On 11/30/2012 06:59 PM, Tejun Heo wrote: > 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. > Of course, there was a purely rhetorical statement, as indicated by "Tejun won't like it very much" =p Take a look at the final result, I just posted a couple of hours ago. Let me know if there is still something extremely funny, and I'll look into fixing it. -- 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>