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 18CE9C43381 for ; Mon, 18 Feb 2019 14:55:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DF8DE21479 for ; Mon, 18 Feb 2019 14:55:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729852AbfBROzJ (ORCPT ); Mon, 18 Feb 2019 09:55:09 -0500 Received: from mail-wm1-f68.google.com ([209.85.128.68]:51712 "EHLO mail-wm1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729832AbfBROzJ (ORCPT ); Mon, 18 Feb 2019 09:55:09 -0500 Received: by mail-wm1-f68.google.com with SMTP id n19so5535477wmi.1 for ; Mon, 18 Feb 2019 06:55:08 -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=8X22xUNzyBITgd8y0sQOWbINFajpb27+VnnWJtIQNC4=; b=AWPR/Fljo0jEz6qW05+jwotejjXUMz79LT/hoqxHq2hLRax9TTKs9nbyVUB7tTOmHc hZnsfUcjTHcHiYEJhTBN87IVXGrMOi6HF2PLqrn3MZJC4KLWNgYYwWFfdjO1qopUhjfR d0r47ws/MWBqaj1Rxg3ZID24jfWCxvvt/1DoRxj9p815rPaLAb5n9cjXnu4M7mB3pIg6 FgoDULgRzHCcaIs4bxU+evGuSDi1hhu+qNLA4wDWo7GOlznNmPRVPFmZRg79PiXdI4V4 PVXmBltvOoHW2pwedDbq+H4HL33pTpcLhJS5vv2lFrgd7ACCUbTNbKbeJC/B5X7t45vF e+pQ== X-Gm-Message-State: AHQUAuawgIw63ouJgBFUigWUkyb/0COou/bmHuuCYdCu3WniAMRIKrGZ UOa4rpXDHSo12oTm+b33nQ== X-Google-Smtp-Source: AHgI3IYkiJsKfgfI+mLQdK3H8CuXA3eSQrXgVsxoOxNJGUSYsL9KXJmBOOYqeLbrXvE0smjU2QdRIw== X-Received: by 2002:a1c:f509:: with SMTP id t9mr17052007wmh.76.1550501707769; Mon, 18 Feb 2019 06:55:07 -0800 (PST) Received: from localhost.localdomain ([146.247.46.6]) by smtp.gmail.com with ESMTPSA id n11sm10172528wrw.60.2019.02.18.06.55.06 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 18 Feb 2019 06:55:06 -0800 (PST) From: Slavomir Kaslev To: rostedt@vmware.com, rostedt@goodmis.org Cc: linux-trace-devel@vger.kernel.org, slavomir.kaslev@gmail.com Subject: [RFC PATCH v7 08/13] trace-cmd: Use splice(2) for vsockets if available Date: Mon, 18 Feb 2019 16:54:44 +0200 Message-Id: <20190218145449.13360-9-kaslevs@vmware.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190218145449.13360-1-kaslevs@vmware.com> References: <20190218145449.13360-1-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 vsockets (Linux 4.20 and later) and use it, or fallback to read/write-ing otherwise. Signed-off-by: Slavomir Kaslev --- lib/trace-cmd/trace-recorder.c | 6 ++-- tracecmd/trace-record.c | 56 ++++++++++++++++++++++++++++++++-- 2 files changed, 56 insertions(+), 6 deletions(-) diff --git a/lib/trace-cmd/trace-recorder.c b/lib/trace-cmd/trace-recorder.c index 1b84bb5..d66f112 100644 --- a/lib/trace-cmd/trace-recorder.c +++ b/lib/trace-cmd/trace-recorder.c @@ -386,10 +386,8 @@ static long splice_data(struct tracecmd_recorder *recorder) ret = splice(recorder->brass[0], NULL, recorder->fd, NULL, read, recorder->fd_flags); if (ret < 0) { - if (errno != EAGAIN && errno != EINTR) { - warning("recorder error in splice output"); - return -1; - } + if (errno != EAGAIN && errno != EINTR) + return ret; return total_read; } else update_fd(recorder, ret); diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c index b401fd9..ca97758 100644 --- a/tracecmd/trace-record.c +++ b/tracecmd/trace-record.c @@ -2660,12 +2660,61 @@ 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 vsockets + * 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) @@ -2870,13 +2919,16 @@ create_recorder_instance(struct buffer_instance *instance, const char *file, int if (is_guest(instance)) { int fd; + unsigned int flags; fd = open_vsock(instance->cid, instance->client_ports[cpu]); if (fd < 0) die("Failed to connect to agent"); - return tracecmd_create_recorder_virt( - file, cpu, recorder_flags | TRACECMD_RECORD_NOSPLICE, fd); + flags = recorder_flags; + if (!can_splice_read_vsock()) + flags |= TRACECMD_RECORD_NOSPLICE; + return tracecmd_create_recorder_virt(file, cpu, flags, fd); } if (brass) -- 2.19.1