On Fri 20-07-18 16:01:25, Andrew Morton wrote:
On Tue, 17 Jul 2018 10:12:01 +0200 Michal Hocko mhocko@kernel.org wrote:
Any suggestions regarding how the driver developers can test this code path? I don't think we presently have a way to fake an oom-killing event? Perhaps we should add such a thing, given the problems we're having with that feature.
The simplest way is to wrap an userspace code which uses these notifiers into a memcg and set the hard limit to hit the oom. This can be done e.g. after the test faults in all the mmu notifier managed memory and set the hard limit to something really small. Then we are looking for a proper process tear down.
Chances are, some of the intended audience don't know how to do this and will either have to hunt down a lot of documentation or will just not test it. But we want them to test it, so a little worked step-by-step example would help things along please.
I am willing to give more specific steps. Is anybody interested? From my experience so far this is not something drivers developers using mmu notifiers would be unfamiliar with.