From: Damien Le Moal <damien.lemoal@wdc.com>
To: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, linux-ide@vger.kernel.org,
"Martin K . Petersen" <martin.petersen@oracle.com>,
linux-scsi@vger.kernel.org
Subject: [PATCH v8 4/5] doc: document sysfs queue/independent_access_ranges attributes
Date: Thu, 9 Sep 2021 11:35:44 +0900 [thread overview]
Message-ID: <20210909023545.1101672-5-damien.lemoal@wdc.com> (raw)
In-Reply-To: <20210909023545.1101672-1-damien.lemoal@wdc.com>
Update the file Documentation/block/queue-sysfs.rst to add a description
of a device queue sysfs entries related to independent access ranges
(e.g. concurrent positioning ranges for multi-actuator hard-disks).
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
Documentation/block/queue-sysfs.rst | 31 +++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/Documentation/block/queue-sysfs.rst b/Documentation/block/queue-sysfs.rst
index 4dc7f0d499a8..b6e8983d8eda 100644
--- a/Documentation/block/queue-sysfs.rst
+++ b/Documentation/block/queue-sysfs.rst
@@ -286,4 +286,35 @@ 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.
+independent_access_ranges (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 have an independent_access_ranges directory if the device
+correctly advertizes the sector ranges of its actuators.
+
+The independent_access_ranges directory contains one directory per access
+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 sectors in the range starting from the first
+sector of the range. For example, a dual-actuator hard-disk will have the
+following independent_access_ranges entries.::
+
+ $ tree /sys/block/<device>/queue/independent_access_ranges/
+ /sys/block/<device>/queue/independent_access_ranges/
+ |-- 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. Independent access ranges do not
+overlap and include all sectors within the device capacity. The access
+ranges are numbered in increasing order of the range start sector,
+that is, the sector attribute of range 0 always has the value 0.
+
Jens Axboe <jens.axboe@oracle.com>, February 2009
--
2.31.1
next prev parent reply other threads:[~2021-09-09 2:36 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-09 2:35 [PATCH v8 0/5] Initial support for multi-actuator HDDs Damien Le Moal
2021-09-09 2:35 ` [PATCH v8 1/5] block: Add independent access ranges support Damien Le Moal
2021-09-09 5:59 ` Hannes Reinecke
2021-09-09 2:35 ` [PATCH v8 2/5] scsi: sd: add concurrent positioning " Damien Le Moal
2021-09-09 6:00 ` Hannes Reinecke
2021-09-09 2:35 ` [PATCH v8 3/5] libata: support concurrent positioning ranges log Damien Le Moal
2021-09-09 2:35 ` Damien Le Moal [this message]
2021-09-09 2:35 ` [PATCH v8 5/5] doc: Fix typo in request queue sysfs documentation Damien Le Moal
2021-09-14 0:38 ` [PATCH v8 0/5] Initial support for multi-actuator HDDs Damien Le Moal
2021-09-27 9:17 ` Damien Le Moal
2021-09-29 3:55 ` Martin K. Petersen
2021-10-11 7:50 ` Damien Le Moal
2021-10-11 11:28 ` Tim Walker
2021-10-15 8:20 ` Damien Le Moal
2021-10-27 0:34 ` Keith Busch
2021-10-27 0:45 ` Jens Axboe
2021-10-27 0:49 ` Damien Le Moal
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