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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 588E0C34047 for ; Wed, 19 Feb 2020 14:58:58 +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 22F2D207FD for ; Wed, 19 Feb 2020 14:58:58 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="fI4d12tt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 22F2D207FD 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]:53982 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j4QoT-00045T-AQ for qemu-devel@archiver.kernel.org; Wed, 19 Feb 2020 09:58:57 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:54109) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j4QnK-0002Sc-26 for qemu-devel@nongnu.org; Wed, 19 Feb 2020 09:57:47 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j4QnI-0005dS-Lu for qemu-devel@nongnu.org; Wed, 19 Feb 2020 09:57:46 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:40507 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j4QnI-0005d4-Hl for qemu-devel@nongnu.org; Wed, 19 Feb 2020 09:57:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582124264; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Y5i0bYGI2Qqaxgl8TlI49IXiVSpNYG6jcrYN0KNd3fI=; b=fI4d12tt4ITtZYNJJJCERV7KC7rF3wqa43TSO61btna4TbQSOgXfyKHEWvwMy8Tk2jzvAI IbohHxIEMJUKf1wm9pzB/b2MD3lRFnr2ez6yabrFrd0GhsKv6YnGOnWLElLtcLR0cgZ3XL EoUMWnpUtyZa2YMtf03cZPftHJmqyEA= 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-121-E8lLcxGFOWmGydQI2BzVmg-1; Wed, 19 Feb 2020 09:57:38 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 92C7F1034B20; Wed, 19 Feb 2020 14:57:37 +0000 (UTC) Received: from linux.fritz.box (unknown [10.36.118.4]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6A9C886CCC; Wed, 19 Feb 2020 14:57:36 +0000 (UTC) Date: Wed, 19 Feb 2020 15:57:34 +0100 From: Kevin Wolf To: Wolfgang Bumiller Subject: Re: [PATCH v5 2/4] vl: Initialise main loop earlier Message-ID: <20200219145734.GB6464@linux.fritz.box> References: <20200218154036.28562-1-kwolf@redhat.com> <20200218154036.28562-3-kwolf@redhat.com> <20200219140739.tfn7p5xsbxofoajq@olga.proxmox.com> MIME-Version: 1.0 In-Reply-To: <20200219140739.tfn7p5xsbxofoajq@olga.proxmox.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-MC-Unique: E8lLcxGFOWmGydQI2BzVmg-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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: marcandre.lureau@gmail.com, qemu-devel@nongnu.org, qemu-block@nongnu.org, armbru@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 19.02.2020 um 15:07 hat Wolfgang Bumiller geschrieben: > On Tue, Feb 18, 2020 at 04:40:34PM +0100, Kevin Wolf wrote: > > We want to be able to use qemu_aio_context in the monitor > > initialisation. > >=20 > > Signed-off-by: Kevin Wolf > > Reviewed-by: Marc-Andr=E9 Lureau > > Reviewed-by: Markus Armbruster > > --- > > vl.c | 10 +++++----- > > 1 file changed, 5 insertions(+), 5 deletions(-) > >=20 > > diff --git a/vl.c b/vl.c > > index 794f2e5733..98bc51e089 100644 > > --- a/vl.c > > +++ b/vl.c > > @@ -2894,6 +2894,11 @@ int main(int argc, char **argv, char **envp) > > runstate_init(); > > precopy_infrastructure_init(); > > postcopy_infrastructure_init(); > > + > > + if (qemu_init_main_loop(&main_loop_err)) { > > + error_report_err(main_loop_err); > > + exit(1); > > + } > > monitor_init_globals(); >=20 > This is a tiny bit scary, as we now have around 1kloc of code between > here and os_daemonize() where in the future we may accidentally cause > the aio context's on-demand thread pool to spawn before fork()ing > (silently losing the threads again - we did have such an issue right > there in monitor_init_globals() in the past) I don't think it's that bad, because while it is many lines, it's just boring option parsing code. I certainly don't think it's likely to start using a thread pool anywhere. However, I also wonder now if this patch is actually necessary. Maybe some intermediate version of the series actually used qemu_aio_context in monitor_init_globals_core(), but none of the versions actually sent to the list do. They all use iohandler_get_aio_context(), which should be safe before the main loop is initialised. To make sure that I didn't miss anything, 'make check' passes without the patch. So maybe we can just drop this patch after all. Kevin