From 22c668d4946f5d369cc40645a0c4ae4c73532693 Mon Sep 17 00:00:00 2001 From: Huawei Xie Date: Thu, 9 Oct 2014 02:54:58 +0800 Subject: [PATCH] vhost: comment identified issues 1) FIXME: concurrent calls to vhost set mem table from different guests could cause mem_temp to be overrided. 2) TODO: cmpset cost quite some cpu cyles. Allow app to disable this feature if there is no contention in real workload. 3) FIXME: fix scatter gather mbuf copy to vhost vring chained buffers. Signed-off-by: Huawei Xie Acked-by: Changchun Ouyang --- lib/librte_vhost/vhost-net-cdev.c | 1 + lib/librte_vhost/vhost_rxtx.c | 2 ++ 2 files changed, 3 insertions(+) diff --git a/lib/librte_vhost/vhost-net-cdev.c b/lib/librte_vhost/vhost-net-cdev.c index e5875ebbc6..91ff0d862e 100644 --- a/lib/librte_vhost/vhost-net-cdev.c +++ b/lib/librte_vhost/vhost-net-cdev.c @@ -214,6 +214,7 @@ vhost_net_ioctl(fuse_req_t req, int cmd, void *arg, break; case VHOST_SET_MEM_TABLE: + /*TODO fix race condition.*/ LOG_DEBUG(VHOST_CONFIG, "(%"PRIu64") IOCTL: VHOST_SET_MEM_TABLE\n", ctx.fh); static struct vhost_memory mem_temp; diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c index 2a1171a783..84ec0e88e8 100644 --- a/lib/librte_vhost/vhost_rxtx.c +++ b/lib/librte_vhost/vhost_rxtx.c @@ -93,6 +93,7 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id, res_end_idx = res_base_idx + count; /* vq->last_used_idx_res is atomically updated. */ + /* TODO: Allow to disable cmpset if no concurrency in application. */ success = rte_atomic16_cmpset(&vq->last_used_idx_res, res_base_idx, res_end_idx); } while (unlikely(success == 0)); @@ -146,6 +147,7 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id, vq->used->ring[res_cur_idx & (vq->size - 1)].len = packet_len; /* Copy mbuf data to buffer */ + /* FIXME for sg mbuf and the case that desc couldn't hold the mbuf data */ rte_memcpy((void *)(uintptr_t)buff_addr, rte_pktmbuf_mtod(buff, const void *), rte_pktmbuf_data_len(buff)); -- 2.20.1