Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 19 Apr 2012 15:58:20 -0700 | Subject | Re: [PATCH 3/3] x86, extable: Handle early exceptions |
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On Thu, Apr 19, 2012 at 3:47 PM, Tony Luck <tony.luck@gmail.com> wrote: > > How many entries are in the extable for a typical module? Perhaps it might > make sense to bundle them all into one sorted combined table? Of course > you would have to have a way to squeeze them back out of the combined > table at module unload time. > > This moves the cost to module load/unload time ... which is hopefully rare > compared to table lookup.
Using a traditional chained hash-table might be very amenable to this kind of situation. It's much easier to populate and doesn't have the size issues. And realistically, we can probably size the hash table for just the built-in kernel, because modules seldom have nearly as many exception table entries, so adding them later to a fixed-size table likely won't be too painful.
In fact, doing an "objdump" on the few modules I have, I didn't find a *single* exception table entry. Maybe I did something wrong? Isn't it the __ex_table in modules too?
(Admittedly, I avoid modules like the plague, so I don't tend to have very many modules, and the ones I do have tend to be pretty limited. So my module usage is absolutely not representative even if I think it should be ;^).
Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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