Commit c0ba10b5 authored Nov 21, 2010 by Russell King

ARM: improve compiler's ability to optimize page tables



Allow the compiler to better optimize the page table walking code
by avoiding over-complex pmd_addr_end() calculations.  These
calculations prevent the compiler spotting that we'll never iterate
over the PMD table, causing it to create double nested loops where
a single loop will do.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

parent 589136bf

arch/arm/include/asm/pgtable.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -374,6 +374,9 @@ static inline pte_t *pmd_page_vaddr(pmd_t pmd)

		#define pmd_page(pmd) pfn_to_page(__phys_to_pfn(pmd_val(pmd)))

		/* we don't need complex calculations here as the pmd is folded into the pgd */
		#define pmd_addr_end(addr,end) (end)

		/*
		* Conversion functions: convert a page and protection to a page entry,
		* and a page entry and page directory to the page they refer to.