v6: - Add a missing free_percpu() into blkcg_css_free() in patch 3. - Integrating the documentation patch 4 back into patch 3. v5: - Add a new patch 2 to eliminate the use of intermediate "ret" variable in blkcg_css_alloc() to fix compilation warning reported by kernel test robot. v4: - Update comment and eliminate "inline" keywords as suggested by TJ. v3: - Update comments in patch 2. - Put rcu_read_lock/unlock() in blkcg_rstat_flush(). - Use READ_ONCE/WRITE_ONCE() to access lnode->next to reduce data races. - Get a blkg reference when putting into the lockless list and put it back when removed. This patch series improves blkcg_rstat_flush() performance by eliminating unnecessary blkg enumeration and flush operations for those blkg's and blkg_iostat_set's that haven't been updated since the last flush. Waiman Long (3): blk-cgroup: Correctly free percpu iostat_cpu in blkg on error exit blk-cgroup: Return -ENOMEM directly in blkcg_css_alloc() error path blk-cgroup: Optimize blkcg_rstat_flush() block/blk-cgroup.c | 119 +++++++++++++++++++++++++++++++++++++++------ block/blk-cgroup.h | 9 ++++ 2 files changed, 112 insertions(+), 16 deletions(-) -- 2.31.1