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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 9B8B5C282DD for ; Wed, 8 Jan 2020 13:02:46 +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 643C6206F0 for ; Wed, 8 Jan 2020 13:02:46 +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="IVJpXUu9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 643C6206F0 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]:43284 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ipAyz-0003LC-9L for qemu-devel@archiver.kernel.org; Wed, 08 Jan 2020 08:02:45 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:34725) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ipAck-0005cA-U1 for qemu-devel@nongnu.org; Wed, 08 Jan 2020 07:39:48 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ipAci-0008Hv-69 for qemu-devel@nongnu.org; Wed, 08 Jan 2020 07:39:45 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:31253 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 1ipAci-0008HF-1T for qemu-devel@nongnu.org; Wed, 08 Jan 2020 07:39:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1578487183; h=from:from:reply-to: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=4+TS0nQmTlVo2nhUseZ6PlP0uxHPUsELi34gf94fJFE=; b=IVJpXUu90MjmxGfZGAiTRdE5JGyNr3I8ey4mzBezfmAmEPSS4g8DhrdIbW4sdjqzAzRIxj TzhErbHSjsqjuS23XBJLFUxiQrTx/sjnjVs04ogsL2uSjb4UmRGMHGw/adOC2GNurg58SB d8W/FIk7pzhjobLO3nRUEgDbs+UvxHM= 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-340-OLbXjUdvMn2NQuCafsZRQA-1; Wed, 08 Jan 2020 07:39:41 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0FA7C800EBF for ; Wed, 8 Jan 2020 12:39:41 +0000 (UTC) Received: from redhat.com (unknown [10.36.118.112]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5830E5D9E1; Wed, 8 Jan 2020 12:39:40 +0000 (UTC) From: Juan Quintela To: Laurent Vivier Subject: Re: [PATCH] runstate: ignore finishmigrate -> prelaunch transition In-Reply-To: (Laurent Vivier's message of "Wed, 18 Dec 2019 17:21:17 +0100") References: <20191129115132.285988-1-lvivier@redhat.com> <20191206195230.GJ2878@work-vm> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) Date: Wed, 08 Jan 2020 13:39:36 +0100 Message-ID: <87imlmi0l3.fsf@secure.laptop> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-MC-Unique: OLbXjUdvMn2NQuCafsZRQA-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.61 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: , Reply-To: quintela@redhat.com Cc: Paolo Bonzini , "Dr. David Alan Gilbert" , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Laurent Vivier wrote: > Ping? > > Thanks, > Laurent > > On 12/12/2019 20:40, Laurent Vivier wrote: >> On 06/12/2019 20:52, Dr. David Alan Gilbert wrote: >>> * Laurent Vivier (lvivier@redhat.com) wrote: >>>> Commit 1bd71dce4bf2 tries to prevent a finishmigrate -> prelaunch >>>> transition by exiting at the beginning of the main_loop_should_exit() >>>> function if the state is already finishmigrate. >>>> >>>> As the finishmigrate state is set in the migration thread it can >>>> happen concurrently to the function. The migration thread and the >>>> function are normally protected by the iothread mutex and thus the >>>> state should no evolve between the start of the function and its end. >>>> >>>> Unfortunately during the function life the lock is released by >>>> pause_all_vcpus() just before the point we need to be sure we are >>>> not in finishmigrate state and if the migration thread is waiting >>>> for the lock it will take the opportunity to change the state >>>> to finishmigrate. >>> >>> Ewww. >>> I hate those short wakeups for pause_all_vcpus; I'm sure there are load= s >>> more corners that break. >>> >>> Still, I _think_ this is an improvement, so: >>> >>> Reviewed-by: Dr. David Alan Gilbert >>> >>=20 >> Who volunteers to take this in his queue? Reviewed-by: Juan Quintela queued