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 Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 68225C624D4 for ; Wed, 2 Sep 2026 21:28:21 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1x1sUu-0002gI-Ty; Wed, 02 Sep 2026 17:27:56 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1x1sUs-0002g0-Rc for qemu-devel@nongnu.org; Wed, 02 Sep 2026 17:27:54 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1x1sUr-0004nQ-8m for qemu-devel@nongnu.org; Wed, 02 Sep 2026 17:27:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1788384472; 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=klYIkCh8fmLPHcVe2b4mm1l7dFqolnxcjWy9ktgx27U=; b=S3ImjaCdllcnJsY8MqHvmSp2UhHGXxgBcaBr4ryQhpeKKzeGk7y1JtxEyV42IFHhgnj5iR G8GftGky8jLDSRLQnSI5yxyKF/Lpam8JZga5kgxhyWNS7EsZHPPcJv+OuTVCEO12Ti9bV+ NxHVBNv8YivyXVqA0DVBIqPp4pX0J50= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-650-p2OQF7KFNSC1AwkFzi7JHA-1; Wed, 02 Sep 2026 17:27:47 -0400 X-MC-Unique: p2OQF7KFNSC1AwkFzi7JHA-1 X-Mimecast-MFC-AGG-ID: p2OQF7KFNSC1AwkFzi7JHA_1788384466 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 5BD631805A20; Wed, 2 Sep 2026 21:27:46 +0000 (UTC) Received: from localhost (headnet04.pony-001.prod.iad2.dc.redhat.com [10.2.32.116]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id A11ED1956044; Wed, 2 Sep 2026 21:27:45 +0000 (UTC) Date: Wed, 2 Sep 2026 15:35:18 -0400 From: Stefan Hajnoczi To: Zhang Chen Cc: qemu-devel , Eric Blake , Markus Armbruster , "'Michael S . Tsirkin'" , Paolo Bonzini , 'Daniel P =?iso-8859-1?Q?=2E_Berrang=E9'?= , Jason Wang Subject: Re: [PATCH V14 06/15] monitor: track IOThread users with QOM paths Message-ID: <20260902193518.GB787498@fedora> References: <20260831160038.221776-1-zhangckid@gmail.com> <20260831160038.221776-7-zhangckid@gmail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="kLrcqgJw+T0EYOR1" Content-Disposition: inline In-Reply-To: <20260831160038.221776-7-zhangckid@gmail.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_PASS=-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: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org --kLrcqgJw+T0EYOR1 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Sep 01, 2026 at 12:00:27AM +0800, Zhang Chen wrote: > Monitors that require an IOThread share the internal mon_iothread. > Account for each monitor explicitly in IOThread holder tracking, using > the monitor's canonical QOM path to distinguish holders. >=20 > Acquire the shared monitor IOThread AioContext once, using the monitor > QOM path as the holder, and reuse the stored context for later > operations. >=20 > Release the holder from the Monitor ObjectClass::unparent callback, > while the canonical QOM path is still available. This covers every > object_unparent() path and avoids duplicating the cleanup in > monitor_cleanup() and monitor_qmp_prepare_delete(). >=20 > The internal mon_iothread remains hidden from query-iothreads, as before. > Management applications therefore cannot use it to determine which > monitors are using the IOThread. Nevertheless, track the monitor > holders so that they follow the same explicit holder and > IOThread reference lifecycle as other AioContext users. >=20 > Signed-off-by: Zhang Chen > --- > monitor/monitor-internal.h | 3 +++ > monitor/monitor.c | 33 ++++++++++++++++++++++++++++----- > monitor/qmp.c | 5 +++-- > 3 files changed, 34 insertions(+), 7 deletions(-) >=20 > diff --git a/monitor/monitor-internal.h b/monitor/monitor-internal.h > index e0a124a317..74ea15c85f 100644 > --- a/monitor/monitor-internal.h > +++ b/monitor/monitor-internal.h > @@ -154,6 +154,9 @@ struct Monitor { > guint out_watch; > int mux_out; > int reset_seen; > + > + /* iothread context */ > + AioContext *ctx; > }; > =20 > struct MonitorHMPClass { > diff --git a/monitor/monitor.c b/monitor/monitor.c > index 6af09f2f6e..9e3b639eff 100644 > --- a/monitor/monitor.c > +++ b/monitor/monitor.c > @@ -81,6 +81,22 @@ int monitor_device_index; > OBJECT_DEFINE_TYPE_EXTENDED(Monitor, monitor, MONITOR, OBJECT, true, > { TYPE_USER_CREATABLE }, {}); > =20 > +static void monitor_unparent(Object *obj) > +{ > + Monitor *mon =3D MONITOR(obj); > + > + if (mon->ctx && monitor_requires_iothread(mon)) { > + g_autofree char *path =3D object_get_canonical_path(obj); > + const IOThreadHolder io_holder =3D { > + .type =3D IO_THREAD_HOLDER_KIND_QOM_OBJECT, > + .u.qom_object.qom_path =3D path, > + }; > + > + iothread_unref_and_put_aio_context(mon_iothread, &io_holder); > + mon->ctx =3D NULL; mon->accept_input_bh still exits and uses the AioContext at this point (it is freed in monitor_finalize()). Strictly speaking, this violates the idea of not using the AioContext anymore after calling iothread_unref_and_put_aio_context(). This could be a source of bugs, but mon->accept_input_bh won't be scheduled anymore in this code path, so I think we can live with this. Reviewed-by: Stefan Hajnoczi --kLrcqgJw+T0EYOR1 Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmqYenYACgkQnKSrs4Gr c8hPOwgAmDWTTjCfP4g+PTRNM1ONn8vl3azoHn+AteVWbHzEprDoS5Qma0tfwqYT 76+F5OjJ7UyVaf0uNYuWnKLtdLu95kFpJ/pZbjADfjyO2p3IKUf3yvZA1GZ2CXJU N5oyijAm4uREmQfjs9p3cJjMPbr11Gi3AsZs0s29sZYPIGgQ1P/BCylvXAU5LYAo ZzT3aLRx8BqXyZuTW5Ncn0LJlAgnGbvZjoezk/nXXG+hwh1OZPpVqZbIlO61fK6X 3X+Mj8mzRqO9XDovyge7zSqfUUMxapnZMFQqaLhbrE7ZuFhQO+VSLHt3swB3TO51 WW9OB4yrz3nXwxXWGbYSzNQ9I9JLpg== =xwnC -----END PGP SIGNATURE----- --kLrcqgJw+T0EYOR1--