| From 2839bdc1bfc0af76a2f0f11eca011590520a04fa Mon Sep 17 00:00:00 2001 |
| From: Andrea Arcangeli <aarcange@redhat.com> |
| Date: Wed, 2 Nov 2011 13:37:03 -0700 |
| Subject: powerpc: remove superfluous PageTail checks on the pte gup_fast |
| |
| From: Andrea Arcangeli <aarcange@redhat.com> |
| |
| commit 2839bdc1bfc0af76a2f0f11eca011590520a04fa upstream. |
| |
| This part of gup_fast doesn't seem capable of handling hugetlbfs ptes, |
| those should be handled by gup_hugepd only, so these checks are |
| superfluous. |
| |
| Plus if this wasn't a noop, it would have oopsed because, the insistence |
| of using the speculative refcounting would trigger a VM_BUG_ON if a tail |
| page was encountered in the page_cache_get_speculative(). |
| |
| 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/gup.c | 13 ------------- |
| 1 file changed, 13 deletions(-) |
| |
| --- a/arch/powerpc/mm/gup.c |
| +++ b/arch/powerpc/mm/gup.c |
| @@ -16,17 +16,6 @@ |
| |
| #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(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 |
| @@ -58,8 +47,6 @@ static noinline int gup_pte_range(pmd_t |
| put_page(page); |
| return 0; |
| } |
| - if (PageTail(page)) |
| - get_huge_page_tail(page); |
| pages[*nr] = page; |
| (*nr)++; |
| |
