diff options
| author | Andrea Arcangeli <aarcange@redhat.com> | 2011-01-13 15:46:32 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-13 17:32:39 -0800 |
| commit | 9180706344487700b40da9eca5dedd3d11cb33b4 (patch) | |
| tree | eb0347efe7e40adc78a271752c7382aa67875d6a /arch/x86/mm/gup.c | |
| parent | e9da73d67729b58bba256123e2b4651e0d8a01ac (diff) | |
thp: alter compound get_page/put_page
Alter compound get_page/put_page to keep references on subpages too, in
order to allow __split_huge_page_refcount to split an hugepage even while
subpages have been pinned by one of the get_user_pages() variants.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86/mm/gup.c')
| -rw-r--r-- | arch/x86/mm/gup.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c index 738e6593799..06f56fcf9a7 100644 --- a/arch/x86/mm/gup.c +++ b/arch/x86/mm/gup.c @@ -105,6 +105,16 @@ static inline void get_head_page_multiple(struct page *page, int nr) atomic_add(nr, &page->_count); } +static inline void get_huge_page_tail(struct page *page) +{ + /* + * __split_huge_page_refcount() cannot run + * from under us. + */ + VM_BUG_ON(atomic_read(&page->_count) < 0); + atomic_inc(&page->_count); +} + static noinline int gup_huge_pmd(pmd_t pmd, unsigned long addr, unsigned long end, int write, struct page **pages, int *nr) { @@ -128,6 +138,8 @@ static noinline int gup_huge_pmd(pmd_t pmd, unsigned long addr, do { VM_BUG_ON(compound_head(page) != head); pages[*nr] = page; + if (PageTail(page)) + get_huge_page_tail(page); (*nr)++; page++; refs++; |