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Commit 606ee44d authored by Jan Beulich's avatar Jan Beulich Committed by Ingo Molnar
Browse files

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: default avatarJan Beulich <jbeulich@novell.com>
Cc: "Nick Piggin" <npiggin@suse.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 5e72d9e4

arch/x86/mm/gup.c

+5 −5
Original line number Diff line number Diff line
@@ -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;

include/asm-x86/pgtable.h

+1 −1
Original line number Diff line number Diff line
@@ -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)