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GET /api/patches/41647/?format=api
{ "id": 41647, "url": "http://patchwork.dpdk.org/api/patches/41647/?format=api", "web_url": "http://patchwork.dpdk.org/project/dpdk/patch/164824cc66c16755416bb8d3d6911385f52f8c1e.1530092380.git.anatoly.burakov@intel.com/", "project": { "id": 1, "url": "http://patchwork.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": "<164824cc66c16755416bb8d3d6911385f52f8c1e.1530092380.git.anatoly.burakov@intel.com>", "list_archive_url": "https://inbox.dpdk.org/dev/164824cc66c16755416bb8d3d6911385f52f8c1e.1530092380.git.anatoly.burakov@intel.com", "date": "2018-06-27T09:44:25", "name": "ipc: fix locking while sending messages", "commit_ref": null, "pull_url": null, "state": "accepted", "archived": true, "hash": "79d0f9a3c66c299ec0cd76f3d727dea557ff1eba", "submitter": { "id": 4, "url": "http://patchwork.dpdk.org/api/people/4/?format=api", "name": "Anatoly Burakov", "email": "anatoly.burakov@intel.com" }, "delegate": { "id": 1, "url": "http://patchwork.dpdk.org/api/users/1/?format=api", "username": "tmonjalo", "first_name": "Thomas", "last_name": "Monjalon", "email": "thomas@monjalon.net" }, "mbox": "http://patchwork.dpdk.org/project/dpdk/patch/164824cc66c16755416bb8d3d6911385f52f8c1e.1530092380.git.anatoly.burakov@intel.com/mbox/", "series": [ { "id": 258, "url": "http://patchwork.dpdk.org/api/series/258/?format=api", "web_url": "http://patchwork.dpdk.org/project/dpdk/list/?series=258", "date": "2018-06-27T09:44:25", "name": "ipc: fix locking while sending messages", "version": 1, "mbox": "http://patchwork.dpdk.org/series/258/mbox/" } ], "comments": "http://patchwork.dpdk.org/api/patches/41647/comments/", "check": "success", "checks": "http://patchwork.dpdk.org/api/patches/41647/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 E032E1BE1C;\n\tWed, 27 Jun 2018 11:44:29 +0200 (CEST)", "from mga05.intel.com (mga05.intel.com [192.55.52.43])\n\tby dpdk.org (Postfix) with ESMTP id 5324D1B8C8;\n\tWed, 27 Jun 2018 11:44:28 +0200 (CEST)", "from fmsmga004.fm.intel.com ([10.253.24.48])\n\tby fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384;\n\t27 Jun 2018 02:44:27 -0700", "from irvmail001.ir.intel.com ([163.33.26.43])\n\tby fmsmga004.fm.intel.com with ESMTP; 27 Jun 2018 02:44:26 -0700", "from sivswdev01.ir.intel.com (sivswdev01.ir.intel.com\n\t[10.237.217.45])\n\tby irvmail001.ir.intel.com (8.14.3/8.13.6/MailSET/Hub) with ESMTP id\n\tw5R9iPT8025963; Wed, 27 Jun 2018 10:44:25 +0100", "from sivswdev01.ir.intel.com (localhost [127.0.0.1])\n\tby sivswdev01.ir.intel.com with ESMTP id w5R9iPRN014459;\n\tWed, 27 Jun 2018 10:44:25 +0100", "(from aburakov@localhost)\n\tby sivswdev01.ir.intel.com with LOCAL id w5R9iPIp014455;\n\tWed, 27 Jun 2018 10:44:25 +0100" ], "X-Amp-Result": "SKIPPED(no attachment in message)", "X-Amp-File-Uploaded": "False", "X-ExtLoop1": "1", "X-IronPort-AV": "E=Sophos;i=\"5.51,278,1526367600\"; d=\"scan'208\";a=\"66720547\"", "From": "Anatoly Burakov <anatoly.burakov@intel.com>", "To": "dev@dpdk.org", "Cc": "qi.z.zhang@intel.com, stable@dpdk.org", "Date": "Wed, 27 Jun 2018 10:44:25 +0100", "Message-Id": "<164824cc66c16755416bb8d3d6911385f52f8c1e.1530092380.git.anatoly.burakov@intel.com>", "X-Mailer": "git-send-email 1.7.0.7", "Subject": "[dpdk-dev] [PATCH] ipc: fix locking while sending messages", "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": "Previously, we were putting an exclusive lock to prevent secondary\nprocesses spinning up while we are sending our messages. However,\nusing exclusive locks had an effect of disallowing multiple\nsimultaenous unrelated messages/requests being sent, which was\nnot the intention behind locking.\n\nFix it to put a shared lock on the directory. That way, we still\nprevent secondary process initializations while sending data over\nIPC, but allow multiple unrelated transmissions to proceed.\n\nFixes: 89f1fe7e6d95 (\"eal: lock IPC directory on init and send\")\nCc: stable@dpdk.org\n\nSigned-off-by: Anatoly Burakov <anatoly.burakov@intel.com>\n---\n\nNotes:\n This patch is needed for multiprocess hotplug support [1], to avoid cases\n where multiple requests deadlock while in progress.\n \n [1] http://patches.dpdk.org/project/dpdk/list/?series=252\n\n lib/librte_eal/common/eal_common_proc.c | 6 +++---\n 1 file changed, 3 insertions(+), 3 deletions(-)", "diff": "diff --git a/lib/librte_eal/common/eal_common_proc.c b/lib/librte_eal/common/eal_common_proc.c\nindex 707d8ab30..f010ef59e 100644\n--- a/lib/librte_eal/common/eal_common_proc.c\n+++ b/lib/librte_eal/common/eal_common_proc.c\n@@ -786,7 +786,7 @@ mp_send(struct rte_mp_msg *msg, const char *peer, int type)\n \n \tdir_fd = dirfd(mp_dir);\n \t/* lock the directory to prevent processes spinning up while we send */\n-\tif (flock(dir_fd, LOCK_EX)) {\n+\tif (flock(dir_fd, LOCK_SH)) {\n \t\tRTE_LOG(ERR, EAL, \"Unable to lock directory %s\\n\",\n \t\t\tmp_dir_path);\n \t\trte_errno = errno;\n@@ -1020,7 +1020,7 @@ rte_mp_request_sync(struct rte_mp_msg *req, struct rte_mp_reply *reply,\n \n \tdir_fd = dirfd(mp_dir);\n \t/* lock the directory to prevent processes spinning up while we send */\n-\tif (flock(dir_fd, LOCK_EX)) {\n+\tif (flock(dir_fd, LOCK_SH)) {\n \t\tRTE_LOG(ERR, EAL, \"Unable to lock directory %s\\n\",\n \t\t\tmp_dir_path);\n \t\tclosedir(mp_dir);\n@@ -1146,7 +1146,7 @@ rte_mp_request_async(struct rte_mp_msg *req, const struct timespec *ts,\n \tdir_fd = dirfd(mp_dir);\n \n \t/* lock the directory to prevent processes spinning up while we send */\n-\tif (flock(dir_fd, LOCK_EX)) {\n+\tif (flock(dir_fd, LOCK_SH)) {\n \t\tRTE_LOG(ERR, EAL, \"Unable to lock directory %s\\n\",\n \t\t\tmp_dir_path);\n \t\trte_errno = errno;\n", "prefixes": [] }