Patch Detail
get:
Show a patch.
patch:
Update a patch.
put:
Update a patch.
GET /api/patches/12731/?format=api
{ "id": 12731, "url": "http://patches.dpdk.org/api/patches/12731/?format=api", "web_url": "http://patches.dpdk.org/project/dpdk/patch/1463120192-24200-5-git-send-email-yuanhan.liu@linux.intel.com/", "project": { "id": 1, "url": "http://patches.dpdk.org/api/projects/1/?format=api", "name": "DPDK", "link_name": "dpdk", "list_id": "dev.dpdk.org", "list_email": "dev@dpdk.org", "web_url": "http://core.dpdk.org", "scm_url": "git://dpdk.org/dpdk", "webscm_url": "http://git.dpdk.org/dpdk", "list_archive_url": "https://inbox.dpdk.org/dev", "list_archive_url_format": "https://inbox.dpdk.org/dev/{}", "commit_url_format": "" }, "msgid": "<1463120192-24200-5-git-send-email-yuanhan.liu@linux.intel.com>", "list_archive_url": "https://inbox.dpdk.org/dev/1463120192-24200-5-git-send-email-yuanhan.liu@linux.intel.com", "date": "2016-05-13T06:16:30", "name": "[dpdk-dev,v2,4/6] vhost: workaround stale vring base", "commit_ref": null, "pull_url": null, "state": "superseded", "archived": true, "hash": "f925b03e01c7c85ca576049630317f6dd330bb4b", "submitter": { "id": 307, "url": "http://patches.dpdk.org/api/people/307/?format=api", "name": "Yuanhan Liu", "email": "yuanhan.liu@linux.intel.com" }, "delegate": { "id": 355, "url": "http://patches.dpdk.org/api/users/355/?format=api", "username": "yliu", "first_name": "Yuanhan", "last_name": "Liu", "email": "yuanhan.liu@linux.intel.com" }, "mbox": "http://patches.dpdk.org/project/dpdk/patch/1463120192-24200-5-git-send-email-yuanhan.liu@linux.intel.com/mbox/", "series": [], "comments": "http://patches.dpdk.org/api/patches/12731/comments/", "check": "pending", "checks": "http://patches.dpdk.org/api/patches/12731/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<dev-bounces@dpdk.org>", "X-Original-To": "patchwork@dpdk.org", "Delivered-To": "patchwork@dpdk.org", "Received": [ "from [92.243.14.124] (localhost [IPv6:::1])\n\tby dpdk.org (Postfix) with ESMTP id B2AFA95EF;\n\tFri, 13 May 2016 08:11:32 +0200 (CEST)", "from mga14.intel.com (mga14.intel.com [192.55.52.115])\n\tby dpdk.org (Postfix) with ESMTP id B916495CE\n\tfor <dev@dpdk.org>; Fri, 13 May 2016 08:11:29 +0200 (CEST)", "from orsmga002.jf.intel.com ([10.7.209.21])\n\tby fmsmga103.fm.intel.com with ESMTP; 12 May 2016 23:11:29 -0700", "from yliu-dev.sh.intel.com ([10.239.67.162])\n\tby orsmga002.jf.intel.com with ESMTP; 12 May 2016 23:11:28 -0700" ], "X-ExtLoop1": "1", "X-IronPort-AV": "E=Sophos;i=\"5.24,612,1455004800\"; d=\"scan'208\";a=\"975524159\"", "From": "Yuanhan Liu <yuanhan.liu@linux.intel.com>", "To": "dev@dpdk.org", "Cc": "huawei.xie@intel.com, Traynor Kevin <kevin.traynor@intel.com>,\n\tmarcandre.lureau@redhat.com, Yuanhan Liu <yuanhan.liu@linux.intel.com>,\n\t\"Michael S. Tsirkin\" <mst@redhat.com>", "Date": "Thu, 12 May 2016 23:16:30 -0700", "Message-Id": "<1463120192-24200-5-git-send-email-yuanhan.liu@linux.intel.com>", "X-Mailer": "git-send-email 