Hello, Christoph. On Tue, Jun 17, 2014 at 10:56:10AM -0500, Christoph Lameter wrote: > Uhhh no. The percpu stuff and the associated per cpu atomics are to be > used for stuff that is per cpu specific and runs at the fastest speed > doable at that level. Introducing implicit barriers is not that good an > idea.
Hmmm? Read barriers are noops on all archs except for alpha and percpu pointer assignments aren't exactly a high frequency operation and I'm pretty sure we'll end up with a raw variant anyway. > The concurrency guarantees for the per cpu operations are related to being > interrupted or rescheduled but not for accesses from other processors. > > Cpus maintain at least the appearance of operations being visible in > sequence for code running on the same processor. Therefore no barriers are > needed. Huh? We're talking about percpu *pointer* assignments not assignments to percpu areas. Thanks. -- tejun -- 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/
