hisi_sas: Reduce unnecessary spin lock contention
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
Undecided
|
dann frazier | ||
Bionic |
Fix Released
|
Undecided
|
dann frazier | ||
Cosmic |
Fix Released
|
Undecided
|
dann frazier |
Bug Description
[Impact]
The current design of hisi_sas_
[Test Case]
Use fio to measure performance difference, and verify that there is no performance decrease. Sample config attached. Test on D05 and D06 systems, since both are impacted.
[Fix]
commit 6cca51ee0aa2540
Author: Xiang Chen <email address hidden>
Date: Wed Jul 18 22:14:31 2018 +0800
scsi: hisi_sas: Tidy hisi_sas_
[Regression Risk]
It's possible that decreasing the lock granularity like this will lead to unforeseen latency issues. However, the additional work done under the new spin lock is just a single list_add_tail() call, which appears to run in constant time.
CVE References
Changed in linux (Ubuntu Cosmic): | |
status: | In Progress → Fix Committed |
Changed in linux (Ubuntu Bionic): | |
status: | In Progress → Fix Committed |
tags: | added: cscc |
This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification- needed- bionic' to 'verification- done-bionic' . If the problem still exists, change the tag 'verification- needed- bionic' to 'verification- failed- bionic' .
If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.
See https:/ /wiki.ubuntu. com/Testing/ EnableProposed for documentation how to enable and use -proposed. Thank you!