On Saturday, July 04, 2015 10:19:55 AM Alan Stern wrote: > On Sat, 4 Jul 2015, Rafael J. Wysocki wrote: > > > The only argument against dropping sys_sync() from the suspend code path > > I've seen in this thread that I entirely agree with is that it may lead to > > regressions, because we've done it practically forever and it may hide > > latent > > bugs somewhere in block drivers etc. Dropping it, though, is the only way > > to see those bugs, if any, and if we want to ever fix them, we need to see > > them. That's why I think that it may be a good idea to allow people to > > drop it if they are willing to accept some extra risk (via the kernel > > command line, for example). > > I'd be perfectly happy to have the sync selectable at runtime, one way > or another. The three most reasonable options seem to be: > > kernel command line > > sysfs file > > sysctl setting > > The command line is less flexible (it can't be changed after booting). > Either of the other two would be fine with me.
We'll probably use a sysfs file (possibly plus a Kconfig option to set the boot time default). > > Moreover, question is if we really need to carry out the sync on *every* > > suspend even if it is not pointless overall. That shouldn't really be > > necessary if we suspend and resume often enough or if we resume only for > > a while and then suspend again. Maybe it should be rate limited somehow > > at least? > > For example, skip the sync if the system has been awake for < 100 ms? Yes, something like that. > The cutoff time could also be controlled by the sysfs file: -1 => > never sync, 0 => always sync, > 0 => sync if the system has been awake > longer than the value. That sounds like a good idea to me. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
