bitbake: server/process: Run idle commands in a separate idle thread

When bitbake is off running heavier "idle" commands, it doesn't service it's
command socket which means stopping/interrupting it is hard. It also means we
can't "ping" from the UI to know if it is still alive.

For those reasons, split idle command execution into it's own thread.

The commands are generally already self containted so this is easier than
expected. We do have to be careful to only handle inotify poll() from a single
thread at a time. It also means we always have to use a thread lock when sending
events since both the idle thread and the command thread may generate log messages
(and hence events). The patch depends on  previous fixes to the builtins locking
in event.py and the heartbeat enable/disable changes as well as other locking
additions.

We use a condition to signal from the idle thread when other sections of code
can continue, thanks to Joshua Watt for the review and tweaks squashed into this
patch. We do have some sync points where we need to ensure any currently executing
commands have finished before we can start a new async command for example.

(Bitbake rev: 67dd9a5e84811df8869a82da6a37a41ee8fe94e2)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 21 insertions, 8 deletions

diff --git a/bitbake/lib/bb/cooker.py b/bitbake/lib/bb/cooker.py
index ded9369787..a5a635858c 100644
--- a/bitbake/lib/bb/cooker.py
+++ b/bitbake/lib/bb/cooker.py
@@ -149,7 +149,7 @@ class BBCooker:
     Manages one bitbake build run
     """
 
-    def __init__(self, featureSet=None, idleCallBackRegister=None):
+    def __init__(self, featureSet=None, idleCallBackRegister=None, waitIdle=None):
         self.recipecaches = None
         self.eventlog = None
         self.skiplist = {}
@@ -164,6 +164,7 @@ class BBCooker:
         self.configuration = bb.cookerdata.CookerConfiguration()
 
         self.idleCallBackRegister = idleCallBackRegister
+        self.waitIdle = waitIdle
 
         bb.debug(1, "BBCooker starting %s" % time.time())
         sys.stdout.flush()
@@ -220,6 +221,8 @@ class BBCooker:
         bb.debug(1, "BBCooker startup complete %s" % time.time())
         sys.stdout.flush()
 
+        self.inotify_threadlock = threading.Lock()
+
     def init_configdata(self):
         if not hasattr(self, "data"):
             self.initConfigurationData()
@@ -248,11 +251,18 @@ class BBCooker:
         self.notifier = pyinotify.Notifier(self.watcher, self.notifications)
 
     def process_inotify_updates(self):
-        for n in [self.confignotifier, self.notifier]:
-            if n and n.check_events(timeout=0):
-                # read notified events and enqueue them
-                n.read_events()
-                n.process_events()
+        with self.inotify_threadlock:
+            for n in [self.confignotifier, self.notifier]:
+                if n and n.check_events(timeout=0):
+                    # read notified events and enqueue them
+                    n.read_events()
+
+    def process_inotify_updates_apply(self):
+        with self.inotify_threadlock:
+            for n in [self.confignotifier, self.notifier]:
+                if n and n.check_events(timeout=0):
+                    n.read_events()
+                    n.process_events()
 
     def config_notifications(self, event):
         if event.maskname == "IN_Q_OVERFLOW":
@@ -1744,7 +1754,7 @@ class BBCooker:
         return
 
     def post_serve(self):
-        self.shutdown(force=True)
+        self.shutdown(force=True, idle=False)
         prserv.serv.auto_shutdown()
         if hasattr(bb.parse, "siggen"):
             bb.parse.siggen.exit()
@@ -1754,12 +1764,15 @@ class BBCooker:
         if hasattr(self, "data"):
             bb.event.fire(CookerExit(), self.data)
 
-    def shutdown(self, force = False):
+    def shutdown(self, force=False, idle=True):
         if force:
             self.state = state.forceshutdown
         else:
             self.state = state.shutdown
 
+        if idle:
+            self.waitIdle(30)
+
         if self.parser:
             self.parser.shutdown(clean=not force)
             self.parser.final_cleanup()