Re: [dpdk-dev] [PATCH] vhost: make iotlb cache name unique among multi processes

[Ye Xiaolong <xiaolong.ye@intel.com>]

On 03/10, Itsuro Oda wrote:
>Currently, iotlb cache name is comprised of vid and virtqueue
>index. For example, "iotlb_cache_0_0". Because vid is assigned
>per process, iotlb cache name is not unique among multi processes.
>For example a secondary process uses a vhost
>(ex. eth_vhost0,iface=/tmp/sock0) and another secondary process
>uses a vhost (ex. eth_vhost1,iface=/tmp/sock1), iotlb cache
>name of both vhost ("iotlb_cache_0_0") are same and as a result
>iotlb cache is broken.
>
>This patch makes iotlb cache name unique among milti processes
>by using the interface name not vid to comprise iotlb cache name.
>Since the length of interface name is variable, this patch uses
>hash value calculated by the interface name.
>
>Fixes: d012d1f293f4 (vhost: add IOTLB helper functions)
>Cc: stable@dpdk.org
>
>Signed-off-by: Itsuro Oda <oda@valinux.co.jp>
>---
> lib/librte_vhost/iotlb.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
>diff --git a/lib/librte_vhost/iotlb.c b/lib/librte_vhost/iotlb.c
>index bc1758528..0992c145b 100644
>--- a/lib/librte_vhost/iotlb.c
>+++ b/lib/librte_vhost/iotlb.c
>@@ -6,6 +6,7 @@
> #include <numaif.h>
> #endif
> 
>+#include <rte_jhash.h>
> #include <rte_tailq.h>
> 
> #include "iotlb.h"
>@@ -288,6 +289,7 @@ vhost_user_iotlb_init(struct virtio_net *dev, int vq_index)
> 	char pool_name[RTE_MEMPOOL_NAMESIZE];
> 	struct vhost_virtqueue *vq = dev->virtqueue[vq_index];
> 	int socket = 0;
>+	uint32_t val;
> 
> 	if (vq->iotlb_pool) {
> 		/*
>@@ -308,8 +310,10 @@ vhost_user_iotlb_init(struct virtio_net *dev, int vq_index)
> 	TAILQ_INIT(&vq->iotlb_list);
> 	TAILQ_INIT(&vq->iotlb_pending_list);
> 
>-	snprintf(pool_name, sizeof(pool_name), "iotlb_cache_%d_%d",
>-			dev->vid, vq_index);
>+	val = rte_jhash(dev->ifname, strlen(dev->ifname), 0);
>+	snprintf(pool_name, sizeof(pool_name), "iotlb_cache_%08x_%d",
>+			val, vq_index);
>+	VHOST_LOG_CONFIG(DEBUG, "IOTLB cache name: %s\n", pool_name);
> 
> 	/* If already created, free it and recreate */
> 	vq->iotlb_pool = rte_mempool_lookup(pool_name);
>-- 
>2.17.0
>

Acked-by: Xiaolong Ye <xiaolong.ye@intel.com>