From 5dc37642cbce34619e4588a9f0bdad1d2f870956 Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Mon, 14 Dec 2009 18:00:01 -0800 Subject: [PATCH] mm hugetlb: add hugepage support to pagemap This patch enables extraction of the pfn of a hugepage from /proc/pid/pagemap in an architecture independent manner. Details ------- My test program (leak_pagemap) works as follows: - creat() and mmap() a file on hugetlbfs (file size is 200MB == 100 hugepages,) - read()/write() something on it, - call page-types with option -p, - munmap() and unlink() the file on hugetlbfs Without my patches ------------------ $ ./leak_pagemap flags page-count MB symbolic-flags long-symbolic-flags 0x0000000000000000 1 0 __________________________________ 0x0000000000000804 1 0 __R________M______________________ referenced,mmap 0x000000000000086c 81 0 __RU_lA____M______________________ referenced,uptodate,lru,active,mmap 0x0000000000005808 5 0 ___U_______Ma_b___________________ uptodate,mmap,anonymous,swapbacked 0x0000000000005868 12 0 ___U_lA____Ma_b___________________ uptodate,lru,active,mmap,anonymous,swapbacked 0x000000000000586c 1 0 __RU_lA____Ma_b___________________ referenced,uptodate,lru,active,mmap,anonymous,swapbacked total 101 0 The output of page-types don't show any hugepage. With my patches --------------- $ ./leak_pagemap flags page-count MB symbolic-flags long-symbolic-flags 0x0000000000000000 1 0 __________________________________ 0x0000000000030000 51100 199 ________________TG________________ compound_tail,huge 0x0000000000028018 100 0 ___UD__________H_G________________ uptodate,dirty,compound_head,huge 0x0000000000000804 1 0 __R________M______________________ referenced,mmap 0x000000000000080c 1 0 __RU_______M______________________ referenced,uptodate,mmap 0x000000000000086c 80 0 __RU_lA____M______________________ referenced,uptodate,lru,active,mmap 0x0000000000005808 4 0 ___U_______Ma_b___________________ uptodate,mmap,anonymous,swapbacked 0x0000000000005868 12 0 ___U_lA____Ma_b___________________ uptodate,lru,active,mmap,anonymous,swapbacked 0x000000000000586c 1 0 __RU_lA____Ma_b___________________ referenced,uptodate,lru,active,mmap,anonymous,swapbacked total 51300 200 The output of page-types shows 51200 pages contributing to hugepages, containing 100 head pages and 51100 tail pages as expected. [akpm@linux-foundation.org: build fix] Signed-off-by: Naoya Horiguchi Cc: Andi Kleen Cc: Wu Fengguang Cc: Hugh Dickins Cc: Mel Gorman Cc: Lee Schermerhorn Cc: Andy Whitcroft Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/task_mmu.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/mm.h | 3 +++ mm/pagewalk.c | 22 +++++++++++++++++++--- 3 files changed, 67 insertions(+), 3 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 2a1bef9203c6..47c03f4336b8 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -650,6 +650,50 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, return err; } +static u64 huge_pte_to_pagemap_entry(pte_t pte, int offset) +{ + u64 pme = 0; + if (pte_present(pte)) + pme = PM_PFRAME(pte_pfn(pte) + offset) + | PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT; + return pme; +} + +static int pagemap_hugetlb_range(pte_t *pte, unsigned long addr, + unsigned long end, struct mm_walk *walk) +{ + struct vm_area_struct *vma; + struct pagemapread *pm = walk->private; + struct hstate *hs = NULL; + int err = 0; + + vma = find_vma(walk->mm, addr); + if (vma) + hs = hstate_vma(vma); + for (; addr != end; addr += PAGE_SIZE) { + u64 pfn = PM_NOT_PRESENT; + + if (vma && (addr >= vma->vm_end)) { + vma = find_vma(walk->mm, addr); + if (vma) + hs = hstate_vma(vma); + } + + if (vma && (vma->vm_start <= addr) && is_vm_hugetlb_page(vma)) { + /* calculate pfn of the "raw" page in the hugepage. */ + int offset = (addr & ~huge_page_mask(hs)) >> PAGE_SHIFT; + pfn = huge_pte_to_pagemap_entry(*pte, offset); + } + err = add_to_pagemap(addr, pfn, pm); + if (err) + return err; + } + + cond_resched(); + + return err; +} + /* * /proc/pid/pagemap - an array mapping virtual pages to pfns * @@ -742,6 +786,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf, pagemap_walk.pmd_entry = pagemap_pte_range; pagemap_walk.pte_hole = pagemap_pte_hole; + pagemap_walk.hugetlb_entry = pagemap_hugetlb_range; pagemap_walk.mm = mm; pagemap_walk.private = ± diff --git a/include/linux/mm.h b/include/linux/mm.h index 52b264563cd9..9d65ae4ba0e0 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -770,6 +770,7 @@ unsigned long unmap_vmas(struct mmu_gather **tlb, * @pmd_entry: if set, called for each non-empty PMD (3rd-level) entry * @pte_entry: if set, called for each non-empty PTE (4th-level) entry * @pte_hole: if set, called for each hole at all levels + * @hugetlb_entry: if set, called for each hugetlb entry * * (see walk_page_range for more details) */ @@ -779,6 +780,8 @@ struct mm_walk { int (*pmd_entry)(pmd_t *, unsigned long, unsigned long, struct mm_walk *); int (*pte_entry)(pte_t *, unsigned long, unsigned long, struct mm_walk *); int (*pte_hole)(unsigned long, unsigned long, struct mm_walk *); + int (*hugetlb_entry)(pte_t *, unsigned long, unsigned long, + struct mm_walk *); struct mm_struct *mm; void *private; }; diff --git a/mm/pagewalk.c b/mm/pagewalk.c index a286915e23ef..7b47a57b6646 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -120,15 +120,31 @@ int walk_page_range(unsigned long addr, unsigned long end, do { next = pgd_addr_end(addr, end); - /* skip hugetlb vma to avoid hugepage PMD being cleared - * in pmd_none_or_clear_bad(). */ + /* + * handle hugetlb vma individually because pagetable walk for + * the hugetlb page is dependent on the architecture and + * we can't handled it in the same manner as non-huge pages. + */ vma = find_vma(walk->mm, addr); +#ifdef CONFIG_HUGETLB_PAGE if (vma && is_vm_hugetlb_page(vma)) { + pte_t *pte; + struct hstate *hs; + if (vma->vm_end < next) next = vma->vm_end; + hs = hstate_vma(vma); + pte = huge_pte_offset(walk->mm, + addr & huge_page_mask(hs)); + if (pte && !huge_pte_none(huge_ptep_get(pte)) + && walk->hugetlb_entry) + err = walk->hugetlb_entry(pte, addr, + next, walk); + if (err) + break; continue; } - +#endif if (pgd_none_or_clear_bad(pgd)) { if (walk->pte_hole) err = walk->pte_hole(addr, next, walk); -- 2.30.2