From 0e5c9f39f64d8a55c5db37a5ea43e37d3422fd92 Mon Sep 17 00:00:00 2001 From: "Chen, Kenneth W" Date: Sat, 3 Sep 2005 15:55:02 -0700 Subject: [PATCH] [PATCH] remove hugetlb_clean_stale_pgtable() and fix huge_pte_alloc() I don't think we need to call hugetlb_clean_stale_pgtable() anymore in 2.6.13 because of the rework with free_pgtables(). It now collect all the pte page at the time of munmap. It used to only collect page table pages when entire one pgd can be freed and left with staled pte pages. Not anymore with 2.6.13. This function will never be called and We should turn it into a BUG_ON. I also spotted two problems here, not Adam's fault :-) (1) in huge_pte_alloc(), it looks like a bug to me that pud is not checked before calling pmd_alloc() (2) in hugetlb_clean_stale_pgtable(), it also missed a call to pmd_free_tlb. I think a tlb flush is required to flush the mapping for the page table itself when we clear out the pmd pointing to a pte page. However, since hugetlb_clean_stale_pgtable() is never called, so it won't trigger the bug. Signed-off-by: Ken Chen Cc: Adam Litke Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/mm/hugetlbpage.c | 23 +++-------------------- include/asm-i386/page.h | 1 - include/asm-x86_64/page.h | 1 - include/linux/hugetlb.h | 6 ------ 4 files changed, 3 insertions(+), 28 deletions(-) diff --git a/arch/i386/mm/hugetlbpage.c b/arch/i386/mm/hugetlbpage.c index 24c8a536b588..d524127c9afc 100644 --- a/arch/i386/mm/hugetlbpage.c +++ b/arch/i386/mm/hugetlbpage.c @@ -22,20 +22,14 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr) { pgd_t *pgd; pud_t *pud; - pmd_t *pmd; pte_t *pte = NULL; pgd = pgd_offset(mm, addr); pud = pud_alloc(mm, pgd, addr); - pmd = pmd_alloc(mm, pud, addr); + if (pud) + pte = (pte_t *) pmd_alloc(mm, pud, addr); + BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte)); - if (!pmd) - goto out; - - pte = (pte_t *) pmd; - if (!pte_none(*pte) && !pte_huge(*pte)) - hugetlb_clean_stale_pgtable(pte); -out: return pte; } @@ -130,17 +124,6 @@ follow_huge_pmd(struct mm_struct *mm, unsigned long address, } #endif -void hugetlb_clean_stale_pgtable(pte_t *pte) -{ - pmd_t *pmd = (pmd_t *) pte; - struct page *page; - - page = pmd_page(*pmd); - pmd_clear(pmd); - dec_page_state(nr_page_table_pages); - page_cache_release(page); -} - /* x86_64 also uses this file */ #ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA diff --git a/include/asm-i386/page.h b/include/asm-i386/page.h index 10045fd82103..73296d9924fb 100644 --- a/include/asm-i386/page.h +++ b/include/asm-i386/page.h @@ -68,7 +68,6 @@ typedef struct { unsigned long pgprot; } pgprot_t; #define HPAGE_MASK (~(HPAGE_SIZE - 1)) #define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT) #define HAVE_ARCH_HUGETLB_UNMAPPED_AREA -#define ARCH_HAS_HUGETLB_CLEAN_STALE_PGTABLE #endif #define pgd_val(x) ((x).pgd) diff --git a/include/asm-x86_64/page.h b/include/asm-x86_64/page.h index fcf890aa8c81..135ffaa0393b 100644 --- a/include/asm-x86_64/page.h +++ b/include/asm-x86_64/page.h @@ -28,7 +28,6 @@ #define HPAGE_SIZE ((1UL) << HPAGE_SHIFT) #define HPAGE_MASK (~(HPAGE_SIZE - 1)) #define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT) -#define ARCH_HAS_HUGETLB_CLEAN_STALE_PGTABLE #ifdef __KERNEL__ #ifndef __ASSEMBLY__ diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index f529d1442815..e670b0d13fe0 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -70,12 +70,6 @@ pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, void hugetlb_prefault_arch_hook(struct mm_struct *mm); #endif -#ifndef ARCH_HAS_HUGETLB_CLEAN_STALE_PGTABLE -#define hugetlb_clean_stale_pgtable(pte) BUG() -#else -void hugetlb_clean_stale_pgtable(pte_t *pte); -#endif - #else /* !CONFIG_HUGETLB_PAGE */ static inline int is_vm_hugetlb_page(struct vm_area_struct *vma) -- GitLab