Hi Tejun, On Mon, Jan 19, 2015 at 09:30:01AM -0500, Tejun Heo wrote: > On Mon, Jan 19, 2015 at 02:23:21PM +0300, Vladimir Davydov wrote: > > Currently, we release css->id in css_release_work_fn, right before > > calling css_free callback, so that when css_free is called, the id may > > have already been reused for a new cgroup. > > > > I am going to use css->id to create unique names for per memcg kmem > > caches. Since kmem caches are destroyed only on css_free, I need css->id > > to be freed after css_free was called to avoid name clashes. This patch > > therefore moves css->id removal to css_free_work_fn. To prevent > > css_from_id from returning a pointer to a stale css, it makes > > css_release_work_fn replace the css ptr at css_idr:css->id with NULL. > > I think it'd be better if you create a separate id for this purpose. > The requirement is pretty unusual and likely contradictory with other > usages. Could you please elaborate this? I mean, what problems do you think can arise if we release css->id a little bit (one grace period) later? Of course, I can introduce yet another id per memcg, but I think we have css->id to avoid code duplication in controllers. Thanks, Vladimir -- 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>