1.9.0", "In-Reply-To": "<1463120192-24200-1-git-send-email-yuanhan.liu@linux.intel.com>", "References": "<1462603224-29510-1-git-send-email-yuanhan.liu@linux.intel.com>\n\t<1463120192-24200-1-git-send-email-yuanhan.liu@linux.intel.com>", "Subject": "[dpdk-dev] [PATCH v2 4/6] vhost: workaround stale vring base", "X-BeenThere": "dev@dpdk.org", "X-Mailman-Version": "2.1.15", "Precedence": "list", "List-Id": "patches and discussions about DPDK <dev.dpdk.org>", "List-Unsubscribe": "<http://dpdk.org/ml/options/dev>,\n\t<mailto:dev-request@dpdk.org?subject=unsubscribe>", "List-Archive": "<http://dpdk.org/ml/archives/dev/>", "List-Post": "<mailto:dev@dpdk.org>", "List-Help": "<mailto:dev-request@dpdk.org?subject=help>", "List-Subscribe": "<http://dpdk.org/ml/listinfo/dev>,\n\t<mailto:dev-request@dpdk.org?subject=subscribe>", "Errors-To": "dev-bounces@dpdk.org", "Sender": "\"dev\" <dev-bounces@dpdk.org>" }, "content": "When DPDK app crashes (or quits, or gets killed), a restart of DPDK\napp would get stale vring base from QEMU. That would break the kernel\nvirtio net completely, making it non-work any more, unless a driver\nreset is done.\n\nSo, instead of getting the stale vring base from QEMU, Huawei suggested\nwe could get a much saner (and may not the most accurate) vring base\nfrom used->idx. That would work because:\n\n- there is a memory barrier between updating used ring entries and\n used->idx. So, even though we crashed at updating the used ring\n entries, it will not cause any issue, as the guest driver will not\n process those stale used entries, for used-idx is not updated yet.\n\n- DPDK process vring in order, that means a crash may just lead some\n packet retransmission for Tx and drop for Rx.\n\nCc: \"Michael S. Tsirkin\" <mst@redhat.com>\nSuggested-by: Huawei Xie <huawei.xie@intel.com>\nSigned-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>\nAcked-by: \"Michael S. Tsirkin\" <mst@redhat.com>\nAcked-by: Huawei Xie <huawei.xie@intel.com>\n---\n\nv2: log on packets resent for Tx and drop for Rx\n---\n lib/librte_vhost/virtio-net.c | 9 +++++++++\n 1 file changed, 9 insertions(+)", "diff": "diff --git a/lib/librte_vhost/virtio-net.c b/lib/librte_vhost/virtio-net.c\nindex 835ab3a..bd7e55e 100644\n--- a/lib/librte_vhost/virtio-net.c\n+++ b/lib/librte_vhost/virtio-net.c\n@@ -561,6 +561,15 @@ vhost_set_vring_addr(int vid, struct vhost_vring_addr *addr)\n \t\treturn -1;\n \t}\n \n+\tif (vq->last_used_idx != vq->used->idx) {\n+\t\tRTE_LOG(WARNING, VHOST_CONFIG,\n+\t\t\t\"last_used_idx (%u) and vq->used->idx (%u) mismatches; \"\n+\t\t\t\"some packets maybe resent for Tx and dropped for Rx\\n\",\n+\t\t\tvq->last_used_idx, vq->used->idx);\n+\t\tvq->last_used_idx = vq->used->idx;\n+\t\tvq->last_used_idx_res = vq->used->idx;\n+\t}\n+\n \tvq->log_guest_addr = addr->log_guest_addr;\n \n \tLOG_DEBUG(VHOST_CONFIG, \"(%d) mapped address desc: %p\\n\",\n", "prefixes": [ "dpdk-dev", "v2", "4/6" ] }