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![Naoya Horiguchi](/assets/img/avatar_default.png)
When we look into pagemap using page-types with option -p, the value of pfn for hugepages looks wrong (see below.) This is because pte was evaluated only once for one vma although it should be updated for each hugepage. This patch fixes it. $ page-types -p 3277 -Nl -b huge voffset offset len flags 7f21e8a00 11e400 1 ___U___________H_G________________ 7f21e8a01 11e401 1ff ________________TG________________ ^^^ 7f21e8c00 11e400 1 ___U___________H_G________________ 7f21e8c01 11e401 1ff ________________TG________________ ^^^ One hugepage contains 1 head page and 511 tail pages in x86_64 and each two lines represent each hugepage. Voffset and offset mean virtual address and physical address in the page unit, respectively. The different hugepages should not have the same offset value. With this patch applied: $ page-types -p 3386 -Nl -b huge voffset offset len flags 7fec7a600 112c00 1 ___UD__________H_G________________ 7fec7a601 112c01 1ff ________________TG________________ ^^^ 7fec7a800 113200 1 ___UD__________H_G________________ 7fec7a801 113201 1ff ________________TG________________ ^^^ OK More info: - This patch modifies walk_page_range()'s hugepage walker. But the change only affects pagemap_read(), which is the only caller of hugepage callback. - Without this patch, hugetlb_entry() callback is called per vma, that doesn't match the natural expectation from its name. - With this patch, hugetlb_entry() is called per hugepte entry and the callback can become much simpler. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
194 lines
4.7 KiB
C
194 lines
4.7 KiB
C
#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <linux/sched.h>
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#include <linux/hugetlb.h>
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static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
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struct mm_walk *walk)
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{
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pte_t *pte;
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int err = 0;
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pte = pte_offset_map(pmd, addr);
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for (;;) {
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err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, walk);
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if (err)
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break;
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addr += PAGE_SIZE;
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if (addr == end)
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break;
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pte++;
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}
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pte_unmap(pte);
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return err;
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}
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static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
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struct mm_walk *walk)
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{
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pmd_t *pmd;
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unsigned long next;
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int err = 0;
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pmd = pmd_offset(pud, addr);
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do {
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next = pmd_addr_end(addr, end);
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if (pmd_none_or_clear_bad(pmd)) {
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if (walk->pte_hole)
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err = walk->pte_hole(addr, next, walk);
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if (err)
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break;
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continue;
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}
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if (walk->pmd_entry)
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err = walk->pmd_entry(pmd, addr, next, walk);
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if (!err && walk->pte_entry)
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err = walk_pte_range(pmd, addr, next, walk);
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if (err)
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break;
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} while (pmd++, addr = next, addr != end);
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return err;
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}
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static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
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struct mm_walk *walk)
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{
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pud_t *pud;
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unsigned long next;
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int err = 0;
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pud = pud_offset(pgd, addr);
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do {
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next = pud_addr_end(addr, end);
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if (pud_none_or_clear_bad(pud)) {
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if (walk->pte_hole)
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err = walk->pte_hole(addr, next, walk);
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if (err)
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break;
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continue;
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}
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if (walk->pud_entry)
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err = walk->pud_entry(pud, addr, next, walk);
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if (!err && (walk->pmd_entry || walk->pte_entry))
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err = walk_pmd_range(pud, addr, next, walk);
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if (err)
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break;
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} while (pud++, addr = next, addr != end);
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return err;
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}
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#ifdef CONFIG_HUGETLB_PAGE
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static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
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unsigned long end)
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{
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unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h);
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return boundary < end ? boundary : end;
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}
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static int walk_hugetlb_range(struct vm_area_struct *vma,
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unsigned long addr, unsigned long end,
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struct mm_walk *walk)
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{
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struct hstate *h = hstate_vma(vma);
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unsigned long next;
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unsigned long hmask = huge_page_mask(h);
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pte_t *pte;
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int err = 0;
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do {
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next = hugetlb_entry_end(h, addr, end);
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pte = huge_pte_offset(walk->mm, addr & hmask);
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if (pte && walk->hugetlb_entry)
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err = walk->hugetlb_entry(pte, hmask, addr, next, walk);
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if (err)
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return err;
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} while (addr = next, addr != end);
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return 0;
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}
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#endif
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/**
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* walk_page_range - walk a memory map's page tables with a callback
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* @mm: memory map to walk
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* @addr: starting address
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* @end: ending address
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* @walk: set of callbacks to invoke for each level of the tree
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*
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* Recursively walk the page table for the memory area in a VMA,
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* calling supplied callbacks. Callbacks are called in-order (first
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* PGD, first PUD, first PMD, first PTE, second PTE... second PMD,
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* etc.). If lower-level callbacks are omitted, walking depth is reduced.
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*
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* Each callback receives an entry pointer and the start and end of the
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* associated range, and a copy of the original mm_walk for access to
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* the ->private or ->mm fields.
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*
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* No locks are taken, but the bottom level iterator will map PTE
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* directories from highmem if necessary.
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*
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* If any callback returns a non-zero value, the walk is aborted and
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* the return value is propagated back to the caller. Otherwise 0 is returned.
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*/
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int walk_page_range(unsigned long addr, unsigned long end,
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struct mm_walk *walk)
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{
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pgd_t *pgd;
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unsigned long next;
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int err = 0;
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struct vm_area_struct *vma;
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if (addr >= end)
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return err;
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if (!walk->mm)
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return -EINVAL;
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pgd = pgd_offset(walk->mm, addr);
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do {
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next = pgd_addr_end(addr, end);
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/*
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* handle hugetlb vma individually because pagetable walk for
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* the hugetlb page is dependent on the architecture and
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* we can't handled it in the same manner as non-huge pages.
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*/
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vma = find_vma(walk->mm, addr);
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#ifdef CONFIG_HUGETLB_PAGE
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if (vma && is_vm_hugetlb_page(vma)) {
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if (vma->vm_end < next)
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next = vma->vm_end;
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/*
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* Hugepage is very tightly coupled with vma, so
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* walk through hugetlb entries within a given vma.
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*/
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err = walk_hugetlb_range(vma, addr, next, walk);
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if (err)
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break;
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pgd = pgd_offset(walk->mm, next);
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continue;
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}
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#endif
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if (pgd_none_or_clear_bad(pgd)) {
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if (walk->pte_hole)
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err = walk->pte_hole(addr, next, walk);
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if (err)
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break;
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pgd++;
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continue;
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}
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if (walk->pgd_entry)
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err = walk->pgd_entry(pgd, addr, next, walk);
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if (!err &&
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(walk->pud_entry || walk->pmd_entry || walk->pte_entry))
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err = walk_pud_range(pgd, addr, next, walk);
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if (err)
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break;
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pgd++;
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} while (addr = next, addr != end);
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return err;
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}
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