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 E91BCC61DD3 for ; Thu, 3 Sep 2026 13:43:12 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1x27iV-0002OV-72; Thu, 03 Sep 2026 09:42:59 -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 1x27iT-0002OD-RS for qemu-devel@nongnu.org; Thu, 03 Sep 2026 09:42:57 -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 1x27iS-0004x2-9I for qemu-devel@nongnu.org; Thu, 03 Sep 2026 09:42:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1788442975; 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=Mw66taxuYNvbDQ2Xa33WbGOLYBm+n690UOnVs7lLSb8=; b=E4Fk/vh+w7IPokE0LmQcM4n2ShfQUuDR1EORpTXjTGzPq0iyI5A6FHMZyrxe4p0cM9tPGF siq+hsjnJCLa8JvBeKRtvn5HZSVx8xxAMLA4gwB1Wxqknhv5QsnUKKAAYTS0F3YLiO1kgu 5S2Ygso5UOOkBPZ78oyANFuwutuj164= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-272-XQXqV1NSPgGIrDfzmqHx4g-1; Thu, 03 Sep 2026 09:42:53 -0400 X-MC-Unique: XQXqV1NSPgGIrDfzmqHx4g-1 X-Mimecast-MFC-AGG-ID: XQXqV1NSPgGIrDfzmqHx4g_1788442972 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B131F1926B6D; Thu, 3 Sep 2026 13:42:52 +0000 (UTC) Received: from localhost (headnet05.pony-001.prod.iad2.dc.redhat.com [10.2.32.117]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id EABEB1955F0A; Thu, 3 Sep 2026 13:42:51 +0000 (UTC) Date: Thu, 3 Sep 2026 09:42:50 -0400 From: Stefan Hajnoczi To: Markus Armbruster Cc: Zhang Chen , qemu-devel , Eric Blake , "'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: <20260903134250.GB825275@fedora> References: <20260831160038.221776-1-zhangckid@gmail.com> <20260831160038.221776-7-zhangckid@gmail.com> <20260902193518.GB787498@fedora> <87ik4mzx7p.fsf@pond.sub.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="nQcwaCgT4OZ7WBjL" Content-Disposition: inline In-Reply-To: <87ik4mzx7p.fsf@pond.sub.org> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 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: 12 X-Spam_score: 1.2 X-Spam_bar: + X-Spam_report: (1.2 / 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, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no 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 --nQcwaCgT4OZ7WBjL Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Sep 03, 2026 at 08:05:14AM +0200, Markus Armbruster wrote: > Stefan Hajnoczi writes: >=20 > > 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 befo= re. > >> 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 exits -> exists > > (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. >=20 > Worth a comment? Yes. >=20 > > Reviewed-by: Stefan Hajnoczi >=20 --nQcwaCgT4OZ7WBjL Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmqZeVoACgkQnKSrs4Gr c8ik6ggAs2qv0KgcSHiYRAJjVOFr323grhPOLmeuXrCQHJiEIfdOXmi6EPLlyAtB CDmCc/PadPvNdOcVRbkUQVRtPI37aPYgdm73Gqeox5xHGQZsDWzxZh1ccfjxSvzr pnrjutlPng1WmWKNG7z1VseSA3oGl41pr9nOrali1rxDrqHcNOfX3XD0ykAKEaNj +UJMCtvcG4XG0LS0VvO1ZKATkIbm6HpaoUYjG7sbv8qpr3cYRxNidnTFm4v3rQGQ 8/jYmuwhez2/zFprzDHWC8L1AMK6RzRw0P9m/Lwp+BsbLPFKRW3AmL1KsjDp+zF9 TVGlax9+xK31jBE3V/97O7yZkXi/7A== =LJ5p -----END PGP SIGNATURE----- --nQcwaCgT4OZ7WBjL--