Messages in this thread | | | Date | Wed, 25 May 2022 19:04:34 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] sche/fair: static cpumasks for load balance |
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On Mon, May 23, 2022 at 05:42:16PM +0800, Bing Huang wrote: > The both cpu mask load_balance_mask and select_idle_mask just only used > in fair.c, but allocation in core.c in CONFIG_CPUMASK_OFFSTACK=y case, > and global via declare per cpu variations. More or less, it looks wired. > > Signed-off-by: Bing Huang <huangbing@kylinos.cn> > --- > kernel/sched/core.c | 13 +++---------- > kernel/sched/fair.c | 18 ++++++++++++++++-- > kernel/sched/sched.h | 4 ++++ > 3 files changed, 23 insertions(+), 12 deletions(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index d58c0389eb23..64934c5e236d 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -9448,9 +9448,6 @@ LIST_HEAD(task_groups); > static struct kmem_cache *task_group_cache __read_mostly; > #endif > > -DECLARE_PER_CPU(cpumask_var_t, load_balance_mask); > -DECLARE_PER_CPU(cpumask_var_t, select_idle_mask); > - > void __init sched_init(void) > { > unsigned long ptr = 0; > @@ -9494,14 +9491,10 @@ void __init sched_init(void) > > #endif /* CONFIG_RT_GROUP_SCHED */ > } > + > #ifdef CONFIG_CPUMASK_OFFSTACK > - for_each_possible_cpu(i) { > - per_cpu(load_balance_mask, i) = (cpumask_var_t)kzalloc_node( > - cpumask_size(), GFP_KERNEL, cpu_to_node(i)); > - per_cpu(select_idle_mask, i) = (cpumask_var_t)kzalloc_node( > - cpumask_size(), GFP_KERNEL, cpu_to_node(i)); > - } > -#endif /* CONFIG_CPUMASK_OFFSTACK */ > + init_working_cpumask(); > +#endif
We already have init_sched_fair_class(), can't you use that?
> > init_rt_bandwidth(&def_rt_bandwidth, global_rt_period(), global_rt_runtime()); > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index a68482d66535..3a4b0dd1beb5 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -5831,8 +5831,8 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) > #ifdef CONFIG_SMP > > /* Working cpumask for: load_balance, load_balance_newidle. */ > -DEFINE_PER_CPU(cpumask_var_t, load_balance_mask); > -DEFINE_PER_CPU(cpumask_var_t, select_idle_mask); > +static DEFINE_PER_CPU(cpumask_var_t, load_balance_mask); > +static DEFINE_PER_CPU(cpumask_var_t, select_idle_mask); > > #ifdef CONFIG_NO_HZ_COMMON > > @@ -7052,6 +7052,20 @@ balance_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) > } > #endif /* CONFIG_SMP */ > > +#ifdef CONFIG_CPUMASK_OFFSTACK > +void __init init_working_cpumask(void) > +{ > + int i; > + > + for_each_possible_cpu(i) { > + per_cpu(load_balance_mask, i) = (cpumask_var_t)kzalloc_node( > + cpumask_size(), GFP_KERNEL, cpu_to_node(i)); > + per_cpu(select_idle_mask, i) = (cpumask_var_t)kzalloc_node( > + cpumask_size(), GFP_KERNEL, cpu_to_node(i)); > + } > +} > +#endif
If you stick that #ifdef inside the function, you can remove it everwhere else. Less #ifdef is more better.
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