linprocfs: Add /proc/self/oom_score_adj.

[dchagin]

Summary

To avoid annoyng messages from LTP test suites add the simple
implementation of /proc/self/oom_score_adj which is do nothing.

[emaste]

Seems fine to implement as a nop, a couple of comments inline

sys/compat/linprocfs/linprocfs.c

1939

extra comment line

1942

Maybe add some underscores, do_oom_score_adj? dooomscoreadj is hard to read/parse

sys/compat/linux/linux_emul.c

190

Does Linux start at max? That seems somewhat surprising, I'd expect it to default to 0 with the ability to choose more or less susceptible to OOM killer than default.

[dchagin]

fixed, thanks