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Commit 0b1fbfe5 authored by Naoya Horiguchi's avatar Naoya Horiguchi Committed by Linus Torvalds
Browse files

mm/pagewalk: remove pgd_entry() and pud_entry() 



Currently no user of page table walker sets ->pgd_entry() or
->pud_entry(), so checking their existence in each loop is just wasting
CPU cycle.  So let's remove it to reduce overhead.

Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 05fbf357

include/linux/mm.h

+0 −6
Original line number Diff line number Diff line
@@ -1164,8 +1164,6 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma, 


/**

 * mm_walk - callbacks for walk_page_range

 * @pgd_entry: if set, called for each non-empty PGD (top-level) entry

 * @pud_entry: if set, called for each non-empty PUD (2nd-level) entry

 * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry

 *	       this handler is required to be able to handle

 *	       pmd_trans_huge() pmds.  They may simply choose to
@@ -1179,10 +1177,6 @@ void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *start_vma, 
 * (see walk_page_range for more details)

 */

struct mm_walk {

	int (*pgd_entry)(pgd_t *pgd, unsigned long addr,

			 unsigned long next, struct mm_walk *walk);

	int (*pud_entry)(pud_t *pud, unsigned long addr,

	                 unsigned long next, struct mm_walk *walk);

	int (*pmd_entry)(pmd_t *pmd, unsigned long addr,

			 unsigned long next, struct mm_walk *walk);

	int (*pte_entry)(pte_t *pte, unsigned long addr,

mm/pagewalk.c

+2 −7
Original line number Diff line number Diff line
@@ -86,9 +86,7 @@ static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end, 
				break;

			continue;

		}

		if (walk->pud_entry)

			err = walk->pud_entry(pud, addr, next, walk);

		if (!err && (walk->pmd_entry || walk->pte_entry))

		if (walk->pmd_entry || walk->pte_entry)

			err = walk_pmd_range(pud, addr, next, walk);

		if (err)

			break;
@@ -237,10 +235,7 @@ int walk_page_range(unsigned long addr, unsigned long end, 
			pgd++;

			continue;

		}

		if (walk->pgd_entry)

			err = walk->pgd_entry(pgd, addr, next, walk);

		if (!err &&

		    (walk->pud_entry || walk->pmd_entry || walk->pte_entry))

		if (walk->pmd_entry || walk->pte_entry)

			err = walk_pud_range(pgd, addr, next, walk);

		if (err)

			break;