From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f67.google.com (mail-wm0-f67.google.com [74.125.82.67]) by dpdk.org (Postfix) with ESMTP id D25E3374C for ; Mon, 14 Nov 2016 11:46:24 +0100 (CET) Received: by mail-wm0-f67.google.com with SMTP id g23so14133171wme.1 for ; Mon, 14 Nov 2016 02:46:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id; bh=iDNWamP6Fx2Tf6OwsOVXtE0Kv1j8DfyYAjMvwRJKKPQ=; b=TpoLa779f5pXwFdxmanDDCSEb7ERMvgwdC/YSVRIrGx5TwYdBfj3QqPN84RhSbnyua 9pVxW3MprAJGJSaxqtJkPye+vU7b7ZL3ODKfWZ1y/6MQIgeV873/6fdAIdwAYsiI1iDn qLsGo337et0CkEwK8qMOV10P/plhJzm/pMuIQtvbTMqmP115SO1CffPg8UUo2JrGKWg+ ngJCyqg+NRiplPIpHUop5IngrBxhCadH5lOw7J6nS62j8H4GACuLGb4BrTITKntvUG96 qrMw2WGuCTXFW5WFz93kR0ZwPxxrVcY0Dc109ACx7CPM4F5UeWReS6rWIeHQw0FqUe8b xvtg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=iDNWamP6Fx2Tf6OwsOVXtE0Kv1j8DfyYAjMvwRJKKPQ=; b=AC+tWOWcpSi07FjDcq3NhAi7U6V/Ujx3yudMARCPmDawKgHX6N0lrFOmS2T1SECK3j Yo49l9de3X7/bqZVlAU6AjNvA72xWw4hKD9noVsLOwzrC4xAXMaS/G3y5daDN55aoWeH i9DIpJmS/gttMXA1wegV3o0v17VzdOfaq0u64Ya5n1/xHHq6EeBeYd+7d3NwZo3eHs0c TQCxJa4j5axs5emoX/5IXRScxfsCkTJ38GEhNlf1MbJSqTw3ii0MeroiOZGm7j/g02NL K8MxjhsJRoNU7sS945UntgzOlygF9PQKcpR6+u+GJNWrUtxhXahSMUF/tooaKhAngrCB OhVA== X-Gm-Message-State: ABUngve8bJmdgF11Q29ejL0O1bFySrOpj4+whr2mMqqvqgWYLOhvkLEm/A+3dgpbyJuhFg== X-Received: by 10.28.27.133 with SMTP id b127mr10926032wmb.59.1479120384521; Mon, 14 Nov 2016 02:46:24 -0800 (PST) Received: from spuiu-vm2.anuesystems.local ([109.100.41.154]) by smtp.gmail.com with ESMTPSA id e5sm8980722wma.12.2016.11.14.02.46.23 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 14 Nov 2016 02:46:23 -0800 (PST) From: Stefan Puiu To: dev@dpdk.org Cc: mac_leehk@yahoo.com.hk, yongwang@vmware.com, Stefan Puiu Date: Mon, 14 Nov 2016 12:46:16 +0200 Message-Id: <1479120376-48723-1-git-send-email-stefan.puiu@gmail.com> X-Mailer: git-send-email 1.9.1 Subject: [dpdk-dev] [PATCH] vmxnet3: fix Rx deadlock X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 14 Nov 2016 10:46:25 -0000 Our use case is that we have an app that needs to keep mbufs around for a while. We've seen cases when calling vmxnet3_post_rx_bufs() from vmxet3_recv_pkts(), it might not succeed to add any mbufs to any RX descriptors (where it returns -err). Since there are no mbufs that the virtual hardware can use, and since nobody calls vmxnet3_post_rx_bufs() after that, no packets will be received after this. I call this a deadlock for lack of a better term - the virtual HW waits for free mbufs, while the app waits for the hardware to notify it for data. Note that after this, the app can't recover. This fix is a rework of this patch by Marco Lee: http://dpdk.org/dev/patchwork/patch/6575/. I had to forward port it, address review comments and also reverted the allocation failure handing to the first version of the patch (http://dpdk.org/ml/archives/dev/2015-July/022079.html), since that's the only approach that seems to work, and seems to be what other drivers are doing (I checked ixgbe and em). Reusing the mbuf that's getting passed to the application doesn't seem to make sense, and it was causing weird issues in our app. Also, reusing rxm without checking if it's NULL could cause the code to crash. Signed-off-by: Stefan Puiu --- drivers/net/vmxnet3/vmxnet3_rxtx.c | 38 ++++++++++++++++++++++++++++++++++++-- 1 file changed, 36 insertions(+), 2 deletions(-) diff --git a/drivers/net/vmxnet3/vmxnet3_rxtx.c b/drivers/net/vmxnet3/vmxnet3_rxtx.c index b109168..c9d2488 100644 --- a/drivers/net/vmxnet3/vmxnet3_rxtx.c +++ b/drivers/net/vmxnet3/vmxnet3_rxtx.c @@ -518,6 +518,32 @@ return nb_tx; } +static inline void +vmxnet3_renew_desc(vmxnet3_rx_queue_t *rxq, uint8_t ring_id, + struct rte_mbuf *mbuf) +{ + uint32_t val = 0; + struct vmxnet3_cmd_ring *ring = &rxq->cmd_ring[ring_id]; + struct Vmxnet3_RxDesc *rxd = + (struct Vmxnet3_RxDesc *)(ring->base + ring->next2fill); + vmxnet3_buf_info_t *buf_info = &ring->buf_info[ring->next2fill]; + + if (ring_id == 0) + val = VMXNET3_RXD_BTYPE_HEAD; + else + val = VMXNET3_RXD_BTYPE_BODY; + + buf_info->m = mbuf; + buf_info->len = (uint16_t)(mbuf->buf_len - RTE_PKTMBUF_HEADROOM); + buf_info->bufPA = rte_mbuf_data_dma_addr_default(mbuf); + + rxd->addr = buf_info->bufPA; + rxd->btype = val; + rxd->len = buf_info->len; + rxd->gen = ring->gen; + + vmxnet3_cmd_ring_adv_next2fill(ring); +} /* * Allocates mbufs and clusters. Post rx descriptors with buffer details * so that device can receive packets in those buffers. @@ -657,9 +683,17 @@ } while (rcd->gen == rxq->comp_ring.gen) { + struct rte_mbuf *newm; if (nb_rx >= nb_pkts) break; + newm = rte_mbuf_raw_alloc(rxq->mp); + if (unlikely(newm == NULL)) { + PMD_RX_LOG(ERR, "Error allocating mbuf"); + rxq->stats.rx_buf_alloc_failure++; + break; + } + idx = rcd->rxdIdx; ring_idx = (uint8_t)((rcd->rqID == rxq->qid1) ? 0 : 1); rxd = (Vmxnet3_RxDesc *)rxq->cmd_ring[ring_idx].base + idx; @@ -759,8 +793,8 @@ VMXNET3_INC_RING_IDX_ONLY(rxq->cmd_ring[ring_idx].next2comp, rxq->cmd_ring[ring_idx].size); - /* It's time to allocate some new buf and renew descriptors */ - vmxnet3_post_rx_bufs(rxq, ring_idx); + /* It's time to renew descriptors */ + vmxnet3_renew_desc(rxq, ring_idx, newm); if (unlikely(rxq->shared->ctrl.updateRxProd)) { VMXNET3_WRITE_BAR0_REG(hw, rxprod_reg[ring_idx] + (rxq->queue_id * VMXNET3_REG_ALIGN), rxq->cmd_ring[ring_idx].next2fill); -- 1.9.1