Re: [dpdk-dev] [PATCH v6 2/7] vhost: fix missing guest pages table NUMA realloc

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

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Friday, June 18, 2021 10:04 PM
> To: dev@dpdk.org; david.marchand@redhat.com; Xia, Chenbo <chenbo.xia@intel.com>
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>; stable@dpdk.org
> Subject: [PATCH v6 2/7] vhost: fix missing guest pages table NUMA realloc
> 
> When the guest allocates virtqueues on a different NUMA node
> than the one the Vhost metadata are allocated, both the Vhost
> device struct and the virtqueues struct are reallocated.
> 
> However, reallocating the guest pages table was missing, which
> likely causes at least one cross-NUMA accesses for every burst
> of packets.
> 
> This patch reallocates this table on the same NUMA node as the
> other metadata.
> 
> Fixes: e246896178e6 ("vhost: get guest/host physical address mappings")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  lib/vhost/vhost_user.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
> index b5a84f3dcd..5fb055ea2e 100644
> --- a/lib/vhost/vhost_user.c
> +++ b/lib/vhost/vhost_user.c
> @@ -558,7 +558,8 @@ numa_realloc(struct virtio_net *dev, int index)
>  	}
>  	if (oldnode != newnode) {
>  		struct rte_vhost_memory *old_mem;
> -		ssize_t mem_size;
> +		struct guest_page *old_gp;
> +		ssize_t mem_size, gp_size;
> 
>  		VHOST_LOG_CONFIG(INFO,
>  			"reallocate dev from %d to %d node\n",
> @@ -583,6 +584,17 @@ numa_realloc(struct virtio_net *dev, int index)
> 
>  		memcpy(dev->mem, old_mem, mem_size);
>  		rte_free(old_mem);
> +
> +		gp_size = dev->max_guest_pages * sizeof(*dev->guest_pages);
> +		old_gp = dev->guest_pages;
> +		dev->guest_pages = rte_malloc_socket(NULL, gp_size,
> RTE_CACHE_LINE_SIZE, newnode);
> +		if (!dev->guest_pages) {
> +			dev->guest_pages = old_gp;
> +			goto out;
> +		}
> +
> +		memcpy(dev->guest_pages, old_gp, gp_size);
> +		rte_free(old_gp);
>  	}
> 
>  out:
> --
> 2.31.1


Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>