From: Damien Le Moal <damien.lemoal@wdc.com>
To: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org,
"Martin K . Petersen" <martin.petersen@oracle.com>,
linux-scsi@vger.kernel.org
Subject: [PATCH v4 4/5] doc: document sysfs queue/cranges attributes
Date: Thu, 12 Aug 2021 11:26:25 +0900 [thread overview]
Message-ID: <20210812022626.694329-5-damien.lemoal@wdc.com> (raw)
In-Reply-To: <20210812022626.694329-1-damien.lemoal@wdc.com>
Update the file Documentation/block/queue-sysfs.rst to add a description
of a device queue sysfs entries related to concurrent sector ranges
(e.g. concurrent positioning ranges for multi-actuator hard-disks).
While at it, also fix a typo in this file introduction paragraph.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
Documentation/block/queue-sysfs.rst | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
diff --git a/Documentation/block/queue-sysfs.rst b/Documentation/block/queue-sysfs.rst
index 4dc7f0d499a8..757609bbb1e2 100644
--- a/Documentation/block/queue-sysfs.rst
+++ b/Documentation/block/queue-sysfs.rst
@@ -286,4 +286,32 @@ sequential zones of zoned block devices (devices with a zoned attributed
that reports "host-managed" or "host-aware"). This value is always 0 for
regular block devices.
+cranges (RO)
+------------
+
+The presence of this sub-directory of the /sys/block/xxx/queue/ directory
+indicates that the device is capable of executing requests targeting
+different sector ranges in parallel. For instance, single LUN multi-actuator
+hard-disks will likely have a cranges directory if the device correctly
+advertizes the sector ranges of its actuators.
+
+The cranges directory contains one directory per concurrent range, with each
+range described using the sector (RO) attribute file to indicate the first
+sector of the range and the nr_sectors (RO) attribute file to indicate the
+total number of sector in the range starting from the first sector.
+For example, a dual-actuator hard disk will have the following cranges
+entries.::
+
+ $ tree /sys/block/<device>/queue/cranges/
+ /sys/block/<device>/queue/cranges/
+ |-- 0
+ | |-- nr_sectors
+ | `-- sector
+ `-- 1
+ |-- nr_sectors
+ `-- sector
+
+The sector and nr_sectors attributes use 512B sector unit, regardless of
+the actual block size of the device.
+
Jens Axboe <jens.axboe@oracle.com>, February 2009
--
2.31.1
next prev parent reply other threads:[~2021-08-12 2:26 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-12 2:26 [PATCH v4 0/5] Initial support for multi-actuator HDDs Damien Le Moal
2021-08-12 2:26 ` [PATCH v4 1/5] block: Add concurrent positioning ranges support Damien Le Moal
2021-08-12 6:06 ` kernel test robot
2021-08-12 2:26 ` [PATCH v4 2/5] scsi: sd: add " Damien Le Moal
2021-08-12 2:26 ` [PATCH v4 3/5] libata: support concurrent positioning ranges log Damien Le Moal
2021-08-12 2:26 ` Damien Le Moal [this message]
2021-08-12 2:26 ` [PATCH v4 5/5] doc: Fix typo in request queue sysfs documentation Damien Le Moal
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