Changes since v2:
1) optimize away a few more locked ops in the get_page/put_page
hugetlbfs and slab paths (see 3/8 and 4/8).
3/8 is the least trivial addition to the series as we now are
running PageSlab and PageHeadHuge on random page structure without
holding any reference count on this. A smp_rmb() if any of the two
checks succeeds is what is supposed to make it safe doing so and
it's lighter weight than get_page_unless_zero (hence the supposed
optimization out of it). 3/8 makes no difference whatsoever to the
speed of the THP case. It's unclear if 3/8 is worth it but it seems
every bit is affecting performance for directio over hugetlbfs with
>8GB/sec storage devices so I thought of trying it. 4/8 is quite
self explanatory and it removes some smp_rmb which is not needed
with the current layout of the struct page.
2) two nice cleanups from Andrew
3) Removed the PageHeadHuge export as it's not needed right now
Andrea Arcangeli (6):
mm: hugetlbfs: fix hugetlbfs optimization
mm: hugetlb: use get_page_foll in follow_hugetlb_page
mm: hugetlbfs: move the put/get_page slab and hugetlbfs optimization
in a faster path
mm: thp: optimize compound_trans_huge
mm: tail page refcounting optimization for slab and hugetlbfs
mm/hugetlb.c: defer PageHeadHuge() symbol export
Andrew Morton (2):
mm/hugetlb.c: simplify PageHeadHuge() and PageHuge()
mm/swap.c: reorganize put_compound_page()
include/linux/huge_mm.h | 23 ++++
include/linux/mm.h | 32 +++++-
mm/hugetlb.c | 20 +++-
mm/internal.h | 3 +-
mm/swap.c | 284 +++++++++++++++++++++++++++++-------------------
5 files changed, 240 insertions(+), 122 deletions(-)
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