Messages in this thread | | | Date | Tue, 11 Apr 2023 14:23:32 +0200 | From | Michal Koutný <> | Subject | Re: [PATCH v4] mm: oom: introduce cpuset oom |
| |
Hello.
On Tue, Apr 11, 2023 at 02:58:15PM +0800, Gang Li <ligang.bdlg@bytedance.com> wrote: > +int cpuset_scan_tasks(int (*fn)(struct task_struct *, void *), void *arg) > +{ > + int ret = 0; > + struct css_task_iter it; > + struct task_struct *task; > + struct cpuset *cs; > + struct cgroup_subsys_state *pos_css; > + > + /* > + * Situation gets complex with overlapping nodemasks in different cpusets. > + * TODO: Maybe we should calculate the "distance" between different mems_allowed. > + * > + * But for now, let's make it simple. Just iterate through all cpusets > + * with the same mems_allowed as the current cpuset. > + */ > + cpuset_read_lock(); > + rcu_read_lock(); > + cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) { > + if (nodes_equal(cs->mems_allowed, task_cs(current)->mems_allowed)) { > + css_task_iter_start(&(cs->css), CSS_TASK_ITER_PROCS, &it); > + while (!ret && (task = css_task_iter_next(&it))) > + ret = fn(task, arg); > + css_task_iter_end(&it); > + } > + } > + rcu_read_unlock(); > + cpuset_read_unlock(); > + return ret; > +}
I see this traverses all cpusets without the hierarchy actually mattering that much. Wouldn't the CONSTRAINT_CPUSET better achieved by globally (or per-memcg) scanning all processes and filtering with: nodes_intersect(current->mems_allowed, p->mems_allowed) (`current` triggers the OOM, `p` is the iterated task) ?
Thanks, Michal [unhandled content-type:application/pgp-signature] | |