From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2569C43387 for ; Wed, 16 Jan 2019 13:43:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7AB61206C2 for ; Wed, 16 Jan 2019 13:43:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390597AbfAPNnb (ORCPT ); Wed, 16 Jan 2019 08:43:31 -0500 Received: from mail-wm1-f65.google.com ([209.85.128.65]:39732 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2393238AbfAPNnb (ORCPT ); Wed, 16 Jan 2019 08:43:31 -0500 Received: by mail-wm1-f65.google.com with SMTP id y8so2028685wmi.4 for ; Wed, 16 Jan 2019 05:43:29 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=O7V6rYXgz87+rMg4j9CZD+X3Wk8alHg55qvqsEDG/MY=; b=LpfowkoF4ptlu/48er9GEom8oIvGScb61ccBcMHRQDA8H6M8AgjTl/KXLcFp9XrgAi xV0fwGPON+DFvKuaw0oV3bvza3MrDeTi/lxMV4JUaNsUoYxmkUz7fYJPwX8abHrq2YW2 YJEY/eByyO4djtW8zhQJFdnOfNH2CTzbOW71HuGCy6pvUxCJHVcNuTNoyCq066ZNM2H9 qJWfAJNiYRjkpbaR4emT2B+CB12tgaWAPtUu/0Ecfg1mwNr/rvwxPKxI9eQpOnW5qqp4 fZ6MVNRxoHUr4LBdPkOPkPJBJalZ7hzxLp0+Nik/l6teCK5H81xlHgaNP7bv6U92Q13Q yGOg== X-Gm-Message-State: AJcUukeQU2EqziCQhMXeIykPKbUC3Yk+wEgwwO5BP5QfLlKSN8gxZoFA 57aInlLYJmgrNQFADde4EP/M6cKGLw== X-Google-Smtp-Source: ALg8bN6e8KVwqNmWuD2+mv6m+i9V/tPt7IIa84QhDbQHy757WAEgnxX53troWneQEumJ7MTM7XBGAw== X-Received: by 2002:a1c:570d:: with SMTP id l13mr7865560wmb.139.1547646208950; Wed, 16 Jan 2019 05:43:28 -0800 (PST) Received: from box.eng.vmware.com ([146.247.46.5]) by smtp.gmail.com with ESMTPSA id y13sm34636460wme.2.2019.01.16.05.43.27 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 16 Jan 2019 05:43:28 -0800 (PST) From: Slavomir Kaslev To: linux-trace-devel@vger.kernel.org Cc: rostedt@goodmis.org, ykaradzhov@vmware.com, tstoyanov@vmware.com Subject: [PATCH v4 8/8] trace-cmd: Use splice(2) for vsock sockets if available Date: Wed, 16 Jan 2019 15:43:07 +0200 Message-Id: <20190116134307.4185-9-kaslevs@vmware.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190116134307.4185-1-kaslevs@vmware.com> References: <20190116134307.4185-1-kaslevs@vmware.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org Detect if splice(2) reading is supported for vsock sockets (Linux 4.20 and later) and use it, or fallback to read/write-ing otherwise. Signed-off-by: Slavomir Kaslev --- tracecmd/trace-record.c | 59 ++++++++++++++++++++++++++++++++++++++--- 1 file changed, 56 insertions(+), 3 deletions(-) diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c index 1622b5e..cd80462 100644 --- a/tracecmd/trace-record.c +++ b/tracecmd/trace-record.c @@ -2658,12 +2658,61 @@ static int open_vsock(unsigned int cid, unsigned int port) return sd; } + +static int try_splice_read_vsock(void) +{ + int ret, sd, brass[2]; + + sd = socket(AF_VSOCK, SOCK_STREAM, 0); + if (sd < 0) + return sd; + + ret = pipe(brass); + if (ret < 0) + goto out_close_sd; + + /* + * On kernels that don't support splice reading from vsock sockets + * this will fail with EINVAL, or ENOTCONN otherwise. + * Technically, it should never succeed but if it does, claim splice + * reading is supported. + */ + ret = splice(sd, NULL, brass[1], NULL, 10, 0); + if (ret < 0) + ret = errno != EINVAL; + else + ret = 1; + + close(brass[0]); + close(brass[1]); +out_close_sd: + close(sd); + return ret; +} + +static bool can_splice_read_vsock(void) +{ + static bool initialized, res; + + if (initialized) + return res; + + res = try_splice_read_vsock() > 0; + initialized = true; + return res; +} + #else static inline int open_vsock(unsigned int cid, unsigned int port) { die("vsock is not supported"); return -1; } + +static bool can_splice_read_vsock(void) +{ + return false; +} #endif static int do_accept(int sd) @@ -2868,13 +2917,16 @@ create_recorder_instance(struct buffer_instance *instance, const char *file, int if (instance->flags & BUFFER_FL_GUEST) { int sd; + unsigned int flags; sd = open_vsock(instance->cid, instance->client_ports[cpu]); if (sd < 0) die("Failed to connect to agent"); - return tracecmd_create_recorder_virt( - file, cpu, recorder_flags | TRACECMD_RECORD_NOSPLICE, sd); + flags = recorder_flags; + if (!can_splice_read_vsock()) + flags |= TRACECMD_RECORD_NOSPLICE; + return tracecmd_create_recorder_virt(file, cpu, flags, sd); } if (brass) @@ -2928,7 +2980,8 @@ static int create_recorder(struct buffer_instance *instance, int cpu, if (instance->flags & BUFFER_FL_AGENT) { fd = do_accept(instance->fds[cpu]); - flags |= TRACECMD_RECORD_NOSPLICE; + if (!can_splice_read_vsock()) + flags |= TRACECMD_RECORD_NOSPLICE; } else { fd = connect_port(host, instance->client_ports[cpu]); } -- 2.19.1