From patchwork Tue Apr 2 13:42:20 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Slavomir Kaslev X-Patchwork-Id: 10881735 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6779C184E for ; Tue, 2 Apr 2019 13:42:55 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5289B286C4 for ; Tue, 2 Apr 2019 13:42:55 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4757528895; Tue, 2 Apr 2019 13:42:55 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 860F928892 for ; Tue, 2 Apr 2019 13:42:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731753AbfDBNmy (ORCPT ); Tue, 2 Apr 2019 09:42:54 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:41051 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731745AbfDBNmx (ORCPT ); Tue, 2 Apr 2019 09:42:53 -0400 Received: by mail-wr1-f65.google.com with SMTP id r4so16724031wrq.8 for ; Tue, 02 Apr 2019 06:42:52 -0700 (PDT) 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=pF8lNHju2ICh9CEM/kthrPxNeplJ5k/gj4E/aMvPvs4=; b=qofbKUT7oSABUP+2W6BJKUvts++GWuSwmIs3pZO5Wbxr0o5RYKacPSI3hWxt6I+wXr S+WQbz9at4GMfz3nq1NzqgckPKixDqLocEtRj+FG74t0mHlbTRKS1jCw69MzUAjMF/oK EibMPByw925nr7fzTGflrcwUUf3TZtVd2MmJ2BVw+ODZuGsXrpliSogQA+x6xQHnTPrk ManhlpZrP3ETacGug2vu5k7HqZovuxMywTQg02lOybXrmELdXh8vtNkA5eerhYyWIjsQ kPLa/GUlSaN1uVoBi8J1XZ3Sv1hAz5UYhCZo1GcYPf3Q7kA+jTzgi/8TTJnQ8Girazci 7ZeQ== X-Gm-Message-State: APjAAAXCfK7GnGEEuIi4po85ykYy53D8lVYtBhq9WPUcTK8RHHRXFIYF JDWHmVorjOovlXb+RuPfIA== X-Google-Smtp-Source: APXvYqz0lSw+O8X2vxL6AsfOEyGQ6YGqNRc4Qvj3dl3L487AyRwFKSt7us8NwqYNjA3N4WvKz7FB7g== X-Received: by 2002:adf:cd83:: with SMTP id q3mr42723414wrj.228.1554212572283; Tue, 02 Apr 2019 06:42:52 -0700 (PDT) Received: from box.eng.vmware.com ([146.247.46.5]) by smtp.gmail.com with ESMTPSA id h84sm19207083wmf.15.2019.04.02.06.42.51 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 02 Apr 2019 06:42:51 -0700 (PDT) From: Slavomir Kaslev To: rostedt@goodmis.org Cc: linux-trace-devel@vger.kernel.org, slavomir.kaslev@gmail.com Subject: [RFC PATCH v8 07/11] trace-cmd: Use splice(2) for vsockets if available Date: Tue, 2 Apr 2019 16:42:20 +0300 Message-Id: <20190402134230.30988-15-kaslevs@vmware.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190402134230.30988-1-kaslevs@vmware.com> References: <20190402134230.30988-1-kaslevs@vmware.com> MIME-Version: 1.0 Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 9067811..6c51200 100644 --- a/tracecmd/trace-record.c +++ b/tracecmd/trace-record.c @@ -2654,12 +2654,61 @@ 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) @@ -2864,13 +2913,16 @@ 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)