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Subject[PATCH 0/7] mm: faster get user pages
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Pinning user pages out of nvdimm dax memory is significantly slower
compared to system ram. Analysis points to software overhead incurred
from a radix tree lookup. This patch series fixes that by removing the
relatively costly dev_pagemap lookup that was repeated for each page,
significantly increasing gup time.

The first 5 patches are just updating the benchmark to help test and
demonstrate the value of the last 2 patches.

The results were compared with following benchmark command for device
DAX memory:

# gup_benchmark -m $((12*1024)) -n 512 -L -f /dev/dax0.0

Before: 1037581 usec
After: 375786 usec

Not bad; the after is the same time as using baseline anonymous system
RAM after this patch set, where before was nearly 3x longer.

Keith Busch (7):
mm/gup_benchmark: Time put_page
mm/gup_benchmark: Add additional pinning methods
tools/gup_benchmark: Fix 'write' flag usage
tools/gup_benchmark: Allow user specified file
tools/gup_benchmark: Add parameter for hugetlb
mm/gup: Combine parameters into struct
mm/gup: Cache dev_pagemap while pinning pages

include/linux/huge_mm.h | 12 +-
include/linux/hugetlb.h | 2 +-
include/linux/mm.h | 27 ++-
mm/gup.c | 279 ++++++++++++++---------------
mm/gup_benchmark.c | 36 +++-
mm/huge_memory.c | 67 ++++---
mm/nommu.c | 6 +-
tools/testing/selftests/vm/gup_benchmark.c | 40 ++++-
8 files changed, 262 insertions(+), 207 deletions(-)

--
2.14.4

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