On Sat, 18 Dec 2010, Tejun Heo wrote: > It's bothersome that these methods don't have any indication that > they're bound to local CPU when they can't be called with @pr for > another CPU as MSRs can only be accessed from local CPU. Right. > In the longer run, it would be nice if there's an indication that this > is only for the local CPU and maybe a WARN_ON_ONCE(). Maybe dropping > @pr and using this_cpu_*() is better for performance too? That is precisely the difficulty with many other functions that take pointers to cpu_info. If we can establish that they are called *only* with pointers to the current cpu then we can improve the function by dropping the parameter and using this_cpu ops to access the cpu_info fields. Using this_cpu ops instead of access to a field of a struct pointed to by an array avoids an addition of pointers and replacest with a operation that essentially takes a global address with a segment prefix. It reduces register pressure and avoids the additions of pointers but it will encode the address in the instruction. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
