From c1b6e1aef9c528b9fb183c8d607f0f99e1856468 Mon Sep 17 00:00:00 2001 From: Sean Dague Date: Thu, 23 Apr 2015 10:40:34 -0400 Subject: [PATCH] sync oslo: service child process normal SIGTERM exit service.py had some code where the child process would catch the SIGTERM from the parent just so it could exit with 1 status rather than with an indication that it exited due to SIGTERM. When shutting down the parent doesn't care in what way the child ended, only that they're all gone, so this code is unnecessary. Also, for some reason this caused the child to never exit while there was an open connection from a client. Probably something with eventlet and signal handling. Syncs commit: 702bc569987854b602ef189655c201c348de84cb Change-Id: I3c5249f5e59bb396bcb50964907ea61ebb2a3c8a Closes-Bug: #1446583 (cherry picked from commit f0f158af375efcc91e7c75859fceeec0111f424b) --- nova/openstack/common/service.py | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/nova/openstack/common/service.py b/nova/openstack/common/service.py index 58aaa79d4bac..ea94f9e2dd83 100644 --- a/nova/openstack/common/service.py +++ b/nova/openstack/common/service.py @@ -206,12 +206,16 @@ class ProcessLauncher(object): for handler in cls._signal_handlers_set: handler(*args, **kwargs) - def __init__(self): - """Constructor.""" + def __init__(self, wait_interval=0.01): + """Constructor. + :param wait_interval: The interval to sleep for between checks + of child process exit. + """ self.children = {} self.sigcaught = None self.running = True + self.wait_interval = wait_interval rfd, self.writepipe = os.pipe() self.readpipe = eventlet.greenio.GreenPipe(rfd, 'r') self.handle_signal() @@ -238,15 +242,12 @@ class ProcessLauncher(object): def _child_process_handle_signal(self): # Setup child signal handlers differently - def _sigterm(*args): - signal.signal(signal.SIGTERM, signal.SIG_DFL) - raise SignalExit(signal.SIGTERM) - def _sighup(*args): signal.signal(signal.SIGHUP, signal.SIG_DFL) raise SignalExit(signal.SIGHUP) - signal.signal(signal.SIGTERM, _sigterm) + # Parent signals with SIGTERM when it wants us to go away. + signal.signal(signal.SIGTERM, signal.SIG_DFL) if _sighup_supported(): signal.signal(signal.SIGHUP, _sighup) # Block SIGINT and let the parent send us a SIGTERM @@ -337,8 +338,8 @@ class ProcessLauncher(object): def _wait_child(self): try: - # Block while any of child processes have exited - pid, status = os.waitpid(0, 0) + # Don't block if no child processes have exited + pid, status = os.waitpid(0, os.WNOHANG) if not pid: return None except OSError as exc: @@ -367,6 +368,10 @@ class ProcessLauncher(object): while self.running: wrap = self._wait_child() if not wrap: + # Yield to other threads if no children have exited + # Sleep for a short time to avoid excessive CPU usage + # (see bug #1095346) + eventlet.greenthread.sleep(self.wait_interval) continue while self.running and len(wrap.children) < wrap.workers: self._start_child(wrap)