Re: [PATCH v2] cpusets: randomize node rotor used in cpuset_mem_spread_node()

From: KOSAKI Motohiro
Date: Fri Apr 15 2011 - 04:29:21 EST


> [I just realized that I forgot to CC mm mailing list]
>
> On Fri 15-04-11 16:18:45, KOSAKI Motohiro wrote:
> > Oops.
> > I should have look into !mempolicy part too.
> > I'm sorry.
> >
> [...]
> > Michal, I think this should be
> >
> > #ifdef CONFIG_CPUSETS
> > if (cpuset_do_page_mem_spread())
> > p->cpuset_mem_spread_rotor = node_random(&p->mems_allowed);
> > if (cpuset_do_slab_mem_spread())
> > p->cpuset_slab_spread_rotor = node_random(&p->mems_allowed);
> > #endif
> >
> > because 99.999% people don't use cpuset's spread mem/slab feature and
> > get_random_int() isn't zero cost.
> >
> > What do you think?
>
> You are right. I was thinking about lazy approach and initialize those
> values when they are used for the first time. What about the patch
> below?
>
> Change from v1:
> - initialize cpuset_{mem,slab}_spread_rotor lazily

Yeah! This is much much better than mine. Thank you!
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>



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