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From:   Wanpeng Li <kernellwp@gmail.com>
Date:   Mon, 8 Jul 2019 12:05:44 +0800
Message-ID: <CANRm+CyBP8qd6pYcyX_biGBwOcdjdqMqazNjSnq2H6QNE+OsHw@mail.gmail.com>
Subject: Re: [PATCH v4 1/2] sched/isolation: Prefer housekeeping cpu in local node
To:     LKML <linux-kernel@vger.kernel.org>
Cc:     Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Frederic Weisbecker <frederic@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Srikar Dronamraju <srikar@linux.vnet.ibm.com>
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Sender: linux-kernel-owner@vger.kernel.org
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Kindly ping for these two patches, :)
On Fri, 28 Jun 2019 at 16:51, Wanpeng Li <kernellwp@gmail.com> wrote:
>
> From: Wanpeng Li <wanpengli@tencent.com>
>
> In real product setup, there will be houseeking cpus in each nodes, it
> is prefer to do housekeeping from local node, fallback to global online
> cpumask if failed to find houseeking cpu from local node.
>
> Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
> Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Frederic Weisbecker <frederic@kernel.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> ---
> v3 -> v4:
>  * have a static function for sched_numa_find_closest
>  * cleanup sched_numa_find_closest comments
> v2 -> v3:
>  * add sched_numa_find_closest comments
> v1 -> v2:
>  * introduce sched_numa_find_closest
>
>  kernel/sched/isolation.c | 12 ++++++++++--
>  kernel/sched/sched.h     |  8 +++++---
>  kernel/sched/topology.c  | 20 ++++++++++++++++++++
>  3 files changed, 35 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
> index 7b9e1e0..191f751 100644
> --- a/kernel/sched/isolation.c
> +++ b/kernel/sched/isolation.c
> @@ -16,9 +16,17 @@ static unsigned int housekeeping_flags;
>
>  int housekeeping_any_cpu(enum hk_flags flags)
>  {
> -       if (static_branch_unlikely(&housekeeping_overridden))
> -               if (housekeeping_flags & flags)
> +       int cpu;
> +
> +       if (static_branch_unlikely(&housekeeping_overridden)) {
> +               if (housekeeping_flags & flags) {
> +                       cpu = sched_numa_find_closest(housekeeping_mask, smp_processor_id());
> +                       if (cpu < nr_cpu_ids)
> +                               return cpu;
> +
>                         return cpumask_any_and(housekeeping_mask, cpu_online_mask);
> +               }
> +       }
>         return smp_processor_id();
>  }
>  EXPORT_SYMBOL_GPL(housekeeping_any_cpu);
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index 802b1f3..ec65d90 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -1261,16 +1261,18 @@ enum numa_topology_type {
>  extern enum numa_topology_type sched_numa_topology_type;
>  extern int sched_max_numa_distance;
>  extern bool find_numa_distance(int distance);
> -#endif
> -
> -#ifdef CONFIG_NUMA
>  extern void sched_init_numa(void);
>  extern void sched_domains_numa_masks_set(unsigned int cpu);
>  extern void sched_domains_numa_masks_clear(unsigned int cpu);
> +extern int sched_numa_find_closest(const struct cpumask *cpus, int cpu);
>  #else
>  static inline void sched_init_numa(void) { }
>  static inline void sched_domains_numa_masks_set(unsigned int cpu) { }
>  static inline void sched_domains_numa_masks_clear(unsigned int cpu) { }
> +static inline int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
> +{
> +       return nr_cpu_ids;
> +}
>  #endif
>
>  #ifdef CONFIG_NUMA_BALANCING
> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
> index f751ce0..4eea2c9 100644
> --- a/kernel/sched/topology.c
> +++ b/kernel/sched/topology.c
> @@ -1724,6 +1724,26 @@ void sched_domains_numa_masks_clear(unsigned int cpu)
>         }
>  }
>
> +/*
> + * sched_numa_find_closest() - given the NUMA topology, find the cpu
> + *                             closest to @cpu from @cpumask.
> + * cpumask: cpumask to find a cpu from
> + * cpu: cpu to be close to
> + *
> + * returns: cpu, or nr_cpu_ids when nothing found.
> + */
> +int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
> +{
> +       int i, j = cpu_to_node(cpu);
> +
> +       for (i = 0; i < sched_domains_numa_levels; i++) {
> +               cpu = cpumask_any_and(cpus, sched_domains_numa_masks[i][j]);
> +               if (cpu < nr_cpu_ids)
> +                       return cpu;
> +       }
> +       return nr_cpu_ids;
> +}
> +
>  #endif /* CONFIG_NUMA */
>
>  static int __sdt_alloc(const struct cpumask *cpu_map)
> --
> 2.7.4
>