Bug 1976679 - blk-mq: fix/improve io scheduler batching dispatch
Summary: blk-mq: fix/improve io scheduler batching dispatch
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: kernel
Version: 8.5
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: beta
: 8.5
Assignee: Ming Lei
QA Contact: ChanghuiZhong
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2021-06-28 02:24 UTC by Ming Lei
Modified: 2021-11-10 05:17 UTC (History)
2 users (show)

Fixed In Version: kernel-4.18.0-327.el8
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2021-11-09 19:18:09 UTC
Type: Bug
Target Upstream Version:


Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Gitlab redhat/rhel/src/kernel rhel-8 merge_requests 912 0 None None None 2021-07-02 08:09:33 UTC
Red Hat Product Errata RHSA-2021:4356 0 None None None 2021-11-09 19:18:49 UTC

Description Ming Lei 2021-06-28 02:24:08 UTC
Description of problem:

https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git/commit/?h=for-5.14/block&id=613471549f366cdf4170b81ce0f99f3867ec4d16

https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git/commit/?h=for-5.14/block&id=cb9516be7708a2a18ec0a19fe3a225b5b3bc92c7

One patch is for avoiding to dequeue two many requests, so io merge can be
improved.

Another patch is for fixing batching dispatch, in which hctx->dispatch_busy
is evaluated, but not get updated.

Comment 6 ChanghuiZhong 2021-08-04 08:58:03 UTC
sanity test passed with kernel-4.18.0-327.el8:
https://beaker.engineering.redhat.com/jobs/5654211
https://beaker.engineering.redhat.com/jobs/5655252

All fix patches has included to kernel tree:
$ git log kernel-4.18.0-327.el8 --oneline --grep=1976679
14b1478fd252 Merge: block: improve batching dispatch and fix discard request merge
377ced4accb4 blk-mq: update hctx->dispatch_busy in case of real scheduler
40aa7107656c block: Do not pull requests from the scheduler when we cannot dispatch them

move to verified + sanityonly

Comment 9 errata-xmlrpc 2021-11-09 19:18:09 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Moderate: kernel security, bug fix, and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2021:4356


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