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    SubjectRe: [RFC][PATCH 00/26] sched/numa
    Hi Peter,

    Sorry if this has already been reported, but

    On Fri, Mar 16, 2012 at 7:40 AM, Peter Zijlstra <> 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.

    >  [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

    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’

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