Re: [RFC] high preempt off latency in vfree path

[Joel Fernandes]

On 03/22/16 19:44, Andi Kleen wrote:
> > (1)
> > One is we reduce the number of lazy_max_pages (right now its around 32MB per core worth of pages).
> >
> > diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> > index aa3891e..2720f4f 100644
> > --- a/mm/vmalloc.c
> > +++ b/mm/vmalloc.c
> > @@ -564,7 +564,7 @@ static unsigned long lazy_max_pages(void)
> >
> >          log = fls(num_online_cpus());
> >
> > -       return log * (32UL * 1024 * 1024 / PAGE_SIZE);
> > +       return log * (8UL * 1024 * 1024 / PAGE_SIZE);
> >   }
>
> This seems like the right fix to me.  Perhaps even make it somewhat smaller.
>
> Even on larger systems it's probably fine because they have a lot more
> cores/threads these days, so it will be still sufficiently large.

Thanks Andi. I'll post a patch then.

Regards,
Joel

> -Andi