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Subject[PATCH v4 01/13] mm/pagewalk: remove pgd_entry() and pud_entry()
Date
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: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
include/linux/mm.h | 6 ------
mm/pagewalk.c | 9 ++-------
2 files changed, 2 insertions(+), 13 deletions(-)

diff --git v3.16-rc3.orig/include/linux/mm.h v3.16-rc3/include/linux/mm.h
index e03dd29145a0..c5cb6394e6cb 100644
--- v3.16-rc3.orig/include/linux/mm.h
+++ v3.16-rc3/include/linux/mm.h
@@ -1100,8 +1100,6 @@ 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
@@ -1115,10 +1113,6 @@ 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,
diff --git v3.16-rc3.orig/mm/pagewalk.c v3.16-rc3/mm/pagewalk.c
index 2beeabf502c5..335690650b12 100644
--- v3.16-rc3.orig/mm/pagewalk.c
+++ v3.16-rc3/mm/pagewalk.c
@@ -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;
@@ -234,10 +232,7 @@ 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;
--
1.9.3


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