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GET /api/patches/44916/?format=api
{ "id": 44916, "url": "https://patches.dpdk.org/api/patches/44916/?format=api", "web_url": "https://patches.dpdk.org/project/dpdk/patch/1537364560-4124-2-git-send-email-phil.yang@arm.com/", "project": { "id": 1, "url": "https://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": "<1537364560-4124-2-git-send-email-phil.yang@arm.com>", "list_archive_url": "https://inbox.dpdk.org/dev/1537364560-4124-2-git-send-email-phil.yang@arm.com", "date": "2018-09-19T13:42:39", "name": "[v2,2/3] kni: fix kni fifo synchronization", "commit_ref": null, "pull_url": null, "state": "superseded", "archived": true, "hash": "672e1f9f1ca57455d415dd68df0c2a31bdacc2fc", "submitter": { "id": 833, "url": "https://patches.dpdk.org/api/people/833/?format=api", "name": "Phil Yang", "email": "phil.yang@arm.com" }, "delegate": { "id": 1, "url": "https://patches.dpdk.org/api/users/1/?format=api", "username": "tmonjalo", "first_name": "Thomas", "last_name": "Monjalon", "email": "thomas@monjalon.net" }, "mbox": "https://patches.dpdk.org/project/dpdk/patch/1537364560-4124-2-git-send-email-phil.yang@arm.com/mbox/", "series": [ { "id": 1389, "url": "https://patches.dpdk.org/api/series/1389/?format=api", "web_url": "https://patches.dpdk.org/project/dpdk/list/?series=1389", "date": "2018-09-19T13:42:38", "name": "[v2,1/3] config: use one single config option for C11 memory model", "version": 2, "mbox": "https://patches.dpdk.org/series/1389/mbox/" } ], "comments": "https://patches.dpdk.org/api/patches/44916/comments/", "check": "warning", "checks": "https://patches.dpdk.org/api/patches/44916/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 [127.0.0.1])\n\tby dpdk.org (Postfix) with ESMTP id 14A53378B;\n\tWed, 19 Sep 2018 15:44:23 +0200 (CEST)", "from foss.arm.com (foss.arm.com [217.140.101.70])\n\tby dpdk.org (Postfix) with ESMTP id 4EEB2326C\n\tfor <dev@dpdk.org>; Wed, 19 Sep 2018 15:44:20 +0200 (CEST)", "from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249])\n\tby usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A9CAC1596;\n\tWed, 19 Sep 2018 06:44:19 -0700 (PDT)", "from localhost.localdomain (usa-sjc-mx-foss1.foss.arm.com\n\t[217.140.101.70])\n\tby usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id\n\tC431E3F703; Wed, 19 Sep 2018 06:44:17 -0700 (PDT)" ], "From": "Phil Yang <phil.yang@arm.com>", "To": "dev@dpdk.org", "Cc": "nd@arm.com, jerin.jacob@caviumnetworks.com,\n\tkkokkilagadda@caviumnetworks.com, Honnappa.Nagarahalli@arm.com,\n\tGavin.Hu@arm.com", "Date": "Wed, 19 Sep 2018 21:42:39 +0800", "Message-Id": "<1537364560-4124-2-git-send-email-phil.yang@arm.com>", "X-Mailer": "git-send-email 2.7.4", "In-Reply-To": "<1537364560-4124-1-git-send-email-phil.yang@arm.com>", "References": "<1537363820-3827-1-git-send-email-phil.yang@arm.com>\n\t<1537364560-4124-1-git-send-email-phil.yang@arm.com>", "Subject": "[dpdk-dev] [PATCH v2 2/3] kni: fix kni fifo synchronization", "X-BeenThere": "dev@dpdk.org", "X-Mailman-Version": "2.1.15", "Precedence": "list", "List-Id": "DPDK patches and discussions <dev.dpdk.org>", "List-Unsubscribe": "<https://mails.dpdk.org/options/dev>,\n\t<mailto:dev-request@dpdk.org?subject=unsubscribe>", "List-Archive": "<http://mails.dpdk.org/archives/dev/>", "List-Post": "<mailto:dev@dpdk.org>", "List-Help": "<mailto:dev-request@dpdk.org?subject=help>", "List-Subscribe": "<https://mails.dpdk.org/listinfo/dev>,\n\t<mailto:dev-request@dpdk.org?subject=subscribe>", "Errors-To": "dev-bounces@dpdk.org", "Sender": "\"dev\" <dev-bounces@dpdk.org>" }, "content": "With existing code in kni_fifo_put, rx_q values are not being updated\nbefore updating fifo_write. While reading rx_q in kni_net_rx_normal,\nThis is causing the sync issue on other core. The same situation happens\nin kni_fifo_get as well.