forked from Minki/linux
83467efbdb
Currently hugepage migration works well only for pmd-based hugepages (mainly due to lack of testing,) so we had better not enable migration of other levels of hugepages until we are ready for it. Some users of hugepage migration (mbind, move_pages, and migrate_pages) do page table walk and check pud/pmd_huge() there, so they are safe. But the other users (softoffline and memory hotremove) don't do this, so without this patch they can try to migrate unexpected types of hugepages. To prevent this, we introduce hugepage_migration_support() as an architecture dependent check of whether hugepage are implemented on a pmd basis or not. And on some architecture multiple sizes of hugepages are available, so hugepage_migration_support() also checks hugepage size. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Rik van Riel <riel@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
96 lines
1.5 KiB
C
96 lines
1.5 KiB
C
/*
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* arch/sh/mm/hugetlbpage.c
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*
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* SuperH HugeTLB page support.
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*
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* Cloned from sparc64 by Paul Mundt.
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*
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* Copyright (C) 2002, 2003 David S. Miller (davem@redhat.com)
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*/
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <linux/pagemap.h>
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#include <linux/sysctl.h>
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#include <asm/mman.h>
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#include <asm/pgalloc.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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#include <asm/cacheflush.h>
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pte_t *huge_pte_alloc(struct mm_struct *mm,
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unsigned long addr, unsigned long sz)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte = NULL;
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pgd = pgd_offset(mm, addr);
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if (pgd) {
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pud = pud_alloc(mm, pgd, addr);
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if (pud) {
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pmd = pmd_alloc(mm, pud, addr);
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if (pmd)
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pte = pte_alloc_map(mm, NULL, pmd, addr);
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}
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}
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return pte;
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}
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pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte = NULL;
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pgd = pgd_offset(mm, addr);
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if (pgd) {
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pud = pud_offset(pgd, addr);
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if (pud) {
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pmd = pmd_offset(pud, addr);
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if (pmd)
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pte = pte_offset_map(pmd, addr);
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}
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}
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return pte;
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}
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int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
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{
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return 0;
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}
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struct page *follow_huge_addr(struct mm_struct *mm,
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unsigned long address, int write)
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{
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return ERR_PTR(-EINVAL);
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}
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int pmd_huge(pmd_t pmd)
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{
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return 0;
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}
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int pud_huge(pud_t pud)
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{
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return 0;
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}
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int pmd_huge_support(void)
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{
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return 0;
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}
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struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
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pmd_t *pmd, int write)
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{
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return NULL;
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}
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