On Sat, Mar 28, 2009 at 10:38:50AM +0100, Andi Kleen wrote: > To be honest that sounds more like a bug in your architecture. > > I don't think it's the right solution to make a new rule > "you shall not do 64bit switch()", because that's a reasonable > thing to do and will be hard to enforce over millions of lines > of random Linux code. > > There was a explicit decision to not support implicit 64bit > divides on 32bit because they're very costly, but that doesn't > really apply to 64bit switch(). At least they shouldn't be very costly > in theory. It seems indeed weird to call a function to compare > a 64bit value. I bet the call sequence is larger than just > doing two cmps. Perhaps your gcc should be fixed? Or alternatively > at least that function be added to the kernel runtime library. > i386 will do this kind of stupidity too if you let it. I had to fix this in nouveau a few weeks back because they were doing a u64 modulus (a power of 2 too, no idea why gcc was so clueless as to not properly reduce it...) GCC is getting much worse in this regard... regards, Kyle -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
