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authorAndrea Arcangeli <aarcange@redhat.com>2011-01-13 15:46:32 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-13 17:32:39 -0800
commit9180706344487700b40da9eca5dedd3d11cb33b4 (patch)
treeeb0347efe7e40adc78a271752c7382aa67875d6a /arch/powerpc/mm
parente9da73d67729b58bba256123e2b4651e0d8a01ac (diff)
downloadlinaro-lsk-9180706344487700b40da9eca5dedd3d11cb33b4.tar.gz
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/powerpc/mm')
-rw-r--r--arch/powerpc/mm/gup.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/arch/powerpc/mm/gup.c b/arch/powerpc/mm/gup.c
index d7efdbf640c..fec13200868 100644
--- a/arch/powerpc/mm/gup.c
+++ b/arch/powerpc/mm/gup.c
@@ -16,6 +16,16 @@
#ifdef __HAVE_ARCH_PTE_SPECIAL
+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);
+}
+
/*
* The performance critical leaf functions are made noinline otherwise gcc
* inlines everything into a single function which results in too much
@@ -47,6 +57,8 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr,
put_page(page);
return 0;
}
+ if (PageTail(page))
+ get_huge_page_tail(page);
pages[*nr] = page;
(*nr)++;