Hello Jens, This patch series not only enables runtime power management for blk-mq but also fixes a starvation issue in the power management code for the legacy block layer. Please consider this patch series for kernel v4.19. Thanks, Bart. Changes compared to v2: - Fixed the build for CONFIG_BLOCK=n. - Added a patch that introduces percpu_ref_read() in the percpu-counter code. - Added a patch that makes it easier to detect missing pm_runtime_get*() calls. - Addressed Jianchao's feedback including the comment about runtime overhead of switching a per-cpu counter to atomic mode. Changes compared to v1: - Moved the runtime power management code into a separate file. - Addressed Ming's feedback. Bart Van Assche (9): block: Fix a comment in a header file block: Move power management functions into new source files block: Serialize queue freezing and blk_pre_runtime_suspend() percpu-refcount: Introduce percpu_ref_read() block, scsi: Rework runtime power management block: Warn if pm_runtime_get*() has not been called block: Remove blk_pm_requeue_request() blk-mq: Insert blk_pm_{add,put}_request() calls blk-mq: Enable support for runtime power management block/Kconfig | 5 + block/Makefile | 1 + block/blk-core.c | 246 +++---------------------------- block/blk-mq-debugfs.c | 1 - block/blk-mq-sched.c | 13 +- block/blk-mq.c | 11 ++ block/blk-pm.c | 253 ++++++++++++++++++++++++++++++++ block/blk-pm.h | 35 +++++ block/elevator.c | 24 +-- drivers/scsi/scsi_pm.c | 1 + drivers/scsi/sd.c | 5 +- drivers/scsi/sr.c | 1 + drivers/scsi/ufs/ufshcd.c | 10 +- include/linux/blk-pm.h | 30 ++++ include/linux/blkdev.h | 37 +---- include/linux/percpu-refcount.h | 2 + lib/percpu-refcount.c | 29 ++++ 17 files changed, 420 insertions(+), 284 deletions(-) create mode 100644 block/blk-pm.c create mode 100644 block/blk-pm.h create mode 100644 include/linux/blk-pm.h -- 2.18.0