On Wed 07-08-13 09:47:41, Tejun Heo wrote: > Hello, > > On Wed, Aug 07, 2013 at 03:37:46PM +0200, Michal Hocko wrote: > > > It isn't different from listening from epoll, for example. > > > > epoll limits the number of watchers, no? > > Not that I know of. It'll be limited by max open fds but I don't > think there are other limits. max_user_watches seems to be a limit (4% of lowmem in maximum). > Why would there be? Because userspace should hog kernel resources without any limit. > > > If there needs to be kernel memory limit, shouldn't that be handled by > > > kmemcg? > > > > kmemcg would surely help but turning it on just because of potential > > abuse of the event registration API sounds like an overkill. > > > > I think having a cap for user trigable kernel resources is a good thing > > in general. > > I don't know. It's just very arbitrary because listening to events > itself isn't (and shouldn't) be something which consumes resource > which isn't attributed to the listener and this artificially creates a > global resource. The problem with memory usage event is breaching > that rule with shared kmalloc() so putting well-defined limit on it is > fine but the latter two create additional artificial restrictions > which are both unnecessary and unconventional. No? Hmm, OK so you think that the fd limit is sufficient already? -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>