Hello, 11/25/2009 07:50 PM, Ingo Molnar wrote: > Tejun, is it perhaps a problem of the percpu code getting confused > between the local and file scope 'dr7' variable shadowing each other? Yes. > If yes then that needs to be fixed in the percpu tree. per-cpu variables > used to have a __per_cpu prefix and that should be maintained - the two > namespaces are obviously separate on the logical space, so they should > never overlap in the implementational space either. If all we ever have are static variables, the prefix may be fine but with dynamic percpu variables now basically being the same first class citizen but prefix just doesn't cut it. It just ends up adding more confusion. The transition will be a bit painful (but not too much, how many of these reports have we had? Only several) but after that it's just plain local/global symbol collision the compiler would have no problem warning about. It behaves exactly like other global symbols. Percpu symbols and variables belong to a different address space than normal symbols. Unfortunately, C doesn't have support for such thing. Prefixing kind of works but simply breaks when the addresses are allowed to be handled as values. We have had the exactly same problem and solution for years now - iomem. Percpu memory isn't different from iomem at all. Once the conversion is complete and annotations and code are upstream, it won't be painful at all. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
