diff options
| author | Markus Armbruster <armbru@redhat.com> | 2021-02-01 17:15:04 +0100 |
|---|---|---|
| committer | Markus Armbruster <armbru@redhat.com> | 2021-02-04 13:20:29 +0100 |
| commit | 88daf0996cd0488e93e67bcb0af258f2c24f117a (patch) | |
| tree | 4fb5645e5c3db6ceca5d12e5980345a51fe2af1b | |
| parent | f680405f45afab692bd8021a35d40d037366abf1 (diff) | |
qmp: Resume OOB-enabled monitor before processing the request
monitor_qmp_dispatcher_co() needs to resume the monitor if
handle_qmp_command() suspended it. Two cases:
1. OOB enabled: suspended if mon->qmp_requests has no more space
2. OOB disabled: suspended always
We resume only after we processed the request. Which can take a long
time.
Resume the monitor right when the queue has space to keep the monitor
available for out-of-band commands even in this corner case.
Leave the "OOB disabled" case alone.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210201161504.1976989-4-armbru@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
[Trailing whitespace tidied up]
| -rw-r--r-- | monitor/qmp.c | 33 |
1 files changed, 27 insertions, 6 deletions
diff --git a/monitor/qmp.c b/monitor/qmp.c index e37b047c8a..43880fa623 100644 --- a/monitor/qmp.c +++ b/monitor/qmp.c @@ -214,7 +214,7 @@ void coroutine_fn monitor_qmp_dispatcher_co(void *data) { QMPRequest *req_obj = NULL; QDict *rsp; - bool need_resume; + bool oob_enabled; MonitorQMP *mon; while (true) { @@ -273,11 +273,32 @@ void coroutine_fn monitor_qmp_dispatcher_co(void *data) aio_co_schedule(qemu_get_aio_context(), qmp_dispatcher_co); qemu_coroutine_yield(); + /* + * @req_obj has a request, we hold req_obj->mon->qmp_queue_lock + */ + mon = req_obj->mon; - /* qmp_oob_enabled() might change after "qmp_capabilities" */ - need_resume = !qmp_oob_enabled(mon) || - mon->qmp_requests->length == QMP_REQ_QUEUE_LEN_MAX - 1; + + /* + * We need to resume the monitor if handle_qmp_command() + * suspended it. Two cases: + * 1. OOB enabled: mon->qmp_requests has no more space + * Resume right away, so that OOB commands can get executed while + * this request is being processed. + * 2. OOB disabled: always + * Resume only after we're done processing the request, + * We need to save qmp_oob_enabled() for later, because + * qmp_qmp_capabilities() can change it. + */ + oob_enabled = qmp_oob_enabled(mon); + if (oob_enabled + && mon->qmp_requests->length == QMP_REQ_QUEUE_LEN_MAX - 1) { + monitor_resume(&mon->common); + } + qemu_mutex_unlock(&mon->qmp_queue_lock); + + /* Process request */ if (req_obj->req) { if (trace_event_get_state(TRACE_MONITOR_QMP_CMD_IN_BAND)) { QDict *qdict = qobject_to(QDict, req_obj->req); @@ -298,10 +319,10 @@ void coroutine_fn monitor_qmp_dispatcher_co(void *data) qobject_unref(rsp); } - if (need_resume) { - /* Pairs with the monitor_suspend() in handle_qmp_command() */ + if (!oob_enabled) { monitor_resume(&mon->common); } + qmp_request_free(req_obj); /* |