On Mon 02-07-18 15:33:11, Laurent Dufour wrote: > > > On 02/07/2018 14:45, Michal Hocko wrote: > > On Mon 02-07-18 14:26:09, Laurent Dufour wrote: > >> On 02/07/2018 14:15, Michal Hocko wrote: [...] > >>> We already do have a model for that. Have a look at MMF_UNSTABLE. > >> > >> MMF_UNSTABLE is a mm's flag, here this is a VMA's flag which is checked. > > > > Yeah, and we have the VMA ready for all places where we do check the > > flag. check_stable_address_space can be made to get vma rather than mm. > > Yeah, this would have been more efficient to check that flag at the beginning > of the page fault handler rather than the end, but this way it will be easier > to handle the speculative page fault too ;)
The thing is that it doesn't really need to be called earlier. You are not risking data corruption on file backed mappings. -- Michal Hocko SUSE Labs
