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authorLinus Torvalds <torvalds@woody.linux-foundation.org>2007-11-12 14:14:44 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-11-12 14:14:44 -0800
commit44048d700bcbfaf4bcca6e2e0a73d89d01ec0878 (patch)
tree975427ee367023b6e3a254519d5e5fdced2c0969
parente6a5c27f3b0fef72e528fc35e343af4b2db790ff (diff)
Revert "Bias the placement of kernel pages at lower PFNs"
This reverts commit 5adc5be7cd1bcef6bb64f5255d2a33f20a3cf5be. Alexey Dobriyan reports that it causes huge slowdowns under some loads, in his case a "mkfs.ext2" on a 30G partition. With the placement bias, the mkfs took over four minutes, with it reverted it's back to about ten seconds for Alexey. Reported-and-tested-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/page_alloc.c20
1 files changed, 0 insertions, 20 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index da69d833e06..12376ae3f73 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -749,23 +749,6 @@ int move_freepages_block(struct zone *zone, struct page *page, int migratetype)
return move_freepages(zone, start_page, end_page, migratetype);
}
-/* Return the page with the lowest PFN in the list */
-static struct page *min_page(struct list_head *list)
-{
- unsigned long min_pfn = -1UL;
- struct page *min_page = NULL, *page;;
-
- list_for_each_entry(page, list, lru) {
- unsigned long pfn = page_to_pfn(page);
- if (pfn < min_pfn) {
- min_pfn = pfn;
- min_page = page;
- }
- }
-
- return min_page;
-}
-
/* Remove an element from the buddy allocator from the fallback list */
static struct page *__rmqueue_fallback(struct zone *zone, int order,
int start_migratetype)
@@ -789,11 +772,8 @@ static struct page *__rmqueue_fallback(struct zone *zone, int order,
if (list_empty(&area->free_list[migratetype]))
continue;
- /* Bias kernel allocations towards low pfns */
page = list_entry(area->free_list[migratetype].next,
struct page, lru);
- if (unlikely(start_migratetype != MIGRATE_MOVABLE))
- page = min_page(&area->free_list[migratetype]);
area->nr_free--;
/*