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authorAndrea Arcangeli2011-11-02 13:37:31 -0700
committerLinus Torvalds2011-11-02 16:06:58 -0700
commite0d85a366c2300efd230ef82a9b22110b0658331 (patch)
tree4965cd894ac64947afc7fbb7f5a0303c99e76b28 /arch/sparc
parent0693bc9ce2cc4f6a1b9c3c05790fc149a74c0b87 (diff)
sparc: gup_pte_range() support THP based tail recounting
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>
Diffstat (limited to 'arch/sparc')
-rw-r--r--arch/sparc/mm/gup.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c
index a986b5d05712..afcebac144fb 100644
--- 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 pmd, unsigned long addr,
put_page(head);
return 0;
}
+ if (head != page)
+ get_huge_page_tail(page);
pages[*nr] = page;
(*nr)++;