Commit c361be55 authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

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: default avatarMel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: default avatarYasunori Goto <y-goto@jp.fujitsu.com>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: default avatarAndy Whitcroft <andyw@uk.ibm.com>
Cc: Bob Picco <bob.picco@hp.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e2c55dc8
......@@ -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);
......
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