From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org, Ming Lei <ming.lei@redhat.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Alan Stern <stern@rowland.harvard.edu>,
linux-pm@vger.kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Christoph Hellwig <hch@lst.de>,
Bart Van Assche <bart.vanassche@wdc.com>,
Hannes Reinecke <hare@suse.de>,
Johannes Thumshirn <jthumshirn@suse.de>,
Adrian Hunter <adrian.hunter@intel.com>,
"James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
linux-scsi@vger.kernel.org
Subject: [PATCH RFC V2 0/3] blk-mq: support runtime PM
Date: Fri, 13 Jul 2018 16:05:59 +0800 [thread overview]
Message-ID: <20180713080602.31602-1-ming.lei@redhat.com> (raw)
Hi Guys,
Runtime PM is usually enabled for SCSI devices, and we are switching to
SCSI_MQ recently, but runtime PM isn't supported yet by blk-mq, and
people may complain that.
This patch tries to support runtime PM for blk-mq. And one chanllenge is
that it can be quite expensive to account the active in-flight IOs for
figuring out when to mark the last busy. This patch simply marks busy
after each non-PM IO is done, and this way is workable because:
1) pm_runtime_mark_last_busy() is very cheap
2) in-flight non-PM IO is checked in blk_pre_runtime_suspend(), so
if there is any IO queued, the device will be prevented from being
suspened.
3) Generally speaking, autosuspend_delay_ms is often big, and should
be in unit of second, so it shouldn't be a big deal to check if queue
is idle in blk_pre_runtime_suspend().
V2:
- re-organize code as suggested by Christoph
- use seqlock to sync runtime PM and IO path
Ming Lei (3):
block: put runtime PM code into common helpers
blk-mq: prepare for supporting runtime PM
scsi_mq: enable runtime PM
block/blk-core.c | 176 +++++++++++++++++++++++++++++++++++++++---------
block/blk-mq.c | 71 +++++++++++++++++++
block/blk-mq.h | 10 +++
drivers/scsi/scsi_lib.c | 3 +-
include/linux/blk-mq.h | 1 +
include/linux/blkdev.h | 1 +
6 files changed, 228 insertions(+), 34 deletions(-)
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: linux-pm@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org
--
2.9.5
next reply other threads:[~2018-07-13 8:05 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-13 8:05 Ming Lei [this message]
2018-07-13 8:06 ` [PATCH RFC V2 1/3] block: put runtime PM code into common helpers Ming Lei
2018-07-17 13:21 ` Christoph Hellwig
2018-07-13 8:06 ` [PATCH RFC V2 2/3] blk-mq: prepare for supporting runtime PM Ming Lei
2018-07-13 20:16 ` Alan Stern
2018-07-17 13:23 ` Christoph Hellwig
2018-07-13 8:06 ` [PATCH RFC V2 3/3] scsi_mq: enable " Ming Lei
2018-07-17 13:24 ` Christoph Hellwig
2018-07-17 15:30 ` Ming Lei
2018-07-17 15:34 ` Bart Van Assche
2018-07-17 15:38 ` Ming Lei
2018-07-17 19:50 ` hch
2018-07-17 20:54 ` Alan Stern
2018-07-17 21:49 ` Jens Axboe
2018-07-18 12:06 ` Ming Lei
2018-07-18 12:28 ` Johannes Thumshirn
2018-07-18 12:37 ` Ming Lei
2018-07-18 14:12 ` Alan Stern
2018-07-18 14:18 ` Johannes Thumshirn
2018-07-18 15:01 ` Alan Stern
2018-07-19 6:41 ` Johannes Thumshirn
2018-07-19 14:35 ` Alan Stern
2018-07-19 14:43 ` Johannes Thumshirn
2018-07-18 14:50 ` Jens Axboe
2018-07-18 18:46 ` Alan Stern
2018-07-18 23:08 ` Ming Lei
2018-07-18 12:43 ` Hannes Reinecke
2018-07-18 13:05 ` Ming Lei
2018-07-13 14:21 ` [PATCH RFC V2 0/3] blk-mq: support " Jens Axboe
2018-07-14 2:37 ` Ming Lei
2018-07-14 2:54 ` Jens Axboe
2018-07-16 16:21 ` Bart Van Assche
2018-07-16 16:03 ` Bart Van Assche
2018-07-17 1:12 ` Ming Lei
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