> On Apr 18, 2017, at 3:59 PM, Michal Hocko <mhocko@xxxxxxxxxx> wrote: > >> On Tue 18-04-17 14:48:39, Hoeun Ryu wrote: >> vm_area_add_early/vm_area_register_early() are used to reserve vmalloc area >> during boot process and those virtually mapped areas are never unmapped. >> So `OR` VM_STATIC flag to the areas in vmalloc_init() when importing >> existing vmlist entries and prevent those areas from being removed from the >> rbtree by accident. > > Has this been a problem in the past or currently so that it is worth > handling? > >> This flags can be also used by other vmalloc APIs to >> specify that the area will never go away. > > Do we have a user for that? > >> This makes remove_vm_area() more robust against other kind of errors (eg. >> programming errors). > > Well, yes it will help to prevent from vfree(early_mem) but we have 4 > users of vm_area_register_early so I am really wondering whether this is > worth additional code. It would really help to understand your > motivation for the patch if we were explicit about the problem you are > trying to solve. I just think that it would be good to make it robust against various kind of errors. You might think that's not an enough reason to do so though. > > Thanks > > -- > Michal Hocko > SUSE Labs
