x86: make mm/gup.c more virtualization friendly

Since pte_flags() is much cheaper than pte_val() in some virtualized
environments (namely, Xen), use the former whereever possible.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: "Nick Piggin" <npiggin@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c
index 007bb06..4ba373c 100644 (file)
--- a/arch/x86/mm/gup.c
+++ b/arch/x86/mm/gup.c
@@ -82,7 +82,7 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr,
                pte_t pte = gup_get_pte(ptep);
                struct page *page;
 
-               if ((pte_val(pte) & (mask | _PAGE_SPECIAL)) != mask) {
+               if ((pte_flags(pte) & (mask | _PAGE_SPECIAL)) != mask) {
                        pte_unmap(ptep);
                        return 0;
                }
@@ -116,10 +116,10 @@ static noinline int gup_huge_pmd(pmd_t pmd, unsigned long addr,
        mask = _PAGE_PRESENT|_PAGE_USER;
        if (write)
                mask |= _PAGE_RW;
-       if ((pte_val(pte) & mask) != mask)
+       if ((pte_flags(pte) & mask) != mask)
                return 0;
        /* hugepages are never "special" */
-       VM_BUG_ON(pte_val(pte) & _PAGE_SPECIAL);
+       VM_BUG_ON(pte_flags(pte) & _PAGE_SPECIAL);
        VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
 
        refs = 0;
@@ -173,10 +173,10 @@ static noinline int gup_huge_pud(pud_t pud, unsigned long addr,
        mask = _PAGE_PRESENT|_PAGE_USER;
        if (write)
                mask |= _PAGE_RW;
-       if ((pte_val(pte) & mask) != mask)
+       if ((pte_flags(pte) & mask) != mask)
                return 0;
        /* hugepages are never "special" */
-       VM_BUG_ON(pte_val(pte) & _PAGE_SPECIAL);
+       VM_BUG_ON(pte_flags(pte) & _PAGE_SPECIAL);
        VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
 
        refs = 0;

diff --git a/include/asm-x86/pgtable.h b/include/asm-x86/pgtable.h
index 8180540..182f9d4 100644 (file)
--- a/include/asm-x86/pgtable.h
+++ b/include/asm-x86/pgtable.h
@@ -206,7 +206,7 @@ static inline int pte_exec(pte_t pte)
 
 static inline int pte_special(pte_t pte)
 {
-       return pte_val(pte) & _PAGE_SPECIAL;
+       return pte_flags(pte) & _PAGE_SPECIAL;
 }
 
 static inline unsigned long pte_pfn(pte_t pte)