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Commit 13e7444b authored by Nick Piggin's avatar Nick Piggin Committed by Linus Torvalds
Browse files

[PATCH] mm: remove bad_range 



bad_range is supposed to be a temporary check.  It would be a pity to throw it
out.  Make it depend on CONFIG_DEBUG_VM instead.

CONFIG_HOLES_IN_ZONE systems were relying on this to check pfn_valid in the
page allocator.  Add that to page_is_buddy instead.

Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 92be2e33

lib/Kconfig.debug

+2 −1
Original line number Diff line number Diff line
@@ -172,7 +172,8 @@ config DEBUG_VM 
	bool "Debug VM"

	depends on DEBUG_KERNEL

	help

	  Enable this to debug the virtual-memory system.

	  Enable this to turn on extended checks in the virtual-memory system

          that may impact performance.



	  If unsure, say N.

mm/page_alloc.c

+19 −7
Original line number Diff line number Diff line
@@ -81,6 +81,7 @@ int min_free_kbytes = 1024; 
unsigned long __initdata nr_kernel_pages;

unsigned long __initdata nr_all_pages;



#ifdef CONFIG_DEBUG_VM

static int page_outside_zone_boundaries(struct zone *zone, struct page *page)

{

	int ret = 0;
@@ -122,6 +123,13 @@ static int bad_range(struct zone *zone, struct page *page) 
	return 0;

}



#else

static inline int bad_range(struct zone *zone, struct page *page)

{

	return 0;

}

#endif



static void bad_page(const char *function, struct page *page)

{

	printk(KERN_EMERG "Bad page state at %s (in process '%s', page %p)\n",
@@ -255,14 +263,20 @@ __find_combined_index(unsigned long page_idx, unsigned int order) 
/*

 * This function checks whether a page is free && is the buddy

 * we can do coalesce a page and its buddy if

 * (a) the buddy is free &&

 * (b) the buddy is on the buddy system &&

 * (c) a page and its buddy have the same order.

 * (a) the buddy is not in a hole &&

 * (b) the buddy is free &&

 * (c) the buddy is on the buddy system &&

 * (d) a page and its buddy have the same order.

 * for recording page's order, we use page_private(page) and PG_private.

 *

 */

static inline int page_is_buddy(struct page *page, int order)

{

#ifdef CONFIG_HOLES_IN_ZONE

	if (!pfn_valid(page_to_pfn(page)))

		return 0;

#endif



       if (PagePrivate(page)           &&

           (page_order(page) == order) &&

            page_count(page) == 0)
@@ -314,17 +328,15 @@ static inline void __free_pages_bulk (struct page *page, 
		struct free_area *area;

		struct page *buddy;



		combined_idx = __find_combined_index(page_idx, order);

		buddy = __page_find_buddy(page, page_idx, order);



		if (bad_range(zone, buddy))

			break;

		if (!page_is_buddy(buddy, order))

			break;		/* Move the buddy up one level. */



		list_del(&buddy->lru);

		area = zone->free_area + order;

		area->nr_free--;

		rmv_page_order(buddy);

		combined_idx = __find_combined_index(page_idx, order);

		page = page + (combined_idx - page_idx);

		page_idx = combined_idx;

		order++;