Re: [dpdk-dev] [PATCH] vhost: restore IOTLB mempool allocation

["Xia, Chenbo" <chenbo.xia@intel.com>]

> -----Original Message-----
> From: David Marchand <david.marchand@redhat.com>
> Sent: Monday, May 17, 2021 5:00 PM
> To: dev@dpdk.org
> Cc: thomas@monjalon.net; Yigit, Ferruh <ferruh.yigit@intel.com>; Maxime
> Coquelin <maxime.coquelin@redhat.com>; Xia, Chenbo <chenbo.xia@intel.com>;
> Zhihong Wang <wangzhihong.wzh@bytedance.com>; Junjie Wan
> <wanjunjie@bytedance.com>
> Subject: [PATCH] vhost: restore IOTLB mempool allocation
> 
> As explained by Chenbo, IOTLB messages will be sent when some queues
> are not enabled. If we initialize IOTLB in vhost_user_set_vring_num,
> it could happen that IOTLB update comes when IOTLB pool of disabled
> queues are not initialized.
> 
> Fixes: 968bbc7e2e50 ("vhost: avoid IOTLB mempool allocation while IOMMU
> disabled")
> 
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---
> Summary of a discussion with Maxime:
> 
> To keep the mempool allocation optimization, we could try to initialise
> the per-vring mempools at reception of the first IOTLB message.
> Since those pools are used as caches, it is not an issue if some vrings
> received more IOTLB updates than others.
> 
> But looking/testing this now is too late for 21.05, hence reverting is
> the safer.
> 
> ---
>  lib/vhost/vhost.c      | 5 +++--
>  lib/vhost/vhost_user.c | 6 +-----
>  2 files changed, 4 insertions(+), 7 deletions(-)
> --
> 2.23.0

Applied to next-virtio/main. Thanks