> So there are two users of frontswap for which the synchronous > interface makes sense. I believe there may be more in the > future and you disagree but, as Jeremy said, "a general Linux > principle is not to overdesign interfaces for hypothetical users, > only for real needs." We have demonstrated there is a need > with at least two users so the debate is only whether the > number of users is two or more than two. > > Frontswap is a very non-invasive patch and is very cleanly > layered so that if it is not in the presence of either of > the intended "users", it can be turned off in many different > ways with zero overhead (CONFIG'ed off) or extremely small overhead > (frontswap_ops is never set; or frontswap_ops is set but the > underlying hypervisor doesn't support it so frontswap_poolid > never gets set). Yet there are less invasive solutions available, like 'add trim operation to swap_ops'. So what needs to be said here is 'frontswap is XX times faster than swap_ops based solution on workload YY'. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>