[PATCH 0/8] Follow-up for speed up page cache truncation v2

[Mel Gorman]

Changelog since v1
o Remove "private" parameter from radix tree callbacks
o Rebase on v4.14-rc5 + Jan's v2 series
o Acked/Reviews by

This series is a follow-on for Jan Kara's series "Speed up page cache
truncation" series. We both ended up looking at the same problem but saw
different problems based on the same data. This series builds upon his work.

A variety of workloads were compared on four separate machines but each
machine showed gains albeit at different levels. Minimally, some of the
differences are due to NUMA where truncating data from a remote node is
slower than a local node. The workloads checked were

o sparse truncate microbenchmark, tiny
o sparse truncate microbenchmark, large
o reaim-io disk workfile
o dbench4 (modified by mmtests to produce more stable results)
o filebench varmail configuration for small memory size
o bonnie, directory operations, working set size 2*RAM

reaim-io, dbench and filebench all showed minor gains.  Truncation does not
dominate those workloads but were tested to ensure no other regressions.
They will not be reported further.

The sparse truncate microbench was written by Jan. It creates a number of
files and then times how long it takes to truncate each one. The "tiny"
configuraiton creates a number of files that easily fits in memory and
times how long it takes to truncate files with page cache. The large
configuration uses enough files to have data that is twice the size of
memory and so timings there include truncating page cache and working set
shadow entries in the radix tree.

Patches 1-4 are the most relevant parts of this series. Patches 5-8 are
optional as they are deleting code that is essentially useless but has a
negligible performance impact.

The changelogs have more information on performance but just for bonnie
delete options, the main comparison is

bonnie
                                      4.14.0-rc5             4.14.0-rc5             4.14.0-rc5
                                          jan-v2                vanilla                 mel-v2
Hmean     SeqCreate ops         76.20 (   0.00%)       75.80 (  -0.53%)       76.80 (   0.79%)
Hmean     SeqCreate read        85.00 (   0.00%)       85.00 (   0.00%)       85.00 (   0.00%)
Hmean     SeqCreate del      13752.31 (   0.00%)    12090.23 ( -12.09%)    15304.84 (  11.29%)
Hmean     RandCreate ops        76.00 (   0.00%)       75.60 (  -0.53%)       77.00 (   1.32%)
Hmean     RandCreate read       96.80 (   0.00%)       96.80 (   0.00%)       97.00 (   0.21%)
Hmean     RandCreate del     13233.75 (   0.00%)    11525.35 ( -12.91%)    14446.61 (   9.16%)

Jan's series is the baseline and the vanilla kernel is 12% slower where as
this series on top gains another 11%.  This is from a different machine
than the data in the changelogs but the detailed data was not collected
as there was no substantial change in v2.

 arch/powerpc/mm/mmu_context_book3s64.c             |  2 +-
 arch/powerpc/mm/pgtable_64.c                       |  2 +-
 arch/sparc/mm/init_64.c                            |  2 +-
 arch/tile/mm/homecache.c                           |  2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c             |  6 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c            |  2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c            |  2 +-
 drivers/gpu/drm/etnaviv/etnaviv_gem.c              |  6 +-
 drivers/gpu/drm/i915/i915_gem_gtt.c                |  2 +-
 drivers/gpu/drm/i915/i915_gem_userptr.c            |  4 +-
 drivers/gpu/drm/radeon/radeon_ttm.c                |  2 +-
 drivers/net/ethernet/amazon/ena/ena_netdev.c       |  2 +-
 drivers/net/ethernet/amd/xgbe/xgbe-desc.c          |  2 +-
 drivers/net/ethernet/aquantia/atlantic/aq_ring.c   |  3 +-
 .../net/ethernet/cavium/liquidio/octeon_network.h  |  2 +-
 drivers/net/ethernet/mellanox/mlx4/en_rx.c         |  5 +-
 .../net/ethernet/netronome/nfp/nfp_net_common.c    |  4 +-
 drivers/net/ethernet/qlogic/qlge/qlge_main.c       |  3 +-
 drivers/net/ethernet/sfc/falcon/rx.c               |  2 +-
 drivers/net/ethernet/sfc/rx.c                      |  2 +-
 drivers/net/ethernet/synopsys/dwc-xlgmac-desc.c    |  2 +-
 drivers/net/ethernet/ti/netcp_core.c               |  2 +-
 drivers/net/virtio_net.c                           |  1 -
 drivers/staging/lustre/lustre/mdc/mdc_request.c    |  2 +-
 fs/afs/write.c                                     |  4 +-
 fs/btrfs/extent_io.c                               |  4 +-
 fs/buffer.c                                        |  4 +-
 fs/cachefiles/rdwr.c                               | 10 +--
 fs/ceph/addr.c                                     |  4 +-
 fs/dax.c                                           |  4 +-
 fs/ext4/file.c                                     |  2 +-
 fs/ext4/inode.c                                    |  6 +-
 fs/f2fs/checkpoint.c                               |  2 +-
 fs/f2fs/data.c                                     |  2 +-
 fs/f2fs/file.c                                     |  2 +-
 fs/f2fs/node.c                                     |  8 +-
 fs/fscache/page.c                                  |  2 +-
 fs/fuse/dev.c                                      |  2 +-
 fs/gfs2/aops.c                                     |  2 +-
 fs/hugetlbfs/inode.c                               |  2 +-
 fs/nilfs2/btree.c                                  |  2 +-
 fs/nilfs2/page.c                                   |  8 +-
 fs/nilfs2/segment.c                                |  4 +-
 include/linux/gfp.h                                |  9 +--
 include/linux/pagemap.h                            | 10 +--
 include/linux/pagevec.h                            |  6 +-
 include/linux/radix-tree.h                         |  7 +-
 include/linux/skbuff.h                             |  2 +-
 include/linux/slab.h                               |  3 -
 include/linux/swap.h                               | 15 +++-
 include/trace/events/kmem.h                        | 11 +--
 include/trace/events/mmflags.h                     |  1 -
 kernel/power/snapshot.c                            |  4 +-
 lib/idr.c                                          |  2 +-
 lib/radix-tree.c                                   | 30 +++----
 mm/filemap.c                                       | 15 ++--
 mm/mlock.c                                         |  4 +-
 mm/page-writeback.c                                |  2 +-
 mm/page_alloc.c                                    | 89 +++++++++++---------
 mm/percpu-vm.c                                     |  2 +-
 mm/rmap.c                                          |  2 +-
 mm/shmem.c                                         |  8 +-
 mm/swap.c                                          | 15 ++--
 mm/swap_state.c                                    |  2 +-
 mm/truncate.c                                      | 94 +++++++++++++++-------
 mm/vmscan.c                                        |  6 +-
 mm/workingset.c                                    | 10 +--
 net/core/skbuff.c                                  |  4 +-
 tools/perf/builtin-kmem.c                          |  1 -
 tools/testing/radix-tree/multiorder.c              |  2 +-
 70 files changed, 262 insertions(+), 232 deletions(-)

-- 
2.14.0