On 9/10/21 5:55 PM, Michal Hocko wrote: > On Fri 10-09-21 16:20:58, Vasily Averin wrote: >> On 9/10/21 4:04 PM, Tetsuo Handa wrote: >>> Can't we add fatal_signal_pending(current) test to vmalloc() loop? > > We can and we should. > >> 1) this has been done in the past but has been reverted later. > > The reason for that should be addressed IIRC. I don't know the details of this, and I need some time to investigate it. >> 2) any vmalloc changes will affect non-memcg allocations too. >> If we're doing memcg-related checks it's better to do it in one place. > > I think those two things are just orthogonal. Bailing out from vmalloc > early sounds reasonable to me on its own. Allocating a large thing that > is likely to go away with the allocating context is just a waste of > resources and potential reason to disruptions to others. I doubt that fatal signal should block any vmalloc allocations. I assume there are situations where rollback of some cancelled operation uses vmalloc. Or coredump saving on some remote storage can uses vmalloc. However for me it's abnormal that even OOM-killer cannot cancel huge vmalloc allocation. So I think tsk_is_oom_victim(current) check should be added to vm_area_alloc_pages() to break vmalloc cycle. Thank you, Vasily Averin
