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ARM: ZERO_PAGE: Avoid flush_dcache_page() for zero page

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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 <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King
2009-10-25 10:23:04 +00:00
parent b7dc0b2cfc
commit 421fe93cc4
3 changed files with 18 additions and 2 deletions
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11
arch/arm/mm/flush.c
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@@ -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))