Hello, On Fri, Nov 30, 2012 at 02:00:21PM +0400, Glauber Costa wrote: > Now, what I am actually seeing with cgroup creation, is that the > children will copy a lot of the values from the parent, like swappiness, > hierarchy, etc. Once the child copies it, we should no longer be able to > change those values in the parent: otherwise we'll get funny things like > parent.use_hierarchy = 1, child.use_hierarchy = 0. So, the best way to do this is from ->css_online(). If memcg synchronizes and inherits from ->css_online(), it can guarantee that the new cgroup will be visible in any following iterations. Just have an online flag which is turned on and off from ->css_on/offline() and ignore any cgroups w/o online set. > One option is to take a global lock in memcg_alloc_css(), and keep it > locked until we did all the cgroup bookkeeping, and then unlock it in > css_online. But I am guessing Tejun won't like it very much. No, please *NEVER* *EVER* do that. You'll be creating a bunch of locking dependencies as cgroup walks through different controllers. memcg should be able to synchornize fully both css on/offlining and task attachments in memcg proper. Let's please be boring about locking. Thanks. -- tejun -- 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>