Re: [patch 2/13] signal/timer/event fds v6 - signalfd core ...

From: Arnd Bergmann
Date: Sun Mar 18 2007 - 19:46:31 EST


On Sunday 18 March 2007, Davide Libenzi wrote:
> bah, __put_user is basically a move, so I don't think that efficency would
> be that different (assuming that it'd matter in this case). The only thing
> many __put_user do, is increase the exception table sizes.

The cost of user access functions varies a lot depending on the
architectures. Those platforms with a 4G/4G split e.g. need to do more
than a simple move, and for s390 it may even come down to an indirect
function call, which incurs significant register pressure.

Arnd <><
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/