Christoph Lameter wrote:
On Fri, 31 Mar 2006, Nick Piggin wrote:
You acknowledge that you have to fix ia64 to match current semantics first, right?Right. I believe I have done so by making both smb_mb_* full barriers.
All bitop and atomic test_and_set, inc_return, etc etc (ie. everything that modifies the operand and returns something) needs to be a full barrier before and after too.
Now people seem to be worried about the performance impact that will have, so I simply suggest that adding two or three new macros for the important cases to give you a 90% solution.We could transition some key locations of core code to use _mode bitops if there are performance problems.I think Documentation/atomic_ops.txt isn't bad. smp_mb__* really is a smp_mb, which can be optimised sometimes.Ok. Then we are on the same page and the solution I presented may be acceptable. I have a new rev here that changes the naming a bit but I think we are okay right?
Not sure, to be honest. I think it is probably something which needs input from all the other arch people, and Linus, if you intend to use it to introduce new types of barriers. -- SUSE Labs, Novell Inc.Send instant messages to your online friends http://au.messenger.yahoo.com -
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