From c361be55b3128474aa66d31092db330b07539103 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Tue, 16 Oct 2007 01:25:51 -0700 Subject: [PATCH] Move free pages between lists on steal When a fallback occurs, there will be free pages for one allocation type stored on the list for another. When a large steal occurs, this patch will move all the free pages within one list to the other. [y-goto@jp.fujitsu.com: fix BUG_ON check at move_freepages()] [apw@shadowen.org: Move to using pfn_valid_within()] Signed-off-by: Mel Gorman Cc: Christoph Lameter Signed-off-by: Yasunori Goto Cc: Bjorn Helgaas Signed-off-by: Andy Whitcroft Cc: Bob Picco Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 71 insertions(+), 3 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index aa7e5d2f28a..d575a3ee8dd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -680,6 +680,72 @@ static int fallbacks[MIGRATE_TYPES][MIGRATE_TYPES-1] = { [MIGRATE_MOVABLE] = { MIGRATE_UNMOVABLE }, }; +/* + * Move the free pages in a range to the free lists of the requested type. + * Note that start_page and end_pages are not aligned in a MAX_ORDER_NR_PAGES + * boundary. If alignment is required, use move_freepages_block() + */ +int move_freepages(struct zone *zone, + struct page *start_page, struct page *end_page, + int migratetype) +{ + struct page *page; + unsigned long order; + int blocks_moved = 0; + +#ifndef CONFIG_HOLES_IN_ZONE + /* + * page_zone is not safe to call in this context when + * CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant + * anyway as we check zone boundaries in move_freepages_block(). + * Remove at a later date when no bug reports exist related to + * CONFIG_PAGE_GROUP_BY_MOBILITY + */ + BUG_ON(page_zone(start_page) != page_zone(end_page)); +#endif + + for (page = start_page; page <= end_page;) { + if (!pfn_valid_within(page_to_pfn(page))) { + page++; + continue; + } + + if (!PageBuddy(page)) { + page++; + continue; + } + + order = page_order(page); + list_del(&page->lru); + list_add(&page->lru, + &zone->free_area[order].free_list[migratetype]); + page += 1 << order; + blocks_moved++; + } + + return blocks_moved; +} + +int move_freepages_block(struct zone *zone, struct page *page, int migratetype) +{ + unsigned long start_pfn, end_pfn; + struct page *start_page, *end_page; + + start_pfn = page_to_pfn(page); + start_pfn = start_pfn & ~(MAX_ORDER_NR_PAGES-1); + start_page = pfn_to_page(start_pfn); + end_page = start_page + MAX_ORDER_NR_PAGES - 1; + end_pfn = start_pfn + MAX_ORDER_NR_PAGES - 1; + + /* Do not cross zone boundaries */ + if (start_pfn < zone->zone_start_pfn) + start_page = page; + if (end_pfn >= zone->zone_start_pfn + zone->spanned_pages) + return 0; + + return move_freepages(zone, start_page, end_page, migratetype); +} + /* Remove an element from the buddy allocator from the fallback list */ static struct page *__rmqueue_fallback(struct zone *zone, int order, int start_migratetype) @@ -704,11 +770,13 @@ static struct page *__rmqueue_fallback(struct zone *zone, int order, area->nr_free--; /* - * If breaking a large block of pages, place the buddies - * on the preferred allocation list + * If breaking a large block of pages, move all free + * pages to the preferred allocation list */ - if (unlikely(current_order >= MAX_ORDER / 2)) + if (unlikely(current_order >= MAX_ORDER / 2)) { migratetype = start_migratetype; + move_freepages_block(zone, page, migratetype); + } /* Remove the page from the freelists */ list_del(&page->lru); -- 2.11.4.GIT