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authorRussell King <rmk+kernel@arm.linux.org.uk>2010-11-21 14:42:47 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2010-11-21 14:42:47 +0000
commitc0ba10b512eb2e2a3888b6e6cc0e089f5e7a191b (patch)
treea5e2ebdb4147df5653ce481a78465d28aa5b15c2
parent589136bfa784a4558b397f017ca2f06f0ca9080e (diff)
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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>
-rw-r--r--arch/arm/include/asm/pgtable.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm/include/asm/pgtable.h b/arch/arm/include/asm/pgtable.h
index b155414192d..53d1d5deb11 100644
--- a/arch/arm/include/asm/pgtable.h
+++ b/arch/arm/include/asm/pgtable.h
@@ -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.