Messages in this thread Patch in this message | | | Date | Wed, 08 Sep 2004 20:51:46 +0900 | From | Hiroyuki KAMEZAWA <> | Subject | [RFC][PATCH] no bitmap buddy allocator : modifies expand() (2/4) |
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This is part (2/4) and modifies expand().
This patch removes bitmap operation from alloc_pages().
Instead of using MARK_USED() bitmap operation, this patch records page's order in page struct itself, page->private field.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
---
test-kernel-kamezawa/mm/page_alloc.c | 17 +++++++---------- 1 files changed, 7 insertions(+), 10 deletions(-)
diff -puN mm/page_alloc.c~eliminate-bitmap-alloc mm/page_alloc.c --- test-kernel/mm/page_alloc.c~eliminate-bitmap-alloc 2004-09-08 18:48:40.667294640 +0900 +++ test-kernel-kamezawa/mm/page_alloc.c 2004-09-08 19:04:05.398714096 +0900 @@ -296,9 +296,6 @@ void __free_pages_ok(struct page *page, free_pages_bulk(page_zone(page), 1, &list, order); }
-#define MARK_USED(index, order, area) \ - __change_bit((index) >> (1+(order)), (area)->map) - /* * The order of subdivision here is critical for the IO subsystem. * Please do not alter this order without good reasons and regression @@ -315,7 +312,7 @@ void __free_pages_ok(struct page *page, */ static inline struct page * expand(struct zone *zone, struct page *page, - unsigned long index, int low, int high, struct free_area *area) + int low, int high, struct free_area *area) { unsigned long size = 1 << high;
@@ -325,7 +322,9 @@ expand(struct zone *zone, struct page *p size >>= 1; BUG_ON(bad_range(zone, &page[size])); list_add(&page[size].lru, &area->free_list); - MARK_USED(index + size, high, area); + /* Note: already have lock, we don't need to use atomic ops */ + set_page_order(&page[size], high); + SetPagePrivate(&page[size]); } return page; } @@ -379,7 +378,6 @@ static struct page *__rmqueue(struct zon struct free_area * area; unsigned int current_order; struct page *page; - unsigned int index;
for (current_order = order; current_order < MAX_ORDER; ++current_order) { area = zone->free_area + current_order; @@ -388,11 +386,10 @@ static struct page *__rmqueue(struct zon
page = list_entry(area->free_list.next, struct page, lru); list_del(&page->lru); - index = page - zone->zone_mem_map; - if (current_order != MAX_ORDER-1) - MARK_USED(index, current_order, area); + /* Note: already have lock, we don't need to use atomic ops */ + ClearPagePrivate(page); zone->free_pages -= 1UL << order; - return expand(zone, page, index, order, current_order, area); + return expand(zone, page, order, current_order, area); }
return NULL; _
--
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