It's not unrelated, the LSM function gives an arbitrary 3% bonus to
CAP_SYS_ADMIN. Such threads should also be preferred in the oom killer
over other threads since they tend to be more important but not an overly
drastic bias such that they don't get killed when using an egregious
amount of memory. So in selecting a small percentage of memory that tends
to be a significant bias but not overwhelming, I went with the 3% found
elsewhere in the kernel. __vm_enough_memory() doesn't have that
preference for any scientifically calculated reason, it's a heuristic just
like oom_badness().
You just said killing any CAP_SYS_RAWIO task may make the system crash, so
presuming that you don't want the system to crash, you are suggesting we
should make these threads completely immune? That's never been the case
(and isn't for oom_kill_allocating_task, either), so there's no history
you can draw from to support your argument.
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