lkml.org 
[lkml]   [2022]   [Oct]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v6 1/3] sched/topology: Introduce sched_numa_hop_mask()
    Date
    Tariq has pointed out that drivers allocating IRQ vectors would benefit
    from having smarter NUMA-awareness - cpumask_local_spread() only knows
    about the local node and everything outside is in the same bucket.

    sched_domains_numa_masks is pretty much what we want to hand out (a cpumask
    of CPUs reachable within a given distance budget), introduce
    sched_numa_hop_mask() to export those cpumasks.

    Link: http://lore.kernel.org/r/20220728191203.4055-1-tariqt@nvidia.com
    Signed-off-by: Valentin Schneider <vschneid@redhat.com>
    Reviewed-by: Yury Norov <yury.norov@gmail.com>
    ---
    include/linux/topology.h | 10 ++++++++++
    kernel/sched/topology.c | 32 ++++++++++++++++++++++++++++++++
    2 files changed, 42 insertions(+)

    diff --git a/include/linux/topology.h b/include/linux/topology.h
    index 4564faafd0e12..64199545d7cf6 100644
    --- a/include/linux/topology.h
    +++ b/include/linux/topology.h
    @@ -245,5 +245,15 @@ static inline const struct cpumask *cpu_cpu_mask(int cpu)
    return cpumask_of_node(cpu_to_node(cpu));
    }

    +#ifdef CONFIG_NUMA
    +extern const struct cpumask *sched_numa_hop_mask(unsigned int node, unsigned int hops);
    +#else
    +static inline const struct cpumask *
    +sched_numa_hop_mask(unsigned int node, unsigned int hops)
    +{
    + return ERR_PTR(-EOPNOTSUPP);
    +}
    +#endif /* CONFIG_NUMA */
    +

    #endif /* _LINUX_TOPOLOGY_H */
    diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
    index 8739c2a5a54ea..3bce567241fc4 100644
    --- a/kernel/sched/topology.c
    +++ b/kernel/sched/topology.c
    @@ -2067,6 +2067,38 @@ int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
    return found;
    }

    +/**
    + * sched_numa_hop_mask() - Get the cpumask of CPUs at most @hops hops away from
    + * @node
    + * @node: The node to count hops from.
    + * @hops: Include CPUs up to that many hops away. 0 means local node.
    + *
    + * Return: On success, a pointer to a cpumask of CPUs at most @hops away from
    + * @node, an error value otherwise.
    + *
    + * Requires rcu_lock to be held. Returned cpumask is only valid within that
    + * read-side section, copy it if required beyond that.
    + *
    + * Note that not all hops are equal in distance; see sched_init_numa() for how
    + * distances and masks are handled.
    + * Also note that this is a reflection of sched_domains_numa_masks, which may change
    + * during the lifetime of the system (offline nodes are taken out of the masks).
    + */
    +const struct cpumask *sched_numa_hop_mask(unsigned int node, unsigned int hops)
    +{
    + struct cpumask ***masks;
    +
    + if (node >= nr_node_ids || hops >= sched_domains_numa_levels)
    + return ERR_PTR(-EINVAL);
    +
    + masks = rcu_dereference(sched_domains_numa_masks);
    + if (!masks)
    + return ERR_PTR(-EBUSY);
    +
    + return masks[hops][node];
    +}
    +EXPORT_SYMBOL_GPL(sched_numa_hop_mask);
    +
    #endif /* CONFIG_NUMA */

    static int __sdt_alloc(const struct cpumask *cpu_map)
    --
    2.31.1
    \
     
     \ /
      Last update: 2022-10-28 18:52    [W:3.261 / U:0.932 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site