On Wed, Sep 20, 2006 at 09:23:25PM +0100, Christoph Hellwig wrote: > On Wed, Sep 20, 2006 at 12:53:47PM -0700, Stephane Eranian wrote: > > Hello Tony, > > > > For Montecito PMU support, I need to determine, in a kernel module, whether > > or not threads are enabled. The only reliable way of doing this is to > > compute the bit-weight of cpu_sibling_map[]. This symbol is exported on > > x86 systems, but not on IA-64 so far. This patch exports the symbol. > > Exporting global variables is a very bad thing, and we only do it if we > can't avoid it at all. In this case it could be easily avoided by > exporting a nr_siblings_per_cpu() helper. I also have my doubts about this in terms of hotplug cpu ... what do you do if not all of the cpus have their siblings on-line? The question "Are threads enabled?" doesn't seem to have a simple yes/no answer. At best you might ask "Does cpu N have any online siblings?" but the answer to that question could change before you could make use of the information. -Tony - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
|