在 2023/8/4 21:34, Michal Hocko 写道:
On Fri 04-08-23 21:15:57, Chuyi Zhou wrote:
[...]
+ switch (bpf_oom_evaluate_task(task, oc, &points)) {
+ case -EOPNOTSUPP: break; /* No BPF policy */
+ case -EBUSY: goto abort; /* abort search process */
+ case 0: goto next; /* ignore process */
+ default: goto select; /* note the task */
+ }
Why we need to change the *points* value if we do not care about oom_badness
? Is it used to record some state? If so, we could record it through bpf
map.
Strictly speaking we do not need to. That would require BPF to keep the
state internally. Many will do I suppose but we have to keep track of
the victim so that the oom killer knows what to kill so I thought that
it doesn't hurt to keep track of an abstract concept of points as well.
If you think this is not needed then oc->points could be always 0 for
bpf selected victims. The value is not used anyway in the proposed
scheme.
Btw. we will need another hook or metadata for the reporting side of
things. Generally dump_header() to know what has been the selection
policy.
OK. Maybe a integer like policy_type is enough to distinguish different
policies and the default method is zero. Or we can let BPF return a
string like policy_name.
Which one should I start implementing in next version? Do you have a
better idea?
Thanks.
