Fix NUMA problems in transparent hugepages and KSM

Andi Kleen
2011-02-21T19:08:11Z

The current transparent hugepages daemon can mess up local
memory affinity on NUMA systems. When it copies memory to a
huge page it does not necessarily keep it on the same
node as the local allocations.

While fixing this I also found some more related issues:
- The NUMA policy interleaving for THP was using the small
page size, not the large parse size.
- KSM and THP copies also did not preserve the local node
- The accounting for local/remote allocations in the daemon
was misleading.
- There were no VM statistics counters for THP, which made it
impossible to analyze.

At least some of the bug fixes are 2.6.38 candidates IMHO
because some of the NUMA problems are pretty bad. In some workloads
this can cause performance problems.

What can be delayed are GFP_OTHERNODE and the statistics changes.

Git tree:

git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc-2.6.git thp-numa

Andi Kleen (8):
Fix interleaving for transparent hugepages
Change alloc_pages_vma to pass down the policy node for local policy
Preserve local node for KSM copies
Preserve original node for transparent huge page copies
Use correct numa policy node for transparent hugepages
Add __GFP_OTHER_NODE flag
Use GFP_OTHER_NODE for transparent huge pages
Add VM counters for transparent hugepages

include/linux/gfp.h | 13 ++++++++---
include/linux/vmstat.h | 11 ++++++++-
mm/huge_memory.c | 49 +++++++++++++++++++++++++++++++++--------------
mm/ksm.c | 3 +-
mm/mempolicy.c | 16 +++++++-------
mm/page_alloc.c | 2 +-
mm/vmstat.c | 17 ++++++++++++++-
7 files changed, 78 insertions(+), 33 deletions(-)

-Andi