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Commit 2839bdc1bfc0af76a2f0f11eca011590520a04fa

Authored by Andrea Arcangeli
Committed by Linus Torvalds
1 parent 70b50f94f1
Exists in master and in 6 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

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>

Showing 1 changed file with 0 additions and 13 deletions Side-by-side Diff

arch/powerpc/mm/gup.c
Diff comments   View file @ 2839bdc
... ... @@ -16,17 +16,6 @@
16 16  
17 17 #ifdef __HAVE_ARCH_PTE_SPECIAL
18 18  
19   -static inline void get_huge_page_tail(struct page *page)
20   -{
21   - /*
22   - * __split_huge_page_refcount() cannot run
23   - * from under us.
24   - */
25   - VM_BUG_ON(page_mapcount(page) < 0);
26   - VM_BUG_ON(atomic_read(&page->_count) != 0);
27   - atomic_inc(&page->_mapcount);
28   -}
29   -
30 19 /*
31 20 * The performance critical leaf functions are made noinline otherwise gcc
32 21 * inlines everything into a single function which results in too much
... ... @@ -58,8 +47,6 @@
58 47 put_page(page);
59 48 return 0;
60 49 }
61   - if (PageTail(page))
62   - get_huge_page_tail(page);
63 50 pages[*nr] = page;
64 51 (*nr)++;
65 52