Re: Threads and multiple interpreters
Jeff Allen <[email protected]>
| Newsgroups | gmane.comp.lang.jython.devel |
|---|---|
| Message-ID | <[email protected]> |
On 19/03/2018 11:32, Eero Aaltonen wrote: > > Hi Jeff, > > Having just read this, a potential counterexample came to my mind. > > Suppose we want to pass a PyObject Pyo from PyInterpreterState PySa to > PyInterpreterState PySb. I'm not familiar with Jythons internals, but > I would assume many of the things that apply to passing object between > classloaders would apply here as well. > If the Pyo was loaded in a common classloader, the module of Pyo would > likely be loaded by that common classloader and the module would then > be unusable for distinguishing PySa and PySb. > > Disclaimer: This is with very limited knowledge of Jython. > > -- > Eero Aaltonen Too great a knowledge of actual Jython internals may be a disadvantage. Mine is helpfully blurred. Thanks for thinking about this. A module source compiles to a Java class (or CPython PyCode) but the object in sys.modules is a PyModule instance which references the compiled class, and I suggest could contain a reference to an importing interpreter. The compiled module is a constant, while the PyModule contains the variable state (per interpreter I propose). We would use the reference upon entry to Python-aware code in that module to find the right sys module, codec registry, etc. and PyThread. In Jython there is a call to ThreadStateMapping.getThreadState and later ThreadStateMapping.enterCall and although that is mechanism I'm questioning, it is around there that this would happen. It cannot *I think* depend on class loader identity, but needs a specific reference. I didn't mention the important matter of class loaders because I don't quite know what I think about them. It seems likely that module finders/loaders are the Python idea that corresponds most closely to a Java class loader, in the same way that the Python and JVM threads correspond (but are not the same). It might be that each finder references a class loader. And of course each interpreter has its own sequence of finders, including a default one whose class loader might be the one that loaded the interpreter class of which it is an instance. There is at least some coherency required between interpreters and class loaders, so that two applications using Jython in the same JVM work without interference. Jeff ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Jython-dev mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/jython-dev