From ee392641efd89bd42b2be3f30689fc61b02cb921 Mon Sep 17 00:00:00 2001 From: Andrea Arcangeli <aarcange@redhat.com> Date: Wed, 2 Nov 2011 13:37:31 -0700 Subject: [PATCH] sparc: gup_pte_range() support THP based tail recounting 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> --- arch/sparc/mm/gup.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c index a986b5d057128..afcebac144fb7 100644 --- 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 pmd, unsigned long addr, put_page(head); return 0; } + if (head != page) + get_huge_page_tail(page); pages[*nr] = page; (*nr)++; -- 2.39.5