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Subject[PATCH 0/3] fixes for large mm_populate() and munlock() operations
These 3 changes are to improve the handling of large mm_populate and
munlock operations. They apply on top of mmotm (in particular, they
depend on both my prior mm_populate work and Kirill's "thp: avoid
dumping huge zero page" change).

- Patch 1 fixes an integer overflow issue when populating 2^32 pages.
The nr_pages argument to get_user_pages would overflow, resulting in 0
pages being processed per iteration. I am proposing to simply convert
the nr_pages argument to a long.

- Patch 2 accelerates populating regions with THP pages. get_user_pages()
can increment the address by a huge page size in this case instead of
a small page size, and avoid repeated mm->page_table_lock acquisitions.
This fixes an issue reported by Roman Dubtsov where populating regions
via mmap MAP_POPULATE was significantly slower than doing so by
touching pages from userspace.

- Patch 3 is a similar acceleration for the munlock case. I would actually
like to get Andrea's attention on this one, as I can't explain how
munlock_vma_page() is safe against racing with split_huge_page().

Note that patches 1-2 are logically independent of patch 3, so if the
discussion of patch 3 takes too long I would ask Andrew to consider
merging patches 1-2 first.

Michel Lespinasse (3):
mm: use long type for page counts in mm_populate() and get_user_pages()
mm: accelerate mm_populate() treatment of THP pages
mm: accelerate munlock() treatment of THP pages

arch/ia64/xen/xencomm.c | 3 ++-
arch/powerpc/kernel/vdso.c | 9 +++++----
arch/s390/mm/pgtable.c | 3 ++-
include/linux/hugetlb.h | 6 +++---
include/linux/mm.h | 16 ++++++++--------
mm/hugetlb.c | 10 +++++-----
mm/internal.h | 2 +-
mm/ksm.c | 10 +++++++---
mm/memory.c | 39 ++++++++++++++++++++++++++-------------
mm/migrate.c | 7 +++++--
mm/mlock.c | 37 ++++++++++++++++++++++++-------------
11 files changed, 88 insertions(+), 54 deletions(-)


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