From 5ef5ea453b322430c8ec11ddcfbf129ade840331 Mon Sep 17 00:00:00 2001
From: Guido Trotter <ultrotter@google.com>
Date: Fri, 7 May 2010 10:11:37 +0200
Subject: [PATCH] IsProcessAlive: retry stat() a few times
On multiprocessor dom0 stat() on /proc can sometimes return EINVAL.
Before giving up, we try a few times to get a consistent answer.
Signed-off-by: Guido Trotter <ultrotter@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>
---
lib/utils.py | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
diff --git a/lib/utils.py b/lib/utils.py
index 6d2cd0fee..1d0750e30 100644
--- a/lib/utils.py
+++ b/lib/utils.py
@@ -566,16 +566,28 @@ def IsProcessAlive(pid):
@return: True if the process exists
"""
+ def _TryStat(name):
+ try:
+ os.stat(name)
+ return True
+ except EnvironmentError, err:
+ if err.errno in (errno.ENOENT, errno.ENOTDIR):
+ return False
+ elif err.errno == errno.EINVAL:
+ raise RetryAgain(err)
+ raise
+
+ assert isinstance(pid, int), "pid must be an integer"
if pid <= 0:
return False
+ proc_entry = "/proc/%d/status" % pid
+ # /proc in a multiprocessor environment can have strange behaviors.
+ # Retry the os.stat a few times until we get a good result.
try:
- os.stat("/proc/%d/status" % pid)
- return True
- except EnvironmentError, err:
- if err.errno in (errno.ENOENT, errno.ENOTDIR):
- return False
- raise
+ return Retry(_TryStat, (0.01, 1.5, 0.1), 0.5, args=[proc_entry])
+ except RetryTimeout, err:
+ err.RaiseInner()
def ReadPidFile(pidfile):
--
GitLab