On Mon, 2016-06-06 at 20:24 +0100, Al Viro wrote: > On Mon, Jun 06, 2016 at 11:50:04AM +0200, Mike Galbraith wrote: > > (CCs Al, who knows, maybe he'll make them go *poof*) > > > > > > > In v4.7, Al added those buggers to NFS. BCACHE is disabled in RT > > > > > because of same.. but that's a somewhat suboptimal solution for > > > > > something as widely used as NFS. > > > > > > > > > > Suggestions? I reverted the offending commit to get 4.7-rt up and > > > > > running, but that's not gonna fly long term. > > > > > > > > This API should be avoided according to the comment and completions > > > > should be used. I am for removal of those. Were the locking people okay > > > > with this change in the first place or did this just sneak in? > > > > > > It just snuck in. Al reworked sillyunlink, whacking the wait_event() > > > stuff that was there, using annoying $subject instead. > > It's more than just wait_event() crap being killed (and crap it certainly > was). The situation is pretty much the same as with bcache; we don't want > readers to stick around until the initiated action has been completed. > > What exactly is RT problem, just to be sure to avoid reproducing exact same > issue in the replacement? These primitives take a lock class that's wired for PI, and break it. What RT used to do about that was to create a whole new lock type, and inject it into the tree wherever non_owner was used. When non_owner was killed, RT maintainers happily trashed that workaround.. but then bcache came along and brought the damn things back from the grave. -Mike -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
