Allow preemptable tasks schedule without checking proportion

[Cdayz]

Resolve #2966

[volcano-sh-bot]

Welcome @Cdayz!

It looks like this is your first PR to volcano-sh/volcano 馃帀.

Thank you, and welcome to Volcano. 😃

[volcano-sh-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
To complete the pull request process, please assign k82cn
You can assign the PR to them by writing /assign @k82cn in a comment when ready.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• pkg/scheduler/plugins/OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[Cdayz]

/assign @k82cn

[Cdayz]

/assign @Thor-wl

[wangyang0616]

The task here is the role of the preemptor, and task.Preemptable indicates whether the current task is allowed to be preempted.
Sorry, I don't quite understand the purpose of the judgment here.

[Cdayz]

Main idea of this PR, that preemptable tasks can skip this proportional check, because they can be preempted, so there are no problem to schedule them. In system which I maintain in my organisation should be available ability to schedule preemptible tasks bypassing proportional plugin.

[wangyang0616]

Thanks for your response, I see what you mean.

However, the proportional logic is designed to ensure that resources are available in the allocate scene, and is not bound to preempt. In reality, many users will not configure preempt actions.

I am worried that the modification here will affect the existing proportional function. So I have reservations about the current pr, and I can refer to the ideas of other contributors in the community.

[Cdayz]

Maybe we can add an optional parameter to proportional plugin configuration, which by default will save current behavior but allow to enable changes made by this pr?

[lowang-bh]

It sounds more reasonable to add a config. And what's more, job's queue should support Reclaimable so that the job in this queue can be reclaimed.

[lowang-bh]

need to add more check about job/pod/queue's preemtable/reclaimable.

/hold

[stale]

Is this still relevant? If so, what is blocking it? Is there anything you can do to help move it forward?

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.

[Cdayz]

I think we can close this PR in prior to #3158 where implemented more wide check.