On Wed, Mar 9, 2022 at 12:27 PM Yosry Ahmed <yosryahmed@xxxxxxxxxx> wrote: > [...] > > The map usage by BPF programs and integration with rstat can be as follows: > - Internally, each map entry has per-cpu arrays, a total array, and a > pending array. BPF programs and user space only see one array. > - The update interface is disabled. BPF programs use helpers to modify > elements. Internally, the modifications are made to per-cpu arrays, > and invoke a call to cgroup_bpf_updated() or an equivalent. > - Lookups (from BPF programs or user space) invoke an rstat flush and > read from the total array. Lookups invoke a rstat flush, so we still walk every node of a subtree for each lookup, no? So the actual cost should be similar than walking the subtree with some BPF program? Did I miss something? Thanks, Song > - In cgroup_rstat_flush_locked() flush BPF stats as well. > [...]
