Messages in this thread | | | Date | Sun, 18 Mar 2007 17:22:48 -0700 (PDT) | From | Davide Libenzi <> | Subject | Re: [patch 2/13] signal/timer/event fds v6 - signalfd core ... |
| |
On Mon, 19 Mar 2007, Arnd Bergmann wrote:
> 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.
Heh, I'd like ppl to agree on this, because I clearly remember in having an argoument with Andrew for the same thing, where I was doing stack setup plus copy_to_user() ;)
- Davide
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |