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=-3.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 8D951C2D0E5 for ; Mon, 30 Mar 2020 12:34:08 +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 5C8FC206E6 for ; Mon, 30 Mar 2020 12:34:08 +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="ap/heK3r" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5C8FC206E6 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]:48994 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jItcF-0000Tt-Gj for qemu-devel@archiver.kernel.org; Mon, 30 Mar 2020 08:34:07 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39367) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jItbM-0008A2-5N for qemu-devel@nongnu.org; Mon, 30 Mar 2020 08:33:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jItbJ-0004Vw-Sa for qemu-devel@nongnu.org; Mon, 30 Mar 2020 08:33:12 -0400 Received: from us-smtp-delivery-74.mimecast.com ([63.128.21.74]:45669) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jItbJ-0004Ub-Hi for qemu-devel@nongnu.org; Mon, 30 Mar 2020 08:33:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1585571587; 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=Nc4wG0sBjgGi3UrNVX8TW70exIY8POyNjXhT0Hi9CYw=; b=ap/heK3rhKCfUagNneF/3x36/v5p2UAZqQe3xItDgqHmxbkvEoDw6EhTvDbTINhGE5rg9B UKpoiRqILqBvwAw0csvJvD0j+CaSomILe8iwNJh9gVSWKrV7gnY86J6MGQ4JD7GZdrMkVY ISQ6tUOa4yRUx7h3yFvVAz+ON+6HvF4= 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-80-dvqYEnZ0OAu6SjpJjCGaCg-1; Mon, 30 Mar 2020 08:33:05 -0400 X-MC-Unique: dvqYEnZ0OAu6SjpJjCGaCg-1 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 A7F40A0CBF; Mon, 30 Mar 2020 12:33:04 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-112-69.ams2.redhat.com [10.36.112.69]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7861997B12; Mon, 30 Mar 2020 12:33:04 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 47ABA11385E2; Mon, 30 Mar 2020 14:33:03 +0200 (CEST) From: Markus Armbruster To: =?utf-8?Q?Marc-Andr=C3=A9?= Lureau Subject: Re: [PATCH v5 3/4] qmp: Move dispatcher to a coroutine References: <20200218154036.28562-1-kwolf@redhat.com> <20200218154036.28562-4-kwolf@redhat.com> <87d09965g3.fsf@dusky.pond.sub.org> <20200323174108.GD8049@linux.fritz.box> Date: Mon, 30 Mar 2020 14:33:03 +0200 In-Reply-To: (=?utf-8?Q?=22Marc-Andr=C3=A9?= Lureau"'s message of "Mon, 23 Mar 2020 19:03:01 +0100") Message-ID: <87d08uvx8g.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 63.128.21.74 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: Kevin Wolf , QEMU , "open list:Block layer core" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Marc-Andr=C3=A9 Lureau writes: > Hi > > On Mon, Mar 23, 2020 at 6:41 PM Kevin Wolf wrote: >> >> Am 18.03.2020 um 16:36 hat Markus Armbruster geschrieben: >> > Kevin Wolf writes: >> > >> > > This moves the QMP dispatcher to a coroutine and runs all QMP comman= d >> > > handlers that declare 'coroutine': true in coroutine context so they >> > > can avoid blocking the main loop while doing I/O or waiting for othe= r >> > > events. >> > > >> > > For commands that are not declared safe to run in a coroutine, the >> > > dispatcher drops out of coroutine context by calling the QMP command >> > > handler from a bottom half. >> > > >> > > Signed-off-by: Kevin Wolf >> > >> > Uh, what about @cur_mon? >> > >> > @cur_mon points to the current monitor while a command executes. >> > Initial value is null. It is set in three places (not counting unit >> > tests), and all three save, set, do something that may use @cur_mon, >> > restore: >> > >> > * monitor_qmp_dispatch(), for use within qmp_dispatch() >> > * monitor_read(), for use within handle_hmp_command() >> > * qmp_human_monitor_command(), also for use within handle_hmp_command(= ) >> > >> > Therefore, @cur_mon is null unless we're running within qmp_dispatch() >> > or handle_hmp_command(). >> >> Can we make it NULL for coroutine-enabled handlers? > > fwiw, I think /dev/fdset doesn't care about cur_mon. However, qmp > handlers that use monitor_get_fd() usually depend on cur_mon. > > Note: I wonder if add-fd (fdsets) and getfd (monitor fds) deserve to co-e= xist. Beats me. If one of them is more general, we could consider deprecating the other one.