powerpc: gup_hugepte() avoid freeing the head page too many times
Andrea Arcangeli [Wed, 2 Nov 2011 20:37:11 +0000 (13:37 -0700)]
commit 8596468487e2062cae2aad56e973784e03959245 upstream.

We only taken "refs" pins on the head page not "*nr" pins.

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>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
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/powerpc/mm/hugetlbpage.c

index b649c28..78b14ab 100644 (file)
@@ -428,10 +428,9 @@ static noinline int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long add
 
        if (unlikely(pte_val(pte) != pte_val(*ptep))) {
                /* Could be optimized better */
-               while (*nr) {
+               *nr -= refs;
+               while (refs--)
                        put_page(head);
-                       (*nr)--;
-               }
        }
 
        return 1;