On Wed 23-10-19 12:27:29, Mike Christie wrote: > On 10/23/2019 02:11 AM, Michal Hocko wrote: > > On Wed 23-10-19 07:43:44, Dave Chinner wrote: > >> On Tue, Oct 22, 2019 at 06:33:10PM +0200, Michal Hocko wrote: > > > > Thanks for more clarifiation regarding PF_LESS_THROTTLE. > > > > [...] > >>> PF_IO_FLUSHER would mean that the user > >>> context is a part of the IO path and therefore there are certain reclaim > >>> recursion restrictions. > >> > >> If PF_IO_FLUSHER just maps to PF_LESS_THROTTLE|PF_MEMALLOC_NOIO, > >> then I'm not sure we need a new definition. Maybe that's the ptrace > >> flag name, but in the kernel we don't need a PF_IO_FLUSHER process > >> flag... > > > > Yes, the internal implementation would do something like that. I was > > more interested in the user space visible API at this stage. Something > > generic enough because exporting MEMALLOC flags is just a bad idea IMHO > > (especially PF_MEMALLOC). > > Do you mean we would do something like: > > prctl() > .... > case PF_SET_IO_FLUSHER: > current->flags |= PF_MEMALLOC_NOIO; > .... yes, along with PF_LESS_THROTTLE. -- Michal Hocko SUSE Labs
