// We will only check <candidates> with extenders that support preemption.
// Extenders which do not support preemption may later prevent preemptor from being scheduled on the nominated
// node. In that case, scheduler will find a different host for the preemptor in subsequent scheduling cycles.

// stack bound to a value that will cause the next stack bound check
// to fail and enter the stack growth implementation, which will
// detect that it was actually a preemption and redirect to preemption
// handling.
//
// Preemption at asynchronous safe-points is implemented by suspending
// the thread using an OS mechanism (e.g., signals) and inspecting its
// state to determine if the goroutine was at an asynchronous

func debug_modinfo() string {
	return modinfo
}

// mayMoreStackPreempt is a maymorestack hook that forces a preemption
// at every possible cooperative preemption point.
//
// This is valuable to apply to the runtime, which can be sensitive to
// preemption points. To apply this to all preemption points in the
// runtime and runtime-like code, use the following in bash or zsh:
//

	// this fails, a preemption is in progress, so the thread must
	// wait for the preemption. preemptM also CASes this from 0 to
	// 1. If this fails, the preemption fails (as it would if the
	// PC weren't in Go code). The value is reset to 0 when
	// returning from external code or after a preemption is
	// complete.
	//
	// TODO(austin): We may not need this if preemption were more

			},
			wantResult: framework.NewPostFilterResultWithNominatedNode(""),
			wantStatus: framework.NewStatus(framework.Unschedulable, "preemption: 0/1 nodes are available: 1 No preemption victims found for incoming pod."),
		},
		{
			name: "preemption should respect filteredNodesStatuses",
			pod:  st.MakePod().Name("p").UID("p").Namespace(v1.NamespaceDefault).Priority(highPriority).Obj(),
			pods: []*v1.Pod{

			ctxt.pushCall(abi.FuncPCABI0(asyncPreempt), newpc)
		}
	}

	// Acknowledge the preemption.
	gp.m.preemptGen.Add(1)
	gp.m.signalPending.Store(0)

	if GOOS == "darwin" || GOOS == "ios" {
		pendingPreemptSignals.Add(-1)
	}
}

const preemptMSupported = true

// preemptM sends a preemption request to mp. This request may be
// handled asynchronously and may be coalesced with other requests to

// Package exithook provides limited support for on-exit cleanup.
//
// CAREFUL! The expectation is that Add should only be called
// from a safe context (e.g. not an error/panic path or signal
// handler, preemption enabled, allocation allowed, write barriers
// allowed, etc), and that the exit function F will be invoked under
// similar circumstances. That is the say, we are expecting that F

	// NodeInfoSnapshot because we don't guarantee that they will be the same.
	// For example, during preemption, we may pass a copy of the original
	// nodeInfo object that has some pods removed from it to evaluate the
	// possibility of preempting them to schedule the target pod.
	Filter(ctx context.Context, state *CycleState, pod *v1.Pod, nodeInfo *NodeInfo) *Status
}

  # Configure this to a higher priority class in order to make sure your Istio gateway pods
  # will not be killed because of low priority class.
  # Refer to https://kubernetes.io/docs/concepts/configuration/pod-priority-preemption/#priorityclass
  # for more detail.

		},
	)
	PreemptionVictims = metrics.NewHistogram(
		&metrics.HistogramOpts{
			Subsystem: SchedulerSubsystem,
			Name:      "preemption_victims",
			Help:      "Number of selected preemption victims",
			// we think #victims>64 is pretty rare, therefore [64, +Inf) is considered a single bucket.
			Buckets:        metrics.ExponentialBuckets(1, 2, 7),
			StabilityLevel: metrics.STABLE,
		})