On Fri, 24 Oct 2014, Peter Zijlstra wrote: > The hold time isn't relevant, in fact breaking up the mmap_sem such that > we require multiple acquisitions will just increase the cacheline > bouncing. Well this wont be happening anymore once you RCUify the stuff. If you go to sleep then its best to release mmap_sem and then the bouncing wont matter. Dropping mmap_sem there will also expose you to races you will see later too when you RCUify the code paths. That way those can be deal with beforehand. > Also I think it makes more sense to continue an entire fault operation, > including blocking, if at all possible. Every retry will just waste more > time. Ok then dont retry. Just drop mmap_sem before going to sleep. When you come back evaluate the situation and if we can proceed do so otherwise retry. -- 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>