On Fri, Nov 16, 2018 at 04:38:26PM -0800, Roman Gushchin wrote: > Now the number of descendant cgroups and the number of dying > descendant cgroups are synchronized using the cgroup_mutex. > > The number of descendant cgroups will be required by the cgroup v2 > freezer, which will use it to determine if a cgroup is frozen > (depending on total number of descendants and number of frozen > descendants). It's not always acceptable to grab the cgroup_mutex, > especially from quite hot paths (e.g. exit()). > > To avoid this, let's additionally synchronize these counters > using the css_set_lock. Can you change it so that writes are cgroup_mutex and css_set_lock protected and reads can be done under either cgroup_mutex or css_set_lock? Thanks. -- tejun
