Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [patch 2/13] signal/timer/event fds v6 - signalfd core ... | Date | Mon, 19 Mar 2007 00:45:23 +0100 |
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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.
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