From nobody Tue Feb 10 15:01:30 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1510838112046604.4231850457572; Thu, 16 Nov 2017 05:15:12 -0800 (PST) Received: from localhost ([::1]:40811 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eFK0V-0006KZ-3T for importer@patchew.org; Thu, 16 Nov 2017 08:15:03 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39097) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eFJtu-0000Xy-V7 for qemu-devel@nongnu.org; Thu, 16 Nov 2017 08:08:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eFJts-0000Gi-A0 for qemu-devel@nongnu.org; Thu, 16 Nov 2017 08:08:14 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50400) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eFJts-0000ER-43 for qemu-devel@nongnu.org; Thu, 16 Nov 2017 08:08:12 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 61FEBC047B6B; Thu, 16 Nov 2017 13:08:11 +0000 (UTC) Received: from xz-mi.nay.redhat.com (dhcp-14-111.nay.redhat.com [10.66.14.111]) by smtp.corp.redhat.com (Postfix) with ESMTP id A40C26058D; Thu, 16 Nov 2017 13:08:02 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Thu, 16 Nov 2017 21:06:01 +0800 Message-Id: <20171116130610.23582-19-peterx@redhat.com> In-Reply-To: <20171116130610.23582-1-peterx@redhat.com> References: <20171116130610.23582-1-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 16 Nov 2017 13:08:11 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [RFC v4 18/27] monitor: send event when request queue full X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Laurent Vivier , Fam Zheng , Juan Quintela , mdroth@linux.vnet.ibm.com, peterx@redhat.com, Markus Armbruster , marcandre.lureau@redhat.com, Stefan Hajnoczi , Paolo Bonzini , "Dr . David Alan Gilbert" Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Set maximum QMP request queue length to 8. If queue full, instead of queue the command, we directly return a "request-dropped" event, telling client that specific command is dropped. Note that this flow control mechanism is only valid if OOB is enabled. If it's not, the effective queue length will always be 1, which strictly follows original behavior of QMP command handling (which never drop messages). Signed-off-by: Peter Xu --- monitor.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/monitor.c b/monitor.c index 0e2ff114cc..92e846e195 100644 --- a/monitor.c +++ b/monitor.c @@ -4029,6 +4029,8 @@ static void monitor_qmp_bh_dispatcher(void *data) } } =20 +#define QMP_REQ_QUEUE_LEN_MAX (8) + static void handle_qmp_command(JSONMessageParser *parser, GQueue *tokens, void *opaque) { @@ -4061,6 +4063,19 @@ static void handle_qmp_command(JSONMessageParser *pa= rser, GQueue *tokens, req_obj->id =3D id; req_obj->req =3D req; =20 + if (qmp_oob_enabled(mon)) { + /* Drop the request if queue is full. */ + if (mon->qmp.qmp_requests->length >=3D QMP_REQ_QUEUE_LEN_MAX) { + qapi_event_send_request_dropped(id, + REQUEST_DROP_REASON_QUEUE_FULL, + NULL); + qobject_decref(id); + qobject_decref(req); + g_free(req_obj); + return; + } + } + /* * Put the request to the end of queue so that requests will be * handled in time order. Ownership for req_obj, req, id, --=20 2.13.6