storage: remove AdjustCompactionConcurrency

This is not used.

Epic: none
Release note: None

Author: RaduBerinde

pkg/storage/engine.go

@@ -1106,10 +1106,6 @@ type Engine interface {
 	// concurrency. It returns the previous compaction concurrency.
 	SetCompactionConcurrency(n uint64) uint64
 
-	// AdjustCompactionConcurrency adjusts the compaction concurrency up or down by
-	// the passed delta, down to a minimum of 1.
-	AdjustCompactionConcurrency(delta int64) uint64
-
 	// SetStoreID informs the engine of the store ID, once it is known.
 	// Used to show the store ID in logs and to initialize the shared object
 	// creator ID (if shared object storage is configured).

pkg/storage/pebble.go

@@ -595,21 +595,6 @@ func (p *Pebble) RegisterLowDiskSpaceCallback(f func(info pebble.LowDiskSpaceInf
 	p.lowDiskSpaceFunc.Store(&f)
 }
 
-// AdjustCompactionConcurrency adjusts the compaction concurrency up or down by
-// the passed delta, down to a minimum of 1.
-func (p *Pebble) AdjustCompactionConcurrency(delta int64) uint64 {
-	for {
-		current := atomic.LoadUint64(&p.atomic.compactionConcurrency)
-		adjusted := int64(current) + delta
-		if adjusted < 1 {
-			adjusted = 1
-		}
-		if atomic.CompareAndSwapUint64(&p.atomic.compactionConcurrency, current, uint64(adjusted)) {
-			return uint64(adjusted)
-		}
-	}
-}
-
 // SetStoreID adds the store id to pebble logs.
 func (p *Pebble) SetStoreID(ctx context.Context, storeID int32) error {
 	if p == nil {