| Date | Wed, 09 Nov 2011 13:33:52 -0800 | From | Greg KH <> | Subject | [185/264] sparc: gup_pte_range() support THP based tail recounting |
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3.1-stable review patch. If anyone has any objections, please let me know.
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From: Andrea Arcangeli <aarcange@redhat.com>
commit e0d85a366c2300efd230ef82a9b22110b0658331 upstream.
Up to this point the code assumed old refcounting for hugepages (pre-thp). This updates the code directly to the thp mapcount tail page refcounting.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- arch/sparc/mm/gup.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
--- a/arch/sparc/mm/gup.c +++ b/arch/sparc/mm/gup.c @@ -12,6 +12,17 @@ #include <linux/rwsem.h> #include <asm/pgtable.h> +static inline void get_huge_page_tail(struct page *page) +{ + /* + * __split_huge_page_refcount() cannot run + * from under us. + */ + VM_BUG_ON(page_mapcount(page) < 0); + VM_BUG_ON(atomic_read(&page->_count) != 0); + atomic_inc(&page->_mapcount); +} + /* * The performance critical leaf functions are made noinline otherwise gcc * inlines everything into a single function which results in too much @@ -56,6 +67,8 @@ static noinline int gup_pte_range(pmd_t put_page(head); return 0; } + if (head != page) + get_huge_page_tail(page); pages[*nr] = page; (*nr)++;
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