On Saturday, April 16, 2011, Mike Frysinger wrote: > On Fri, Apr 15, 2011 at 19:11, Rafael J. Wysocki wrote: > > On Friday, April 15, 2011, Mike Frysinger wrote: > >> On Fri, Apr 15, 2011 at 12:29, Pavel Machek wrote: > >> >> > > I believe the code is correct as is. > >> >> > > >> >> > that isnt what the code / documentation says. unless i'm reading them > >> >> > wrong, both seem to indicate that the proposed patch is what we > >> >> > actually want. > >> >> > >> >> The existing code is correct but it isn't optimal. > >> >> > >> >> wmb() and rmb() are heavy-duty operations, and you don't want to call > >> >> them when they aren't needed. That's exactly what smp_wmb() and > >> >> smp_rmb() are for -- they call wmb() and rmb(), but only in SMP > >> >> kernels. > >> >> > >> >> Unless you need to synchronize with another processor (not necessarily > >> >> a CPU, it could be something embedded within a device), you should > >> >> always use smp_wmb() and smp_rmb() rather than wmb() and rmb(). > >> > > >> > Maybe; but this code is not performance critical and I believe being > >> > obvious here is better... > >> > >> isnt it though ? especially when we talk about suspending/resuming on > >> embedded systems to get more savings over just cpu idle ? we want > >> that latency to be as low as possible. > > > > I agree, we can switch the freezer to smp_ barriers, but not for the reason > > you gave before. :-) > > > > Care to repost the patch with a suitable changelog? > > np > > to be clear, what you said wrt the Blackfin smp barriers still holds > true right ? I think so. > so this changset i merged doesnt need any tweaking ... > http://git.kernel.org/?p=linux/kernel/git/vapier/blackfin.git;a=commitdiff;h=943aee0c685d0563228d5a2ad9c8394ad0300fb5 Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
