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[Qemu-devel] [PATCH v8 13/23] monitor: let suspend/resume work even with
From: |
Peter Xu |
Subject: |
[Qemu-devel] [PATCH v8 13/23] monitor: let suspend/resume work even with QMPs |
Date: |
Fri, 9 Mar 2018 16:59:56 +0800 |
This patches allows QMP monitors to be suspended/resumed.
One thing to mention is that for QMPs that are using IOThreads, we need
an explicit kick for the IOThread in case it is sleeping.
Meanwhile, we need to take special care on non-interactive HMPs.
Currently only gdbserver is using that. For these monitors, we still
don't allow suspend/resume operations.
Since at it, add traces for the operations.
Signed-off-by: Peter Xu <address@hidden>
---
monitor.c | 47 ++++++++++++++++++++++++++++++++++++++++++++---
trace-events | 1 +
2 files changed, 45 insertions(+), 3 deletions(-)
diff --git a/monitor.c b/monitor.c
index 71b696c8f3..de9343be87 100644
--- a/monitor.c
+++ b/monitor.c
@@ -250,6 +250,21 @@ static inline bool monitor_is_qmp(const Monitor *mon)
return (mon->flags & MONITOR_USE_CONTROL);
}
+/**
+ * Whether @mon is using readline? Note: not all HMP monitors use
+ * readline, e.g., gdbserver has a non-interactive HMP monitor, so
+ * readline is not used there.
+ */
+static inline bool monitor_uses_readline(const Monitor *mon)
+{
+ return mon->flags & MONITOR_USE_READLINE;
+}
+
+static inline bool monitor_is_hmp_non_interactive(const Monitor *mon)
+{
+ return !monitor_is_qmp(mon) && !monitor_uses_readline(mon);
+}
+
/**
* Is the current monitor, if any, a QMP monitor?
*/
@@ -3946,19 +3961,45 @@ static void monitor_command_cb(void *opaque, const char
*cmdline,
int monitor_suspend(Monitor *mon)
{
- if (!mon->rs)
+ if (monitor_is_hmp_non_interactive(mon)) {
return -ENOTTY;
+ }
+
atomic_inc(&mon->suspend_cnt);
+
+ if (monitor_is_qmp(mon)) {
+ /*
+ * Kick iothread to make sure this takes effect. It'll be
+ * evaluated again in prepare() of the watch object.
+ */
+ aio_notify(iothread_get_aio_context(mon_global.mon_iothread));
+ }
+
+ trace_monitor_suspend(mon, 1);
return 0;
}
void monitor_resume(Monitor *mon)
{
- if (!mon->rs)
+ if (monitor_is_hmp_non_interactive(mon)) {
return;
+ }
+
if (atomic_dec_fetch(&mon->suspend_cnt) == 0) {
- readline_show_prompt(mon->rs);
+ if (monitor_is_qmp(mon)) {
+ /*
+ * For QMP monitors that are running in IOThread, let's
+ * kick the thread in case it's sleeping.
+ */
+ if (mon->use_io_thr) {
+ aio_notify(iothread_get_aio_context(mon_global.mon_iothread));
+ }
+ } else {
+ assert(mon->rs);
+ readline_show_prompt(mon->rs);
+ }
}
+ trace_monitor_suspend(mon, -1);
}
static QObject *get_qmp_greeting(Monitor *mon)
diff --git a/trace-events b/trace-events
index 89fcad0fd1..fe10c3b487 100644
--- a/trace-events
+++ b/trace-events
@@ -47,6 +47,7 @@ monitor_protocol_event_emit(uint32_t event, void *data)
"event=%d data=%p"
monitor_protocol_event_queue(uint32_t event, void *qdict, uint64_t rate)
"event=%d data=%p rate=%" PRId64
handle_hmp_command(void *mon, const char *cmdline) "mon %p cmdline: %s"
handle_qmp_command(void *mon, const char *req) "mon %p req: %s"
+monitor_suspend(void *ptr, int cnt) "mon %p: %d"
# dma-helpers.c
dma_blk_io(void *dbs, void *bs, int64_t offset, bool to_dev) "dbs=%p bs=%p
offset=%" PRId64 " to_dev=%d"
--
2.14.3
- Re: [Qemu-devel] [PATCH v8 06/23] monitor: move the cur_mon hack deeper for QMP, (continued)
- [Qemu-devel] [PATCH v8 08/23] monitor: let mon_list be tail queue, Peter Xu, 2018/03/09
- [Qemu-devel] [PATCH v8 07/23] monitor: unify global init, Peter Xu, 2018/03/09
- [Qemu-devel] [PATCH v8 09/23] monitor: allow using IO thread for parsing, Peter Xu, 2018/03/09
- [Qemu-devel] [PATCH v8 10/23] qmp: introduce QMPCapability, Peter Xu, 2018/03/09
- [Qemu-devel] [PATCH v8 11/23] monitor: introduce monitor_qmp_respond(), Peter Xu, 2018/03/09
- [Qemu-devel] [PATCH v8 12/23] monitor: let suspend_cnt be thread safe, Peter Xu, 2018/03/09
- [Qemu-devel] [PATCH v8 13/23] monitor: let suspend/resume work even with QMPs,
Peter Xu <=
- [Qemu-devel] [PATCH v8 14/23] monitor: separate QMP parser and dispatcher, Peter Xu, 2018/03/09
- Re: [Qemu-devel] [PATCH v8 14/23] monitor: separate QMP parser and dispatcher, Eric Blake, 2018/03/10
- Re: [Qemu-devel] [PATCH v8 14/23] monitor: separate QMP parser and dispatcher, Marc-André Lureau, 2018/03/21
- Re: [Qemu-devel] [PATCH v8 14/23] monitor: separate QMP parser and dispatcher, Dr. David Alan Gilbert, 2018/03/21
- Re: [Qemu-devel] [PATCH v8 14/23] monitor: separate QMP parser and dispatcher, Eric Blake, 2018/03/21
- Re: [Qemu-devel] [PATCH v8 14/23] monitor: separate QMP parser and dispatcher, Marc-André Lureau, 2018/03/21
- Re: [Qemu-devel] [PATCH v8 14/23] monitor: separate QMP parser and dispatcher, Peter Xu, 2018/03/22
- Re: [Qemu-devel] [PATCH v8 14/23] monitor: separate QMP parser and dispatcher, Eric Blake, 2018/03/22
Re: [Qemu-devel] [PATCH v8 14/23] monitor: separate QMP parser and dispatcher, Marc-André Lureau, 2018/03/23