On 26/08/22 16:14, Yicong Yang wrote: > On 2022/8/26 2:12, Valentin Schneider wrote: >> 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@xxxxxxxxxx >> Signed-off-by: Valentin Schneider <vschneid@xxxxxxxxxx> >> --- >> include/linux/topology.h | 9 +++++++++ >> kernel/sched/topology.c | 28 ++++++++++++++++++++++++++++ >> 2 files changed, 37 insertions(+) >> >> diff --git a/include/linux/topology.h b/include/linux/topology.h >> index 4564faafd0e1..13b82b83e547 100644 >> --- a/include/linux/topology.h >> +++ b/include/linux/topology.h >> @@ -245,5 +245,14 @@ 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(int node, int hops); >> +#else >> +static inline const struct cpumask *sched_numa_hop_mask(int node, int hops) >> +{ >> + return ERR_PTR(-EOPNOTSUPP); >> +} >> +#endif /* CONFIG_NUMA */ >> + >> > > I think it should be better to return cpu_online_mask() if CONFIG_NUMA=n and hop is 0. Then we > can keep the behaviour consistent with cpumask_local_spread() which for_each_numa_hop_cpu is > going to replace. > That's a good point, thanks. > The macro checking maybe unnecessary, check whether node is NUMA_NO_NODE will handle the case > where NUMA is not configured. > > Thanks.
