[dpdk-dev] The limitation of VHOST_MEMORY_MAX_NREGIONS in virtio-user with vhost-user backend

[Tan, Jianfeng]

> -----Original Message-----
> From: Yuanhan Liu [mailto:yliu at fridaylinux.org]
> Sent: Tuesday, December 5, 2017 10:42 PM
> To: Wang, Wei 5. (NSB - CN/Hangzhou)
> Cc: dev at dpdk.org; Tan, Jianfeng
> Subject: Re: [dpdk-dev] The limitation of VHOST_MEMORY_MAX_NREGIONS
> in virtio-user with vhost-user backend
> 
> On Tue, Dec 05, 2017 at 06:58:53AM +0000, Wang, Wei 5. (NSB -
> CN/Hangzhou) wrote:
> >
> >
> > Hi, all
> >
> > In DPDK document, it it described that Virtio in containers Cannot work
> when there are more than VHOST_MEMORY_MAX_NREGIONS(8)
> hugepages. In another word, do not use 2MB hugepage so far. Do you know
> the reason of this limitation?
> 
> It comes from the vhost-user spec.
> 
> > In my envirionment, the pdpe1gb is not set in cpu flag, so hugepage can't
> be set to 1GB size. The hugepage number shall be more than 8
> >
> >
> > So is there any solution or workaround to fix this limitation? Or change
> dpdk code to fix this limitation?
> >
> 
> AFAIK, there are no workarounds. And I think the DPDK EAL memory code
> need be
> refactored a bit to fix this limitation. Unforunately, seems there are no work
> on that recently.

For more info, you can refer to: http://dpdk.org/dev/patchwork/patch/10406/

Thanks,
Jianfeng

> 
> 	--yliu