[performance] update go-structr and go-mutexes with memory usage improvements (#2909)

* update go-structr and go-mutexes with memory usage improvements

* bump to go-structr v0.8.4

vendor/codeberg.org/gruf/go-mutexes/map.go

@@ -3,17 +3,16 @@ package mutexes
 import (
 	"sync"
 	"sync/atomic"
+	"unsafe"
+
+	"codeberg.org/gruf/go-mempool"
+	"github.com/dolthub/swiss"
 )
 
 const (
 	// possible lock types.
 	lockTypeRead  = uint8(1) << 0
 	lockTypeWrite = uint8(1) << 1
-
-	// frequency of GC cycles
-	// per no. unlocks. i.e.
-	// every 'gcfreq' unlocks.
-	gcfreq = 1024
 )
 
 // MutexMap is a structure that allows read / write locking
@@ -28,15 +27,15 @@ const (
 // like structures for sleeping / awaking awaiting goroutines.
 type MutexMap struct {
 	mapmu  sync.Mutex
-	mumap  map[string]*rwmutex
-	mupool rwmutexPool
-	count  uint32
+	mumap  *swiss.Map[string, *rwmutex]
+	mupool mempool.UnsafePool
 }
 
 // checkInit ensures MutexMap is initialized (UNSAFE).
 func (mm *MutexMap) checkInit() {
 	if mm.mumap == nil {
-		mm.mumap = make(map[string]*rwmutex)
+		mm.mumap = swiss.NewMap[string, *rwmutex](0)
+		mm.mupool.DirtyFactor = 256
 	}
 }
 
@@ -58,13 +57,13 @@ func (mm *MutexMap) lock(key string, lt uint8) func() {
 	mm.checkInit()
 
 	for {
-		// Check map for mu.
-		mu := mm.mumap[key]
+		// Check map for mutex.
+		mu, _ := mm.mumap.Get(key)
 
 		if mu == nil {
-			// Allocate new mutex.
-			mu = mm.mupool.Acquire()
-			mm.mumap[key] = mu
+			// Allocate mutex.
+			mu = mm.acquire()
+			mm.mumap.Put(key, mu)
 		}
 
 		if !mu.Lock(lt) {
@@ -87,63 +86,58 @@ func (mm *MutexMap) unlock(key string, mu *rwmutex) {
 	mm.mapmu.Lock()
 
 	// Unlock mutex.
-	if mu.Unlock() {
+	if !mu.Unlock() {
 
-		// Mutex fully unlocked
-		// with zero waiters. Self
-		// evict and release it.
-		delete(mm.mumap, key)
-		mm.mupool.Release(mu)
+		// Fast path. Mutex still
+		// used so no map change.
+		mm.mapmu.Unlock()
+		return
 	}
 
-	if mm.count++; mm.count%gcfreq == 0 {
-		// Every 'gcfreq' unlocks perform
-		// a garbage collection to keep
-		// us squeaky clean :]
-		mm.mupool.GC()
+	// Mutex fully unlocked
+	// with zero waiters. Self
+	// evict and release it.
+	mm.mumap.Delete(key)
+	mm.release(mu)
+
+	// Maximum load factor before
+	// 'swiss' allocates new hmap:
+	// maxLoad = 7 / 8
+	//
+	// So we apply the inverse/2, once
+	// $maxLoad/2 % of hmap is empty we
+	// compact the map to drop buckets.
+	len := mm.mumap.Count()
+	cap := mm.mumap.Capacity()
+	if cap-len > (cap*7)/(8*2) {
+
+		// Create a new map only as big as required.
+		mumap := swiss.NewMap[string, *rwmutex](uint32(len))
+		mm.mumap.Iter(func(k string, v *rwmutex) (stop bool) {
+			mumap.Put(k, v)
+			return false
+		})
+
+		// Set new map.
+		mm.mumap = mumap
 	}
 
 	// Done with map.
 	mm.mapmu.Unlock()
 }
 
-// rwmutexPool is a very simply memory rwmutexPool.
-type rwmutexPool struct {
-	current []*rwmutex
-	victim  []*rwmutex
-}
-
-// Acquire will returns a rwmutexState from rwmutexPool (or alloc new).
-func (p *rwmutexPool) Acquire() *rwmutex {
-	// First try the current queue
-	if l := len(p.current) - 1; l >= 0 {
-		mu := p.current[l]
-		p.current = p.current[:l]
-		return mu
+// acquire will acquire mutex from memory pool, or alloc new.
+func (mm *MutexMap) acquire() *rwmutex {
+	if ptr := mm.mupool.Get(); ptr != nil {
+		return (*rwmutex)(ptr)
 	}
-
-	// Next try the victim queue.
-	if l := len(p.victim) - 1; l >= 0 {
-		mu := p.victim[l]
-		p.victim = p.victim[:l]
-		return mu
-	}
-
-	// Lastly, alloc new.
-	mu := new(rwmutex)
-	return mu
+	return new(rwmutex)
 }
 
-// Release places a sync.rwmutexState back in the rwmutexPool.
-func (p *rwmutexPool) Release(mu *rwmutex) {
-	p.current = append(p.current, mu)
-}
-
-// GC will clear out unused entries from the rwmutexPool.
-func (p *rwmutexPool) GC() {
-	current := p.current
-	p.current = nil
-	p.victim = current
+// release will release given mutex to memory pool.
+func (mm *MutexMap) release(mu *rwmutex) {
+	ptr := unsafe.Pointer(mu)
+	mm.mupool.Put(ptr)
 }
 
 // rwmutex represents a RW mutex when used correctly within