On 2021-12-13 11:08:26 [+0100], Michal Hocko wrote: > On Fri 10-12-21 16:22:01, Sebastian Andrzej Siewior wrote: > [...] > I am sorry but I didn't get to read and digest the rest of the message > yet. Let me just point out this > > > The problematic part here is mem_cgroup_tree_per_node::lock which can > > not be acquired with disabled interrupts on PREEMPT_RT. The "locking > > scope" is not always clear to me. Also, if it is _just_ the counter, > > then we might solve this differently. > > I do not think you should be losing sleep over soft limit reclaim. This > is certainly not something to be used for RT workloads and rather than > touching that code I think it makes some sense to simply disallow soft > limit with RT enabled (i.e. do not allow to set any soft limit). Okay. So instead of disabling it entirely you suggest I should take another stab at it? Okay. Disabling softlimit, where should I start with it? Should mem_cgroup_write() for RES_SOFT_LIMIT always return an error or something else? In the meantime I try to swap in my memcg memory… Sebastian
