linux-ide.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
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 v7 4/5] doc: document sysfs queue/independent_access_ranges attributes
Date: Mon,  6 Sep 2021 10:58:09 +0900	[thread overview]
Message-ID: <20210906015810.732799-5-damien.lemoal@wdc.com> (raw)
In-Reply-To: <20210906015810.732799-1-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>
---
 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


  parent reply	other threads:[~2021-09-06  1:58 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-06  1:58 [PATCH v7 0/5] Initial support for multi-actuator HDDs Damien Le Moal
2021-09-06  1:58 ` [PATCH v7 1/5] block: Add independent access ranges support Damien Le Moal
2021-09-06  8:14   ` Hannes Reinecke
2021-09-06 17:38   ` Jens Axboe
2021-09-06 22:31     ` Damien Le Moal
2021-09-06  1:58 ` [PATCH v7 2/5] scsi: sd: add concurrent positioning " Damien Le Moal
2021-09-06  8:35   ` Hannes Reinecke
2021-09-06  1:58 ` [PATCH v7 3/5] libata: support concurrent positioning ranges log Damien Le Moal
2021-09-06  1:58 ` Damien Le Moal [this message]
2021-09-06  8:37   ` [PATCH v7 4/5] doc: document sysfs queue/independent_access_ranges attributes Hannes Reinecke
2021-09-06  1:58 ` [PATCH v7 5/5] doc: Fix typo in request queue sysfs documentation Damien Le Moal
2021-09-06  8:37   ` Hannes Reinecke

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210906015810.732799-5-damien.lemoal@wdc.com \
    --to=damien.lemoal@wdc.com \
    --cc=axboe@kernel.dk \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-ide@vger.kernel.org \
    --cc=linux-scsi@vger.kernel.org \
    --cc=martin.petersen@oracle.com \
    --subject='Re: [PATCH v7 4/5] doc: document sysfs queue/independent_access_ranges attributes' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).