Commit 2ace5a67 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

mm: make is_free_buddy_page() take a const argument 

This function does not modify its argument; let the callers know that so
they can make better optimisation decisions.

Link: https://lkml.kernel.org/r/20240326171045.410737-6-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent e3089fd0

include/linux/page-flags.h

+1 −1
Original line number Diff line number Diff line
@@ -1088,7 +1088,7 @@ static inline bool is_page_hwpoison(const struct page *page) 
	return folio_test_hugetlb(folio) && PageHWPoison(&folio->page);

}



extern bool is_free_buddy_page(struct page *page);

bool is_free_buddy_page(const struct page *page);



PAGEFLAG(Isolated, isolated, PF_ANY);

mm/page_alloc.c

+4 −4
Original line number Diff line number Diff line
@@ -6745,16 +6745,16 @@ void __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) 
/*

 * This function returns a stable result only if called under zone lock.

 */

bool is_free_buddy_page(struct page *page)

bool is_free_buddy_page(const struct page *page)

{

	unsigned long pfn = page_to_pfn(page);

	unsigned int order;



	for (order = 0; order < NR_PAGE_ORDERS; order++) {

		struct page *page_head = page - (pfn & ((1 << order) - 1));

		const struct page *head = page - (pfn & ((1 << order) - 1));



		if (PageBuddy(page_head) &&

		    buddy_order_unsafe(page_head) >= order)

		if (PageBuddy(head) &&

		    buddy_order_unsafe(head) >= order)

			break;

	}