Bug 216321 - cpuset: can cpuset_hotplug_workfn() be skipped during suspend/resume
Summary: cpuset: can cpuset_hotplug_workfn() be skipped during suspend/resume
Status: NEW
Alias: None
Product: Process Management
Classification: Unclassified
Component: Other (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: process_other
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2022-08-03 09:06 UTC by Rick Yiu
Modified: 2022-08-03 09:08 UTC (History)
3 users (show)

See Also:
Kernel Version: 5.10.134
Subsystem:
Regression: No
Bisected commit-id:


Attachments

Description Rick Yiu 2022-08-03 09:06:13 UTC
Hi,

We are checking suspend/resume performance on our platform. We found that when device resumes, it took 10+ ms in the function cpuset_hotplug_workfn(), and to be more specific, the time is spending in the function rebuild_root_domains() mostly.

From the comment of cpuset_hotplug_workfn(), it seems like there is no necessary to do rebuild_root_domains() or even cpuset_hotplug_workfn() itself in suspend/resume path. I tried to bypass the functions for suspend/resume, and I didn't see problem so far.

Because I am not an expert of this part, I would like to know if there is any risk to skip either function when suspend/resume. Thanks.



/*
...
 * Note that CPU offlining during suspend is ignored.  We don't modify
 * cpusets across suspend/resume cycles at all.
 */
void cpuset_hotplug_workfn(struct work_struct *work)

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