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=-15.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 16DD4C433E0 for ; Fri, 5 Feb 2021 20:21:49 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5F9D064FBA for ; Fri, 5 Feb 2021 20:21:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5F9D064FBA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:34408 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l87bv-0003NK-C0 for qemu-devel@archiver.kernel.org; Fri, 05 Feb 2021 15:21:47 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:59858) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l87aA-00020i-L5 for qemu-devel@nongnu.org; Fri, 05 Feb 2021 15:19:58 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:47358) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l87a8-0005zV-WC for qemu-devel@nongnu.org; Fri, 05 Feb 2021 15:19:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1612556396; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=LLXxOpjbl3RvI1qQFufN6zEpaY8cWmrAGT3wMg1DQGc=; b=JPqDbSUqW8A32plnqO/abj+nMKEekhc1d6znyZT6Y637vNb1pNC8wlzBQ7U8MZ8J97Vbzl rKyp/1Lharg0XHV95GXg/ygLkiDPISWoC5aIKgf8EcfHw8MQC71hu0f1sL1EeUxCwJlUR/ zNTDSDfd3yonvdYei+aQvdnDv24s/kc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-459-PK0-xrQ-P_yq2fey4op2ew-1; Fri, 05 Feb 2021 15:19:50 -0500 X-MC-Unique: PK0-xrQ-P_yq2fey4op2ew-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DF8B3107ACC7; Fri, 5 Feb 2021 20:19:49 +0000 (UTC) Received: from localhost (ovpn-114-98.ams2.redhat.com [10.36.114.98]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8C28019727; Fri, 5 Feb 2021 20:19:49 +0000 (UTC) Date: Fri, 5 Feb 2021 20:19:48 +0000 From: "Richard W.M. Jones" To: Eric Blake Subject: Re: [PATCH v2] qemu-nbd: Use SOMAXCONN for socket listen() backlog Message-ID: <20210205201948.GH30079@redhat.com> References: <20210205185705.1502071-1-eblake@redhat.com> MIME-Version: 1.0 In-Reply-To: <20210205185705.1502071-1-eblake@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=rjones@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.124; envelope-from=rjones@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.352, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: berrange@redhat.com, qemu-devel@nongnu.org, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Feb 05, 2021 at 12:57:05PM -0600, Eric Blake wrote: > Our default of a backlog of 1 connection is rather puny, particularly > for scenarios where we expect multiple listeners to connect (such as > qemu-nbd -e X). This is especially important for Unix sockets, as a > definite benefit to clients: at least on Linux, a client trying to > connect to a Unix socket with a backlog gets an EAGAIN failure with no > way to poll() for when the backlog is no longer present short of > sleeping an arbitrary amount of time before retrying. > > See https://bugzilla.redhat.com/1925045 for a demonstration of where > our low backlog prevents libnbd from connecting as many parallel > clients as it wants. > > Reported-by: Richard W.M. Jones > Signed-off-by: Eric Blake > --- > > v2: target the correct API used by qemu-nbd, rather than an unrelated > legacy wrapper [Dan] > > qemu-nbd.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/qemu-nbd.c b/qemu-nbd.c > index 608c63e82a25..cd20ee73be19 100644 > --- a/qemu-nbd.c > +++ b/qemu-nbd.c > @@ -965,7 +965,8 @@ int main(int argc, char **argv) > server = qio_net_listener_new(); > if (socket_activation == 0) { > saddr = nbd_build_socket_address(sockpath, bindto, port); > - if (qio_net_listener_open_sync(server, saddr, 1, &local_err) < 0) { > + if (qio_net_listener_open_sync(server, saddr, SOMAXCONN, > + &local_err) < 0) { > object_unref(OBJECT(server)); > error_report_err(local_err); > exit(EXIT_FAILURE); This one works: Tested-by: Richard W.M. Jones Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top