On Thu, Aug 16, 2007 at 04:56:21PM +1000, Paul Mackerras wrote: > > Note that I said these are the cases _where one might want to allow > caching_, so of course adding volatile doesn't help _these_ cases. > There are of course other cases where one definitely doesn't want to > allow the compiler to cache the value, such as when polling an atomic > variable waiting for another CPU to change it, and from my inspection > so far these cases seem to be the majority.
We've been through that already. If it's a busy-wait it should use cpu_relax. If it's scheduling away that already forces the compiler to reread anyway. Do you have an actual example where volatile is needed? > - It matches the normal expectation based on the name "atomic_read" > - It matches the behaviour of the other atomic_* primitives Can't argue since you left out what those expectations or properties are. > - It avoids bugs in the cases where "volatile" behaviour is required Do you (or anyone else for that matter) have an example of this? Cheers, -- Visit Openswan at http://www.openswan.org/ Email: Herbert Xu ~{PmV>HI~} <[EMAIL PROTECTED]> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
