From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41816) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1euDu8-0008GW-3Z for qemu-devel@nongnu.org; Fri, 09 Mar 2018 04:01:34 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1euDu4-0008H6-5z for qemu-devel@nongnu.org; Fri, 09 Mar 2018 04:01:32 -0500 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:60284 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1euDu4-0008Gs-0E for qemu-devel@nongnu.org; Fri, 09 Mar 2018 04:01:28 -0500 From: Peter Xu Date: Fri, 9 Mar 2018 16:59:56 +0800 Message-Id: <20180309090006.10018-14-peterx@redhat.com> In-Reply-To: <20180309090006.10018-1-peterx@redhat.com> References: <20180309090006.10018-1-peterx@redhat.com> Subject: [Qemu-devel] [PATCH v8 13/23] monitor: let suspend/resume work even with QMPs List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Stefan Hajnoczi , "Daniel P . Berrange" , Paolo Bonzini , Fam Zheng , Juan Quintela , mdroth@linux.vnet.ibm.com, peterx@redhat.com, Eric Blake , Laurent Vivier , Markus Armbruster , marcandre.lureau@redhat.com, "Dr . David Alan Gilbert" 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 --- 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