Hi Peter,

Sorry if this has already been reported, but

On Fri, Mar 16, 2012 at 7:40 AM, Peter Zijlstra [off-list ref] wrote:

Hi All,

While the current scheduler has knowledge of the machine topology, including
NUMA (although there's room for improvement there as well [1]), it is
completely insensitive to which nodes a task's memory actually is on.

Current upstream task memory allocation prefers to use the node the task is
currently running on (unless explicitly told otherwise, see
mbind()/set_mempolicy()), and with the scheduler free to move the task about at
will, the task's memory can end up being spread all over the machine's nodes.

While the scheduler does a reasonable job of keeping short running tasks on a
single node (by means of simply not doing the cross-node migration very often),
it completely blows for long-running processes with a large memory footprint.

This patch-set aims at improving this situation. It does so by assigning a
preferred, or home, node to every process/thread_group. Memory allocation is
then directed by this preference instead of the node the task might actually be
running on momentarily. The load-balancer is also modified to prefer running
the task on its home-node, although not at the cost of letting CPUs go idle or
at the cost of execution fairness.

<snip>

 [24/26] mm, mpol: Implement numa_group RSS accounting

I was going to try and test this on power, but it fails to build:

  mm/filemap_xip.c: In function ‘__xip_unmap’:
  mm/filemap_xip.c:199: error: implicit declaration of function
‘numa_add_vma_counter’

and I think

 [26/26] sched, numa: A few debug bits

introduced a new warning:

  kernel/sched/numa.c: In function ‘process_cpu_runtime’:
  kernel/sched/numa.c:210: warning: format ‘%lu’ expects type ‘long
unsigned int’, but argument 3 has type ‘u64’
  kernel/sched/numa.c:210: warning: format ‘%lu’ expects type ‘long
unsigned int’, but argument 4 has type ‘u64’

Thanks,
Nish

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