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 <[email protected]> --- include/linux/mm.h | 6 ------ mm/pagewalk.c | 18 +----------------- 2 files changed, 1 insertion(+), 23 deletions(-) diff --git v3.15-rc8-mmots-2014-06-03-16-28.orig/include/linux/mm.h v3.15-rc8-mmots-2014-06-03-16-28/include/linux/mm.h index 563c79ea07bd..b4aa6579f2b1 100644 --- v3.15-rc8-mmots-2014-06-03-16-28.orig/include/linux/mm.h +++ v3.15-rc8-mmots-2014-06-03-16-28/include/linux/mm.h @@ -1092,8 +1092,6 @@ 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 the comment on 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 v3.15-rc8-mmots-2014-06-03-16-28.orig/mm/pagewalk.c v3.15-rc8-mmots-2014-06-03-16-28/mm/pagewalk.c index b2a075ffb96e..15c7585e8684 100644 --- v3.15-rc8-mmots-2014-06-03-16-28.orig/mm/pagewalk.c +++ v3.15-rc8-mmots-2014-06-03-16-28/mm/pagewalk.c @@ -115,14 +115,6 @@ static int walk_pud_range(pgd_t *pgd, unsigned long addr, continue; } - if (walk->pud_entry) { - err = walk->pud_entry(pud, addr, next, walk); - if (skip_lower_level_walking(walk)) - continue; - if (err) - break; - } - if (walk->pmd_entry || walk->pte_entry) { err = walk_pmd_range(pud, addr, next, walk); if (err) @@ -152,15 +144,7 @@ static int walk_pgd_range(unsigned long addr, unsigned long end, continue; } - if (walk->pgd_entry) { - err = walk->pgd_entry(pgd, addr, next, walk); - if (skip_lower_level_walking(walk)) - continue; - if (err) - break; - } - - if (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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
