On Tue 19-10-21 09:30:18, Vasily Averin wrote:
[...]

With my patch ("memcg: prohibit unconditional exceeding the limit of dying tasks") try_charge_memcg() can fail:
a) due to fatal signal
b) when mem_cgroup_oom -> mem_cgroup_out_of_memory -> out_of_memory() returns false (when select_bad_process() found nothing)

To handle a) we can follow to your suggestion and skip excution of out_of_memory() in pagefault_out_of memory()
To handle b) we can go to retry: if mem_cgroup_oom() return OOM_FAILED.

How is b) possible without current being killed? Do we allow remote
charging?

However all these cases can be successfully handled by my new patch
"memcg: prevent false global OOM triggered by memcg limited task"
and I think it is better solution.

I have already replied to your approach in other email. Sorry our
replies have crossed.
-- 
Michal Hocko
SUSE Labs