Eric Dumazet wrote:
On Wed, 11 Apr 2007 19:23:26 +1000
Nick Piggin <[EMAIL PROTECTED]> wrote:
As this external thing certainly is not doing the check itself, to be on the
safe side we should enforce it in get_futex_key(). I agree with you : If we
want to maximize performance, we could say : The check *must* be done by the
caller.
Well we _control_ the API, so let's make it as clean and performant as possible
from the start.
Take a look at do_futex().
Adding checks in callers just increase code size. I tried this got only bad
results.
This would speedup only the slow path (ie when some user code want to give us
non aligned addrs)
A single factorized check is cleaner and not slower, since we reduce icache
pressure.
1 extra check versus all that additional argument passing? I don't think it
is conclusive.
--
SUSE Labs, Novell Inc.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
