From patchwork Mon Nov 6 09:46:33 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 834554 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=2001:4830:134:3::11; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3yVnxW3Jwxz9s7c for ; Mon, 6 Nov 2017 20:55:43 +1100 (AEDT) Received: from localhost ([::1]:47205 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eBe85-0001nE-D4 for incoming@patchwork.ozlabs.org; Mon, 06 Nov 2017 04:55:41 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49131) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eBe2r-0005zN-PR for qemu-devel@nongnu.org; Mon, 06 Nov 2017 04:50:22 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eBe2q-0004vU-9z for qemu-devel@nongnu.org; Mon, 06 Nov 2017 04:50:17 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43026) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eBe2p-0004vD-PR for qemu-devel@nongnu.org; Mon, 06 Nov 2017 04:50:16 -0500 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 mx1.redhat.com (Postfix) with ESMTPS id C51FD3B738; Mon, 6 Nov 2017 09:50:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com C51FD3B738 Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=peterx@redhat.com Received: from pxdev.xzpeter.org.com (ovpn-12-165.pek2.redhat.com [10.72.12.165]) by smtp.corp.redhat.com (Postfix) with ESMTP id 30E8760D5F; Mon, 6 Nov 2017 09:50:05 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Mon, 6 Nov 2017 17:46:33 +0800 Message-Id: <20171106094643.14881-18-peterx@redhat.com> In-Reply-To: <20171106094643.14881-1-peterx@redhat.com> References: <20171106094643.14881-1-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Mon, 06 Nov 2017 09:50:14 +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 v3 17/27] monitor: separate QMP parser and dispatcher 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 , Jiri Denemark , "Dr . David Alan Gilbert" Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Originally QMP goes throw these steps: JSON Parser --> QMP Dispatcher --> Respond /|\ (2) (3) | (1) | \|/ (4) +--------- main thread --------+ This patch does this: JSON Parser QMP Dispatcher --> Respond /|\ | /|\ (4) | | | (2) | (3) | (5) (1) | +-----> | \|/ +--------- main thread <-------+ So the parsing job and the dispatching job is isolated now. It gives us a chance in following up patches to totally move the parser outside. The isloation is done using one QEMUBH. Only one dispatcher QEMUBH is used for all the monitors. Signed-off-by: Peter Xu --- monitor.c | 179 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 157 insertions(+), 22 deletions(-) diff --git a/monitor.c b/monitor.c index 47e969244d..e327ae115b 100644 --- a/monitor.c +++ b/monitor.c @@ -168,6 +168,10 @@ typedef struct { */ QmpCommandList *commands; bool qmp_caps[QMP_CAPABILITY__MAX]; + /* Protects qmp request/response queue. */ + QemuMutex qmp_queue_lock; + /* Input queue that holds all the parsed QMP requests */ + GQueue *qmp_requests; } MonitorQMP; /* @@ -213,6 +217,8 @@ struct Monitor { struct MonitorGlobal { IOThread *mon_iothread; + /* Bottom half to dispatch the requests received from IO thread */ + QEMUBH *qmp_dispatcher_bh; }; static struct MonitorGlobal mon_global; @@ -582,11 +588,13 @@ static void monitor_data_init(Monitor *mon, bool skip_flush, { memset(mon, 0, sizeof(Monitor)); qemu_mutex_init(&mon->out_lock); + qemu_mutex_init(&mon->qmp.qmp_queue_lock); mon->outbuf = qstring_new(); /* Use *mon_cmds by default. */ mon->cmd_table = mon_cmds; mon->skip_flush = skip_flush; mon->use_io_thr = use_io_thr; + mon->qmp.qmp_requests = g_queue_new(); } static void monitor_data_destroy(Monitor *mon) @@ -599,6 +607,8 @@ static void monitor_data_destroy(Monitor *mon) g_free(mon->rs); QDECREF(mon->outbuf); qemu_mutex_destroy(&mon->out_lock); + qemu_mutex_destroy(&mon->qmp.qmp_queue_lock); + g_queue_free(mon->qmp.qmp_requests); } char *qmp_human_monitor_command(const char *command_line, bool has_cpu_index, @@ -3907,29 +3917,31 @@ static void monitor_qmp_respond(Monitor *mon, QObject *rsp, qobject_decref(rsp); } -static void handle_qmp_command(JSONMessageParser *parser, GQueue *tokens, - void *opaque) +struct QMPRequest { + /* Owner of the request */ + Monitor *mon; + /* "id" field of the request */ + QObject *id; + /* Request object to be handled */ + QObject *req; +}; +typedef struct QMPRequest QMPRequest; + +/* + * Dispatch one single QMP request. The function will free the req_obj + * and objects inside it before return. + */ +static void monitor_qmp_dispatch_one(QMPRequest *req_obj) { - QObject *req, *rsp = NULL, *id = NULL; + Monitor *mon, *old_mon; + QObject *req, *rsp = NULL, *id; QDict *qdict = NULL; - Monitor *mon = opaque, *old_mon; - Error *err = NULL; - req = json_parser_parse_err(tokens, NULL, &err); - if (!req && !err) { - /* json_parser_parse_err() sucks: can fail without setting @err */ - error_setg(&err, QERR_JSON_PARSING); - } - if (err) { - goto err_out; - } + req = req_obj->req; + mon = req_obj->mon; + id = req_obj->id; - qdict = qobject_to_qdict(req); - if (qdict) { - id = qdict_get(qdict, "id"); - qobject_incref(id); - qdict_del(qdict, "id"); - } /* else will fail qmp_dispatch() */ + g_free(req_obj); if (trace_event_get_state_backends(TRACE_HANDLE_QMP_COMMAND)) { QString *req_json = qobject_to_json(req); @@ -3940,7 +3952,7 @@ static void handle_qmp_command(JSONMessageParser *parser, GQueue *tokens, old_mon = cur_mon; cur_mon = mon; - rsp = qmp_dispatch(cur_mon->qmp.commands, req); + rsp = qmp_dispatch(mon->qmp.commands, req); cur_mon = old_mon; @@ -3956,12 +3968,122 @@ static void handle_qmp_command(JSONMessageParser *parser, GQueue *tokens, } } -err_out: - monitor_qmp_respond(mon, rsp, err, id); + /* Respond if necessary */ + monitor_qmp_respond(mon, rsp, NULL, id); + + /* This pairs with the monitor_suspend() in handle_qmp_command(). */ + if (!qmp_oob_enabled(mon)) { + monitor_resume(mon); + } qobject_decref(req); } +/* + * Pop one QMP request from monitor queues, return NULL if not found. + * We are using round-robin fasion to pop the request, to avoid + * processing command only on a very busy monitor. To achieve that, + * when we processed one request on specific monitor, we put that + * monitor to the end of mon_list queue. + */ +static QMPRequest *monitor_qmp_requests_pop_one(void) +{ + QMPRequest *req_obj = NULL; + Monitor *mon; + + qemu_mutex_lock(&monitor_lock); + + QTAILQ_FOREACH(mon, &mon_list, entry) { + qemu_mutex_lock(&mon->qmp.qmp_queue_lock); + req_obj = g_queue_pop_head(mon->qmp.qmp_requests); + qemu_mutex_unlock(&mon->qmp.qmp_queue_lock); + if (req_obj) { + break; + } + } + + if (req_obj) { + /* + * We found one request on the monitor. Degrade this monitor's + * priority to lowest by re-inserting it to end of queue. + */ + QTAILQ_REMOVE(&mon_list, mon, entry); + QTAILQ_INSERT_TAIL(&mon_list, mon, entry); + } + + qemu_mutex_unlock(&monitor_lock); + + return req_obj; +} + +static void monitor_qmp_bh_dispatcher(void *data) +{ + QMPRequest *req_obj; + + while (true) { + req_obj = monitor_qmp_requests_pop_one(); + if (!req_obj) { + break; + } + monitor_qmp_dispatch_one(req_obj); + } +} + +static void handle_qmp_command(JSONMessageParser *parser, GQueue *tokens, + void *opaque) +{ + QObject *req, *id = NULL; + QDict *qdict = NULL; + Monitor *mon = opaque; + Error *err = NULL; + QMPRequest *req_obj; + + req = json_parser_parse_err(tokens, NULL, &err); + if (!req && !err) { + /* json_parser_parse_err() sucks: can fail without setting @err */ + error_setg(&err, QERR_JSON_PARSING); + } + if (err) { + monitor_qmp_respond(mon, NULL, err, NULL); + qobject_decref(req); + return; + } + + qdict = qobject_to_qdict(req); + if (qdict) { + id = qdict_get(qdict, "id"); + qobject_incref(id); + qdict_del(qdict, "id"); + } /* else will fail qmp_dispatch() */ + + req_obj = g_new0(QMPRequest, 1); + req_obj->mon = mon; + req_obj->id = id; + req_obj->req = req; + + /* + * Put the request to the end of queue so that requests will be + * handled in time order. Ownership for req_obj, req, id, + * etc. will be delivered to the handler side. + */ + qemu_mutex_lock(&mon->qmp.qmp_queue_lock); + g_queue_push_tail(mon->qmp.qmp_requests, req_obj); + qemu_mutex_unlock(&mon->qmp.qmp_queue_lock); + + /* Kick the dispatcher routine */ + qemu_bh_schedule(mon_global.qmp_dispatcher_bh); + + /* + * If OOB is not enabled on current monitor, we'll emulate the old + * behavior that we won't process current monitor any more until + * it is responded. This helps make sure that as long as OOB is + * not enabled, the server will never drop any command. + */ + if (!qmp_oob_enabled(mon)) { + monitor_suspend(mon); + } +} + static void monitor_qmp_read(void *opaque, const uint8_t *buf, int size) { Monitor *mon = opaque; @@ -4148,6 +4270,15 @@ static void monitor_iothread_init(void) * fetch the context we'll have that initialized. */ monitor_io_context_get(); + + /* + * This MUST be on main loop thread since we have commands that + * have assumption to be run on main loop thread (Yeah, we'd + * better remove this assumption in the future). + */ + mon_global.qmp_dispatcher_bh = aio_bh_new(qemu_get_aio_context(), + monitor_qmp_bh_dispatcher, + NULL); } void monitor_init_globals(void) @@ -4268,6 +4399,10 @@ void monitor_cleanup(void) } qemu_mutex_unlock(&monitor_lock); + /* QEMUBHs needs to be deleted before destroying the IOThread. */ + qemu_bh_delete(mon_global.qmp_dispatcher_bh); + mon_global.qmp_dispatcher_bh = NULL; + iothread_destroy(mon_global.mon_iothread); mon_global.mon_iothread = NULL; }