diff mbox series

[v6,3/4] monitor: more comments on lock-free fleids/funcs

Message ID 20180518110704.10849-4-peterx@redhat.com
State New
Headers show
Series monitor: let Monitor be thread safe | expand

Commit Message

Peter Xu May 18, 2018, 11:07 a.m. UTC 
Add some explicit comment for both Readline and cpu_set/cpu_get helpers
that they do not need the mon_lock protection.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 monitor.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/monitor.c b/monitor.c
index d6c3c08932..696109acb4 100644
--- a/monitor.c
+++ b/monitor.c
@@ -207,7 +207,14 @@  struct Monitor {
     int suspend_cnt;            /* Needs to be accessed atomically */
     bool skip_flush;
     bool use_io_thr;
+
+    /*
+     * ReadLineState is only used in parser, and the parser of a
+     * monitor will only be run either in main thread or monitor
+     * IOThread but never both, so no lock is needed when accessing.
+     */
     ReadLineState *rs;
+
     MonitorQMP qmp;
     gchar *mon_cpu_path;
     BlockCompletionFunc *password_completion_cb;
@@ -1313,7 +1320,7 @@  void qmp_qmp_capabilities(bool has_enable, QMPCapabilityList *enable,
     cur_mon->qmp.commands = &qmp_commands;
 }
 
-/* set the current CPU defined by the user */
+/* Set the current CPU defined by the user. Callers must hold BQL. */
 int monitor_set_cpu(int cpu_index)
 {
     CPUState *cpu;
@@ -1327,6 +1334,7 @@  int monitor_set_cpu(int cpu_index)
     return 0;
 }
 
+/* Callers must hold BQL. */
 static CPUState *mon_get_cpu_sync(bool synchronize)
 {
     CPUState *cpu;