Re: [PATCH v2 2/3] sched/fair: Move hot load_avg into its own cacheline

[Waiman Long]

On 12/03/2015 05:56 AM, Peter Zijlstra wrote:
> On Wed, Dec 02, 2015 at 01:41:49PM -0500, Waiman Long wrote:
> > +/*
> > + * Make sure that the task_group structure is cacheline aligned when
> > + * fair group scheduling is enabled.
> > + */
> > +#ifdef CONFIG_FAIR_GROUP_SCHED
> > +static inline struct task_group *alloc_task_group(void)
> > +{
> > +	return kmem_cache_alloc(task_group_cache, GFP_KERNEL | __GFP_ZERO);
> > +}
> > +
> > +static inline void free_task_group(struct task_group *tg)
> > +{
> > +	kmem_cache_free(task_group_cache, tg);
> > +}
> > +#else /* CONFIG_FAIR_GROUP_SCHED */
> > +static inline struct task_group *alloc_task_group(void)
> > +{
> > +	return kzalloc(sizeof(struct task_group), GFP_KERNEL);
> > +}
> > +
> > +static inline void free_task_group(struct task_group *tg)
> > +{
> > +	kfree(tg);
> > +}
> > +#endif /* CONFIG_FAIR_GROUP_SCHED */
> I think we can simply always use the kmem_cache, both slab and slub
> merge slabcaches where appropriate.

I did that as I was not sure how much overhead would the introduction of 
a new kmem_cache bring. It seems like it is not really an issue. So I am 
fine with making the kmem_cache change permanent.

Cheers,
Longman
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