On Tue 03-07-18 09:01:01, Paul E. McKenney wrote: > On Tue, Jul 03, 2018 at 09:24:13AM +0200, Michal Hocko wrote: > > On Mon 02-07-18 14:37:14, Paul E. McKenney wrote: > > [...] > > > commit d2b8d16b97ac2859919713b2d98b8a3ad22943a2 > > > Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> > > > Date: Mon Jul 2 14:30:37 2018 -0700 > > > > > > rcu: Remove OOM code > > > > > > There is reason to believe that RCU's OOM code isn't really helping > > > that much, given that the best it can hope to do is accelerate invoking > > > callbacks by a few seconds, and even then only if some CPUs have no > > > non-lazy callbacks, a condition that has been observed to be rare. > > > This commit therefore removes RCU's OOM code. If this causes problems, > > > it can easily be reinserted. > > > > > > Reported-by: Michal Hocko <mhocko@xxxxxxxxxx> > > > Reported-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> > > > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> > > > > I would also note that waiting in the notifier might be a problem on its > > own because we are holding the oom_lock and the system cannot trigger > > the OOM killer while we are holding it and waiting for oom_callback_wq > > event. I am not familiar with the code to tell whether this can deadlock > > but from a quick glance I _suspect_ that we might depend on __rcu_reclaim > > and basically an arbitrary callback so no good. > > > > Acked-by: Michal Hocko <mhocko@xxxxxxxx> > > > > Thanks! > > Like this? Thanks! -- Michal Hocko SUSE Labs
