Yeah, I think imports inside functions are overused. On 5/9/06, Rotem Yaari <[EMAIL PROTECTED]> wrote: > Hello everyone! > > We have been encountering several deadlocks in a threaded Python > application which calls subprocess.Popen (i.e. fork()) in some of its > threads. > > This has occurred on Python 2.4.1 on a 2.4.27 Linux kernel. > > Preliminary analysis of the hang shows that the child process blocks > upon entering the execvp function, in which the import_lock is acquired > due to the following line: > > def _ execvpe(file, args, env=None): > from errno import ENOENT, ENOTDIR > ... > > It is known that when forking from a pthreaded application, acquisition > attempts on locks which were already locked by other threads while > fork() was called will deadlock. > > Due to these oddities we were wondering if it would be better to extract > the above import line from the execvpe call, to prevent lock > acquisition attempts in such cases. > > Another workaround could be re-assigning a new lock to import_lock > (such a thing is done with the global interpreter lock) at PyOS_AfterFork or > pthread_atfork. > > We'd appreciate any opinions you might have on the subject. > > Thanks in advance, > > Yair and Rotem > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > http://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: > http://mail.python.org/mailman/options/python-dev/guido%40python.org >
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