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| author | Thomas Hellstrom (VMware) <thomas_os@shipmail.org> | 2020-03-24 20:47:17 +0300 |
|---|---|---|
| committer | Thomas Hellstrom (VMware) <thomas_os@shipmail.org> | 2020-03-24 20:47:17 +0300 |
| commit | 2484ca9b6a20451debb789d0a89af6f15de99826 (patch) | |
| tree | 29ba1199f39289ebeabc17631e4ef3bf2e1e0c98 /include/linux/mm.h | |
| parent | f05a3849f6449f67843113778bf56e02f2b4ddf8 (diff) | |
| download | linux-2484ca9b6a20451debb789d0a89af6f15de99826.tar.xz | |
mm: Introduce vma_is_special_huge
For VM_PFNMAP and VM_MIXEDMAP vmas that want to support transhuge pages
and -page table entries, introduce vma_is_special_huge() that takes the
same codepaths as vma_is_dax().
The use of "special" follows the definition in memory.c, vm_normal_page():
"Special" mappings do not wish to be associated with a "struct page"
(either it doesn't exist, or it exists but they don't want to touch it)
For PAGE_SIZE pages, "special" is determined per page table entry to be
able to deal with COW pages. But since we don't have huge COW pages,
we can classify a vma as either "special huge" or "normal huge".
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Thomas Hellstrom (VMware) <thomas_os@shipmail.org>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/mm.h')
| -rw-r--r-- | include/linux/mm.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index c54fb96cb1e6..bdd79a72bb42 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2867,6 +2867,23 @@ extern long copy_huge_page_from_user(struct page *dst_page, const void __user *usr_src, unsigned int pages_per_huge_page, bool allow_pagefault); + +/** + * vma_is_special_huge - Are transhuge page-table entries considered special? + * @vma: Pointer to the struct vm_area_struct to consider + * + * Whether transhuge page-table entries are considered "special" following + * the definition in vm_normal_page(). + * + * Return: true if transhuge page-table entries should be considered special, + * false otherwise. + */ +static inline bool vma_is_special_huge(const struct vm_area_struct *vma) +{ + return vma_is_dax(vma) || (vma->vm_file && + (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))); +} + #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ #ifdef CONFIG_DEBUG_PAGEALLOC |