From 421fe93cc4b06b2f5e875cbe0f692800d4862ee5 Mon Sep 17 00:00:00 2001 From: Russell King Date: Sun, 25 Oct 2009 10:23:04 +0000 Subject: ARM: ZERO_PAGE: Avoid flush_dcache_page() for zero page The zero page is read-only, and has its cache state cleared during boot. No further maintanence for this page is required. Signed-off-by: Russell King --- arch/arm/mm/flush.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'arch/arm/mm/flush.c') diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c index 43474d8752a6..82f4b06bf6b4 100644 --- a/arch/arm/mm/flush.c +++ b/arch/arm/mm/flush.c @@ -189,7 +189,16 @@ static void __flush_dcache_aliases(struct address_space *mapping, struct page *p */ void flush_dcache_page(struct page *page) { - struct address_space *mapping = page_mapping(page); + struct address_space *mapping; + + /* + * The zero page is never written to, so never has any dirty + * cache lines, and therefore never needs to be flushed. + */ + if (page == ZERO_PAGE(0)) + return; + + mapping = page_mapping(page); #ifndef CONFIG_SMP if (!PageHighMem(page) && mapping && !mapping_mapped(mapping)) -- cgit v1.2.3-59-g8ed1b