Messages in this thread | | | Date | Fri, 25 Jul 2003 12:26:51 -0700 | From | Stephen Hemminger <> | Subject | Re: [PATCH] Remove module reference counting. |
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On Fri, 25 Jul 2003 04:00:18 +1000 Rusty Russell <rusty@rustcorp.com.au> wrote:
> Hi all, > > When the initial module patch was submitted, it made modules > start isolated, so they would not be accessible until (if) > initialization had succeeded. This broke partition scanning, and was > immediately reverted, leaving us with a module reference count scheme > identical to the previous one (just a faster implementation): we still > have cases where modules can be access on failed load. > > Then Dave decided that the work of reference counting network > driver modules everywhere is too invasive, so network driver modules > now have zero reference counts always. The idea is that if you don't > want the module removed, don't do it. ie. only remove the module if > there's a bug, or you want to replace it. > > If module removal is to be a rare and unusual event, it > doesn't seem so sensible to go to great lengths in the code to handle > just that case. In fact, it's easier to leave the module memory in > place, and not have the concept of parts of the kernel text (and some > types of kernel data) vanishing. > > Polite feedback welcome, > Rusty. > --
There are two possible objections to this: * Some developers keep the same kernel running and load/unload then reload a new driver when debugging. This would break probably or at least cause a large amount of kernel growth. Not that big an issue for me personally but driver writers seem to get hit with all the changes.
* Drivers might get sloppy about not cleaning up timers and data structures -- more than they are already. You might want to have a kernel debug option that overwrite's the unloaded text with something guaranteed to cause an oops.
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