- Sometimes, the scheduler incorrectly placed a pod in the "unschedulable" queue instead of the "backoff" queue. This happened when some plugin previously declared the pod as "unschedulable" and then in a later attempt encounters some other error. Scheduling of that pod then got delayed by up to five minutes, after which periodic flushing moved the pod back into the "active" queue. ([#120334](https://github.com/kubernetes/kubernetes/pull/120334), [@pohly](https://github.com/pohly))...

    }

    @Override
    public @Nullable ReferenceEntry<K, V> getEntry() {
      return null;
    }

    @Override
    public ValueReference<K, V> copyFor(
        ReferenceQueue<V> queue, V value, ReferenceEntry<K, V> entry) {
      return this;
    }

    public void setLoading(boolean loading) {
      this.loading = loading;
    }

    @Override

    }

    @Override
    public @Nullable ReferenceEntry<K, V> getEntry() {
      return null;
    }

    @Override
    public ValueReference<K, V> copyFor(
        ReferenceQueue<V> queue, V value, ReferenceEntry<K, V> entry) {
      return this;
    }

    public void setLoading(boolean loading) {
      this.loading = loading;
    }

    @Override

### **Instrumentation**

#### **Audit**

*   Adjust batching audit webhook default parameters: increase queue size, batch size, and initial backoff. Add throttling to the batching audit webhook. Default rate limit is 10 QPS. ([#53417](https://github.com/kubernetes/kubernetes/pull/53417),[ @crassirostris](https://github.com/crassirostris))

- Added `SchedulerPopFromBackoffQ` feature gate that is in beta and enabled by default. Improved scheduling queue behavior by popping pods from the backoffQ when the activeQ is empty. This allows to process potentially schedulable pods ASAP, eliminating a penalty effect of the backoff queue. ([#130772](https://github.com/kubernetes/kubernetes/pull/130772), [@macsko](https://github.com/macsko)) [SIG Scheduling and Testing]

    - `scheduler_async_api_call_duration_seconds`: histogram of API call execution duration by call type and result
    - `scheduler_pending_async_api_calls`: gauge showing current number of pending API calls in the queue. ([#133120](https://github.com/kubernetes/kubernetes/pull/133120), [@utam0k](https://github.com/utam0k)) [SIG Release and Scheduling]

- Implement the scheduling framework with `Reserve`, `Prebind`, `Permit`, `Post-bind`, `Queue sort` and `Unreserve` extension points.
([#77567](https://github.com/kubernetes/kubernetes/pull/77567), [@wgliang](https://github.com/wgliang))

- Implemented scoring for DRA-backed extended resources. ([#134058](https://github.com/kubernetes/kubernetes/pull/134058), [@bart0sh](https://github.com/bart0sh)) [SIG Node, Scheduling and Testing]

- Added a `Processing` condition for the `workqueue` API.
  Changed `Shutdown` for the `workqueue` API to wait until the work queue finishes processing all in-flight items. ([#101928](https://github.com/kubernetes/kubernetes/pull/101928), [@alexanderConstantinescu](https://github.com/alexanderConstantinescu))

* Making DHCP_OPTION_SET_ID creation optional ([#27278](https://github.com/kubernetes/kubernetes/pull/27278), [@activars](https://github.com/activars))
* Convert service account token controller to use a work queue ([#23858](https://github.com/kubernetes/kubernetes/pull/23858), [@liggitt](https://github.com/liggitt))