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{
    "id": 395,
    "url": "https://patches.dpdk.org/api/patches/395/",
    "web_url": "https://patches.dpdk.org/patch/395/",
    "project": {
        "id": 1,
        "url": "https://patches.dpdk.org/api/projects/1/",
        "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"
    },
    "msgid": "<1410948102-12740-5-git-send-email-bruce.richardson@intel.com>",
    "date": "2014-09-17T10:01:41",
    "name": "[dpdk-dev,4/5] mbuf: add userdata pointer field",
    "commit_ref": null,
    "pull_url": null,
    "state": "superseded",
    "archived": true,
    "hash": "8a583a7892bf1a1b3425e48e7a24ac2d8db9033e",
    "submitter": {
        "id": 20,
        "url": "https://patches.dpdk.org/api/people/20/",
        "name": "Bruce Richardson",
        "email": "bruce.richardson@intel.com"
    },
    "delegate": null,
    "mbox": "https://patches.dpdk.org/patch/395/mbox/",
    "series": [],
    "comments": "https://patches.dpdk.org/api/patches/395/comments/",
    "check": "pending",
    "checks": "https://patches.dpdk.org/api/patches/395/checks/",
    "tags": {},
    "headers": {
        "Delivered-To": "patchwork@dpdk.org",
        "List-Subscribe": "<http://dpdk.org/ml/listinfo/dev>,\n\t<mailto:dev-request@dpdk.org?subject=subscribe>",
        "X-Original-To": "patchwork@dpdk.org",
        "Date": "Wed, 17 Sep 2014 11:01:41 +0100",
        "In-Reply-To": "<1410948102-12740-1-git-send-email-bruce.richardson@intel.com>",
        "Precedence": "list",
        "X-BeenThere": "dev@dpdk.org",
        "References": "<1410948102-12740-1-git-send-email-bruce.richardson@intel.com>",
        "X-Mailer": "git-send-email 1.7.4.1",
        "List-Archive": "<http://dpdk.org/ml/archives/dev/>",
        "To": "dev@dpdk.org",
        "Errors-To": "dev-bounces@dpdk.org",
        "Received": [
            "from [92.243.14.124] (localhost [IPv6:::1])\n\tby dpdk.org (Postfix) with ESMTP id DDDAEB3AA;\n\tWed, 17 Sep 2014 11:56:40 +0200 (CEST)",
            "from mga02.intel.com (mga02.intel.com [134.134.136.20])\n\tby dpdk.org (Postfix) with ESMTP id EB452B39B\n\tfor <dev@dpdk.org>; Wed, 17 Sep 2014 11:56:38 +0200 (CEST)",
            "from orsmga002.jf.intel.com ([10.7.209.21])\n\tby orsmga101.jf.intel.com with ESMTP; 17 Sep 2014 03:02:16 -0700",
            "from irvmail001.ir.intel.com ([163.33.26.43])\n\tby orsmga002.jf.intel.com with ESMTP; 17 Sep 2014 03:01:43 -0700",
            "from sivswdev02.ir.intel.com (sivswdev02.ir.intel.com\n\t[10.237.217.46])\n\tby irvmail001.ir.intel.com (8.14.3/8.13.6/MailSET/Hub) with ESMTP id\n\ts8HA1g0r017179; Wed, 17 Sep 2014 11:01:42 +0100",
            "from sivswdev02.ir.intel.com (localhost [127.0.0.1])\n\tby sivswdev02.ir.intel.com with ESMTP id s8HA1gRW015704;\n\tWed, 17 Sep 2014 11:01:42 +0100",
            "(from bricha3@localhost)\n\tby sivswdev02.ir.intel.com with  id s8HA1gJK015698;\n\tWed, 17 Sep 2014 11:01:42 +0100"
        ],
        "From": "Bruce Richardson <bruce.richardson@intel.com>",
        "List-Help": "<mailto:dev-request@dpdk.org?subject=help>",
        "X-ExtLoop1": "1",
        "Message-Id": "<1410948102-12740-5-git-send-email-bruce.richardson@intel.com>",
        "Sender": "\"dev\" <dev-bounces@dpdk.org>",
        "List-Id": "patches and discussions about DPDK <dev.dpdk.org>",
        "Subject": "[dpdk-dev] [PATCH 4/5] mbuf: add userdata pointer field",
        "List-Unsubscribe": "<http://dpdk.org/ml/options/dev>,\n\t<mailto:dev-request@dpdk.org?subject=unsubscribe>",
        "Return-Path": "<dev-bounces@dpdk.org>",
        "X-IronPort-AV": "E=Sophos;i=\"5.04,540,1406617200\"; d=\"scan'208\";a=\"604080467\"",
        "List-Post": "<mailto:dev@dpdk.org>",
        "X-Mailman-Version": "2.1.15"
    },
    "content": "While some applications may store metadata about packets in the packet\nmbuf headroom, this is not a workable solution for packet metadata which\nis either:\n* larger than the headroom (or headroom is needed for adding pkt headers)\n* needs to be shared or copied among packets\n\nTo support these use cases in applications, we reserve a general\n\"userdata\" pointer field inside the second cache-line of the mbuf. This\nis better than having the application store the pointer to the external\nmetadata in the packet headroom, as it saves an additional cache-line\nfrom being used.\n\nApart from storing metadata, this field also provides a general 8-byte\nscratch space inside the mbuf for any other application uses that are\napplicable.\n\nSigned-off-by: Bruce Richardson <bruce.richardson@intel.com>\n---\n lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h | 3 ++-\n lib/librte_mbuf/rte_mbuf.h                                    | 3 +++\n 2 files changed, 5 insertions(+), 1 deletion(-)",
    "diff": "diff --git a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h\nindex 25ed672..d27e891 100644\n--- a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h\n+++ b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h\n@@ -117,7 +117,8 @@ struct rte_kni_mbuf {\n \tuint16_t data_len;      /**< Amount of data in segment buffer. */\n \tuint32_t pkt_len;       /**< Total pkt len: sum of all segment data_len. */\n \tchar pad3[8];\n-\tvoid *pool __attribute__((__aligned__(64)));\n+\tvoid *pad4 __attribute__((__aligned__(64)));\n+\tvoid *pool;\n \tvoid *next;\n };\n \ndiff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h\nindex 8e27d2e..b1acfc3 100644\n--- a/lib/librte_mbuf/rte_mbuf.h\n+++ b/lib/librte_mbuf/rte_mbuf.h\n@@ -172,6 +172,9 @@ struct rte_mbuf {\n \n \t/* second cache line - fields only used in slow path or on TX */\n \tMARKER cacheline1 __rte_cache_aligned;\n+\n+\tvoid *userdata;           /**< Can be used for external metadata */\n+\n \tstruct rte_mempool *pool; /**< Pool from which mbuf was allocated. */\n \tstruct rte_mbuf *next;    /**< Next segment of scattered packet. */\n \n",
    "prefixes": [
        "dpdk-dev",
        "4/5"
    ]
}