On 2024/7/30 0:07, Michal Koutný wrote:
> Hello.
>
> On Mon, Jul 29, 2024 at 10:58:24AM GMT, Xiu Jianfeng <xiujianfeng@xxxxxxxxxxxxxxx> wrote:
>> To address this issue, only the cgroups from 'pids_over_limit' to root
>> will have their PIDCG_MAX counter increased and event notifications
>> generated.
>>
>
> For completeness here
>
> Fixes: 385a635cacfe0 ("cgroup/pids: Make event counters hierarchical")>
>> Signed-off-by: Xiu Jianfeng <xiujianfeng@xxxxxxxxxx>
>> ---
>> kernel/cgroup/pids.c | 13 ++++---------
>> 1 file changed, 4 insertions(+), 9 deletions(-)
>
>
>
>> @@ -257,15 +256,11 @@ static void pids_event(struct pids_cgroup *pids_forking,
>> cgrp_dfl_root.flags & CGRP_ROOT_PIDS_LOCAL_EVENTS)
>> return;
>>
>> - for (; parent_pids(p); p = parent_pids(p)) {
>> - if (p == pids_over_limit) {
>> - limit = true;
>> - atomic64_inc(&p->events_local[PIDCG_MAX]);
>> - cgroup_file_notify(&p->events_local_file);
>> - }
>> - if (limit)
>> - atomic64_inc(&p->events[PIDCG_MAX]);
>> + atomic64_inc(&pids_over_limit->events_local[PIDCG_MAX]);
>> + cgroup_file_notify(&pids_over_limit->events_local_file);
>>
>> + for (p = pids_over_limit; parent_pids(p); p = parent_pids(p)) {
>> + atomic64_inc(&p->events[PIDCG_MAX]);
>> cgroup_file_notify(&p->events_file);
>> }
>
> When I look at it applied altogther, there's one extra notification
> (heritage of forkfail events), it should be fixed with:
>
> --- a/kernel/cgroup/pids.c
> +++ b/kernel/cgroup/pids.c
> @@ -251,10 +251,11 @@ static void pids_event(struct pids_cgroup *pids_forking,
> pr_cont_cgroup_path(p->css.cgroup);
> pr_cont("\n");
> }
> - cgroup_file_notify(&p->events_local_file);
> if (!cgroup_subsys_on_dfl(pids_cgrp_subsys) ||
> - cgrp_dfl_root.flags & CGRP_ROOT_PIDS_LOCAL_EVENTS)
> + cgrp_dfl_root.flags & CGRP_ROOT_PIDS_LOCAL_EVENTS) {
> + cgroup_file_notify(&p->events_local_file);
> return;
> + }
Thanks, looks good, will do in the next version.
>
> atomic64_inc(&pids_over_limit->events_local[PIDCG_MAX]);
> cgroup_file_notify(&pids_over_limit->events_local_file);
>
> Besides that it makes sense to me.
>
> Thanks,
> Michal
