On Wed, 2015-06-17 at 09:47 +0200, Michal Hocko wrote: > On the other hand using srcu is a neat idea. Shrinkers only need the > existence guarantee when racing with unregister. Register even shouldn't > be that interesting because such a shrinker wouldn't have much to > shrink anyway so we can safely miss it AFAIU. With the srcu read lock > we can finally get rid of the try_lock. I do not think you need an > ugly spin_is_locked as the replacement though. We have the existence > guarantee and that should be sufficient. So the reason for the spin_is_locked check was that I was concerned about new reader(s) that come in while doing the registry. Currently this is forbidden by the trylock and fake-ish retry. But yes, perhaps I was being over safe and we shouldn't be blockling the reclaim simply because a shrinker is registering. And it would be cleaner to get rid of the whole retry idea and just use rcu guarantees. This is probably a little late in the game to try to push for 4.2, so I'll send a v2 with any other updates that might come up once the merge window closes. Thanks, Davidlohr -- 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>