Commit c1081a7b authored by Tang Yizhou's avatar Tang Yizhou Committed by Jonathan Corbet
Browse files

doc: blk-ioprio: Bring the doc in line with the implementation 



Our system administrator have noted that the names 'rt-to-be' and
'all-to-idle' in the I/O priority policies table appeared without
explanations, leading to confusion. Let's bring these names in line
with the naming in the 'attribute' section.

Additionally,
1. Correct the interface name to 'io.prio.class'.
2. Add a table entry of 'promote-to-rt' for consistency.
3. Fix a typo of 'priority'.

Suggested-by: default avatarYingfu Zhou <yingfu.zhou@shopee.com>
Reviewed-by: default avatarHou Tao <houtao1@huawei.com>
Signed-off-by: default avatarTang Yizhou <yizhou.tang@shopee.com>
Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231012024228.2161283-1-yizhou.tang@shopee.com
parent 16794ed3

Documentation/admin-guide/cgroup-v2.rst

+6 −4
Original line number Diff line number Diff line
@@ -2023,7 +2023,7 @@ IO Priority 
~~~~~~~~~~~



A single attribute controls the behavior of the I/O priority cgroup policy,

namely the blkio.prio.class attribute. The following values are accepted for

namely the io.prio.class attribute. The following values are accepted for

that attribute:



  no-change
@@ -2052,9 +2052,11 @@ The following numerical values are associated with the I/O priority policies: 
+----------------+---+

| no-change      | 0 |

+----------------+---+

| rt-to-be       | 2 |

| promote-to-rt  | 1 |

+----------------+---+

| all-to-idle    | 3 |

| restrict-to-be | 2 |

+----------------+---+

| idle           | 3 |

+----------------+---+



The numerical value that corresponds to each I/O priority class is as follows:
@@ -2074,7 +2076,7 @@ The algorithm to set the I/O priority class for a request is as follows: 
- If I/O priority class policy is promote-to-rt, change the request I/O

  priority class to IOPRIO_CLASS_RT and change the request I/O priority

  level to 4.

- If I/O priorityt class is not promote-to-rt, translate the I/O priority

- If I/O priority class policy is not promote-to-rt, translate the I/O priority

  class policy into a number, then change the request I/O priority class

  into the maximum of the I/O priority class policy number and the numerical

  I/O priority class.