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 v3:
- Avoid adverse interactions between system-wide suspend/resume and runtime
power management by changing the PREEMPT_ONLY flag into a counter.
- Give RQF_PREEMPT back its original meaning, namely that it is only set for
ide_preempt requests.
- Remove the flag BLK_MQ_REQ_PREEMPT.
- Removed the pm_request_resume() call.
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 (10):
block: Change the preempt-only flag into a counter
block, scsi: Give RQF_PREEMPT back its original meaning
block, ide: Remove flag BLK_MQ_REQ_PREEMPT
block: Move power management code into a new source file
block: Serialize queue freezing and blk_pre_runtime_suspend()
percpu-refcount: Introduce percpu_ref_read()
block, scsi: Rework runtime power management
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 | 281 ++++----------------------------
block/blk-mq-debugfs.c | 11 +-
block/blk-mq-sched.c | 13 +-
block/blk-mq.c | 13 +-
block/blk-pm.c | 245 ++++++++++++++++++++++++++++
block/blk-pm.h | 37 +++++
block/elevator.c | 24 +--
drivers/ide/ide-pm.c | 3 +-
drivers/scsi/scsi_lib.c | 36 ++--
drivers/scsi/scsi_pm.c | 1 +
drivers/scsi/sd.c | 1 +
drivers/scsi/sr.c | 1 +
include/linux/blk-mq.h | 4 +-
include/linux/blk-pm.h | 30 ++++
include/linux/blkdev.h | 45 ++---
include/linux/percpu-refcount.h | 2 +
lib/percpu-refcount.c | 29 ++++
19 files changed, 453 insertions(+), 329 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
