Re: [PATCH v9 3/8] cpuset: Rebuild root domain deadline accounting information

[Qais Yousef]

Hi

On 07/19/19 15:59, Juri Lelli wrote:
> When the topology of root domains is modified by CPUset or CPUhotplug
> operations information about the current deadline bandwidth held in the
> root domain is lost.
> 
> This patch addresses the issue by recalculating the lost deadline
> bandwidth information by circling through the deadline tasks held in
> CPUsets and adding their current load to the root domain they are
> associated with.
> 
> Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> Signed-off-by: Juri Lelli <juri.lelli@xxxxxxxxxx>
> ---

We see that rebuild_root_domain() can take 10+ ms (I get a max of 20ms quite
consistently) on suspend/resume.

Do we actually need to rebuild_root_domain() if we're going through
a suspend/resume cycle?

ie: would something like the below make sense? We'd skip this logic if
cpuhp_tasks_frozen is set which indicates it's not a real hotplug operation but
we're suspending/resuming.


Cheers

--
Qais Yousef


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