Re: LOCKDEBUG kernel option crashes if vcpu > 1

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Wed, Nov 19, 2014 at 04:58:19PM +0530, Cherry G. Mathew wrote:
> >>>>> "Manuel" == Manuel Bouyer <bouyer%antioche.eu.org@localhost> writes:
> 
>     Manuel> On Tue, Nov 18, 2014 at 10:30:28PM +0530, Cherry G. Mathew wrote:
>     >> Hi,
>     >> 
>     >> Does the following patch work for you ?
>     >> 
>     >> It's a bit tricky since we use uvm_km_alloc() at early bootup
>     >> (even for ci, I think this should come from a static array or a
>     >> poolcache) which is what triggers the pmap_growkernel() as you
>     >> probably know.
> 
> 
>     Manuel> a static array is probably not appropriate as we can have as
>     Manuel> much as 256 virtual CPUs. I don't think a poolcache would
>     Manuel> help as it has to get the memory from somewhere. And as ci
>     Manuel> is never freeed, a pool or poolcache would be overkill.
> 
> How about if we could map in a few more pages into kva in early boot,
> like below ? 
> 
> 
> -- 
> Cherry
> 
> 
> diff -r 32f09689dc19 sys/arch/xen/x86/x86_xpmap.c
> --- a/sys/arch/xen/x86/x86_xpmap.c      Tue Nov 18 12:26:14 2014 +0530
> +++ b/sys/arch/xen/x86/x86_xpmap.c      Wed Nov 19 22:23:39 2014 +0530
> @@ -644,6 +644,9 @@
>         mapsize += NBPG;
>         mapsize += NBPG;
> 
> +       /* Pre-alloc kva for ci during cpu attach  */
> +       mapsize += round_page(maxcpus * sizeof(struct cpu_info)) * NBPG;
> +

On amd64 this makes 2193 extra slots.
What's the problem with making pmap_growkernel() work as expected ?

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--