[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[PATCH 3/3] qmp: Resume OOB-enabled monitor before processing the reques
From: |
Markus Armbruster |
Subject: |
[PATCH 3/3] qmp: Resume OOB-enabled monitor before processing the request |
Date: |
Mon, 1 Feb 2021 17:15:04 +0100 |
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>
---
monitor/qmp.c | 33 +++++++++++++++++++++++++++------
1 file changed, 27 insertions(+), 6 deletions(-)
diff --git a/monitor/qmp.c b/monitor/qmp.c
index e37b047c8a..d164b9f744 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);
/*
--
2.26.2