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[Qemu-devel] [PATCH 2/2] monitor: delay monitor iothread creation
From: |
Wolfgang Bumiller |
Subject: |
[Qemu-devel] [PATCH 2/2] monitor: delay monitor iothread creation |
Date: |
Fri, 21 Sep 2018 10:28:56 +0200 |
Commit d32749deb615 moved the call to monitor_init_globals()
to before os_daemonize(), making it an unsuitable place to
spawn the monitor iothread as it won't be inherited over the
fork() in os_daemonize().
We now spawn the thread the first time we instantiate a
monitor which actually has use_io_thread == true.
Instantiation of monitors happens only after os_daemonize().
We still need to create the qmp_dispatcher_bh when not using
iothreads, so this now still happens in
monitor_init_globals().
Signed-off-by: Wolfgang Bumiller <address@hidden>
Fixes: d32749deb615 ("monitor: move init global earlier")
---
monitor.c | 38 +++++++++++++++++++++++---------------
1 file changed, 23 insertions(+), 15 deletions(-)
diff --git a/monitor.c b/monitor.c
index 4802148c82..e9d44b443b 100644
--- a/monitor.c
+++ b/monitor.c
@@ -806,9 +806,14 @@ static void monitor_qapi_event_init(void)
static void handle_hmp_command(Monitor *mon, const char *cmdline);
+static void monitor_iothread_init(void);
+
static void monitor_data_init(Monitor *mon, bool skip_flush,
bool use_io_thread)
{
+ if (use_io_thread && !mon_iothread) {
+ monitor_iothread_init();
+ }
memset(mon, 0, sizeof(Monitor));
qemu_mutex_init(&mon->mon_lock);
qemu_mutex_init(&mon->qmp.qmp_queue_lock);
@@ -4551,15 +4556,6 @@ static void monitor_iothread_init(void)
mon_iothread = iothread_create("mon_iothread", &error_abort);
/*
- * The dispatcher BH must run in the main loop thread, since we
- * have commands assuming that context. It would be nice to get
- * rid of those assumptions.
- */
- qmp_dispatcher_bh = aio_bh_new(iohandler_get_aio_context(),
- monitor_qmp_bh_dispatcher,
- NULL);
-
- /*
* The responder BH must be run in the monitor I/O thread, so that
* monitors that are using the I/O thread have their output
* written by the I/O thread.
@@ -4576,7 +4572,15 @@ void monitor_init_globals(void)
sortcmdlist();
qemu_mutex_init(&monitor_lock);
qemu_mutex_init(&mon_fdsets_lock);
- monitor_iothread_init();
+
+ /*
+ * The dispatcher BH must run in the main loop thread, since we
+ * have commands assuming that context. It would be nice to get
+ * rid of those assumptions.
+ */
+ qmp_dispatcher_bh = aio_bh_new(iohandler_get_aio_context(),
+ monitor_qmp_bh_dispatcher,
+ NULL);
}
/* These functions just adapt the readline interface in a typesafe way. We
@@ -4717,7 +4721,9 @@ void monitor_cleanup(void)
* we need to unregister from chardev below in
* monitor_data_destroy(), and chardev is not thread-safe yet
*/
- iothread_stop(mon_iothread);
+ if (mon_iothread) {
+ iothread_stop(mon_iothread);
+ }
/*
* Flush all response queues. Note that even after this flush,
@@ -4738,11 +4744,13 @@ void monitor_cleanup(void)
/* QEMUBHs needs to be deleted before destroying the I/O thread */
qemu_bh_delete(qmp_dispatcher_bh);
qmp_dispatcher_bh = NULL;
- qemu_bh_delete(qmp_respond_bh);
- qmp_respond_bh = NULL;
+ if (mon_iothread) {
+ qemu_bh_delete(qmp_respond_bh);
+ qmp_respond_bh = NULL;
- iothread_destroy(mon_iothread);
- mon_iothread = NULL;
+ iothread_destroy(mon_iothread);
+ mon_iothread = NULL;
+ }
}
QemuOptsList qemu_mon_opts = {
--
2.11.0