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    Subject[PATCH] sched: Fix build problems when CONFIG_NUMA=y and CONFIG_SMP=n
    It is possible to have a single cpu system with both local
    and remote memory.

    Signed-off-by: Tony Luck <tony.luck@intel.com>
    ---

    Broken in linux-next for the past couple of days. Perhaps
    we need some more stubs though - sched_fork() seems to need
    #ifdef CONFIG_SMP around every other line ... not pretty.

    Another approach would be to outlaw such strange configurations
    and make sure that CONFIG_SMP is set whenever CONFIG_NUMA is set.
    We had such a discussion a long time ago, and at that time
    decided to keep supporting it. But with multi-core cpus now
    the norm - perhaps it is time to change our minds.

    kernel/sched/core.c | 2 ++
    kernel/sched/numa.c | 16 ++++++++++++++++
    kernel/sched/sched.h | 2 +-
    3 files changed, 19 insertions(+), 1 deletion(-)

    diff --git a/kernel/sched/core.c b/kernel/sched/core.c
    index 46460ac..f261599 100644
    --- a/kernel/sched/core.c
    +++ b/kernel/sched/core.c
    @@ -1799,7 +1799,9 @@ void sched_fork(struct task_struct *p)
    #endif
    put_cpu();

    +#ifdef CONFIG_SMP
    select_task_node(p, p->mm, SD_BALANCE_FORK);
    +#endif
    }

    /*
    diff --git a/kernel/sched/numa.c b/kernel/sched/numa.c
    index 002f71c..4ff3b7c 100644
    --- a/kernel/sched/numa.c
    +++ b/kernel/sched/numa.c
    @@ -18,6 +18,21 @@
    #include "sched.h"


    +#ifndef CONFIG_SMP
    +void mm_init_numa(struct mm_struct *mm)
    +{
    +}
    +void exit_numa(struct mm_struct *mm)
    +{
    +}
    +void account_numa_dequeue(struct task_struct *p)
    +{
    +}
    +__init void init_sched_numa(void)
    +{
    +}
    +#else
    +
    static const int numa_balance_interval = 2 * HZ; /* 2 seconds */

    struct numa_ops {
    @@ -853,3 +868,4 @@ static __init int numa_init(void)
    return 0;
    }
    early_initcall(numa_init);
    +#endif
    diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
    index 4134d37..9bf5ba8 100644
    --- a/kernel/sched/sched.h
    +++ b/kernel/sched/sched.h
    @@ -473,7 +473,7 @@ struct rq {

    static inline struct list_head *offnode_tasks(struct rq *rq)
    {
    -#ifdef CONFIG_NUMA
    +#if defined(CONFIG_NUMA) && defined(CONFIG_SMP)
    return &rq->offnode_tasks;
    #else
    return NULL;
    --
    1.7.10.2.552.gaa3bb87


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