On Wed, Mar 13, 2019 at 11:39:53AM -0700, Roman Gushchin wrote: > It's possible to remove a big chunk of the redundant code by making > memcg_flush_offline_percpu() to take cpumask as an argument and flush > percpu data on all cpus belonging to the mask instead of all possible cpus. > > Then memcg_hotplug_cpu_dead() can call it with a single CPU bit set. > > This approach allows to remove all duplicated code, but safe the > performance optimization made in memcg_flush_offline_percpu(): > only one atomic operation per data entry. > > for_each_data_entry() > for_each_cpu(cpu. cpumask) > sum_events() > flush() > > Otherwise it would be one atomic operation per data entry per cpu: > for_each_cpu(cpu) > for_each_data_entry() > flush() > > Signed-off-by: Roman Gushchin <guro@xxxxxx> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