\n\nSo syncing the values by adding C11 atomic memory barriers to make sure\nthe values being synced before updating fifo_write and fifo_read.\n\nFixes: 3fc5ca2 (\"kni: initial import\")\nSigned-off-by: Phil Yang <phil.yang@arm.com>\nReviewed-by: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>\nReviewed-by: Gavin Hu <Gavin.Hu@arm.com>\n---\n .../linuxapp/eal/include/exec-env/rte_kni_common.h | 5 ++++\n lib/librte_kni/rte_kni_fifo.h | 30 +++++++++++++++++++++-\n 2 files changed, 34 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 cfa9448..1fd713b 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@@ -54,8 +54,13 @@ struct rte_kni_request {\n * Writing should never overwrite the read position\n */\n struct rte_kni_fifo {\n+#ifndef RTE_USE_C11_MEM_MODEL\n \tvolatile unsigned write; /**< Next position to be written*/\n \tvolatile unsigned read; /**< Next position to be read */\n+#else\n+\tunsigned write; /**< Next position to be written*/\n+\tunsigned read; /**< Next position to be read */\n+#endif\n \tunsigned len; /**< Circular buffer length */\n \tunsigned elem_size; /**< Pointer size - for 32/64 bit OS */\n \tvoid *volatile buffer[]; /**< The buffer contains mbuf pointers */\ndiff --git a/lib/librte_kni/rte_kni_fifo.h b/lib/librte_kni/rte_kni_fifo.h\nindex ac26a8c..f4171a1 100644\n--- a/lib/librte_kni/rte_kni_fifo.h\n+++ b/lib/librte_kni/rte_kni_fifo.h\n@@ -28,8 +28,13 @@ kni_fifo_put(struct rte_kni_fifo *fifo, void **data, unsigned num)\n {\n \tunsigned i = 0;\n \tunsigned fifo_write = fifo->write;\n-\tunsigned fifo_read = fifo->read;\n \tunsigned new_write = fifo_write;\n+#ifdef RTE_USE_C11_MEM_MODEL\n+\tunsigned fifo_read = __atomic_load_n(&fifo->read,\n+\t\t\t\t\t\t __ATOMIC_ACQUIRE);\n+#else\n+\tunsigned fifo_read = fifo->read;\n+#endif\n \n \tfor (i = 0; i < num; i++) {\n \t\tnew_write = (new_write + 1) & (fifo->len - 1);\n@@ -39,7 +44,12 @@ kni_fifo_put(struct rte_kni_fifo *fifo, void **data, unsigned num)\n \t\tfifo->buffer[fifo_write] = data[i];\n \t\tfifo_write = new_write;\n \t}\n+#ifdef RTE_USE_C11_MEM_MODEL\n+\t__atomic_store_n(&fifo->write, fifo_write, __ATOMIC_RELEASE);\n+#else\n+\trte_smp_wmb();\n \tfifo->write = fifo_write;\n+#endif\n \treturn i;\n }\n \n@@ -51,7 +61,12 @@ kni_fifo_get(struct rte_kni_fifo *fifo, void **data, unsigned num)\n {\n \tunsigned i = 0;\n \tunsigned new_read = fifo->read;\n+#ifdef RTE_USE_C11_MEM_MODEL\n+\tunsigned fifo_write = __atomic_load_n(&fifo->write, __ATOMIC_ACQUIRE);\n+#else\n \tunsigned fifo_write = fifo->write;\n+#endif\n+\n \tfor (i = 0; i < num; i++) {\n \t\tif (new_read == fifo_write)\n \t\t\tbreak;\n@@ -59,7 +74,12 @@ kni_fifo_get(struct rte_kni_fifo *fifo, void **data, unsigned num)\n \t\tdata[i] = fifo->buffer[new_read];\n \t\tnew_read = (new_read + 1) & (fifo->len - 1);\n \t}\n+#ifdef RTE_USE_C11_MEM_MODEL\n+\t__atomic_store_n(&fifo->read, new_read, __ATOMIC_RELEASE);\n+#else\n+\trte_smp_wmb();\n \tfifo->read = new_read;\n+#endif\n \treturn i;\n }\n \n@@ -69,5 +89,13 @@ kni_fifo_get(struct rte_kni_fifo *fifo, void **data, unsigned num)\n static inline uint32_t\n kni_fifo_count(struct rte_kni_fifo *fifo)\n {\n+#ifdef RTE_USE_C11_MEM_MODEL\n+\tunsigned fifo_write = __atomic_load_n(&fifo->write,\n+\t\t\t\t\t\t __ATOMIC_ACQUIRE);\n+\tunsigned fifo_read = __atomic_load_n(&fifo->read,\n+\t\t\t\t\t\t __ATOMIC_ACQUIRE);\n+\treturn (fifo->len + fifo_write - fifo_read) & (fifo->len - 1);\n+#else\n \treturn (fifo->len + fifo->write - fifo->read) & (fifo->len - 1);\n+#endif\n }\n", "prefixes": [ "v2", "2/3" ] }