + account_freepages(zone, -nr_pages, migratetype); }
static void check_new_page_bad(struct page *page) @@ -1540,8 +1552,9 @@ 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_list(page, zone, current_order, migratetype); - expand(zone, page, order, current_order, migratetype); + + page_del_and_expand(zone, page, order, current_order, + migratetype); trace_mm_page_alloc_zone_locked(page, order, migratetype, pcp_allowed_order(order) && migratetype < MIGRATE_PCPTYPES); @@ -1892,9 +1905,12 @@ steal_suitable_fallback(struct zone *zone, struct page *page,
/* Take ownership for orders >= pageblock_order */ if (current_order >= pageblock_order) { + unsigned int nr_added; + del_page_from_free_list(page, zone, current_order, block_type); change_pageblock_range(page, current_order, start_type); - expand(zone, page, order, current_order, start_type); + nr_added = expand(zone, page, order, current_order, start_type); + account_freepages(zone, nr_added, start_type); return page; }
@@ -1947,8 +1963,7 @@ steal_suitable_fallback(struct zone *zone, struct page *page, }
single_page: - del_page_from_free_list(page, zone, current_order, block_type); - expand(zone, page, order, current_order, block_type); + page_del_and_expand(zone, page, order, current_order, block_type); return page; }