On May,Friday 21 2010, at 3:04 PM, Paul Goyette wrote: > Is there any documentation on the modules interface or API? There does not > seem to be anything in the man pages... > > My specific questions: > > What actually triggers an autoload of a module? (There seem to be very few > places where module_autoload() is called.)
Device module_autoloading is done in specfs_open. > > What is the semantic difference between module_autoload() and a "normal" > module_load()? module_autoload happens automatically when you try to open device node which doesn't have device driver in kernel. > > Does the code which calls either of these routines need to be concerned with > whether the module has been previously loaded? Is it OK to load a module > that has already been loaded? > I think that this is not possible and these routines return an error when you try to do that. > Given that there is a kernel thread that runs around and attempts to unload > any unreferenced modules that have been loaded "for a while", is it ever > necessary or desirable to explicitly unload a module? It doesn't work this way there is a thread(workqueue) which try to unload module in first 300 seconds or mili seconds I can't remember now. But this thread or whatever is it doesn't unload modules older that set limit AFAIK. > > What happens if a global symbol referenced by a module doesn't exist? Does > the module get loaded anyway, leaving the reference unresolved? If you have a module which uses foo routine and it is not defined in kernel or loaded modules your module will simply not load. > > > Thanks in advance! > > > ------------------------------------------------------------------------- > | Paul Goyette | PGP Key fingerprint: | E-mail addresses: | > | Customer Service | FA29 0E3B 35AF E8AE 6651 | paul at whooppee.com | > | Network Engineer | 0786 F758 55DE 53BA 7731 | pgoyette at juniper.net | > | Kernel Developer | | pgoyette at netbsd.org | > ------------------------------------------------------------------------- Regards Adam.
