On Fri, Sep 21, 2018 at 01:31:14PM -0700, Bart Van Assche wrote: > Hello Jens, > > One of the pieces that is missing before blk-mq can be made the default is > implementing runtime power management support for blk-mq. This patch series > not only implements 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 the upstream kernel. > > Thanks, > > Bart. > > Changes compared to v9: > - Left out the patches that document the functions that iterate over requests > and also the patch that introduces blk_mq_queue_rq_iter(). > - Simplified blk_pre_runtime_suspend(): left out the check whether no requests > are in progress. > - Fixed the race between blk_queue_enter(), queue freezing and runtime power > management that Ming had identified. > - Added a new patch that introduces percpu_ref_resurrect(). > > Changes compared to v8: > - Fixed the race that was reported by Jianchao. > - Fixed another spelling issue in a source code comment. > > Changes compared to v7: > - Addressed Jianchao's feedback about patch "Make blk_get_request() block for > non-PM requests while suspended". > - Added two new patches - one that documents the functions that iterate over > requests and one that introduces a new function that iterates over all > requests associated with a queue. > > Changes compared to v6: > - Left out the patches that split RQF_PREEMPT in three flags. > - Left out the patch that introduces the SCSI device state SDEV_SUSPENDED. > - Left out the patch that introduces blk_pm_runtime_exit(). > - Restored the patch that changes the PREEMPT_ONLY flag into a counter. > > Changes compared to v5: > - Introduced a new flag RQF_DV that replaces RQF_PREEMPT for SCSI domain > validation. > - Introduced a new request queue state QUEUE_FLAG_DV_ONLY for SCSI domain > validation. > - Instead of using SDEV_QUIESCE for both runtime suspend and SCSI domain > validation, use that state for domain validation only and introduce a new > state for runtime suspend, namely SDEV_QUIESCE. > - Reallow system suspend during SCSI domain validation. > - Moved the runtime resume call from the request allocation code into > blk_queue_enter(). > - Instead of relying on q_usage_counter, iterate over the tag set to determine > whether or not any requests are in flight. > > Changes compared to v4: > - Dropped the patches "Give RQF_PREEMPT back its original meaning" and > "Serialize queue freezing and blk_pre_runtime_suspend()". > - Replaced "percpu_ref_read()" with "percpu_is_in_use()". > - Inserted pm_request_resume() calls in the block layer request allocation > code such that the context that submits a request no longer has to call > pm_runtime_get(). > > 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 (8): > block: Move power management code into a new source file > block, scsi: Change the preempt-only flag into a counter > block: Split blk_pm_add_request() and blk_pm_put_request() > block: Schedule runtime resume earlier > percpu-refcount: Introduce percpu_ref_resurrect() > block: Allow unfreezing of a queue while requests are in progress > block: Make blk_get_request() block for non-PM requests while > suspended > blk-mq: Enable support for runtime power management > > block/Kconfig | 3 + > block/Makefile | 1 + > block/blk-core.c | 270 ++++---------------------------- > block/blk-mq-debugfs.c | 10 +- > block/blk-mq.c | 4 +- > block/blk-pm.c | 216 +++++++++++++++++++++++++ > block/blk-pm.h | 69 ++++++++ > block/elevator.c | 22 +-- > drivers/scsi/scsi_lib.c | 11 +- > drivers/scsi/scsi_pm.c | 1 + > drivers/scsi/sd.c | 1 + > drivers/scsi/sr.c | 1 + > include/linux/blk-pm.h | 24 +++ > include/linux/blkdev.h | 37 ++--- > include/linux/percpu-refcount.h | 1 + > lib/percpu-refcount.c | 28 +++- > 16 files changed, 401 insertions(+), 298 deletions(-) > create mode 100644 block/blk-pm.c > create mode 100644 block/blk-pm.h > create mode 100644 include/linux/blk-pm.h > > -- > 2.19.0.444.g18242da7ef-goog >
Looks fine, Reviewed-by: Ming Lei <ming....@redhat.com> thanks, Ming
