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    SubjectRe: [PATCH] sched_groups are expected to be circular linked list, make it so right after allocation
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    On Wed, 2012-05-09 at 14:21 +0200, Peter Zijlstra wrote:
    > Does something like the below give any clues as to how we got there?

    New version that checks we include the right cpu in build_sched_domain()
    too.. on a related note, we should add a printk-%p modifier for cpulist,
    this cpulist_scnprintf() stuff gets annoying.

    ---
    include/linux/sched.h | 9 +++++++++
    kernel/sched/core.c | 26 ++++++++++++++++++++++++++
    2 files changed, 35 insertions(+)

    diff --git a/include/linux/sched.h b/include/linux/sched.h
    index 714fa99..416aad9 100644
    --- a/include/linux/sched.h
    +++ b/include/linux/sched.h
    @@ -1041,6 +1041,15 @@ struct sched_domain {
    unsigned long span[0];
    };

    +static inline char *sched_domain_name(struct sched_domain *sd)
    +{
    +#ifdef CONFIG_SCHED_DEBUG
    + return sd->name;
    +#else
    + return "";
    +#endif
    +}
    +
    static inline struct cpumask *sched_domain_span(struct sched_domain *sd)
    {
    return to_cpumask(sd->span);
    diff --git a/kernel/sched/core.c b/kernel/sched/core.c
    index 7b77e3b..2884134 100644
    --- a/kernel/sched/core.c
    +++ b/kernel/sched/core.c
    @@ -6072,6 +6072,22 @@ build_overlap_sched_groups(struct sched_domain *sd, int cpu)
    last = sg;
    last->next = first;
    }
    + if (!groups) {
    + char str[256];
    +
    + printk(KERN_ERR "sched: Topology is hosed for CPU-%d!!\n", cpu);
    + cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
    + printk(KERN_ERR "sched: domain: %s %s\n", sched_domain_name(sd), str);
    +
    + sg = first;
    + if (sg) do {
    + cpulist_scnprintf(str, sizeof(str), sched_group_cpus(sg));
    + printk(KERN_ERR "sched: group: %s\n", str);
    + sg = sg->next;
    + } while (sg != first);
    +
    + BUG();
    + }
    sd->groups = groups;

    return 0;
    @@ -6440,6 +6456,16 @@ struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,

    set_domain_attribute(sd, attr);
    cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
    + if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
    + char str[256];
    + cpulist_scnprintf(str, sizeof(str), cpu_map);
    + printk(KERN_ERR "sched: Bonkers domain doesn't include its own cpu: %d %s\n",
    + cpu, str);
    + cpulist_scnprintf(str, sizeof(str), tl->mask(cpu));
    + printk(KERN_ERR "sched: Bonkers domain doesn't include its own cpu: %d %s\n",
    + cpu, str);
    + WARN(1);
    + }
    if (child) {
    sd->level = child->level + 1;
    sched_domain_level_max = max(sched_domain_level_max, sd->level);


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      Last update: 2012-05-09 15:01    [W:0.024 / U:5.792 seconds]
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