diff options
| author | Andrea Arcangeli <aarcange@redhat.com> | 2011-11-02 13:37:15 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-11-11 09:36:46 -0800 |
| commit | 87c2bd66eef0c5685bb29fd995f6b77fa4d07ed1 (patch) | |
| tree | 99015d0281ec26b90fa4cd5e6004a22c35578685 /arch | |
| parent | cf2f493ba5c49afe9efd3afa02a505e9b060832d (diff) | |
powerpc: gup_hugepte() support THP based tail recounting
commit 3526741f0964c88bc2ce511e1078359052bf225b upstream.
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>
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>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/mm/hugetlbpage.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index 78b14abded6..a618ef01bfa 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -385,12 +385,23 @@ follow_huge_pmd(struct mm_struct *mm, unsigned long address, return NULL; } +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); +} + static noinline int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr, unsigned long end, int write, struct page **pages, int *nr) { unsigned long mask; unsigned long pte_end; - struct page *head, *page; + struct page *head, *page, *tail; pte_t pte; int refs; @@ -413,6 +424,7 @@ static noinline int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long add head = pte_page(pte); page = head + ((addr & (sz-1)) >> PAGE_SHIFT); + tail = page; do { VM_BUG_ON(compound_head(page) != head); pages[*nr] = page; @@ -431,6 +443,16 @@ static noinline int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long add *nr -= refs; while (refs--) put_page(head); + } else { + /* + * Any tail page need their mapcount reference taken + * before we return. + */ + while (refs--) { + if (PageTail(tail)) + get_huge_page_tail(tail); + tail++; + } } return 1; |