On Tue, Feb 04, 2014 at 02:28:57PM +0100, Michal Hocko wrote: > An ancient comment tries to explain that a given mm might be NULL when a > task is migrated. It has been introduced by 8a9f3ccd (Memory controller: > memory accounting) along with other bigger changes so it is not much > more specific about the conditions. > > Anyway, Even if the task is migrated to another memcg there is no way we > can see NULL mm struct. So either this was not correct from the very > beginning or it is not true anymore. > The only remaining case would be seeing charges after exit_mm but that > would be a bug on its own as the task doesn't have an address space > anymore. > > This patch replaces the check by VM_BUG_ON to make it obvious that we > really expect non-NULL mm_struct. > > Signed-off-by: Michal Hocko <mhocko@xxxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> -- 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>