On Wed, May 30, 2012 at 05:37:57PM +0400, Glauber Costa wrote: > On 05/30/2012 05:37 PM, Frederic Weisbecker wrote: > >Right. __mem_cgroup_get_kmem_cache() fetches the memcg of the owner > >and calls memcg_create_cache_enqueue() which does css_tryget(&memcg->css). > >After this tryget I think you're fine. And in-between you're safe against > >css_set removal due to rcu_read_lock(). > > > >I'm less clear with __mem_cgroup_new_kmem_page() though... > > That one does not get memcg->css but it does call mem_cgroup_get(), > that does prevent against the memcg structure being freed, which I > believe to be good enough. What if the owner calls cgroup_exit() between mem_cgroup_from_task() and mem_cgroup_get()? The css_set which contains the memcg gets freed. Also the reference on the memcg doesn't even prevent the css_set to be removed, does 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>