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From: Julien Grall <julien.grall@citrix.com>
To: Chen Baozi <baozich@gmail.com>, Julien Grall <julien.grall@citrix.com>
Cc: xen-devel@lists.xenproject.org, Campbell Ian <ian.campbell@citrix.com>
Subject: Re: [PATCH V5 10/10] xen/arm64: increase MAX_VIRT_CPUS to 128 on arm64
Date: Mon, 1 Jun 2015 09:04:18 +0100	[thread overview]
Message-ID: <556C1202.6000106@citrix.com> (raw)
In-Reply-To: <20150601005605.GA12742@cbz-thinkpad>

Hi Chen,

On 01/06/2015 01:56, Chen Baozi wrote:
>> For instance, with your series a cluster can use up to 16 cores but the
>> GIC-500 is only supporting up to 8 cores...
>
> Well, if 4096 is a acceptable value, it will cost 512M address space for GICR_*
> (We need to chagne patch #1 too). Although we do have enough space for GICR_*
> before it reaches the GNTTAB region, I don't think it is a good idea to
> increase MAX_VIRT_CPUS to such a big one.

4096 is the limitation of using only AFF1 and AFF0. That would be 
inevitable if one day we decide to support 4096 CPUs :).

>
> And I've also check the old value of MAX_VIRT_CPUS, it used to be 128 before
> aa25a61.
>
> Or do you have a better suggestion?

I'm not against to limit to 128 vCPUs. It's just the commit message is 
not true. You are limiting the number of VCPUs for practical reason
and not because we are implementing GIC-500.

Please update the commit message according to it.

Regards,

-- 
Julien Grall

      reply	other threads:[~2015-06-01  8:08 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-30 11:07 [PATCH V5 00/10] Support more than 8 vcpus on arm64 with GICv3 Chen Baozi
2015-05-30 11:07 ` [PATCH V5 01/10] xen/arm: gic-v3: Increase the size of GICR in address space for guest Chen Baozi
2015-05-30 11:07 ` [PATCH V5 02/10] xen/arm: Add functions of mapping between vCPUID and virtual affinity Chen Baozi
2015-05-31 12:51   ` Julien Grall
2015-05-30 11:07 ` [PATCH V5 03/10] xen/arm: Use the new functions for vCPUID/vaffinity transformation Chen Baozi
2015-05-31 12:53   ` Julien Grall
2015-05-30 11:07 ` [PATCH V5 04/10] xen/arm: Use cpumask_t type for vcpu_mask in vgic_to_sgi Chen Baozi
2015-05-31 13:05   ` Julien Grall
2015-05-30 11:07 ` [PATCH V5 05/10] xen/arm64: gicv3: Use AFF1 when translating ICC_SGI1R_EL1 to cpumask Chen Baozi
2015-05-30 11:15   ` Chen Baozi
2015-05-31 13:14   ` Julien Grall
2015-05-31 15:25     ` Chen Baozi
2015-05-31 17:58       ` Julien Grall
2015-05-30 11:07 ` [PATCH V5 06/10] tools/libxl: Set 'reg' of cpu node equal to MPIDR affinity for domU Chen Baozi
2015-05-31 13:16   ` Julien Grall
2015-05-30 11:07 ` [PATCH V5 07/10] xen/arm: Set 'reg' of cpu node for dom0 to match MPIDR's affinity Chen Baozi
2015-05-31 13:20   ` Julien Grall
2015-05-30 11:07 ` [PATCH V5 08/10] xen: Call arch_domain_create() before evtchn_init() Chen Baozi
2015-05-31 13:29   ` Julien Grall
2015-05-30 11:07 ` [PATCH V5 09/10] xen/arm: make domain_max_vcpus return value from vgic_ops Chen Baozi
2015-05-31 13:35   ` Julien Grall
2015-05-31 15:31     ` Chen Baozi
2015-05-31 18:05       ` Julien Grall
2015-05-31 18:21         ` Andrew Cooper
2015-05-30 11:07 ` [PATCH V5 10/10] xen/arm64: increase MAX_VIRT_CPUS to 128 on arm64 Chen Baozi
2015-05-31 13:40   ` Julien Grall
2015-05-31 15:37     ` Chen Baozi
2015-05-31 18:21       ` Julien Grall
2015-06-01  0:56         ` Chen Baozi
2015-06-01  8:04           ` Julien Grall [this message]

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