| Message ID | 20220105175115.605074-1-jannh@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm, oom: OOM sysrq should always kill a process | expand |
On Wed 05-01-22 18:51:15, Jann Horn wrote: > The OOM kill sysrq (alt+sysrq+F) should allow the user to kill the > process with the highest OOM badness with a single execution. > > However, at the moment, the OOM kill can bail out if an OOM notifier > (e.g. the i915 one) says that it reclaimed a tiny amount of memory > from somewhere. That's probably not what the user wants. > > As documented in struct oom_control, order == -1 means the oom kill is > required by sysrq. So check for that, and if it's true, don't bail out > no matter what the OOM notifiers say. I agree that it is suboptimal to disable sysrq+f because of notfiers because the OOM invocation is not a direct result of the OOM situation but rather an admin will. We already kill a new task even if an oom victim is still pending. > Signed-off-by: Jann Horn <jannh@google.com> with a minor update as below Acked-by: Michal Hocko <mhocko@suse.com> > --- > mm/oom_kill.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > index 1ddabefcfb5a..dc645cbc6e0d 100644 > --- a/mm/oom_kill.c > +++ b/mm/oom_kill.c > @@ -1051,13 +1051,14 @@ EXPORT_SYMBOL_GPL(unregister_oom_notifier); > bool out_of_memory(struct oom_control *oc) > { > unsigned long freed = 0; > + bool sysrq_forced = oc->order == -1; > > if (oom_killer_disabled) > return false; > > if (!is_memcg_oom(oc)) { > blocking_notifier_call_chain(&oom_notify_list, 0, &freed); > - if (freed > 0) > + if (freed > 0 && !sysrq_forced) > /* Got some memory back in the last second. */ > return true; > } is_sysrq_oom(oc) is a more appropriate way to check this. > > base-commit: c9e6606c7fe92b50a02ce51dda82586ebdf99b48 > -- > 2.34.1.448.ga2b2bfdf31-goog
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 1ddabefcfb5a..dc645cbc6e0d 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -1051,13 +1051,14 @@ EXPORT_SYMBOL_GPL(unregister_oom_notifier); bool out_of_memory(struct oom_control *oc) { unsigned long freed = 0; + bool sysrq_forced = oc->order == -1; if (oom_killer_disabled) return false; if (!is_memcg_oom(oc)) { blocking_notifier_call_chain(&oom_notify_list, 0, &freed); - if (freed > 0) + if (freed > 0 && !sysrq_forced) /* Got some memory back in the last second. */ return true; }
The OOM kill sysrq (alt+sysrq+F) should allow the user to kill the process with the highest OOM badness with a single execution. However, at the moment, the OOM kill can bail out if an OOM notifier (e.g. the i915 one) says that it reclaimed a tiny amount of memory from somewhere. That's probably not what the user wants. As documented in struct oom_control, order == -1 means the oom kill is required by sysrq. So check for that, and if it's true, don't bail out no matter what the OOM notifiers say. Signed-off-by: Jann Horn <jannh@google.com> --- mm/oom_kill.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) base-commit: c9e6606c7fe92b50a02ce51dda82586ebdf99b48