[RFC PATCH 0/6] Configurable fair allocation zone policy v3

[Mel Gorman]

This series is currently untested and is being posted to sync up discussions
on the treatment of page cache pages, particularly the sysv part. I have
not thought it through in detail but postings patches is the easiest way
to highlight where I think a problem might be.

Changelog since v2
o Drop an accounting patch, behaviour is deliberate
o Special case tmpfs and shmem pages for discussion

Changelog since v1
o Fix lot of brain damage in the configurable policy patch
o Yoink a page cache annotation patch
o Only account batch pages against allocations eligible for the fair policy
o Add patch that default distributes file pages on remote nodes

Commit 81c0a2bb ("mm: page_alloc: fair zone allocator policy") solved a
bug whereby new pages could be reclaimed before old pages because of how
the page allocator and kswapd interacted on the per-zone LRU lists.

Unfortunately a side-effect missed during review was that it's now very
easy to allocate remote memory on NUMA machines. The problem is that
it is not a simple case of just restoring local allocation policies as
there are genuine reasons why global page aging may be prefereable. It's
still a major change to default behaviour so this patch makes the policy
configurable and sets what I think is a sensible default.

The patches are on top of some NUMA balancing patches currently in -mm.
It's untested and posted to discuss patches 4 and 6.

 Documentation/sysctl/vm.txt |  29 ++++++++++
 include/linux/gfp.h         |   4 +-
 include/linux/mmzone.h      |   2 +
 include/linux/pagemap.h     |   2 +-
 include/linux/swap.h        |   2 +
 kernel/sysctl.c             |   8 +++
 mm/filemap.c                |   2 +
 mm/page_alloc.c             | 136 +++++++++++++++++++++++++++++++++++++-------
 mm/shmem.c                  |  14 +++++
 9 files changed, 176 insertions(+), 23 deletions(-)

-- 
1.8.4

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