mmaprototype: return a pointer for BuildMMARebalanceAdvisor

This commit updates BuildMMARebalanceAdvisor to return a pointer, since future
changes will require passing it around and modifying its fields.

Author: wenyihu6

pkg/kv/kvserver/allocator/allocatorimpl/allocator.go

@@ -1890,7 +1890,7 @@ func (a Allocator) RebalanceTarget(
 	// to compute the means for the original set {s1, s2, s3} ∪ {existing} once
 	// and then use it for all calls to MMA, and bestRebalanceTarget does not need
 	// to copy the candidate set.
-	advisors := make(map[int]mmaprototype.MMARebalanceAdvisor, len(results))
+	advisors := make(map[int]*mmaprototype.MMARebalanceAdvisor, len(results))
 	var bestIdx int
 
 	for {

pkg/kv/kvserver/allocator/allocatorimpl/allocator_scorer.go

@@ -1932,7 +1932,7 @@ func bestRebalanceTarget(
 	randGen allocatorRand,
 	options []rebalanceOptions,
 	as *mmaintegration.AllocatorSync,
-	advisors map[int]mmaprototype.MMARebalanceAdvisor,
+	advisors map[int]*mmaprototype.MMARebalanceAdvisor,
 ) (target, existingCandidate *candidate, bestIdx int) {
 	bestIdx = -1
 	var bestTarget *candidate

pkg/kv/kvserver/allocator/mmaprototype/allocator_state.go

@@ -1311,8 +1311,8 @@ type MMARebalanceAdvisor struct {
 // NoopMMARebalanceAdvisor is a no-op MMARebalanceAdvisor that always returns
 // false for IsInConflictWithMMA. Used when MMA is disabled or mma does not have
 // enough information to determine.
-func NoopMMARebalanceAdvisor() MMARebalanceAdvisor {
-	return MMARebalanceAdvisor{
+func NoopMMARebalanceAdvisor() *MMARebalanceAdvisor {
+	return &MMARebalanceAdvisor{
 		disabled: true,
 	}
 }
@@ -1324,7 +1324,7 @@ func NoopMMARebalanceAdvisor() MMARebalanceAdvisor {
 // existing store. mma should include the existing store in the candidate set.
 func (a *allocatorState) BuildMMARebalanceAdvisor(
 	existing roachpb.StoreID, cands []roachpb.StoreID,
-) MMARebalanceAdvisor {
+) *MMARebalanceAdvisor {
 	// TODO(wenyihu6): for simplicity, we create a new scratchNodes every call.
 	// We should reuse the scratchNodes instead.
 	scratchNodes := map[roachpb.NodeID]*NodeLoad{}
@@ -1334,7 +1334,7 @@ func (a *allocatorState) BuildMMARebalanceAdvisor(
 	// TODO(wenyihu6): pass in the actual ctx here
 	existingSLS := a.cs.computeLoadSummary(context.Background(), existing,
 		&means.storeLoad, &means.nodeLoad)
-	return MMARebalanceAdvisor{
+	return &MMARebalanceAdvisor{
 		existingStoreSLS: existingSLS,
 		means:            means,
 	}
@@ -1345,7 +1345,7 @@ func (a *allocatorState) BuildMMARebalanceAdvisor(
 // for making sure the MMARebalanceAdvisor is for the correct existing store and
 // candidate set.
 func (a *allocatorState) IsInConflictWithMMA(
-	cand roachpb.StoreID, advisor MMARebalanceAdvisor, cpuOnly bool,
+	cand roachpb.StoreID, advisor *MMARebalanceAdvisor, cpuOnly bool,
 ) bool {
 	if advisor.disabled {
 		return false

pkg/kv/kvserver/mmaintegration/allocator_sync.go

@@ -49,10 +49,10 @@ type mmaState interface {
 	// MMARebalanceAdvisor for the given existing store and candidates. The
 	// advisor should be later passed to IsInConflictWithMMA to determine if a
 	// given candidate is in conflict with the existing store.
-	BuildMMARebalanceAdvisor(existing roachpb.StoreID, cands []roachpb.StoreID) mmaprototype.MMARebalanceAdvisor
+	BuildMMARebalanceAdvisor(existing roachpb.StoreID, cands []roachpb.StoreID) *mmaprototype.MMARebalanceAdvisor
 	// IsInConflictWithMMA is called by the allocator sync to determine if the
 	// given candidate is in conflict with the existing store.
-	IsInConflictWithMMA(cand roachpb.StoreID, advisor mmaprototype.MMARebalanceAdvisor, cpuOnly bool) bool
+	IsInConflictWithMMA(cand roachpb.StoreID, advisor *mmaprototype.MMARebalanceAdvisor, cpuOnly bool) bool
 }
 
 // TODO(wenyihu6): make sure allocator sync can tolerate cluster setting

pkg/kv/kvserver/mmaintegration/thrashing.go

@@ -92,7 +92,7 @@ import (
 // and associating it with the corresponding existing store.
 func (as *AllocatorSync) BuildMMARebalanceAdvisor(
 	existing roachpb.StoreID, cands []roachpb.StoreID,
-) mmaprototype.MMARebalanceAdvisor {
+) *mmaprototype.MMARebalanceAdvisor {
 	if kvserverbase.LoadBasedRebalancingMode.Get(&as.st.SV) != kvserverbase.LBRebalancingMultiMetricAndCount {
 		return mmaprototype.NoopMMARebalanceAdvisor()
 	}
@@ -101,7 +101,7 @@ func (as *AllocatorSync) BuildMMARebalanceAdvisor(
 
 // IsInConflictWithMMA determines if a candidate conflicts with MMA's goals.
 func (as *AllocatorSync) IsInConflictWithMMA(
-	cand roachpb.StoreID, advisor mmaprototype.MMARebalanceAdvisor, cpuOnly bool,
+	cand roachpb.StoreID, advisor *mmaprototype.MMARebalanceAdvisor, cpuOnly bool,
 ) bool {
 	if as.knobs != nil && as.knobs.OverrideIsInConflictWithMMA != nil {
 		return as.knobs.OverrideIsInConflictWithMMA(cand)