Messages in this thread | | | Date | Tue, 29 Sep 2015 15:39:45 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [PATCH -mm 2/3] mm/oom_kill: cleanup the "kill sharing same memory" |
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On Tue, 29 Sep 2015, Oleg Nesterov wrote:
> Purely cosmetic, but the complex "if" condition looks annoying to me. > Especially because it is not consistent with OOM_SCORE_ADJ_MIN check > which adds another if/continue. > > Signed-off-by: Oleg Nesterov <oleg@redhat.com> > --- > mm/oom_kill.c | 22 +++++++++++++--------- > 1 file changed, 13 insertions(+), 9 deletions(-) > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index 0d581c6..8e7bed2 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -583,16 +583,20 @@ void oom_kill_process(struct oom_control *oc, struct task_struct *p, > * pending fatal signal. > */ > rcu_read_lock(); > - for_each_process(p) > - if (p->mm == mm && !same_thread_group(p, victim) && > - !(p->flags & PF_KTHREAD)) { > - if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) > - continue; > + for_each_process(p) { > + if (unlikely(p->flags & PF_KTHREAD)) > + continue; > + if (same_thread_group(p, victim)) > + continue; > + if (p->mm != mm) > + continue;
This ordering is a little weird to me, I think we would eliminate the majority of processes by checking for p->mm != mm first. There are certainly pathological cases where that can be defeated, but in practice it seems to happen more often than not.
Unless you object, I think the ordering should be p->mm != mm, same_thread_group(), unlikely(PF_KTHREAD) as it originally was (thanks for adding the unlikely).
I agree your cleanup looks much better than the nested conditional.
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