| From e0d85a366c2300efd230ef82a9b22110b0658331 Mon Sep 17 00:00:00 2001 |
| From: Andrea Arcangeli <aarcange@redhat.com> |
| Date: Wed, 2 Nov 2011 13:37:31 -0700 |
| Subject: sparc: gup_pte_range() support THP based tail recounting |
| |
| 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)++; |