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authorChristian Loehle <christian.loehle@arm.com>2024-01-18 09:29:56 +0000
committerJens Axboe <axboe@kernel.dk>2024-01-18 08:21:14 -0700
commitb2e792ae883a0aa976d4176dfa7dc933263440ea (patch)
treef2d6445a95bf79d3def16daa4f482d6a7ac5c619 /Documentation/block
parentbaa7d536077dcdfe2b70c476a8873d1745d3de0f (diff)
downloadlwn-b2e792ae883a0aa976d4176dfa7dc933263440ea.tar.gz
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Documentation: block: ioprio: Update schedulers
This doc hasn't been touched in a while, in the meantime some new io schedulers were added (e.g. all of mq), some with ioprio support. Also reword the introduction to remove reference to CFQ and the limitation that io priorities only work on reads, which is no longer true. Signed-off-by: Christian Loehle <christian.loehle@arm.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/a86cfdc8-016f-40f1-8b58-0cb15d2a792c@arm.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'Documentation/block')
-rw-r--r--Documentation/block/ioprio.rst13
1 files changed, 6 insertions, 7 deletions
diff --git a/Documentation/block/ioprio.rst b/Documentation/block/ioprio.rst
index a25c6d5df87b..4662e1ff3d81 100644
--- a/Documentation/block/ioprio.rst
+++ b/Documentation/block/ioprio.rst
@@ -6,17 +6,16 @@ Block io priorities
Intro
-----
-With the introduction of cfq v3 (aka cfq-ts or time sliced cfq), basic io
-priorities are supported for reads on files. This enables users to io nice
-processes or process groups, similar to what has been possible with cpu
-scheduling for ages. This document mainly details the current possibilities
-with cfq; other io schedulers do not support io priorities thus far.
+The io priority feature enables users to io nice processes or process groups,
+similar to what has been possible with cpu scheduling for ages. Support for io
+priorities is io scheduler dependent and currently supported by bfq and
+mq-deadline.
Scheduling classes
------------------
-CFQ implements three generic scheduling classes that determine how io is
-served for a process.
+Three generic scheduling classes are implemented for io priorities that
+determine how io is served for a process.
IOPRIO_CLASS_RT: This is the realtime io class. This scheduling class is given
higher priority than any other in the system, processes from this class are