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=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 C39B7C31E5B for ; Tue, 18 Jun 2019 14:45:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9D1FC20B1F for ; Tue, 18 Jun 2019 14:45:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="K1baRbfW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729242AbfFROpL (ORCPT ); Tue, 18 Jun 2019 10:45:11 -0400 Received: from mail-wr1-f68.google.com ([209.85.221.68]:42786 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727105AbfFROpL (ORCPT ); Tue, 18 Jun 2019 10:45:11 -0400 Received: by mail-wr1-f68.google.com with SMTP id x17so14288070wrl.9 for ; Tue, 18 Jun 2019 07:45:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=m8UNWMrEp+kR42c3wAycq8mWrehDVI+QGPZqqALkLZQ=; b=K1baRbfW+nDv/sHk8d8ns+XZG2avhHrRsf3XwtRk9YDM2wBdc3+x4XxqQWHiZFLeSf StLfX2FWiBwYrUfT5CgbYMo3QkG+XIgyJdCxHx3cKKsIlaylxCG2BNqwjkCCwA9YH+/z U0Ok+sDf3IB5quw1/SwWySmQBGAtFdmlyoYARyaKHuywBr1SfqvneL3tb84vbS64JgZK V1JXT3yJI5ek+oxclcmtvs/K07znoYRa7KD24k4ZhQrxWpilKi/nbdToRs7CHPBuftMk YnJsxePazyt5V1dpoiXWPAzKrqkLJ0KVfEf7zJqwgNaTbVMCDbXpqG8c1T+Czs4LmG9Z YnPw== 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=m8UNWMrEp+kR42c3wAycq8mWrehDVI+QGPZqqALkLZQ=; b=oVJtsALMB3wySaq4+S1A81HD0evMz20LvCsmsj4cvO2/B2FIH4jsnqEFfkmtJPzDeh yhw/BFbIwZ8kE4PShmfgGuGoNmVOf1VJpdMuJpbKDV10BSExBolZasLolMxrJPEQUXLa XFMerWU3qcaZDHbIhsKCP5kdXOIF8ahSxTwGDIglWZcewUW7pQb75jBNjBzYp3fAT2eh 2S/izj2UCkLQ5JHRe6I/cQdLjgUNK3kOy/ONR7TjnL1oJ1dCG5caODzuek5pHhEftUVn KCyQpC21z4Qj21upVjbHnVe30tDAyhkEXifOqGxVR0FdAczsPX5Ugg9Q+qABU5v34io5 R0xQ== X-Gm-Message-State: APjAAAVqAaT84Fm2YhdE+0AObaDH+BpfY9F64A8VoXWKkuN6AZiui8lp 4e9sBgLNdEWm3/BGZ8AIWgjeLII= X-Google-Smtp-Source: APXvYqwEj7w3sqSUeDLelvZJ4CUIE8J8CcV6YI1cxZADyT/oxe8b7JC5xlDYYd9k12Qmna7fZyJoog== X-Received: by 2002:a5d:4489:: with SMTP id j9mr37727327wrq.15.1560869109286; Tue, 18 Jun 2019 07:45:09 -0700 (PDT) Received: from box.eng.vmware.com ([146.247.46.5]) by smtp.gmail.com with ESMTPSA id r3sm17686071wrr.61.2019.06.18.07.45.08 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 18 Jun 2019 07:45:08 -0700 (PDT) From: "Slavomir Kaslev (VMware)" To: rostedt@goodmis.org Cc: linux-trace-devel@vger.kernel.org Subject: [PATCH v12 07/13] trace-cmd: Use splice(2) for vsockets if available Date: Tue, 18 Jun 2019 17:44:49 +0300 Message-Id: <20190618144455.3954-8-slavomir.kaslev@gmail.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190618144455.3954-1-slavomir.kaslev@gmail.com> References: <20190618144455.3954-1-slavomir.kaslev@gmail.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 From: Slavomir Kaslev 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 --- tracecmd/trace-record.c | 56 +++++++++++++++++++++++++++++++++++++++-- 1 file changed, 54 insertions(+), 2 deletions(-) diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c index dfad8f2..f6e5c7e 100644 --- a/tracecmd/trace-record.c +++ b/tracecmd/trace-record.c @@ -2715,12 +2715,61 @@ 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) @@ -2925,13 +2974,16 @@ 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) -- 2.20.1