Commit 2839bdc1 authored Nov 02, 2011 by Andrea Arcangeli Committed by Linus Torvalds Nov 02, 2011

powerpc: remove superfluous PageTail checks on the pte gup_fast



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>

parent 70b50f94

arch/powerpc/mm/gup.c

+0 −13

Original line number	Diff line number	Diff line
		@@ -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 pmd, unsigned long addr,
		put_page(page);
		return 0;
		}
		if (PageTail(page))
		get_huge_page_tail(page);
		pages[*nr] = page;
		(*nr)++;