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 26995C48BD6 for ; Wed, 26 Jun 2019 10:52:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 026D020656 for ; Wed, 26 Jun 2019 10:52:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="oZFkrozt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726948AbfFZKw0 (ORCPT ); Wed, 26 Jun 2019 06:52:26 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:35247 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726992AbfFZKw0 (ORCPT ); Wed, 26 Jun 2019 06:52:26 -0400 Received: by mail-wr1-f65.google.com with SMTP id f15so2207277wrp.2 for ; Wed, 26 Jun 2019 03:52:24 -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=0ZoJEAyBgB4UNUmEIVNa+o5MCXZSNvQUkLr7LJOPY8s=; b=oZFkroztP2sfIJfzdSF5v1YHZbEbwUwmapKamAEiUBYTxp4Cxgb1jnAq7rHY3oA6Zi rOwE6JHfwxBQQ5UlZiquYrMUMKVK7sHm4C21lMNqwoV1ibAq0FLvwNO8gHH0DtNZWX3W ZfM8ekkkesLaZogiSDCL/y53p97ViksURE55dX0MHI1hxiTF7vIcijqHUi+1G2BI8DHx DcBdXkpiDfRAS7U5pQ0ktbMW/QnSFnQbIhhnVgxU/CxGnhfRxMH3vhmrdrF8bbpPG4a+ dVR8ZgvY82CeqSpgfVWa05+bu0aTtjOI/af6CtoQlGxfNm57eYb+Vxka9QUCUBxPil4w SoDg== 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=0ZoJEAyBgB4UNUmEIVNa+o5MCXZSNvQUkLr7LJOPY8s=; b=Gv4IczHlJHkUnCO0VkGf8vMgnVKU8gZiVN4iIfYXFcVw13J7C4OY1ljJYDo55xljsb EcB+/8p1WV/U6o4KoyJtSEAaz9EttEzd14Qlc5regGrMvI7YiRgTXtVoMo+pFr6Aomso hDfPN/c+dom80V9SY096YazFjfBA4sdYxFqgiCWHhwackse4fqjsqahbYcNDOjjL2bqO R5hLJK1SVSYNTTjy1QDGds27YuM0InnjRFCC/WXAgAe/uVq3s04XnpdpMfIAnxdt1F3u dVGMDxzG2xwRnq40HtDZ1bxjBnM+359+pvWgrPsZQGVACtPkAz4R94uOAJvsuvxtVlQa sHsA== X-Gm-Message-State: APjAAAVw7U7l2Sslee6BbribtPkOQ77bMCsrL3m3l+6WyH+zPNDJ8os+ tilQh+bZuK1bSlsrztsMVA== X-Google-Smtp-Source: APXvYqwBBe4Bh0IlbksAwtb2qvHsSBuapARIh8ziE+gr2/E99SeIUE+XPB1S/3f5BgLUUROf0OpQAQ== X-Received: by 2002:adf:dfc5:: with SMTP id q5mr3374909wrn.142.1561546344256; Wed, 26 Jun 2019 03:52:24 -0700 (PDT) Received: from box.eng.vmware.com ([146.247.46.5]) by smtp.gmail.com with ESMTPSA id s10sm15456929wrt.49.2019.06.26.03.52.23 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Wed, 26 Jun 2019 03:52:23 -0700 (PDT) From: "Slavomir Kaslev (VMware)" To: rostedt@goodmis.org Cc: linux-trace-devel@vger.kernel.org Subject: [PATCH v13 07/13] trace-cmd: Use splice(2) for vsockets if available Date: Wed, 26 Jun 2019 13:52:03 +0300 Message-Id: <20190626105209.13200-8-slavomir.kaslev@gmail.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190626105209.13200-1-slavomir.kaslev@gmail.com> References: <20190626105209.13200-1-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 a99aa63..130eab7 100644 --- a/tracecmd/trace-record.c +++ b/tracecmd/trace-record.c @@ -2718,12 +2718,61 @@ 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 -errno; + + 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) @@ -2927,13 +2976,16 @@ 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